Biomass-derived porous carbon highly efficient for removal of Pb(Ⅱ) and Cd(Ⅱ)

The utilization of abundant and renewable biomass to fabricate advanced functional materials is considered a promising route for environmental applications.Herein,Lignin-based porous carbon with layered graphene-like structure(LPC)is successfully synthesized and applied to efficiently remove Pb(Ⅱ)and Cd(Ⅱ).The as-synthesized LPC materials are systematically characterized and these results show that LPC has a porous graphene-like structure,facilitating the diffusion and immobilization of heavy metal ions.The influence of different reaction parameters(solution pH,initial concentration of metal ions,contact time and adsorbent amount)on the adsorption performance is investigated in details.The results demonstrate that LPC can achieve superior adsorption capacities of 250.5 mg·g^-1 for Pb(Ⅱ)and 126.4 mg·g^-1 for Cd(Ⅱ),which are far superior to the previously reported adsorbents.Pseudo-second order kinetics model and Freundlich isotherm model describe the adsorption process well.Furthermore,the exhausted LPC can be regenerated easily and exhibits the removal efficiency of 96%and 92%for Pb(Ⅱ)and Cd(Ⅱ)after five continuous runs,respectively.This study shows a sustainable strategy for the design of porous carbon material from na?ve biomass and highlights the great potential in wastewater treatment.

Controllable synthesis of nitrogen-doped porous carbon from metal-polluted miscanthus waste boosting for supercapacitors

High-value reclamation of metal-polluted plants involved in phytoremediation is a big challenge.In this study,nitrogen-doped nanoporous carbon with large specific area of 2359.1 m^(2)g^(-1) is facilely fabricated from metal-polluted miscanthus waste for efficient energy storage.The synergistic effect of KOH,urea and ammonia solution greatly improve the nitrogen quantity and surface area of the synthesized carbon.Electrodes fabricated with this carbon exhibit the excellent capacitance performance of 340.2 F g^(-1) at 0.5 A g^(-1) and a low combined resistance of 0.116Ω,which are competitive with most of previously reported carbon-based electrodes.In addition,the as-obtained carbon electrode shows a high specific capacitance retention of over 99.6%even after 5000 cycles.Furthermore,the symmetric supercapacitor fabricated using the synthesized carbon achieves a superior energy density of 25.3 Wh kg^(-1)(at 400 W kg^(-1))in 1 mol L^(-1) Na_(2)SO_(4)aqueous solution.This work provides an efficient route to upcycle metal-polluted plant waste for supercapacitor applications.

Occurrence and Roles of Comammox Bacteria in Water and Wastewater Treatment Systems:A Critical Review

Nitrogen removal is a critical process in water treatment plants(WIPs)and wastewater treatment plants(WWTPs).The recent discovery of a novel bacterial process,complete ammonia oxidation(comammox,CMX),has refuted a century-long perception of the two-step conversion of NH3to NO3-.Compared with canonical nitrifiers,CMX bacteria offer undeniable advantages,such as a high growth yield propensity and adaptability to nutrient-and growth-limiting conditions,which collectively draw attention to validate the aptness of CMX bacteria to wastewater treatment.As there has been no comprehensive review on the relevance of CMX bacteria for sustainable water and wastewater treatment,this review is intended to discuss the roles and applications of CMX in the removal of nitrogen and pollutants from water and wastewater.We took into account insights into the metabolic versatilities of CMX bacteria at the clade and subclade levels.We focused on the distribution of CMX bacteria in engineered systems,niche differentiation,co-occurrence and interactions with cano nical nitrifiers for a better understanding of CMX bacteria in terms of their ecophysiology.Conceptualized details on the reactor adaptability and stress response of CMX bacteria are provided.The potential of CMX bacteria to degrade micropollutants either directly or co-metabolically was evaluated,and these insights would be an indispensable advantage in opening the doors for wider applications of CMX bacteria in WWTPs.Finally,we summarized future directions of research that are imperative in improving the understanding of CMX biology.

Adsorption and Desorption Characteristics of Cadmium Ion by Ash-Free Biochars

The aim of this study was to investigate adsorption and desorption characteristics of cadmium ion(Cd(II))by ash-free biochars and the adsorption mechanism.Biochars were prepared using peanut shell,bamboo,and Sophora japonica Linn.Ash-free biochars were obtained by treating the biochars with acid elution.Adsorption and desorption data from batch experiments were analyzed using the Langmuir and Freundlich models and three adsorption kinetics models(i.e.,the Pseudo second-order,Elovich model,and the Intraparticle diffusion models).Results showed that the acid elution improved the pore structure of biochars,increased C content and aromatic functional group content,enhanced biochars hydrophobicity and adsorption capacity for Cd(II).Ash-free peanut shell biochar showed the best Cd(II)adsorption performance among the biochars.Adsorption of ash-free peanut shell biochar reached the equilibrium within 6 h with adsorption capacity of 34.2 mg/g.The adsorption conditions were optimized by orthogonal experiment.The Cd(II)removal efficiency achieved 91.7%with the optimized condition:initial concentration of Cd(II)of 50 mg/L,pH of 5,adsorption time of 12 h,and temperature of 15°C.Isothermal adsorption of Cd(II)by the six biochars was best described with the Langmuir model,indicating that the adsorption was a physical-chemical composite process.The desorption isotherm showed the hysteresis between adsorption and desorption.The main mechanism of Cd(II)adsorption of the ash-free biochars was a complex interaction of physical and chemical reactions,mainly including electrostatic adsorption,cationic-π,and ligand exchange.

An Integrated Socio-Economic and Ecological Framework for Evaluating the Societal Costs and Benefits of Fishing Activities in the Pearl River Delta

This paper puts forward a model of Pearl River Delta (PRD) fishery in the South China Sea (SCS) that integrates the ecological, social and economic costs and benefits of fisheries activities in a multidisciplinary framework. In particular, an integrated ECOST model is composed of links between an ecological model constructed by Ecopath with Ecosim (EwE) software and a region Social Accounting Matrix (SAM). Then the costs and benefits of five fishing methods are compared from economic, ecological and social three dimensions base on the ECOST model. The potential effects of fishing effort reduction on fishing communication are explored by a series of dynamic simulations for a 10-year period. Key results from prediction (2005-2015) and policy simulations illustrate that fisheries of PRE are geared toward short-term economic profits at the expense of ecological gains and the whole group of societal benefits associated with fishing. However, the status quo can be improved to better levels by reducing fishing efforts.

Electrodeposited 3D hierarchical NiFe microflowers assembled from nanosheets robust for the selective electrooxidation of furfuryl alcohol

A robust and green strategy for the selective upgrading of biomass-derived platform chemicals towards highly valuable products is important for the sustainable development.Herein,the efficient electrocatalytic oxidation of biomass-derived furfuryl alcohol(FFA)into furoic acid(FurAc)catalyzed by the electrodeposited non-precious NiFe microflowers was successfully reached under the low temperature and ambient pressure.The 3D hierarchical NiFe microflowers assembled from ultrathin nanosheets were controllably synthesized by the electrodeposition method and uniformly grown on carbon fiber paper(CFP).Electrochemical analysis confirmed that NiFe nanosheets more preferred in the selective oxidation of FFA(FFAOR)than oxygen evolution reaction(OER).The linear sweep voltammetry(LSV)in FFAOR displayed a clear decrease towards lower potential,resulting in 30 mV reduction of overpotential at 20 mA cm^(-2) compared with that of OER.The optimal catalyst Ni_(1)Fe_(2) nanosheets exhibited the highest selectivity of FurAc(94.0%)and 81.4%conversion of FFA within 3 h.Besides,the influence of various reaction parameters on FFAOR was then explored in details.After that,the reaction pathway was investigated and rationally proposed.The outstanding performance for FFAOR can be ascribed to the unique structure of 3D flower-like NiFe nanosheets and oxygen vacancies,resulting in large exposure of active sites,faster electron transfer and enhanced adsorption of reactants.Our findings highlight a facile and convenient mean with a promising green future,which is promising for processing of various biomass-derived platform chemicals into value-added products.

Efficient electrooxidation of biomass-derived aldehydes over ultrathin Ni V-layered double hydroxides films

Selective upgrading of C=O bonds to afford carboxylic acid is significant for the petrochemical industry and biomass utilization.Here we declared the efficient electrooxidation of biomass-derived aldehydes family over NiV-layered double hydroxides(LDHs) thin films.Mechanistic studies confirmed the hydroxyl active intermediate(-OH*) generated on the surface of NiV-LDHs films by employing electrochemical impedance spectroscopy and the electron paramagnetic resonance spectroscopy.By using advanced techniques,e.g.,extended X-ray absorption fine structure and high-angle annular dark-field scanning transmission electron microscopy,NiV-LDHs films with 2.6 nm could expose larger specific surface area.Taking benzaldehyde as a model,high current density of 200 mA cm^(-2)at 1.8 V vs.RHE,81.1% conversion,77.6% yield of benzoic acid and 90.8% Faradaic efficiency were reached,which was superior to most of previous studies.Theoretical DFT analysis was well matched with experimental findings and documented that NiV-LDHs had high adsorption capacity for the aldehydes to suppress the side reaction,and the aldehydes were oxidized by the electrophilic hydroxyl radicals formed on NiV-LDHs.Our findings offer a universal strategy for the robust upgrading of diverse biomass-derived platform chemicals.

An overview of bioelectrokinetic and bioelectrochemical remediation of petroleum-contaminated soils

The global problem of petroleum contamination in soils seriously threatens environmental safety and human health.Current studies have successfully demonstrated the feasibility of bioelectrokinetic and bioelectrochemical remediation of petroleum-contaminated soils due to their easy implementation,environmental benignity,and enhanced removal efficiency compared to bioremediation.This paper reviewed recent progress and development associated with bioelectrokinetic and bioelectrochemical remediation of petroleum-contaminated soils.The working principles,removal efficiencies,affecting factors,and constraints of the two technologies were thoroughly summarized and discussed.The potentials,challenges,and future perspectives were also deliberated to shed light on how to overcome the barriers and realize widespread implementation on large scales of these two technologies.

Degradation of aniline by Fe^(2+)-activated persulfate oxidation at ambient temperature

The aniline degradation by persulfate activated with ferrous ion (Fe2+ ) was investigated in batch reactor at ambient temperature. The experimental factors in aqueous solutions including persulfate concentration, Fe2+ concentration, pH and ionic strength level were discussed. It is demonstrated that, aniline degradation rate increases with increasing persulfate concentration, but much more ferrous ion inhibits the aniline degradation. When the aniline concentration is 0.10 mmol/L, the maximum aniline degradation occurs at the S2O82- to Fe2+ molar ratio of 250/5 at pH 7.0. In the pH range of 5.0-8.5, increasing pH causes higher aniline degradation. What's more, the increase of ionic strength in solution causes inhibiting in the reaction. Produced intermediates during the oxidation process were identified using gas chromatography-mass spectrometry (GC-MS) technology. And degradation pathways of aniline were also tentatively proposed.

Upcycling biomass waste into Fe single atom catalysts for pollutant control

Contaminants of heavy metals and antibiotics, which are frequently detected in water, soil and food chains with increasing prevalence in our current society, can cause potential harm to human health and disrupt human ecosystem irreversibly. Herein, we have successfully utilized biomass waste ferns contaminated by iron mines, to fabricate a first-of-its-kind high-performance class of Fe single-atom catalysts(FeSAC) by a facile pyrolysis. The optimal FeSAC-800 shows an excellent efficiency in the fastphotocatalytic degradation of six types of quinolone antibiotics(e.g., norfloxacin, levofloxacin, ciprofloxacin, enrofloxacin, lomefloxacin, flumequine) in 1 h under the simulated natural light irradiation. Based on advanced characterization, a well-defined structure of FeN_(4), confined in the porous carbon is elaborated for the FeSAC-800. Mechanism of the photodegradation is via a Fenton-like oxidation process whereas the reactive oxygen species play a key role. These findings open a new avenue for efficient, sustainable utilization of biomass waste in pollutant control.

Study on Effect of Performance on Excess Sludge Disintegration by Ozone

In order to study the effect of excess sludge ozonation, a continuous experiment in lab scale process was carried out. During the treatment process, a high level of ozone was produced by the electrolysis-type ozone generator, and various parameters, such as Soluble Chemical Oxygen Demand （SCOD）, Mixed Liquor Suspended Solids （MLSS）, Mixed Liquor Volatile Suspended Solids （MLVSS）, pH and so on, which char- acterize sludge were investigated. A substantial reduction in the volume of sludge and the release of intracellular materials were observed： SCOD proliferated as a consequence of extending the ozone feeding time; MLSS and MLVSS, especially the ratio of MLVSS to MLSS, dwindled as the action time rose. Through analyzing the effluent quality and excess sludge activity, the sludge-water volume mixture ratio of 1 ： 20 with 50 -60 minutes＇ oxidation treatment was found to be the optimal condition for ozonic disintegration of excess sludge. A remarkable sludge reduction rate of 57% could be achieved under the ozone feeding time of 40 minutes, which revealed the optimal action time.

Green fabrication of nickel-iron layered double hydroxides nanosheets efficient for the enhanced capacitive performance

Rational synthesis of robust layered double hydroxides(LDHs) nanosheets for high-energy supercapacitors is full of challenges.Herein,we reported an ultrasonication-assisted strategy to eco-friendly fabricate NiFe-LDHs nanosheets for the enhanced capacitive behavior.The experimental results combined with different advanced characterization tools document that the utilization of ultrasonication has a profound effect on the morphology and thickness of the as-obtained NiFe-LDHs,alternatively affecting the capacitive behavior.It shows that NiFe-LDHs nanosheets prepared with 2-h ultrasonic treatments display the exceptional capacitive performance because of the synergetic effect of ultrathin thickness,large specific surface area,and high mesoporous volume.The maximum specific capacitance of Ni_(3) Fe_(1)-LDHs nanosheets with the thickness of 7.39 nm and the specific surface area of 77.16 m~2 g^(-1) reached 1923 F g^(-1),which is competitive with most previously reported values.In addition,the maximum specific energy of the assembled NiFe-LDHs//AC asymmetric supercapacitor achieved 49.13 Wh kg^(-1) at400 W kg^(-1).This work provides a green technology to fabricate LDHs nanosheets,and offers deep insights for understanding the relationship between the morphology/structure and capacitive behavior of LDHs nanosheets,which is helpful for achieving high-performance LDHs-based electrode materials.

Anomalous metastable hcp Ni nanocatalyst induced by non-metal N doping enables promoted ammonia borane dehydrogenation

Developing high-performing non-noble transition metal catalysts for H_(2) evolution from chemical hydrogen storage materials is of great significance for the hydrogen economy system, yet challenging. Herein,we present for the first time that anomalous metastable hexagonal close-packed Ni nanoparticles induced by heteroatom N doping encapsulated in carbon(N-hcp-Ni/C) can exhibit admirable catalytic performance for ammonia borane(AB) dehydrogenation, prominently outperforming conventional fcc Ni counterpart with similar morphology and favorably presenting the state-of-the-art level.Comprehensive experimental and theoretical studies unravel that unusual hcp phase engineering of Ni together with N doping could induce charge redistribution and modulate electronic structure, thereby facilitating H_(2)O adsorption and expediting H_(2)O dissociation(rate-determining step). As a result, AB dehydrogenation can be substantially boosted with the assistance of N-hcp-Ni/C. Our proposed strategy highlights that unconventional crystal phase engineering coupled with non-metal heteroatom doping is a promising avenue to construct advanced transition metal catalysts for future renewable energy technologies.

Tank-dependence of the functionality and network differentiation of activated sludge community in a full-scale anaerobic/anoxic/aerobic municipal sewage treatment plant

Understanding the structures and dynamics of bacterial communities in activated sludge(AS)in full-scale wastewater treatment plants(WWTPs)is of both engineering and ecological significance.Previous investigations have mainly focused on the AS communities of WWTP aeration tanks,and the differences and interactions between the communities in anaerobic and anoxic tanks of the AS system remain poorly understood.Here,we investigated the structures of bacterial communities and their inter-connections in three tanks(anaerobic,anoxic,and aerobic)and influent from a full-scale WWTP with conventional anaerobic/anoxic/aerobic(A/A/O)process over a year to explore their functionality and network differentiation.High-throughput sequencing showed that community compositions did not differ appreciably between the different tanks,likely due to the continuous sludge community interchange between tanks.However,network analysis showed significant differences in inter-species relationships,OTU topological roles,and keystone populations in the different AS communities.Moreover,the anoxic network is expected to be more unstable and easily affected by environmental disturbance.Tank-associated environmental factors,including dissolved oxygen,pH,and nutrients,were found to affect the relative abundance of functional genera(i.e.,AOB,NOB,PAOs,and denitrifiers),suggesting that these groups were more susceptible to environmental variables than other bacteria.Therefore,this work could assist in improving our understanding of tank-associated microbial ecology,particularly the response of functional bacteria to seasonal variations in WWTPs employing A/A/O process.

Boosted urea electro-oxidation over Ni_(3)N-based nanocomposite via systematic regulation tactic

Exploiting high-efficiency Ni-based materials for electrocatalytic urea oxidation reaction(UOR) is critical for urea-related technologies.The catalytic site density,intrinsic activity,charge transfer,and mass diffusion determine overall electrocatalytic efficiency.Simultaneous modulation over the above four factors promises advanced electrocatalysis,yet challenging.Herein we propose a systematic regulation tactic over composition and geometric structure,constructing a nanocomposite comprising Mn doped Ni_(3)N nanoparticles anchored on reduced graphene oxide(rGO/Mn-Ni_(3)N),achieving elegant integration of four design principles into one,thereby eminently boosting UOR.Particularly,Mn doping in Ni_(3)N can modulate electronic state to induce intrinsic activity regulation.Combining metallic Mn-Ni_(3)N with rGO to engineer hierarchical architecture not only promotes charge transfer,but also enriches active site population.Intriguingly,improved hydrophilicity could impart better electrolyte penetration and gas escape.Consequently,such system-optimized rGO/Mn-Ni_(3)N demonstrates state-of-the-art-level UOR electrocatalysis.This work offers a novel paradigm to create advanced catalysts via systematic and integrated modulation.

Temperature-controlled fabrication of hydrophilic manganese oxide microspheres as high-performance electrode materials for supercapacitors

The supercapacitive properties of manganese oxides(MnO_(x))are strongly affected by their crystal structure.Nevertheless,the relationship between the crystal structure and supercapacitive performance of Mn O_(x)is elusive.Herein,a temperature-controlled fabrication method was developed to achieve MnO_(2),Mn_(3)O_(4),MnO and Mn_(2)O_(3)microspheres with various crystal structure as electrode materials tunable for supercapacitors.The detailed material and electrochemical characterizations revealed the structureactivity relationship of Mn O_(x)microspheres by systematically investigating the effect of valence state,specific surface area,conductivity and morphology on supercapacitive performance.Among these MnO_(x)materials,nanoneedle-like Mn O_(2)delivered a relatively high specific capacitance of 274.1 F/g at 1 A/g due to a high Mn valence state of+4,a large specific surface area of 113.4 m^(2)/g and a desirable electronic conductivity of 1.73×10^(-5)S/cm.Furthermore,MnO_(2)presented a remarkable cycle stability with 115%capacitance retention after 10,000 cycles owing to the enhancement of wettability.This work not only provides a facile strategy to modulate MnO_(x)crystal structure,but also offers a deep understanding of structure-dependent supercapacitive performance of MnO_(x).

Genome-resolved metagenomic analysis reveals different functional potentials of multiple Candidatus Brocadia species in a full-scale swine wastewater treatment system

The increasing application of anammox processes suggests their enormous potential for nitrogen removal in wastewater treatment facilities.However,the functional potentials and ecological differentiation of cooccurring anammox species in complex ecosystems have not been well elucidated.Herein,by utilizing functional reconstruction and comparative genome analysis,we deciphered the cooccurring mechanisms of four Candidatus Brocadia species that were spontaneously enriched in a full-scale swine wastewater treatment system.Phylogenetic analysis indicated that species SW172 and SW745 were closely related to Ca.Brocadia caroliniensis and Ca.Brocadia sapporoensis,respectively,whereas the dominant species SW510 and SW773,with a total average abundance of 34.1%,were classified as novel species of the genus Ca.Brocadia.Functional reconstruction revealed that the novel species SW510 can encode both cytochrome cd1-type nitrite reductase and hydroxylamine oxidase for nitrite reduction.In contrast,the detected respiratory pentaheme cytochrome c nitrite reductase and acetate kinase genes suggested that SW773 likely reduced nitrite to ammonium with acetate as a carbon source.Intriguingly,the presence of genes encoding urease and cyanase indicated that both novel species can use diverse organic nitrogen compounds in addition to ammonia and nitrite as substrates.Taken together,the recovery and comparative analysis of these anammox genomes expand our understanding of the functional differentiation and cooccurrence of the genus Ca.Brocadia in wastewater treatment systems.

Influence of cadmium and copper mixtures to rhizosphere bacterial communities

To study the effects of combined Cd and Cu pollution on rhizosphere bacterial community.High-throughput sequencing was used to examine the response of rhizosphere bacterial communities to heavy-metal stress under single and mixed pollution of cadmium(Cd)and copper(Cu).With additions of Cd and Cu,the mean diversity index of rhizosphere bacterial community was in the order Cu alone>Cd-Cu mixtures>Cd alone.In all Cd and Cu treatments,the dominant phyla were Proteobacteria,Actinobacteria,Chloroflexi and Acidobacteria.In the additions with different concentrations of Cd-Cu mixtures,LEfSe indicated that there were differences in the predominant species of rhizosphere bacterial communities.Some genera such as Streptomyces and Microbacterium belonging to Actinobacteria as biomarkers were significantly enriched in both control and treatments,while some genera such as Pseudoxanthomonas and Rhodopseudomonas belonging to Proteobacteria as biomarkers were observed to be enriched in the additions with single and mixture of Cd and Cu.According to the Nonmetric multidimensional scaling(NMDS)analysis,the structure of rhizosphere bacterial community was different between treatments and the CK.Principal Component Analysis(PCA)and permutational multivariate analysis of variance(PERMANOVA)showed that there were significant differences among treatments(p<0.01),and that the addition of Cu might be the primary factor affecting the composition of rhizosphere bacterial communities.

Dynamics of Soil Organic Carbon Under Uncertain Climate Change and Elevated Atmospheric CO_2

Climate change and elevated atmospheric CO2 should affect the dynamics of soil organic carbon (SOC). SOC dynamics under uncertain patterns of climate warming and elevated atmospheric CO2 as well as with different soil erosion extents at Nelson Farm during 1998-2100 were simulated using stochastic modelling. Results based on numerous simulations showed that SOC decreased with elevated atmospheric temperature but increased with atmospheric CO2 concentration. Therefore, there was a counteract effect on SOC dynamics between climate warming and elevated CO2 . For different soil erosion extents, warming 1 C and elevated atmospheric CO2 resulted in SOC increase at least 15%, while warming 5 C and elevated CO2 resulted in SOC decrease more than 29%. SOC predictions with uncertainty assessment were conducted for different scenarios of soil erosion, climate change, and elevated CO2 . Statistically, SOC decreased linearly with the probability. SOC also decreased with time and the degree of soil erosion. For example, in 2100 with a probability of 50%, SOC was 1 617, 1 167, and 892 g m 2 , respectively, for no, minimum, and maximum soil erosion. Under climate warming 5 C and elevated CO2 , the soil carbon pools became a carbon source to the atmosphere (P > 95%). The results suggested that stochastic modelling could be a useful tool to predict future SOC dynamics under uncertain climate change and elevated CO2 .