Labile organic carbon(LOC) and carbon management index(CMI), which are sensitive factors to the changes of environment, can improve evaluating the effect of land management practices changes on soil quality. The objec...Labile organic carbon(LOC) and carbon management index(CMI), which are sensitive factors to the changes of environment, can improve evaluating the effect of land management practices changes on soil quality. The objective of this study was to investigate the effects of land use types and landscape positions on soil quality as a function of LOC and CMI. A field study in a small watershed in the red soil hilly region of southern China was conducted, and soil samples were collected from four typical lands(pine forest(PF) on slope land, barren hill(BH) on slope land, citrus orchard(CO) on terrace land and Cinnarnornum Camphora(CC) on terrace land) at a sampling depth of 20 cm. Soil nutrients, soil organic carbon(SOC), LOC and CMI were measured. Results showed that the LOC and CMI correlated to not only soil carbon but also soil nutrients, and the values of LOC and CMI in different land use types followed the order CC > PF > CO > BH at the upperslope, while CO > CC > BH > PF at mid-slope and down-slope. With respect to slope positions, the values of LOC and CMI in all the lands were followed the order: upper-slope > down-slope > midslope. As whole, the mean values of LOC and CMI in different lands followed the order CC > CO > PF > BH. High CMI and LOC content were found in the terrace lands with broadleaf vegetations. These results indicated that the terracing and appropriate vegetations can increase the carbon input and lability and decrease soil erosion. However, the carbon pools and CMI in these lands were significantly lower than that in reference site. This suggested that it may require a long time for the soil to return to a highquality. Consequently, it is an efficient way to adopt the measures of terracing and appropriate vegetations planting in improving the content of LOC and CMI and controlling water and soil loss in fragile ecosystems.展开更多
An imbedded integrating ecological entity(IIEE) was designed to combine landscaping, replenishing-water purifying and ecosystem maintaining simultaneously. With this IIEE, within 15 d experiment, simulated replenish w...An imbedded integrating ecological entity(IIEE) was designed to combine landscaping, replenishing-water purifying and ecosystem maintaining simultaneously. With this IIEE, within 15 d experiment, simulated replenish water(SRW) with high(SRW-Ⅰ) or low(SRW-Ⅱ) nutrients concentration was well purified. Relative removal rates of CODCr, TP, TN, Chl-a and turbidity reached 84.87%, 84.05%, 94.76%, 188.17%, 110.93% when dealing SRW-Ⅰ, and 52.62%, 90.05%, 82.44%, 166.15%, 202.99%, respectively, when dealing SRW-Ⅱ. The well grew flora and fauna of IIEE benefit eco-maintaining and landscaping. Separately, the maximal root and stem length-increments of Cyperus alternifolius Linn. were 26.1 mm and 28.4 mm, while for Potamogeton crispus Linn. 18.3 mm and 25.7 mm. Mortality for both Bellamya aeruginosa and Misgurnus anguillicaudatus was both under 2.96%. The analysis of variance(ANOVA) indicated that most experimental indexes in each group performed more significantly better than those in their control. All results indicated that the IIEE is a promising technology for future urban waterscapes construction.展开更多
Metal-organic frameworks(MOFs)are promising new materials that have been intensively studied and possibly applied to various environmental remediation.However,little is known about the fate and risk of MOFs to living ...Metal-organic frameworks(MOFs)are promising new materials that have been intensively studied and possibly applied to various environmental remediation.However,little is known about the fate and risk of MOFs to living organisms in thewater environment.Here,the toxic effects of ZIF-8 nanoparticles(NPs)on benthic organisms were confirmed by sub-chronic toxicity experiments(7 and 14 days)using Corbicula fluminea as the model organism.With exposure doses ranging from 0 to 50 mg/L,ZIF-8 NPs induced oxidative stress behaviors similar to the hormesis effect in the tissues of C.fluminea.The oxidative stress induced by ZIF-8 NPs and the released Zn^(2+)was the crucial cause of the toxic effects.Besides,we also found that the ZIF-8 NPs and dissolved Zn^(2+)may result in different mechanisms of toxicity and accumulation depending on the dosages.The Zn^(2+)release rate of ZIF-8NPswas high at low dosages,leading to a higher proportion of Zn^(2+)taken up by C.fluminea than the particulate ZIF-8.Conversely,at high dosages,C.fluminea mainly ingested the ZIF-8 NPs and resulted in increased mortality.The results have important implications for understanding the fate and biological effects of ZIF-8 in natural aquatic environments.展开更多
●Soil erosion resulted in homogenization of bacterial communities in the watershed.●Microbial community heterogeneity among erosion sites made soil tracing possible.●Assembly process results showed that the trackin...●Soil erosion resulted in homogenization of bacterial communities in the watershed.●Microbial community heterogeneity among erosion sites made soil tracing possible.●Assembly process results showed that the tracking results can achieve high precision.●Dryland was the main source of sediment deposition based on the result of FEAST.Sediment source tracing can accurately provide a theoretical basis for controlling soil erosion effectively,by identifying the most serious types of land use.Traditional sediment tracing methods are based on physical,chemical,biological,and composite fingerprinting,which have not included microbes.As high-throughput sequencing becomes more prevalent,microorganisms can provide more information than what we think.Thus,whether the microorganism can also be used as a special fingerprint factor for sediment source identification during soil erosion,we have tested it by using microbial source tracking tool FEAST to quantify the microbe contribution from five types of eroded land(including dryland,urban,paddy field,forest and grassland)to the depositional areas(Niubitan)in the Yuanjiang basin.The source microbial community in the erosive area was heterogeneous,and assembly process analysis further demonstrated that the source tracking results could reach higher accuracy.The results of FEAST showed that dryland(35.50%),urban(17.21%),paddy field(8.14%),and forest(1.07%)were the major contributors to Niubitan.Our results follow the general soil erosion rules and prove its validity.Taken together,a new perspective is provided by these results for tracing sediment sources in erosion-sedimentary systems.展开更多
Switching the reaction routes in peroxymonosulfate(PMS)-based advanced oxidation processes have attracted much attention but remain challenging.Herein,a series of Co-N/C catalysts with different compositions and struc...Switching the reaction routes in peroxymonosulfate(PMS)-based advanced oxidation processes have attracted much attention but remain challenging.Herein,a series of Co-N/C catalysts with different compositions and structures were prepared by using bimetallic zeolitic imidazolate frameworks based on ZIF-8 and ZIF-67(x Zn/Co-ZIFs).Results show that Co doping amount could mediate the transformation of the activation pathway of PMS over CoN/C.When Co doping amount was less than 10%,the constructed x Co-N/C/PMS system(x≤10%)was singlet oxygen-dominated reaction;however further increasing Co doping amount would lead to the generation and coexistence of sulfate radicals and high-valent cobalt,besides singlet oxygen.Furthermore,the nitrogen-coordinated Co(Co-NX)sites could serve as main catalytically active sites to generate singlet oxygen.While excess Co doping amount caused the formation of Co nanoparticles from which leached Co ions were responsible for the generation of sulfate radicals and high-valent cobalt.Compared to undoped N/C,Co doping could significantly enhance the catalytic performance.The 0.5%Co-N/C could achieve the optimum degradation(0.488 min^(-1))and mineralization abilities(78.4%)of sulfamethoxazole among the investigated Co-N/C catalysts,which was superior to most of previously reported catalysts.In addition,the application prospects of the two systems in different environmental scenarios(pH,inorganic anions and natural organic matter)were assessed and showed different degradation behaviors.This study provides a strategy to regulate the reactive species in PMS-based advanced oxidation process.展开更多
To improve soil carbon sequestration capacity,the full soil carbon cycle process needs to be understood and quantified.It is essential to evaluate whether water erosion acts as a net source or sink of atmospheric CO_(...To improve soil carbon sequestration capacity,the full soil carbon cycle process needs to be understood and quantified.It is essential to evaluate whether water erosion acts as a net source or sink of atmospheric CO_(2)at the basin scale,which encompasses the entire hydrological process.This study introduced an approach that combined a spatially distributed sediment delivery model and biogeochemical model to estimate the lateral and vertical carbon fluxes by water erosion at the basin scale.Applying this coupling model to the Dongting Lake Basin,the results showed that the annual average amount of soil erosion during 1980-2020 was 1.33×10^(8)t,displaying a decreasing trend followed by a slight increase.Only 12% of the soil organic carbon displacement was ultimately lost in the riverine systems,and the rest was deposited downhill within the basin.The average lateral soil organic carbon loss induced by erosion was 8.86×10^(11)g C in 1980 and 1.50×10^(11)g C in 2020,with a decline rate of 83%.A net land sink for atmospheric CO_(2)of 5.54×1011g C a^(-1)occurred during erosion,primarily through sediment burial and dynamic replacement.However,ecological restoration projects and tillage practice policies are still significant in reducing erosion,which could improve the capacity of the carbon sink for recovery beyond the rate of horizontal carbon removal.Moreover,our model enables the spatial explicit simulation of erosion-induced carbon fluxes using costeffective and easily accessible input data across large spatial scales and long timeframes.Consequently,it offers a valuable tool for predicting the interactions between carbon dynamics,land use changes,and future climate.展开更多
The effects of Tween-20 and Zn(II) on ethylbenzene removal were evaluated using two biotrickling filters(BTFs), BTF1 and BTF2. Only BTF1 was fed with Tween-20 and Zn(II).Results show that ethylbenzene removal de...The effects of Tween-20 and Zn(II) on ethylbenzene removal were evaluated using two biotrickling filters(BTFs), BTF1 and BTF2. Only BTF1 was fed with Tween-20 and Zn(II).Results show that ethylbenzene removal decreased from 94% to 69% for BTF1 and from 74%to 54% for BTF2 with increased organic loading from 64.8 to 189.0 g ethylbenzene/(m3·hr) at EBRT of 40 sec. The effect of EBRT(60–15 sec) at a constant ethylbenzene inlet concentration was more significant than that of EBRT(30–10 sec) at a constant organic loading. Biomass accumulation rate within packing media was reduced significantly.展开更多
This study investigated the interaction between Cu^2+and nano zero-valent iron(NZVI)coated with three types of stabilizers(i.e., polyacrylic acid [PAA], Tween-20 and starch) by examining the Cu^2+ uptake, coll...This study investigated the interaction between Cu^2+and nano zero-valent iron(NZVI)coated with three types of stabilizers(i.e., polyacrylic acid [PAA], Tween-20 and starch) by examining the Cu^2+ uptake, colloidal stability and mobility of surface-modified NZVI(SM-NZVI) in the presence of Cu^2+. The uptake of Cu^2+ by SM-NZVI and the colloidal stability of the Cu-bearing SM-NZVI were examined in batch tests. The results showed that NZVI coated with different modifiers exhibited different affinities for Cu^2+, which resulted in varying colloidal stability of different SM-NZVI in the presence of Cu^2+. The presence of Cu^2+ exerted a slight influence on the aggregation and settling of NZVI modified with PAA or Tween-20. However, the presence of Cu^2+caused significant aggregation and sedimentation of starch-modified NZVI, which is due to Cu^2+complexation with the starch molecules coated on the surface of the particles. Column experiments were conducted to investigate the co-transport of Cu^2+ in association with SM-NZVI in water-saturated quartz sand. It was presumed that a physical straining mechanism accounted for the retention of Cu-bearing SM-NZVI in the porous media. Moreover, the enhanced aggregation of SM-NZVI in the presence of Cu^2+ may be contributing to this straining effect.展开更多
Aquatic macrophytes are considered to be promising in controlling harmful cyanobacterial blooms. In this research, an aqueous extract of Sagittaria trifolia tubers was prepared to study its inhibitory effect on Microc...Aquatic macrophytes are considered to be promising in controlling harmful cyanobacterial blooms. In this research, an aqueous extract of Sagittaria trifolia tubers was prepared to study its inhibitory effect on Microcystis aeruginosa in the laboratory. Several physiological indices of M. aeruginosa, in response to the environmental stress, were analyzed. Results showed that S. trifolia tuber aqueous extract significantly inhibited the growth of M. aeruginosa in a concentration-dependent way. The highest inhibition rate reached 90% after 6 day treatment. The Chlorophyll-a concentration of M. aeruginosa cells decreased from 343.1 to314.2 μg/L in the treatment group. The activities of superoxide dismutase and peroxidase and the content of reduced glutathione in M. aeruginosa cells initially increased as a response to the oxidative stress posed by S. trifolia tuber aqueous extract, but then decreased as time prolonged. The lipid peroxidation damage of the cyanobacterial cell membranes was reflected by the malondialdehyde level, which was notably higher in the treatment group compared with the controls. It was concluded that the oxidative damage of M. aeruginosa induced by S.trifolia tuber aqueous extract might be one of the mechanisms for the inhibitory effects.展开更多
Quorum sensing (QS) plays an important role in microbial aggregation control. Recently, the optimization of biological waste treatment systems by QS regulation gained an increasing attention. The effects of QS regulat...Quorum sensing (QS) plays an important role in microbial aggregation control. Recently, the optimization of biological waste treatment systems by QS regulation gained an increasing attention. The effects of QS regulation on treatment performances and biofilm were frequently investigated. To understand the state of art of QS regulation, this review summarizes the methods of QS enhancement and QS inhibition in biological waste treatment systems. Typical QS enhancement methods include adding exogenous QS molecules, adding QS accelerants and cultivating QS bacteria, while typical QS inhibition methods include additions of quorum quenching (QQ) bacteria, QS-degrading enzymes, QS-degrading oxidants, and QS inhibitors. The specific improvements after applying these QS regulation methods in different treatment systems are concluded. In addition, the effects of QS regulation methods on biofilm in biological waste treatment systems are reviewed in terms of biofilm formation, extracellular polymeric substances production, microbial viability, and microbial community. In the end, the knowledge gaps in current researches are analyzed, and the requirements for future study are suggested.展开更多
Dispersion and aggregation of nanoparticles in aqueous solutions are important factors for safe application of nanoparticles. In this study, dispersion and aggregation of nano-TiO2 in aqueous solutions containing vari...Dispersion and aggregation of nanoparticles in aqueous solutions are important factors for safe application of nanoparticles. In this study, dispersion and aggregation of nano-TiO2 in aqueous solutions containing various anions were investigated. The influences of anion concentration and valence on the aggregation size, zeta potential and aggregation kinetics were individually investigated. Results showed that the zeta potential decreased from 19.8 to-41.4 mV when PO4^(3-) concentration was increased from 0 to 50 mg/L, while the corresponding average size of nano-TiO2 particles decreased from 613.2 to 540.3 nm. Both SO4^(2-) and NO3^-enhanced aggregation of nano-TiO2in solution. As SO4^(2-) concentration was increased from 0 to 500 mg/L, the zeta potential decreased from 19.8 to 1.4 mV, and aggregate sizes increased from 613.2 to 961.3 nm.The trend for NO3^- fluctuation was similar to that for SO4^(2-) although the range of variation for NO3^- was relatively narrow. SO4^(2-) and NO3^-accelerated the aggregation rapidly, while PO4^(3-) did so slowly. These findings facilitate the understanding of aggregation and dispersion mechanisms of nano-TiO2 in aqueous solutions in the presence of anions of interest.展开更多
Oxidative desulfurization(ODS)is a promising technology to produce clean fuel with requiring superior catalysts to lower kinetic barriers.Although most ODS catalysts are based on crystalline transition-metal oxides(TM...Oxidative desulfurization(ODS)is a promising technology to produce clean fuel with requiring superior catalysts to lower kinetic barriers.Although most ODS catalysts are based on crystalline transition-metal oxides(TMOs),extraordinary activity also can be achieved with amorphous TMOs.However,the origin of the remarkable catalytic activity of the amorphous TMOs remains greatly ambiguous.Here,we found the crucial role of Mo–O covalency in ruling the intrinsic catalytic activity of amorphous molybdenum oxides(MoO_(x)).Experimental and theoretical analysis indicated that the nonequivalent connectivity in the amorphous structure strongly enhanced Mo–O covalency,thereby increasing the content of electrophilic oxygen and nucleophilic molybdenum to favor the MoO_(x)–H_(2)O_(2) interaction.With the boosted Mo–O covalency to improve the flexibility of the charge state,the amorphous MoO_(x)-based composite catalyst(PE-MoO_(x)/S-0.05)exhibited outstanding catalytic activity for ODS of fuel oil.The turnover frequency(TOF)value of the catalyst(18.63 h^(-1))was almost an order of magnitude higher than that of most reported crystalline MoO_(x)/molecular sieve composite catalysts.The in-depth understanding of the origin of the amorphous TMOs activity for ODS provides a valuable reference for developing ODS catalysts.展开更多
Sulfate radicals have been increasingly used for the pathogen inactivation due to their strong redox ability and high selectivity for electron-rich species in the last decade.The application of sulfate radicals in wat...Sulfate radicals have been increasingly used for the pathogen inactivation due to their strong redox ability and high selectivity for electron-rich species in the last decade.The application of sulfate radicals in water disinfection has become a very promising technology.However,there is currently a lack of reviews of sulfate radicals inactivated pathogenic microorganisms.At the same time,less attention has been paid to disinfection by-products produced by the use of sulfate radicals to inactivate microorganisms.This paper begins with a brief overview of sulfate radicals’properties.Then,the progress in water disinfection by sulfate radicals is summarized.The mechanism and inactivation kinetics of inactivating microorganisms are briefly described.After that,the disinfection by-products produced by reactions of sulfate radicals with chlorine,bromine,iodide ions and organic halogens in water are also discussed.In response to these possible challenges,this article concludes with some specific solutions and future research directions.展开更多
Recent studies have proposed that the high-valent iron species(such as Fe^(Ⅳ)O^(2+))rather than sulfate radical(SO_(4)^(·-))and hydroxyl radical(·OH)are the main reactive oxidant species(ROS)in Fe(Ⅱ)/perox...Recent studies have proposed that the high-valent iron species(such as Fe^(Ⅳ)O^(2+))rather than sulfate radical(SO_(4)^(·-))and hydroxyl radical(·OH)are the main reactive oxidant species(ROS)in Fe(Ⅱ)/peroxydisulfate(PDS)system with the methyl phenyl sulfoxide(PMSO)as the Fe^(Ⅳ)O^(2+)probe.However,many operational factors may interfere with the accuracy of this method,so the contribution of Fe^(Ⅳ)O^(2+)calculated by this method is controversial.In this study,the possible effect of Fe(Ⅱ)concentration,pollutant type,reducing agent,or coexisted anions on Fe^(Ⅳ)O^(2+)production and its corresponding contribution to the removal of target pollutants in the Fe(Ⅱ)/PDS system were investigated in detail,and the intrinsic mechanisms involved were also explored.This study shows that ROS generation is a complex process in the Fe(Ⅱ)/PDS system,and multiple combinatorial approaches are urgently required to deeply explore the contribution of ROS to the elimination of target contaminants.展开更多
Numerous studies on eutrophication remediation have mainly focused on purifying water first, then restoring submerged macrophytes. A restoration-promoting integrated floating bed (RPIFB) was designed to combine the ...Numerous studies on eutrophication remediation have mainly focused on purifying water first, then restoring submerged macrophytes. A restoration-promoting integrated floating bed (RPIFB) was designed to combine the processes of water purification and macrophyte restoration simultaneously. Two outdoor experiments were conducted to evaluate the ecological functions of the RP1FB. Trial 1 was conducted to compare the eutrophication purification among floating bed, gradual-submerging bed (GSB) and RPIFB technologies. The results illustrated that RPIFB has the best purification capacity. Removal efficiencies of RPIFB for TN, TP,NH4+-N, NO3-N, CODcr, Chlorophyll-a and turbidity were 74.45%, 98.31%, 74.71%, 88.81%, 71.42%, 90.17% and 85%, respectively. In trial 2, influences of depth of GSB and photic area in RPIFB on biota were investigated. When the depth of GSB decreased and the photic area of RPIFB grew, the height of Potamogeton crispus Linn. increased, but the biomass of Canna indica Linn. was reduced. The mortalities of Misgurnus anguillicaudatus and Bellamya aeruginosa in each group were all less than 7%. All results indicated that when the RPIFB was embedded into the eutrophic water, the regime shift from phytoplankton-dominated to macrophyte-dominated state could be promoted. Thus, the RPIFB is a promising remediation technology for eutrophication and submerged macrophyte restoration.展开更多
Soil degradation,characterized by declines in nutrient status and simultaneous accumulation of pesticide residues,is a major problem affecting agricultural ecosystems.Previous studies indicate that biochar application...Soil degradation,characterized by declines in nutrient status and simultaneous accumulation of pesticide residues,is a major problem affecting agricultural ecosystems.Previous studies indicate that biochar application to soil has promise as a practical method to alleviate these pressures:increasing crop yield and enhancing pesticide degradation.Here,we review the roles of biochar in both chemical and biological promotion of pesticide degradation and the potential benefits of biochar relating to the efficiency of fertilizer use,availability of nutrients,and nutrient exchange.Biochar typically has a high surface area featuring many functional groups,a high cation exchange capacity,and high stability.Major factors that impact on the nutrient retention characteristics of biochar(e.g.,feedstock,pyrolysis temperature,and application rate) are also discussed herein.Nonetheless,more studies of the long-term impacts on soil properties from biochar addition are still required before it can be possible to accurately quantify the sustainability of this approach to sequester carbon and restore soil function.展开更多
A novel joint method of bioleaching with Fenton oxidation was applied to condition sewage sludge. The specific resistance to filtration(SRF) and moisture of sludge cake(MSC) were adopted to evaluate the improvemen...A novel joint method of bioleaching with Fenton oxidation was applied to condition sewage sludge. The specific resistance to filtration(SRF) and moisture of sludge cake(MSC) were adopted to evaluate the improvement of sludge dewaterability. After 2-day bioleaching, the sludge p H dropped to about 2.5 which satisfied the acidic condition for Fenton oxidation.Meanwhile, the SRF declined from 6.45 × 1010 to 2.07 × 1010s2/g, and MSC decreased from91.42% to 87.66%. The bioleached sludge was further conditioned with Fenton oxidation. From an economical point of view, the optimal dosages of H2O2 and Fe2+were 0.12 and 0.036 mol/L,respectively, and the optimal reaction time was 60 min. Under optimal conditions, SRF,volatile solids reduction, and MSC were 3.43 × 108s2/g, 36.93%, and 79.58%, respectively. The stability and settleability of sewage sludge were both improved significantly. Besides,the results indicated that bioleaching-Fenton oxidation was more efficient in dewatering the sewage sludge than traditional Fenton oxidation. The sludge conditioning mechanisms by bioleaching-Fenton oxidation might mainly include the flocculation effects and the releases of extracellular polymeric substances–bound water and intercellular water.展开更多
Nitrogen removal of wastewater containing high-strength ammonium by the constructed wetlands (CWs) has been paid much attention. In this study, the ability of a partially saturated CW to treat anaerobically-digested d...Nitrogen removal of wastewater containing high-strength ammonium by the constructed wetlands (CWs) has been paid much attention. In this study, the ability of a partially saturated CW to treat anaerobically-digested decentralized swine wastewater under varying operating parameters from summer to winter was investigated. The partially saturated CW achieved better NH4^+-N and TN removal by tidal flow than intermittent flow. With surface loading rates of 0.108, 0.027, and 0.029 kg/(m^2·d) for COD, NH4^+-N, and TN, the partially saturated CW by tidal operation achieved corresponding removal efficiencies of 85.94%, 61.20%, and 57.41%, respectively, even at 10℃. When the rapid-adsorption of NH4^+-N and the bioregeneration of zeolites reached dynamically stable, the simultaneous nitrification and denitrification in the aerobic zeolite layer was observed and accounted for 58.82% of the total denitrification of CW. The results of Illumina high-throughput sequencing also indicated that nitnfiers (Nitrospira and Rhizomicrobiurri) and denitrifiers (Rhodanobacter and Thauera) simultaneously existed in the zeolite layer. The dominant existence of versatile organic degraders and nitrifiers/denitrifiers in the zeolite layer was related to the removal of most COD and nitrogen in this zone. The contribution of the possible nitrogen removal pathways in the CW was as follows: nitrification-denitrification (86.55%)>substrate adsorption (11.70%)>plant uptake (1.15%)>microbial assimilation (0.60%).展开更多
Nonradical reaction driven by peroxymonosulfate(PMS)based advanced oxidation pro-cesses has drawn widespread attention in water treatment due to their inherent advantages,but the degradation behavior and mechanism of ...Nonradical reaction driven by peroxymonosulfate(PMS)based advanced oxidation pro-cesses has drawn widespread attention in water treatment due to their inherent advantages,but the degradation behavior and mechanism of organic pollutants are still unclear.In this study,the performance,intermediates,mechanism and toxicity of tetracycline(TC)degra-dation were thoroughly examined in the constructed magnetic nitrogen-doped porous car-bon/peroxymonosulfate(Co-N/C-PMS)system.The results showed that 85.4%of TC could be removed within 15 min when Co-N/C and PMS was simultaneously added and the degra-dation rate was enhanced by 3.4 and 14.7 folds compared with Co-N/C or PMS alone,re-spectively.Moreover,the performance of Co-N/C was superior to that of most previously reported catalysts.Many lines of evidence indicated that Co-N/C-PMS system was a singlet oxygen-dominated nonradical reaction,which was less interfered by pH and water compo-nents,and displayed high adaptability to actual water bodies.Subsequently,the degrada-tion process was elaborated on the basis of three-dimensional excitation-emission matrix spectra and liquid chromatography-mass spectrometry.At last,the toxicity of treated TC was greatly reduced by using microalgae Coelastrella sp.as ecological indicator.This study provides a promising approach based on singlet oxygen-dominated nonradical reaction for eliminating TC in water treatment.展开更多
Biochar is regarded as a promising new class of materials due to its multifunctional character and the possibility of effectively coupling different properties. With increasing introduction into the environment, envir...Biochar is regarded as a promising new class of materials due to its multifunctional character and the possibility of effectively coupling different properties. With increasing introduction into the environment, environmental chemicals such as surfactants will load onto the released biochar and change its physicochemical characteristics and adsorption behavior toward pollutants. In this study, sodium dodecyl sulfate(SDS), as one type of anionic surfactant, was coated onto biochar with different loading amounts. The influence of SDS loading onto biochar's physicochemical properties were investigated by Fourier transform infrared(FT-IR) spectroscopy, elemental analysis, zeta potential and Brunauer–Emmett–Teller(BET) surface area and pore size distribution analysis. Results showed that the pore size of the biochar decreased gradually with the increase of SDS loading because of the surface-adsorption and pore-blocking processes; the p H of the point of zero charge(pHPZC) decreased with increasing SDS loading. Although surface-coating with SDS decreased the pore size of the biochar, its adsorption capacity toward Methylene Blue(MB) significantly increased. The biochar-bound SDS introduced functional groups and negative charges to the biochar surface, which could thus enhance the adsorption of MB via hydrogen bonding and electrostatic interaction. The results can shed light on the underlying mechanism of the influence of anionic surfactants on the adsorption of MB by biochar.展开更多
基金financially supported by the National Natural Science Foundation of China (41271294)the Program for New Century Excellent Talents in University (NCET-09-330)the Natural Science Foundation of Hunan Province of China (11JJ3041)
文摘Labile organic carbon(LOC) and carbon management index(CMI), which are sensitive factors to the changes of environment, can improve evaluating the effect of land management practices changes on soil quality. The objective of this study was to investigate the effects of land use types and landscape positions on soil quality as a function of LOC and CMI. A field study in a small watershed in the red soil hilly region of southern China was conducted, and soil samples were collected from four typical lands(pine forest(PF) on slope land, barren hill(BH) on slope land, citrus orchard(CO) on terrace land and Cinnarnornum Camphora(CC) on terrace land) at a sampling depth of 20 cm. Soil nutrients, soil organic carbon(SOC), LOC and CMI were measured. Results showed that the LOC and CMI correlated to not only soil carbon but also soil nutrients, and the values of LOC and CMI in different land use types followed the order CC > PF > CO > BH at the upperslope, while CO > CC > BH > PF at mid-slope and down-slope. With respect to slope positions, the values of LOC and CMI in all the lands were followed the order: upper-slope > down-slope > midslope. As whole, the mean values of LOC and CMI in different lands followed the order CC > CO > PF > BH. High CMI and LOC content were found in the terrace lands with broadleaf vegetations. These results indicated that the terracing and appropriate vegetations can increase the carbon input and lability and decrease soil erosion. However, the carbon pools and CMI in these lands were significantly lower than that in reference site. This suggested that it may require a long time for the soil to return to a highquality. Consequently, it is an efficient way to adopt the measures of terracing and appropriate vegetations planting in improving the content of LOC and CMI and controlling water and soil loss in fragile ecosystems.
基金Project(2016M590348)supported by China Postdoctoral Science FoundationProjects(41301154,41271332)supported by the National Natural Science Foundation of China
文摘An imbedded integrating ecological entity(IIEE) was designed to combine landscaping, replenishing-water purifying and ecosystem maintaining simultaneously. With this IIEE, within 15 d experiment, simulated replenish water(SRW) with high(SRW-Ⅰ) or low(SRW-Ⅱ) nutrients concentration was well purified. Relative removal rates of CODCr, TP, TN, Chl-a and turbidity reached 84.87%, 84.05%, 94.76%, 188.17%, 110.93% when dealing SRW-Ⅰ, and 52.62%, 90.05%, 82.44%, 166.15%, 202.99%, respectively, when dealing SRW-Ⅱ. The well grew flora and fauna of IIEE benefit eco-maintaining and landscaping. Separately, the maximal root and stem length-increments of Cyperus alternifolius Linn. were 26.1 mm and 28.4 mm, while for Potamogeton crispus Linn. 18.3 mm and 25.7 mm. Mortality for both Bellamya aeruginosa and Misgurnus anguillicaudatus was both under 2.96%. The analysis of variance(ANOVA) indicated that most experimental indexes in each group performed more significantly better than those in their control. All results indicated that the IIEE is a promising technology for future urban waterscapes construction.
文摘Metal-organic frameworks(MOFs)are promising new materials that have been intensively studied and possibly applied to various environmental remediation.However,little is known about the fate and risk of MOFs to living organisms in thewater environment.Here,the toxic effects of ZIF-8 nanoparticles(NPs)on benthic organisms were confirmed by sub-chronic toxicity experiments(7 and 14 days)using Corbicula fluminea as the model organism.With exposure doses ranging from 0 to 50 mg/L,ZIF-8 NPs induced oxidative stress behaviors similar to the hormesis effect in the tissues of C.fluminea.The oxidative stress induced by ZIF-8 NPs and the released Zn^(2+)was the crucial cause of the toxic effects.Besides,we also found that the ZIF-8 NPs and dissolved Zn^(2+)may result in different mechanisms of toxicity and accumulation depending on the dosages.The Zn^(2+)release rate of ZIF-8NPswas high at low dosages,leading to a higher proportion of Zn^(2+)taken up by C.fluminea than the particulate ZIF-8.Conversely,at high dosages,C.fluminea mainly ingested the ZIF-8 NPs and resulted in increased mortality.The results have important implications for understanding the fate and biological effects of ZIF-8 in natural aquatic environments.
基金The National Natural Science Foundation of China provided funding for this project(U19A2047).
文摘●Soil erosion resulted in homogenization of bacterial communities in the watershed.●Microbial community heterogeneity among erosion sites made soil tracing possible.●Assembly process results showed that the tracking results can achieve high precision.●Dryland was the main source of sediment deposition based on the result of FEAST.Sediment source tracing can accurately provide a theoretical basis for controlling soil erosion effectively,by identifying the most serious types of land use.Traditional sediment tracing methods are based on physical,chemical,biological,and composite fingerprinting,which have not included microbes.As high-throughput sequencing becomes more prevalent,microorganisms can provide more information than what we think.Thus,whether the microorganism can also be used as a special fingerprint factor for sediment source identification during soil erosion,we have tested it by using microbial source tracking tool FEAST to quantify the microbe contribution from five types of eroded land(including dryland,urban,paddy field,forest and grassland)to the depositional areas(Niubitan)in the Yuanjiang basin.The source microbial community in the erosive area was heterogeneous,and assembly process analysis further demonstrated that the source tracking results could reach higher accuracy.The results of FEAST showed that dryland(35.50%),urban(17.21%),paddy field(8.14%),and forest(1.07%)were the major contributors to Niubitan.Our results follow the general soil erosion rules and prove its validity.Taken together,a new perspective is provided by these results for tracing sediment sources in erosion-sedimentary systems.
基金supported by the National Natural Science Foundation of China(Nos.52100081,51978178,and 51521006)the Department of Science and Technology of Guangdong Province of China(Nos.2021A1515011797,2023A1515012062,2019A1515012044,and 2022A1515010226)+4 种基金the Department of Education of Guangdong Province of China(No.2021KTSCX078)the Program for Innovative Research Teams of Guangdong Higher Education Institutes of China(No.2021KCXTD043)Maoming Municipal Department of Science and Technology of Guangdong Province of China(No.2018S0013)the Key Laboratory of Petrochemical Pollution Control of Guangdong Higher Education Institutes(No.2017KSYS004)the Startup Fund of GDUPT(Nos.2018rc63 and 2020rc041)。
文摘Switching the reaction routes in peroxymonosulfate(PMS)-based advanced oxidation processes have attracted much attention but remain challenging.Herein,a series of Co-N/C catalysts with different compositions and structures were prepared by using bimetallic zeolitic imidazolate frameworks based on ZIF-8 and ZIF-67(x Zn/Co-ZIFs).Results show that Co doping amount could mediate the transformation of the activation pathway of PMS over CoN/C.When Co doping amount was less than 10%,the constructed x Co-N/C/PMS system(x≤10%)was singlet oxygen-dominated reaction;however further increasing Co doping amount would lead to the generation and coexistence of sulfate radicals and high-valent cobalt,besides singlet oxygen.Furthermore,the nitrogen-coordinated Co(Co-NX)sites could serve as main catalytically active sites to generate singlet oxygen.While excess Co doping amount caused the formation of Co nanoparticles from which leached Co ions were responsible for the generation of sulfate radicals and high-valent cobalt.Compared to undoped N/C,Co doping could significantly enhance the catalytic performance.The 0.5%Co-N/C could achieve the optimum degradation(0.488 min^(-1))and mineralization abilities(78.4%)of sulfamethoxazole among the investigated Co-N/C catalysts,which was superior to most of previously reported catalysts.In addition,the application prospects of the two systems in different environmental scenarios(pH,inorganic anions and natural organic matter)were assessed and showed different degradation behaviors.This study provides a strategy to regulate the reactive species in PMS-based advanced oxidation process.
基金supported by the National Natural Science Foundation of China(Grant No.U19A2047)the Natural Science Foundation of Hunan Province(Grant No.2023JJ20030)。
文摘To improve soil carbon sequestration capacity,the full soil carbon cycle process needs to be understood and quantified.It is essential to evaluate whether water erosion acts as a net source or sink of atmospheric CO_(2)at the basin scale,which encompasses the entire hydrological process.This study introduced an approach that combined a spatially distributed sediment delivery model and biogeochemical model to estimate the lateral and vertical carbon fluxes by water erosion at the basin scale.Applying this coupling model to the Dongting Lake Basin,the results showed that the annual average amount of soil erosion during 1980-2020 was 1.33×10^(8)t,displaying a decreasing trend followed by a slight increase.Only 12% of the soil organic carbon displacement was ultimately lost in the riverine systems,and the rest was deposited downhill within the basin.The average lateral soil organic carbon loss induced by erosion was 8.86×10^(11)g C in 1980 and 1.50×10^(11)g C in 2020,with a decline rate of 83%.A net land sink for atmospheric CO_(2)of 5.54×1011g C a^(-1)occurred during erosion,primarily through sediment burial and dynamic replacement.However,ecological restoration projects and tillage practice policies are still significant in reducing erosion,which could improve the capacity of the carbon sink for recovery beyond the rate of horizontal carbon removal.Moreover,our model enables the spatial explicit simulation of erosion-induced carbon fluxes using costeffective and easily accessible input data across large spatial scales and long timeframes.Consequently,it offers a valuable tool for predicting the interactions between carbon dynamics,land use changes,and future climate.
基金support by the National Natural Science Foundation of China(No.51278464,41301327)
文摘The effects of Tween-20 and Zn(II) on ethylbenzene removal were evaluated using two biotrickling filters(BTFs), BTF1 and BTF2. Only BTF1 was fed with Tween-20 and Zn(II).Results show that ethylbenzene removal decreased from 94% to 69% for BTF1 and from 74%to 54% for BTF2 with increased organic loading from 64.8 to 189.0 g ethylbenzene/(m3·hr) at EBRT of 40 sec. The effect of EBRT(60–15 sec) at a constant ethylbenzene inlet concentration was more significant than that of EBRT(30–10 sec) at a constant organic loading. Biomass accumulation rate within packing media was reduced significantly.
基金supported by the Fundamental Research Funds for the Central Universities (531107040788)the National Natural Science Foundation of China (Nos. 51409100, 51039001, 51378190)the Program for Changjiang Scholars and Innovative Research Team in University (IRT-13R17)
文摘This study investigated the interaction between Cu^2+and nano zero-valent iron(NZVI)coated with three types of stabilizers(i.e., polyacrylic acid [PAA], Tween-20 and starch) by examining the Cu^2+ uptake, colloidal stability and mobility of surface-modified NZVI(SM-NZVI) in the presence of Cu^2+. The uptake of Cu^2+ by SM-NZVI and the colloidal stability of the Cu-bearing SM-NZVI were examined in batch tests. The results showed that NZVI coated with different modifiers exhibited different affinities for Cu^2+, which resulted in varying colloidal stability of different SM-NZVI in the presence of Cu^2+. The presence of Cu^2+ exerted a slight influence on the aggregation and settling of NZVI modified with PAA or Tween-20. However, the presence of Cu^2+caused significant aggregation and sedimentation of starch-modified NZVI, which is due to Cu^2+complexation with the starch molecules coated on the surface of the particles. Column experiments were conducted to investigate the co-transport of Cu^2+ in association with SM-NZVI in water-saturated quartz sand. It was presumed that a physical straining mechanism accounted for the retention of Cu-bearing SM-NZVI in the porous media. Moreover, the enhanced aggregation of SM-NZVI in the presence of Cu^2+ may be contributing to this straining effect.
基金financial support from the National Natural Science Foundation of China (No. 4127133)the Science and Technology Planning Project of Hunan Province, China (No. 2012SK2021)
文摘Aquatic macrophytes are considered to be promising in controlling harmful cyanobacterial blooms. In this research, an aqueous extract of Sagittaria trifolia tubers was prepared to study its inhibitory effect on Microcystis aeruginosa in the laboratory. Several physiological indices of M. aeruginosa, in response to the environmental stress, were analyzed. Results showed that S. trifolia tuber aqueous extract significantly inhibited the growth of M. aeruginosa in a concentration-dependent way. The highest inhibition rate reached 90% after 6 day treatment. The Chlorophyll-a concentration of M. aeruginosa cells decreased from 343.1 to314.2 μg/L in the treatment group. The activities of superoxide dismutase and peroxidase and the content of reduced glutathione in M. aeruginosa cells initially increased as a response to the oxidative stress posed by S. trifolia tuber aqueous extract, but then decreased as time prolonged. The lipid peroxidation damage of the cyanobacterial cell membranes was reflected by the malondialdehyde level, which was notably higher in the treatment group compared with the controls. It was concluded that the oxidative damage of M. aeruginosa induced by S.trifolia tuber aqueous extract might be one of the mechanisms for the inhibitory effects.
基金supported by the National Natural Science Foundation of China(Grant No.52070113).
文摘Quorum sensing (QS) plays an important role in microbial aggregation control. Recently, the optimization of biological waste treatment systems by QS regulation gained an increasing attention. The effects of QS regulation on treatment performances and biofilm were frequently investigated. To understand the state of art of QS regulation, this review summarizes the methods of QS enhancement and QS inhibition in biological waste treatment systems. Typical QS enhancement methods include adding exogenous QS molecules, adding QS accelerants and cultivating QS bacteria, while typical QS inhibition methods include additions of quorum quenching (QQ) bacteria, QS-degrading enzymes, QS-degrading oxidants, and QS inhibitors. The specific improvements after applying these QS regulation methods in different treatment systems are concluded. In addition, the effects of QS regulation methods on biofilm in biological waste treatment systems are reviewed in terms of biofilm formation, extracellular polymeric substances production, microbial viability, and microbial community. In the end, the knowledge gaps in current researches are analyzed, and the requirements for future study are suggested.
基金supported by the International S&T Cooperation Program of China(No.2015DFG92750)the National Natural Science Foundation of China(No.51478172)the Department of Science and Technology of Hunan Province(No.2014GK1012)
文摘Dispersion and aggregation of nanoparticles in aqueous solutions are important factors for safe application of nanoparticles. In this study, dispersion and aggregation of nano-TiO2 in aqueous solutions containing various anions were investigated. The influences of anion concentration and valence on the aggregation size, zeta potential and aggregation kinetics were individually investigated. Results showed that the zeta potential decreased from 19.8 to-41.4 mV when PO4^(3-) concentration was increased from 0 to 50 mg/L, while the corresponding average size of nano-TiO2 particles decreased from 613.2 to 540.3 nm. Both SO4^(2-) and NO3^-enhanced aggregation of nano-TiO2in solution. As SO4^(2-) concentration was increased from 0 to 500 mg/L, the zeta potential decreased from 19.8 to 1.4 mV, and aggregate sizes increased from 613.2 to 961.3 nm.The trend for NO3^- fluctuation was similar to that for SO4^(2-) although the range of variation for NO3^- was relatively narrow. SO4^(2-) and NO3^-accelerated the aggregation rapidly, while PO4^(3-) did so slowly. These findings facilitate the understanding of aggregation and dispersion mechanisms of nano-TiO2 in aqueous solutions in the presence of anions of interest.
基金supported by the National Natural Science Foundation of China(51978178,52270064,and 51521006)the Department of Science and Technology of Guangdong Province of China(2022A1515010226)+3 种基金the Program for Innovative Research Teams of Guangdong Higher Education Institutes of China(2021KCXTD043)Key Laboratory of Petrochemical Pollution Control of Guangdong Higher Education Institutes(KLGHEI 2017KSYS004)the Science and Technology Innovation Program of Hunan Province of China(2021RC2058)the Startup Fund of Guangdong University of Petrochemical Technology(2018rc63)。
文摘Oxidative desulfurization(ODS)is a promising technology to produce clean fuel with requiring superior catalysts to lower kinetic barriers.Although most ODS catalysts are based on crystalline transition-metal oxides(TMOs),extraordinary activity also can be achieved with amorphous TMOs.However,the origin of the remarkable catalytic activity of the amorphous TMOs remains greatly ambiguous.Here,we found the crucial role of Mo–O covalency in ruling the intrinsic catalytic activity of amorphous molybdenum oxides(MoO_(x)).Experimental and theoretical analysis indicated that the nonequivalent connectivity in the amorphous structure strongly enhanced Mo–O covalency,thereby increasing the content of electrophilic oxygen and nucleophilic molybdenum to favor the MoO_(x)–H_(2)O_(2) interaction.With the boosted Mo–O covalency to improve the flexibility of the charge state,the amorphous MoO_(x)-based composite catalyst(PE-MoO_(x)/S-0.05)exhibited outstanding catalytic activity for ODS of fuel oil.The turnover frequency(TOF)value of the catalyst(18.63 h^(-1))was almost an order of magnitude higher than that of most reported crystalline MoO_(x)/molecular sieve composite catalysts.The in-depth understanding of the origin of the amorphous TMOs activity for ODS provides a valuable reference for developing ODS catalysts.
基金the Project of the National Key Research and Development Program of China(No.2021YFC1910404)the National Natural Science Foundation of China(Nos.52100008,52100184,and 52100142)+4 种基金the Funds of Hunan Science and Technology Innovation Project(China)(Nos.2021GK4055 and 2022SK2119)Natural Science Foundation of Hunan ProvinceChina(No.2021JJ40091)the Science and Technology Innovation Program of Hunan Province(China)(No.2021RC2056)the Project funded by China Postdoctoral Science Foundation(No.2021M701149).
文摘Sulfate radicals have been increasingly used for the pathogen inactivation due to their strong redox ability and high selectivity for electron-rich species in the last decade.The application of sulfate radicals in water disinfection has become a very promising technology.However,there is currently a lack of reviews of sulfate radicals inactivated pathogenic microorganisms.At the same time,less attention has been paid to disinfection by-products produced by the use of sulfate radicals to inactivate microorganisms.This paper begins with a brief overview of sulfate radicals’properties.Then,the progress in water disinfection by sulfate radicals is summarized.The mechanism and inactivation kinetics of inactivating microorganisms are briefly described.After that,the disinfection by-products produced by reactions of sulfate radicals with chlorine,bromine,iodide ions and organic halogens in water are also discussed.In response to these possible challenges,this article concludes with some specific solutions and future research directions.
基金financially supported by the National Natural Science Foundation of China(Nos.51779088,51908528)the Fundamental Research Funds for the Central Universities(No.2021CDJQY-014)the Natural Science Foundation of Hunan Province,China(No.2021JJ30126)。
文摘Recent studies have proposed that the high-valent iron species(such as Fe^(Ⅳ)O^(2+))rather than sulfate radical(SO_(4)^(·-))and hydroxyl radical(·OH)are the main reactive oxidant species(ROS)in Fe(Ⅱ)/peroxydisulfate(PDS)system with the methyl phenyl sulfoxide(PMSO)as the Fe^(Ⅳ)O^(2+)probe.However,many operational factors may interfere with the accuracy of this method,so the contribution of Fe^(Ⅳ)O^(2+)calculated by this method is controversial.In this study,the possible effect of Fe(Ⅱ)concentration,pollutant type,reducing agent,or coexisted anions on Fe^(Ⅳ)O^(2+)production and its corresponding contribution to the removal of target pollutants in the Fe(Ⅱ)/PDS system were investigated in detail,and the intrinsic mechanisms involved were also explored.This study shows that ROS generation is a complex process in the Fe(Ⅱ)/PDS system,and multiple combinatorial approaches are urgently required to deeply explore the contribution of ROS to the elimination of target contaminants.
基金supported by the National Natural Science Foundation of China(No.41271332the Natural Science Foundation of Hunan Province,China(No.11JJ2031)
文摘Numerous studies on eutrophication remediation have mainly focused on purifying water first, then restoring submerged macrophytes. A restoration-promoting integrated floating bed (RPIFB) was designed to combine the processes of water purification and macrophyte restoration simultaneously. Two outdoor experiments were conducted to evaluate the ecological functions of the RP1FB. Trial 1 was conducted to compare the eutrophication purification among floating bed, gradual-submerging bed (GSB) and RPIFB technologies. The results illustrated that RPIFB has the best purification capacity. Removal efficiencies of RPIFB for TN, TP,NH4+-N, NO3-N, CODcr, Chlorophyll-a and turbidity were 74.45%, 98.31%, 74.71%, 88.81%, 71.42%, 90.17% and 85%, respectively. In trial 2, influences of depth of GSB and photic area in RPIFB on biota were investigated. When the depth of GSB decreased and the photic area of RPIFB grew, the height of Potamogeton crispus Linn. increased, but the biomass of Canna indica Linn. was reduced. The mortalities of Misgurnus anguillicaudatus and Bellamya aeruginosa in each group were all less than 7%. All results indicated that when the RPIFB was embedded into the eutrophic water, the regime shift from phytoplankton-dominated to macrophyte-dominated state could be promoted. Thus, the RPIFB is a promising remediation technology for eutrophication and submerged macrophyte restoration.
基金financially supported by the National Natural Science Foundation and Innovation Group of China(Nos.41271332 and 51521006)
文摘Soil degradation,characterized by declines in nutrient status and simultaneous accumulation of pesticide residues,is a major problem affecting agricultural ecosystems.Previous studies indicate that biochar application to soil has promise as a practical method to alleviate these pressures:increasing crop yield and enhancing pesticide degradation.Here,we review the roles of biochar in both chemical and biological promotion of pesticide degradation and the potential benefits of biochar relating to the efficiency of fertilizer use,availability of nutrients,and nutrient exchange.Biochar typically has a high surface area featuring many functional groups,a high cation exchange capacity,and high stability.Major factors that impact on the nutrient retention characteristics of biochar(e.g.,feedstock,pyrolysis temperature,and application rate) are also discussed herein.Nonetheless,more studies of the long-term impacts on soil properties from biochar addition are still required before it can be possible to accurately quantify the sustainability of this approach to sequester carbon and restore soil function.
基金supported by the National Natural Science Foundation of China (No. 51178047), Furong Scholar of Hunan Province
文摘A novel joint method of bioleaching with Fenton oxidation was applied to condition sewage sludge. The specific resistance to filtration(SRF) and moisture of sludge cake(MSC) were adopted to evaluate the improvement of sludge dewaterability. After 2-day bioleaching, the sludge p H dropped to about 2.5 which satisfied the acidic condition for Fenton oxidation.Meanwhile, the SRF declined from 6.45 × 1010 to 2.07 × 1010s2/g, and MSC decreased from91.42% to 87.66%. The bioleached sludge was further conditioned with Fenton oxidation. From an economical point of view, the optimal dosages of H2O2 and Fe2+were 0.12 and 0.036 mol/L,respectively, and the optimal reaction time was 60 min. Under optimal conditions, SRF,volatile solids reduction, and MSC were 3.43 × 108s2/g, 36.93%, and 79.58%, respectively. The stability and settleability of sewage sludge were both improved significantly. Besides,the results indicated that bioleaching-Fenton oxidation was more efficient in dewatering the sewage sludge than traditional Fenton oxidation. The sludge conditioning mechanisms by bioleaching-Fenton oxidation might mainly include the flocculation effects and the releases of extracellular polymeric substances–bound water and intercellular water.
基金the National Scientific and Technological Supporting Project, China (No. 2012BAJ21B01 -02)the National Natural Science Foundation of China (No. 51508538)+2 种基金the China Postdoctoral Science Foundation (No. 2012M520351)the Beijing Natural Science Foundation (No. 8164054)the Beijing talented backbones program (No. 2015000021733G171) for their financial support.
文摘Nitrogen removal of wastewater containing high-strength ammonium by the constructed wetlands (CWs) has been paid much attention. In this study, the ability of a partially saturated CW to treat anaerobically-digested decentralized swine wastewater under varying operating parameters from summer to winter was investigated. The partially saturated CW achieved better NH4^+-N and TN removal by tidal flow than intermittent flow. With surface loading rates of 0.108, 0.027, and 0.029 kg/(m^2·d) for COD, NH4^+-N, and TN, the partially saturated CW by tidal operation achieved corresponding removal efficiencies of 85.94%, 61.20%, and 57.41%, respectively, even at 10℃. When the rapid-adsorption of NH4^+-N and the bioregeneration of zeolites reached dynamically stable, the simultaneous nitrification and denitrification in the aerobic zeolite layer was observed and accounted for 58.82% of the total denitrification of CW. The results of Illumina high-throughput sequencing also indicated that nitnfiers (Nitrospira and Rhizomicrobiurri) and denitrifiers (Rhodanobacter and Thauera) simultaneously existed in the zeolite layer. The dominant existence of versatile organic degraders and nitrifiers/denitrifiers in the zeolite layer was related to the removal of most COD and nitrogen in this zone. The contribution of the possible nitrogen removal pathways in the CW was as follows: nitrification-denitrification (86.55%)>substrate adsorption (11.70%)>plant uptake (1.15%)>microbial assimilation (0.60%).
基金This work was supported by the National Natural Science Foundation of China(Nos.51978178 and 51521006)the Department of Science and Technology of Guangdong Province of China(Nos.2019A1515012044 and 2021A1515011797)+3 种基金the International S&T Cooperation Program of China(No.2015DFG92750)the Maoming Municipal Bureau of Science and Technology of Guangdong of China(No.2018S0013)the Startup Fund of Guangdong University of Petrochemical Technology(No.2020rc041)the Shanghai Tongji Gao Tingyao Environmental Science&Technology Development Foundation.
文摘Nonradical reaction driven by peroxymonosulfate(PMS)based advanced oxidation pro-cesses has drawn widespread attention in water treatment due to their inherent advantages,but the degradation behavior and mechanism of organic pollutants are still unclear.In this study,the performance,intermediates,mechanism and toxicity of tetracycline(TC)degra-dation were thoroughly examined in the constructed magnetic nitrogen-doped porous car-bon/peroxymonosulfate(Co-N/C-PMS)system.The results showed that 85.4%of TC could be removed within 15 min when Co-N/C and PMS was simultaneously added and the degra-dation rate was enhanced by 3.4 and 14.7 folds compared with Co-N/C or PMS alone,re-spectively.Moreover,the performance of Co-N/C was superior to that of most previously reported catalysts.Many lines of evidence indicated that Co-N/C-PMS system was a singlet oxygen-dominated nonradical reaction,which was less interfered by pH and water compo-nents,and displayed high adaptability to actual water bodies.Subsequently,the degrada-tion process was elaborated on the basis of three-dimensional excitation-emission matrix spectra and liquid chromatography-mass spectrometry.At last,the toxicity of treated TC was greatly reduced by using microalgae Coelastrella sp.as ecological indicator.This study provides a promising approach based on singlet oxygen-dominated nonradical reaction for eliminating TC in water treatment.
基金supported by the National Natural Science Foundation of China (No. 51609268)the Key Project of Technological Innovation in the Field of Social Development of Hunan Province, China (Nos. 2016SK2010 and 2016SK2001)
文摘Biochar is regarded as a promising new class of materials due to its multifunctional character and the possibility of effectively coupling different properties. With increasing introduction into the environment, environmental chemicals such as surfactants will load onto the released biochar and change its physicochemical characteristics and adsorption behavior toward pollutants. In this study, sodium dodecyl sulfate(SDS), as one type of anionic surfactant, was coated onto biochar with different loading amounts. The influence of SDS loading onto biochar's physicochemical properties were investigated by Fourier transform infrared(FT-IR) spectroscopy, elemental analysis, zeta potential and Brunauer–Emmett–Teller(BET) surface area and pore size distribution analysis. Results showed that the pore size of the biochar decreased gradually with the increase of SDS loading because of the surface-adsorption and pore-blocking processes; the p H of the point of zero charge(pHPZC) decreased with increasing SDS loading. Although surface-coating with SDS decreased the pore size of the biochar, its adsorption capacity toward Methylene Blue(MB) significantly increased. The biochar-bound SDS introduced functional groups and negative charges to the biochar surface, which could thus enhance the adsorption of MB via hydrogen bonding and electrostatic interaction. The results can shed light on the underlying mechanism of the influence of anionic surfactants on the adsorption of MB by biochar.