Adsorption Behavior and Mechanisms of Surfactants by Farmland Soils in Northeast China

The adsorption of two nonionic surfactants polyethylene glycol tert-octylphenyl ether Triton X-100 (TX-100), polyoxyethylene lauryl ether(Brij35) and an anionic surfactant sodium dodecyl benzene sulfonate(SDBS) by two soils(S1, S2) of different natures and their respective organic-matter-extracted samples(S3, S4) were investigated. These adsorption isotherms show different adsorption stages of different types of surfactants by soils. The data fitted Langmuir equation very well. The adsorption maximum capacity(Q0) indicates that TX-100 and SDBS were in the sequence of S3S4S1S2 in adsorption, however, Brij35 was in the sequence of S4S3S1S2 in adsorption. And the adsorption amounts of the different surfactants by soils followed the order of TX-100Brij35SDBS. Meanwhile, the adsorption of the nonionic surfactants TX-100 and Brij35 decreased with the increase of their ethylene oxide(EO) numbers. The results indicate that both soil organic matter and mineral played important roles in the adsorption of surfactants, and the adsorption of the surfactants by soils was affected by the physicochemical properties and structures of the soils and surfactants, especially the mineral type and content of soil.

Runoff Simulation of Shitoukoumen Reservoir Basin Based on SWAT Model

[Objective] The study aimed to simulate the runoff of Shitoukoumen Reservoir basin by using SWAT model. [Method] Based on DEM elevation, land use type, soil type and hydrometeorological data, SWAT model, a distributed hydrological model was established to simulate the monthly runoff of Shitoukoumen Reservoir basin, and the years 2006 and 2010 were chosen as the calibration and validation period respectively. [Result] The simulation results indicated that SWAT model could be used to simulate the runoff of Shitoukoumen Reservoir basin, and the simulation effect was good. However, the response of the model to local rainstorm was not obvious, so that the actual runoff in June and July of 2010 was abnormally higher than the simulation value. [Conclusion] The research could provide theoretical references for the plan and management of water resources in Shitoukoumen Reservoir basin in future.

Enhanced Removal of Phenols by MIZ-Cu Nanozyme Exhibiting Laccase-like Activity and Broader Adaptability to Temperature and pH Conditions

Phenolic compounds,classified as persistent organic pollutants,pose a significant threat to both human health and environmental safety.Therefore,the efficient removal of phenolic substances from water is of paramount importance.Laccase,a multicopper oxidase,is commonly utilized for the efficient removal of phenolic contaminants from water due to its highly effective catalytic activity towards phenolic compounds.However,natural laccase exhibits certain limitations that impede its practical implementation in industrial settings,including a restricted pH activity range,diminished enzymatic efficacy at elevated temperatures,and substantial cost implications.In this work,we prepared a nanozyme(MIZ-Cu,MIZ:2-methylimidazole)with laccase-like activity by coordinating 2-methylimidazole and copper.This nanozyme overcomes the deactivation issues observed in natural laccase under high temperature and alkaline conditions.The catalytic activity of the MIZ-Cu towards phenolic compounds surpasses that of natural laccase across a wide range of temperature and pH conditions.Under pH=9,80℃,and 500 mmol/L NaCl conditions,the removal rate of four phenols(catechol,hydroquinone,resorcinol,and phloroglucinol)by MIZ-Cu was much higher than that of natural laccase.The results also demonstrate exceptional removal rates in natural aquatic environments,thereby presenting a promising approach for the treatment of phenol-containing wastewater originating from industrial facilities.

Performance and Mechanisms of Fluoride Removal from Groundwater by Lanthanum-aluminum-loaded Hydrothermal Palygorskite Composite

Lanthanum-aluminum loaded hydrothermal palygorskite（La-Al-HP） composite was prepared and selected as adsorbent for the fluoride removal from simulated groundwater. The adsorbent was characterized by scanning electron microscopy（SEM）, Brunauer-Emmet-Teller（BET） analysis, X-ray diffraction（XRD） analysis and X-ray pho- toelectron spectroscopy（XPS）. SEM visualization shows that the dense surface structure of raw HP appeared loose and presented micro canals after modification. The BET analysis also proved the specific surface area of La-Al-HP composite（95.58 m^2/g） was higher than that of the raw HP（34.31 m^2/g）. Subsequently, the adsorption capacity of La-Al-HP composite was demonstrated in adsorption experiments. The kinetics of fluoride ion adsorption into La-Al-HP composite followed the pseudo-second order with a correlation coefficient of 0.997. The isotherm data was well fitted with the Langmuir model. The monolayer adsorption capacity of La-Al-HP composite was 1.30 mg/g. The XRD and XPS results reveal that the La^3＋ and Al^3＋ ions were loaded on the surface of modified HP and the fluoride ion was adsorbed onto the La-Al-HP composite. A large amount of La-Al-O composite oxide existing on the surface of La-Al-HP composite might be the immanent cause for the excellent adsorption capacity of fluoride ions.

Influence of the structure and composition of Fe–Mn binary oxides on rGO on As(Ⅲ) removal from aquifers

Fe–Mn binary oxide(FMBO) possesses high efficiency for As(Ⅲ) abatement based on the good adsorption affinity of iron oxide and the oxidizing capacity of Mn(Ⅳ), and the composition and structure of FMBO play important roles in this process.To compare the removal performance and determine the optimum formula for FMBO, magnetic graphene oxide(MRGO)–FMBO and MRGO–MnO2 were synthesized with MRGO as a carrier to improve the dispersity of the adsorbents in aquifers and achieve magnetic recycling.Results indicated that MRGO–FMBO had higher As(Ⅲ) removal than that of MRGO–MnO2,although the ratios of Fe and Mn were similar, because the binary oxide of Fe and Mn facilitated electron transfer from Mn(Ⅳ) to As(Ⅲ), while the separation of Mn and Fe on MRGO–MnO2 restricted the process.The optimal stoichiometry x for MRGO–FMBO(MnxFe3-xO4) was 0.46, and an extraordinary adsorption capacity of 24.38 mg/g for As(Ⅲ) was achieved.MRGO–FMBO showed stable dispersive properties in aquifers, and exhibited excellent practicability and reusability, with a saturation magnetization of 7.6 emu/g and high conservation of magnetic properties after 5 cycles of regeneration and reuse.In addition, the presence of coexisting ions would not restrict the practical application of MRGO–FMBO in groundwater remediation.The redox reactions of As(Ⅲ) and Mn(Ⅳ) on MRGO–FMBO were also described.The deprotonated aqueous As(Ⅲ) on the surface of MRGO–FMBO transferred electrons to Mn(Ⅳ), and the formed As(Ⅴ) oxyanions were bound to ferric oxide as inner-sphere complexes by coordinating their "–OH" groups with Mn(Ⅳ)oxides at the surface of MRGO–FMBO.This work could provide new insights into highperformance removal of As(Ⅲ) in aquifers.

Preparation and Visible-light Photochromism of Phosphomolybdic Acid/Polyvinylpyrrolidone Hybrid Film

The visible-light photochromic hybrid film was constructed by entrapping phosphomolybdic acid（PMoA） into polyvinylpyrrolidone（PVPd） networks. The microstructure, photochromic properties and mechanism were inves- tigated with transmission electron microscopy（TEM）, atomic force microscopy（AFM）, Fourier transform infrared （FTIR） spectroscopy, ultraviolet-visible（UV-Vis） spectra and X-ray photoelectron spectroscopy（XPS）. The results in- dicate that the Keggin geometry of PMoA and the basic structure of PVPd are not destroyed during the composite process. Irradiated with visible light, the transparent PMoA/PVPd film changes color from colorless to blue and ex- hibits reversible photochromism in the presence of oxygen. According to the XPS analysis, the charge-transfer bridge of N-H-O has been built between PMoA and PVPd matrix via non-covalent bonding, and the appearance of Mo5＋ species indicates that the photo-reduction process is in accordance with the proton transfer mechanism.

In situ Remediation of Petroleum Contaminated Groundwater by Permeable Reactive Barrier with Hydrothermal Palygorskite as Medium

The permeable reactive barrier（PRB） has proven to be a costeffective technique to remediate the petro leum contaminated groundwater at a northeast field site in China. In this study, the geology, hydrogeology and con tamination characterization of the field site were investigated and the natural hydrothermal palygorskite was chosen as a reactive medium. Furthermore, the adsorption of the total petroleum hydrocarbons（TPH） in the groundwater onto hydrothermal palygorskite and the adsorption kinetics were investigated. The results indicate that the removal rates of TPH, benzene, naphthalene and phenantharene could all reach up to 90% by hydrothermal palygorskite with a diameter of 0.25-2.00 mm that had been thermally pretreated at 140 ℃. The adsorption of TPH onto hydrothermal palygorskite after pretreatment followed a pseudosecondorder kinetic model and a Langmuir adsorption isotherm, suggesting that the theoretic adsorption capacity of hydrothermal palygorskite for adsorbate could be 4.2 g/g. Scan ning electron microscopy（SEM）, infrared spectroscopy（IR）, Xray diffraction（XRD） and Xray fluorescence spec troscopy（XRF） were carried out to analyze the adsorption mechanism. The results reveal that hydrothermal palygors kite is a fibrous silicate mineral enriched in Mg and A1 with large surface area and porosity. The dense cluster acicular and fibrous crystal of hydrothermal palygorskite, and its effect polar group OH played an important role in the physical and chemical adsorption processes of it for contaminants. This study has demonstrated hydrothermal paly gorskite is a reliable reactive medium for in situ remediation of petroleum contaminated groundwater at field sites.

Thermodynamic Characteristics and Mechanisms of Heavy Metals Adsorbed onto Urban Soil

The thermodynamic characteristics of heavy metals adsorbed onto urban soil and the relative adsorption mechanisms were studied by the batch experiment. The results show that there existed dynamic adsorption-desorption equilibrium processes of cationic and anionic ions of heavy metals onto urban soil, which may have an impact on the pH of the adsorption system. The amounts of heavy metals adsorbed onto urban soil increased with the increase of the equilibrium concentration, but their adsorption amounts were not the maximum adsorption amounts. The higher the pH was, the greater the adsorption capacity of the urban soil at the same equilibrium concentration was, and the adsorption amounts of heavy metals onto urban soil followed the order of Pb〉Cu〉Cd〉Zn〉Ni. There were coordination reaction, hydrolysis reaction, exchange reaction in the adsorption processes of heavy metals onto urban soil. With the increase of pH, the influencing degree of pH on the different reactions of heavy metals in the soil increased, meanwhile the effects of other physicochemical properties of soil on the adsorption of heavy metals were weakened.

Micrometer-sized NiOOH hierarchical spheres for enhanced degradation of sulfadiazine via synergistic adsorption and catalytic oxidation in peroxymonosulfate system

As an antibiotic,sulfadiazine has posed a serious threat to humans and ecosystems due to its chronic toxicity.The advanced oxidation processes (AOPs) via heterogeneous catalytic activation of peroxymonosulfate (PMS) have significant potential for the degradation of antibiotics.However,there are multiple restrictions including non-specifically binding to target contaminants,which would deplete oxidation capacity,and lacking energy effectiveness due to inefficient utilization of reactive oxygen species (ROS).To overcome these obstacles,we adopted the“bait-hook&destroy”strategy in this study.Herein,we synthesized a novel micrometer-sized Ni OOH hierarchical spheres assembled from nanosheets,which have relatively large specific surface areas and yield specified cavities to“bait-hook”sulfadiazine and PMS onto the surface cavities.This process was further conductive to effective generation of ROS and subsequently“destruction”of sulfadiazine with elevated mass transformation rate.20.4%of sulfadiazine can adsorb to Ni OOH surface in less than 30 min (0.0051 min^(-1)),and then sulfadiazine was completely degraded in 90min intervals in the Ni OOH/PMS system.The degradation rate constant (k=0.0537 min^(-1)) was about5.3,2.5 and 2.2 times higher than that in Ni_(2)O_(3)/PMS,NiO/PMS and Ni(OH)_(2)/PMS system,respectively.This was ascribed to the synergistic catalytic oxidation and adsorption process occurred on the surface of Ni OOH.Appreciably,there were both non-radicals (^(1)O_(2)) and radicals (O_(2)^(·-)and SO_(4)^(·-)) involved in the Ni OOH/PMS system,and^(1)O_(2)was distinguished as the dominated ROS for degradation of sulfadiazine.This study provides a novel strategy via synergistic adsorption and catalytic oxidation,and indicates that the micrometer-sized Ni OOH hierarchical sphere as heterogeneous catalyst is an attractive candidate for potential application of the SR-AOPs technology in water treatment.

Cytotoxicity of NiO Nanoparticles and Its Conversion Inside Chiorella vulgaris

Cytotoxicities of nickel oxide nanoparticles（NiO NPs） with average diameter of 20 nln were investigated on cultured Chlorella vulgaris. Alga growth-inhibition tests were taken and ultrastrueture changes of the microalgae were characterized with transmission electron microscopy（TEM）. The biological interface conversion effect between NiO nanoparticles and Chlorella vulgaris was studied by X-ray diffraction（XRD）, high-resolution transmission elec- tron microscopy（HRTEM） and X-ray photoelectron spectroscopy（XPS）. The results indicated that the NiO nanopar- tides had severe inhibitory effect on the growth of microalgae, with a 96 h ECs0 value of 31.4 mg/L. Under the expo- sure to NiO NPs suspensions, ChloreIIa vulgaris cells showed plasmolysis with a shriveled cell shape, disrupted plas- ma membrane, leaked cytosol and disordered thylakoid grana lamella. The NiO NPs were aggregated and partially re- duced to Ni0 inside the Chlorella vulgaris. The bioaccumulation and bio-reduction ability of Chlorella vulgaris provide us with a possible strategy of remediation of aquatic pollution conducted by toxic metal oxide nanoparticles.

Hydrothermal Synthesis of a New Zinc Phosphite （CsH7N2）2·[Zn3（HPO3）4] with Intersecting 8- and 12-Ring Channels

Using 4-aminopyridine as the structure-directing agent（SDA）, a new open-framework zinc phosphite, （CsH7N2）2·[Zna（HPO3）4]（ZnHPO-CJ70）, was synthesized under hydrothermal condition. Single-crystal X-ray diffraction analysis reveals that ZnHPO-CJ70 is constructed by the strictly alternating ZnO4 tetrahedra and HPO3 pseudo-pyramids, with their vertexes linked to generate a three-dimensional（3D） open framework with intersecting 8- and 12-ring channels. Further characterizations of ZnHPO-CJ70 were performed by means of X-ray powder diffraction（XRD）, elemental analysis（ICP, CHN）, infrared spectroscopy（IR） and thermogravimetric（TG） analyses. The results of luminescent test shows that ZnI-IPO-CJ70 exhibits strong fluorescence emissions in the solid state at room temperature.

Gallic Acid/2-Hydroxypropyl-β-cyclodextrin Inclusion Complexes Electrospun Nanofibrous Webs:Fast Dissolution,Improved Aqueous Solubility and Antioxidant Property of Gallic Acid

Gallic acid(GA)is a kind of natural polyphenolic compound,but its low aqueous solubility restricts its application in the fields of food and medicine.Cyclodextrin can form inclusion complexes with guest molecules(e.g.,essential oils,food supplements)through cavities with special properties to improve aqueous solubility,thermal stability,and bioavailability of guest molecules.In this research,gallic acid/2-hydroxypropyl-β-cyclodextrin inclusion complexes(GA/2-HP-β-CD/ICs)were formed in a highly concentrated solution of 2-HP-β-CD.Bead-free and uniform nanofibrous webs(GA/2-HP-β-CD/IC-NWs)were produced successfully by electrospun GA/HP-β-CD/IC aqueous solution.The initial molar ratio(GA:2-HP-β-CD=1:1)of GA/2-HP-β-CD/IC in the solutions was largely maintained in GA/2-HP-β-CD/IC-NW.The aqueous solubility of GA was enhanced and GA/2-HP-β-CD/IC-NW has displayed fast dissolution property.Furthermore,in comparison with GA powder,GA/2-HP-β-CD/IC-NW demonstrated improved antioxidant capacity.The results suggested that GA/2-HP-β-CD/IC-NW have broad application prospects as orally fast dissolution systems for food supplements.

Optimization of multi-stage velocity gradients in a cylindrical fluidized bed flocculator

Flocculation time is conventionally believed to be proportional to the fiocculation effciency of a cylindrical fluidized bed flocculator. However, in a single-stage velocity gradient situation, the flocculation efficiency decreases when the optimal flocculation time is exceeded. A multi-stage velocity gradient was established in a cylindrical fluidized bed flocculator, based on the hydraulic classification theory. This multi-stage velocity gradient fluidized bed flocculator （MGF） created a more suitable environment for floc growth and protection, which was confirmed by the size distribution of flocs along the bed height. Correspondingly, the abatement efficiencies for Kaolin slurry and dyed wastewater treatment in the MGF were enhanced by 5-10%, and by 7-20%, respectively, compared with those in the single-stage velocity gradient fluidized bed flocculators （SGFs）. The initial bed height distribution ratio along the velocity gradients was an important factor for MGF optimization.

Visible-light Photochromism of Phosphomolybdic Acid/ZnO Composite

A novel photochromic hybrid ZnO was synthesized by doping with phosphomolybdic acid（PMoA）. It could respond to visible light and fade in color when treated with hydrogen peroxide（H2O2）. The microstlucture and photochromic properties were investigated via X-ray diffraction（XRD）, Fourier transform infrared spectroscopy（FTIR）, scanning electron microscopy（SEM）, transmission electron microscopy（TEM）, ultraviolet-visible spectroscopy（UV-Vis） and X-ray photoelectron spectroscopy（XPS）. The XRD patterns show that the prepared ZnO is pure and has a hexagonal wurtzite structure. The FTIR results demonstrate the existence of a strong interaction between PMoA and ZnO. Due to PMoA doping, the rough surface morphology of ZnO became smooth, as verified by the SEM images. The TEM images illustrate that pure ZnO exhibits a polycrystalline structure with irregular morphology PMoA was wrapped on the surface of ZnO. After visible-light irradiation, the composite changed from slight yellow to blue and returned to the original color in the presence of H2O2. The composite had good photosensitivity and photochromic reversibility. The photochromic process was in accord with photoinduced electrons transfer mechanism.

Anti-shock loading capability of a fluidized-bed flocculator

The efficiency of a fluidized-bed flocculator with 800-um particles of 1360 kg/m3 in density was studied, and the anti-shock capability of the unit was estimated for three kinds of industrial wastewater： heavy turbidity wastewater, dispersed dyeing wastewater and starch wastewater. Steady removal efficiency was contributed by the following characteristics of the flocculator： （1） the dynamic conditions, flocculation time and velocity gradient, which were stabilized at a steady level as the loading rate changed; （2） hydrodynamic characteristics, especially the considerable rise of expanded bed height with increasing superficial velocity when small and light particles were employed as the solid phase; （3） flocs growth characteristics in the fluidized bed, which caused the density and size of the flocs being maintained at a compensational relationship, resulted the stabilized settling velocity of the flocs.

Porous Organic Polymer Nanoparticles for Sensing of Unsaturated Hydrocarbons

The design and synthesis of porous organic polymers for the potential application in chemical sensors remains a huge challenge nowadays. Herein, a porous organic polymer possessing tetrazole groups（TTZ-3） was synthe-sized via simple Schiff base chemical reaction. Thermogravimetric analysis（TGA）, Fourier transform infrared spec- trometer（FTIR）, solid-state 13C cross polarization/magic angle spinning nuclear magnetic resonance（CP/MAS NMR）, transmission electron microscopies（TEM） and field-scanning electron microscopies（FE-SEM） were adopted to cha- racterize the structure and morphology in detail. Significantly, the formed polymers exhibited special detection of unsaturated hydrocarbons through fluorescence enhancement based on photoactivatable 1,3-dipolar cycloaddition reactions. Furthermore, the reaction activity of different unsaturated hydrocarbons towards the polymers was investigated. This work highlights the great potential of porous organic polymers as chemical sensors in realizing environmental pollution monitoring and reducing the incidence of disease, such as chronic obstructive pulmonary disease.

Reduced graphene oxide-nano zero value iron(rGO-nZVI) micro-electrolysis accelerating Cr(Ⅵ) removal in aquifer

Nanoscale zero-valent iron （nZVI） assembled on graphene oxide （GO） （rGO-nZVI） composites were synthesized by reduction of GO and ferrous ions with potassium borohydride, for use in Cr（VI） removal from aqueous solution. The results showed that the two-dimensional structure of GO could provide a skeleton support for Fe0, thus overcoming the bottleneck of aggregation for nZVI. Also, rGO-nZVI would form a ferric-carbon micro-electrolysis system in Cr（VI）-contaminated aquifers, enhancing and accelerating electron transfer, exhibiting high rate and capacity for Cr（VI） removal. The optimum dosage of the applied rGO-nZVI was linearly correlated with the initial Cr（VI） concentration. Characterization of rGO-nZVI before and after reaction with Cr（VI） revealed the process of Cr（VI） removal： rGO-nZVI firstly transferred electrons from Fe0 cores via their Fe（II）/Fe（III） shells to the GO sheet; there, negatively charged Cr（VI） received electrons and changed into positively charged Cr（III）, which was adsorbed by the negatively charged GO sheet, avoiding the capping and passivating of nZVI rGO-nZVI formed a good electrically conductive network, and thus had long-term electron releasing properties, which was important for groundwater remediation.

Phosphomolybdic acid-modified highly organized TiO2 nanotube arrays with rapid photochromic performance

TiO2 nanotube arrays were prepared by means of an electrochemical anodization technique in an organic electrolyte solution doped with polyvinyl pyrrolidone (PVP) and were subsequently modified with phosphomolybdic acid (PMoA) to obtain PMoA/TiO2 nanotube arrays. The microstructure and photochromic properties were investigated via X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), transmission electron microscopy (TEM), ultraviolet-visible spectroscopy (UV-vis), and X-ray photoelectron spectroscopy (XPS). The results indicated that the Keggin structure of PMoA and the nanotube structure of TiO2 were not destroyed, and there was a strong degree of interaction between PMoA and TiO2 at the biphasic interface with lattice interlacing during the compositing process. The XPS results further indicated that there was a change in the chemical microenvironment during the formation process of the composite, and a new charge transfer bridge was formed through the Mo-O-Ti bond. Under visible light irradiation, the colorless PMoA/TiO2 nanotube array quickly turned blue and exhibited a photochromic response together with reversible photochromism in the presence of H2O2. After visible light irradiation for 60s, the appearance of Mo^5+ species in the XPS spectra indicated a photoreduction process in accordance with a photoinduced electron transfer mechanism.

An innovative wood-chip-framework substrate used as slow-release carbon source to treat high-strength nitrogen wastewater

Removal of nitrogen in wastewater before discharge into receiving water courses is an important consideration in treatment systems.However,nitrogen removal efficiency is usually limited due to the low carbon/nitrogen（C/N） ratio.A common solution is to add external carbon sources,but amount of liquid is difficult to determine.Therefore,a combined wood-chip-framework substrate（with wood,slag and gravel） as a slow-release carbon source was constructed in baffled subsurface-flow constructed wetlands to overcome the problem.Results show that the removal rate of ammonia nitrogen（NH_4~＋-N）,total nitrogen（TN） and chemical oxygen demand（COD） could reach 37.5%-85%,57.4%-86%,32.4%-78%,respectively,indicating the combined substrate could diffuse sufficient oxygen for the nitrification process（slag and gravel zone） and provide carbon source for denitrification process（wood-chip zone）.The nitrification and denitrification were determined according to the location of slag/gravel and wood-chip,respectively.Nitrogen removal was efficient at the steady phase before a shock loading using slag-wood-gravel combined substrate because of nitrification-denitrification process,while nitrogen removal was efficient under a shock loading with wood-slag-gravel combined substrate because of ANAMMOX process.This study provides a new idea for wetland treatment of high-strength nitrogen wastewater.