Immobilization of Functionalized Ionic Liquid on Sol-Gel Derived Silica for Efficient Removal of H_2S

An innovative approach to H2 S capture has been developed using several metal-based ionic liquids([Bmim]Cl·CuCl_2, [Bmim]Cl·FeCl_3, [Bmim]Cl·ZnCl_2, [Bmim]Br·CuCl_2, and [Bmim]Br·FeCl_3) immobilized on the sol-gel derived silica, which is superior to purely viscous ionic liquid with a crucial limit of high temperature, low mass transfer rate,and mass loss. The adsorbents were characterized by the Fourier transform infrared spectrometer, transmission electron microscope, N_2 adsorption/desorption, X-ray photoelectron spectroscopy, and thermal analysis techniques. The effects of the metal and halogen in IL, the loading amount of IL, and the adsorption temperature were studied by dynamic adsorption experiments at a gas flow rate of 100 mL/min. The H2 S adsorption results have showed that the optimal adsorbent and adsorption temperature are 5% [Bmim]Cl·CuCl_2/silica gel and 20—50 ℃, respectively. H_2 S can be captured and oxidized to elemental sulfur, and [Bmim]Cl·CuCl_2/silica gel can be readily regenerated by air. The excellent efficiency of H2 S removal may be attributed to the formation of nano-scaled and high-concentration [Bmim]Cl·CuCl_2 confined in silica gel, indicating that the immobilization of [Bmim]Cl·CuCl_2 on the sol-gel derived silica can be used for H2 S removal promisingly.

Using NH_(2)-MIL-125(Ti)for efficient removal of Cr(Ⅵ)and Rh B from aqueous solutions:Competitive and cooperative behavior in the binary system

The coexistence of inorganic and organic contaminants is a challenge for real-life water treatment applications.Therefore,in this research,we used NH_2-MIL-125(Ti)to evaluate the single adsorption of hexavalent chromium(Cr(Ⅵ))or Rhodamine B(RhB)in an aqueous solution and further investigate simultaneous adsorption experiments to compare the adsorption behavior changes.The main influencing factors,for example,reaction time,initial concentration,reaction temperature,and pH were studied in detail.In all reaction systems,the pseudo-second-order kinetic and Langmuir isotherm models were well illuminated the adsorption progress of Cr(Ⅵ)and RhB.Thermodynamic studies showed that the adsorption process was spontaneous and endothermic.As compared to the single system,the adsorption capacity of Cr(Ⅵ)in the binary system gradually decreased as the additive amount of RhB increased,whereas the adsorption capacity of RhB in the binary system was expanded brilliantly.When the binary reaction system contained 100 mg/L Cr(Ⅵ),the removal rate of RhB increased to 97.58%.The formation of Cr(Ⅵ)-RhB and Cr(Ⅲ)-RhB complexes was the cause that provided facilitation for the adsorption of RhB.These findings prove that the interactions during the water treatment process between contaminants may obtain additional benefits,contributing to a better adsorption capacity of co-existing contaminant.

Insights into sludge granulation during anaerobic treatment of high-strength leachate via a full-scale IC reactor with external circulation system

In this study, a full-scale internal circulation（IC） reactor coupled with an external circulation system was developed to treat high-strength leachate from a municipal solid waste（MSW）incineration plant, in which anaerobic sludge granulation was intensively investigated. Results showed that the IC reactor achieved excellent treatment performance under high organic loading rates（OLR） of 21.06–25.16 kg chemical oxygen demand（COD）/（m3？ day）. The COD removal efficiency and biogas yield respectively reached 89.4%–93.4% and 0.42–0.50 m3/kg COD.The formation of extracellular polymeric substances（EPS） was closely associated with sludge granulation. Protein was the dominant component in sludge EPS, and its content was remarkably increased from 21.6 to 99.7 mg/g Volatile Suspended Solid（VSS） during the reactor operation. The sludge Zeta potential and hydrophobicity positively correlated with the protein/polysaccharide ratio in EPS, and they were respectively increased from-26.2 m V and 30.35% to-10.6 m V and 78.67%, which was beneficial to microbial aggregation. Three-dimensional fluorescence spectroscopy（3 D-EEM） and Fourier transform infrared spectroscopy（FT-IR）analysis further indicated the importance of protein-like EPS substances in the sludge granulation. Moreover, it was also found that the secondary structures of EPS proteins varied during the reactor operation.

Carbonaceous and nitrogenous disinfection byproduct precursor variation during the reversed anaerobic–anoxic–oxic process of a sewage treatment plant

Disinfection byproduct（DBP）precursors in wastewater during the reversed anaerobic–anoxic–oxic（A^2/O）process,as well as their molecular weight（MW）and polarity-based fractions,were characterized with UV scanning,fluorescence excitation emission matrix,Fourier transform infrared and nuclear magnetic resonance spectroscopy.Their DBP formation potentials（DBPFPs）after chlorination were further tested.Results indicated that the reversed A^2/O process could not only effectively remove the dissolved organic carbon（DOC）and dissolved total nitrogen in the wastewater,but also affect the MW distribution and hydrophilic–hydrophobic properties of dissolved organic matter（DOM）.The accumulation of low MW and hydrophobic（HPO）DOM was possibly due to the formation of soluble microbial product-like（SMP-like）matters in the reversed A^2/O treatment,especially in the anoxic and aerobic processes.Moreover,DOM in the wastewater displayed a high carbonaceous disinfection byproduct formation potential（C-DBPFP）in the fractions of MW100 k Da and MW5 k Da,and revealed an increasing tendency of nitrogenous disinfection byproduct formation potential（N-DBPFP）with decrease of MW.For polarity-based fractions,the HPO fraction of wastewater showed significantly higher C-DBPFP and N-DBPFP than hydrophilic and transphilic fractions.Therefore,although the reversed A^2/O process could remove most DBP precursors by DOC reduction,it led to the enhancement of DBPFP with the formation and accumulation of low MW and HPO DOM.In addition,strong correlations between C-DBPFPs and SUVA,and between N-DBPFPs and DON/DOC,were observed in the wastewater,which might be helpful for DBPFP prediction in wastewater and reclaimed water chlorination.

高负荷厌氧氨氧化反应器性能、微生物结构和过程动力学特性研究

本文研究了上流式厌氧污泥床(UASB)中厌氧氨氧化工艺的脱氮性能、污泥性状、微生物群落结构以及过程动力学特性。首先,通过缩短水力停留时间并提高进水基质浓度,研究了负荷提升过程中UASB反应器的脱氮性能,并最终将反应器的总氮去除速率(NRR)提高到15.77kg/(m3·d),富集了成熟的厌氧氨氧化颗粒污泥。其次,选用3种基质去除动力学模型对反应器稳态运行时期的数据进行了拟合,其中Stover-Kincannon模型的结果表明UASB的最大基质利用速率(Umax)可达55.68 kg/(m3·d)。此外,微生物群落结构分析的结果表明反应器在长期高负荷运行后,占主导地位的脱氮细菌为'Candidatus Kuenenia'属。随着脱氮性能的提高,其相对丰度由12.29%提高到了36.95%,颗粒污泥内的厌氧氨氧化优势菌属的组成也发生了改变。

Fabrication of novel thin-film composite membrane based on ultrathin metal-organic framework interlayer for enhancing forward osmosis performance

To improve operation efficiency,an interlayered thin-film composite forward osmosis(iTFC-FO)membrane was designed by introducing an ultrathin and porous interlayer based on aluminum tetra-(4-carboxyphenyl)porphyrin(a stable metal-organic framework nanosheet,Al-MOF).Surface characterization results revealed that Al-MoF spread evenly in the macro-porous substrate,and provided a flat and smooth reaction interface with moderate hydrophilicity and uniform small aperture.The resultant polyamide(PA)layer had a thin base(without intrusion into substrate)and crumpled surface(with abundant leaves).The leaves size and cross-linking degree of PA layer firstly increased and then decreased with the Al-MOF loading.Compared to the original membrane,the iTFC-FO showed an enhanced water permeability and a reduced reverse sodium flux in both modes of active layer facing feed solution(ALFS)and active layer facing draw solution(AL-DS).To be specific,the specific reverse sodium flux(reverse sodium flux/pure water flux)decreased from 0.27 g/L to 0.04 g/L in the AL-FS mode,while from 1.36 g/L to 0.23 g/L in the AL-DS mode with 2 mol/L NaCl as DS.Moreover,the iTFC-FO maintained high stability and high permeability under high-salinity and contaminated environment.This study offers a new possibility for the rational fabrication of high-performance TFC-FO membranes.

Effect of preparation methods on the performance of CuFe-SSZ-13 catalysts for selective catalytic reduction of NO_x with NH_3

CuFe-SSZ-13 catalyst showed excellent performance in the selective catalytic reduction of NO_x with NH_3(NH_3-SCR) for diesel engine exhaust purification. To investigate the effect of preparation methods on NH_3-SCR performance, Fe was loaded into one-pot synthesized Cu-SSZ-13 catalysts through solid-state ion-exchange(SSIE), homogeneous deposition precipitation(HDP) and liquid ion-exchange(IE), respectively. Three CuFe-SSZ-13 catalysts showed similar SO_2 resistance, which was better than that of Cu-SSZ-13. The improvement was attributed to the protection of Fe species. Hydrothermal stability of three CuFe-SSZ-13 catalysts was significantly different, which was attributed to the state of active species caused by different preparation methods. Compared with the other two catalysts, more active species existed inside the zeolite pores of CuFe-SSZ-13 SSIE. During hydrothermal aging, the aggregation of these active species in the pores caused the collapse of catalyst structure, ultimately leading to the deactivation of CuFe-SSZ-13 SSIE. In contrast, Fe species was dispersed better on the surface over CuFe-SSZ-13 IE, enhancing the hydrothermal stability of catalysts. Consequently, Fe loading effectively improved the resistance of SO_2 and H_2O over Cu-SSZ-13. For CuFe-SSZ-13, large amounts of active species located inside the zeolite pores are not beneficial for the hydrothermal stability.

Insight into the distribution of metallic elements in membrane bioreactor: Influence of operational temperature and role of extracellular polymeric substances

The distribution of metallic elements in a submerged membrane bioreactor(MBR) was revealed at different temperatures using inductively coupled plasma-optical emission spectrometry(ICP-OES), and the role of extracellular polymeric substances(EPS) was probed by integrating scanning electron microscopy(SEM) with confocal laser scanning microscopy(CLSM) over long-term operation. More metallic elements in the influent were captured by suspended sludge and built up in the fouling layer at lower temperature. The concentration of metallic elements in the effluent was 5.60 mg/L at 10°C operational temperature, far lower than that in the influent(51.35 mg/L). The total contents of metallic elements in suspended sludge and the membrane fouling layer increased to 40.20 and 52.19 mg/g at 10°C compared to 35.14 and 32.45 mg/g at 30°C, and were dominated by the organically bound fraction. The EPS contents in suspended sludge and membrane fouling layer sharply increased to 37.88 and 101.51 mg/g at 10°C, compared to 16.87 and 30.03 mg/g at 30°C. The increase in EPS content at lower temperature was responsible for the deposition of more metallic ions. The strong bridging between EPS and metallic elements at lower temperature enhanced the compactness of the fouling layer and further decreased membrane flux. This was helpful for understanding the mechanism of membrane fouling at different operational temperatures and the role of EPS, and also of significance for the design of cleaning strategies for fouled membranes after long-term operation.

Fate of proteins of waste activated sludge during thermal alkali pretreatment in terms of sludge protein recovery

Proteins are the major organic component s of waste activated sludge(WAS);the recovery of sludge proteins is economically valuable.To efficiently recover sludge proteins,WAS should undergo hydrolysis pretreatment to fully release proteins from sludge flocs and microbial cells into aqueous phase.One of the most widely used chemical methods for that is thermal alkali hydrolysis(TAH).Here,the soluble protein concentration achieved the highest level over 90 min of TAH pretreatment at 80°C;the sludge floc disintegration and microbial cell destruction were maximized according to the content profiles of bound extracellular polymeric substance(EPS)and ribonucleic acid(RNA)of sludge.Both less proteins broken down to materials with small molecular weight and less melanoidin generated were responsible.TAH pretreatment at 80°C for 90 min resulted in the solubilization of 67.59% of sludge proteins.34.64% of solubilized proteins was present in soluble high molecular;1.55% and 4.85% broke down to polypeptides and amino acids.The lost proteins via being converted to ammonium and nitrate nitrogen accounted for 9.44% of solubilized proteins.It was important to understand the fate of sludge proteins during TAH pretreatment in terms of protein recovery,which would be helpful for designing the downstream protein separation method and its potential application.

Characteristic and correlation analysis of influent and energy consumption of wastewater treatment plants in Taihu Basin

The water quality and energy consumption of wastewater treatment plants(WWTPs)in Taihu Basin were evaluated on the basis of the operation data from 204 municipal WWTPs in the basin by using various statistical methods.The influent ammonia nitrogen(NH3-N)and total nitrogen(TN)of WWTPs in Taihu Basin showed normal distribution,whereas chemical oxygen demand(COD),biochemical oxygen demand(BOD5),suspended solid(SS),and total phosphorus(TP)showed positively skewed distribution.The influent BOD5/COD was 0.4%-0.6%,only 39.2%SS/BOD5 exceeded the standard by 36.3%,the average BOD5/TN was 3.82,and the probability of influent BOD5/TP>20 was 82.8%.The average energy consumption of WWTPs in Taihu Basin in 2017 was 0.458 kWh/m^3.The specific energy consumption of WWTPs with a daily treatment capacity of more than 5×10^4 m^3 in Taihu Basin was stable at 0.33 kWh/m^3.A power function relationship was observed between the reduction in COD and NH3-N and the specific energy consumption of pollutant reduction,and the higher the pollutant reduction is,the lower the specific energy consumption of pollutant reduction presents.In addition,a linear relationship existed between the energy consumption of WWTPs and the specific energy consumption of influent volume and pollutant reduction.Therefore,upgrading and operation with less energy consumption of WWTPs is imperative and the suggestions for Taihu WWTPs based on stringent discharge standard are proposed in detail.

Analysis of the simultaneous adsorption mechanism of ammonium and phosphate on magnesium-modified biochar and the slow release effect of fertiliser

To decrease the eutrophication caused by nitrogen(N)and phosphorus(P)in water,magnesium-modified corn stalk biochar(MgB)was prepared under the synergistic impact of the multi-pyrolysis temperatures and Mg^(2+)contents for the co-adsorption of ammonium(NH_(4)^(+)-N)and phosphate(PO_(4)^(3−)).The co-adsorption mechanism,slow-release performance and plant application of MgB were systematically studied.The results showed that pyrolysis temperatures(350-650℃)and Mg^(2+)(0-3.6 g/L)contents not only altered the physicochemical properties of biochar,but also significantly affected the adsorption efficacy of MgB.The adsorption of NH_(4)^(+)-N and PO_(4)^(3−)was in accordance with Langmuir-Freundlich and pseudo-second-order kinetic models(Q_(max)=37.72 and 73.29 mg/g,respectively).Based on the characteristics,adsorption kinetics and isotherms results,the adsorption mechanism was determined and found to mainly involve struvite precipitation,ion exchange,and surface precipitation or electrostatic attraction.Compared with the leaching performance of chemical fertilizers(CF),after adsorption of NH_(4)^(+)-N and PO_(4)^(3−)(MgB-A),MgB had a more stable pH and lower conductivity.Leaching of NH_(4)^(+)-N and PO_(4)^(3−)by MgB-A was controlled by both the diffusion mechanism and the dissolution rate of struvite and Mg-P.The excel-lent long-term slow-release performance and abundant Mg^(2+)of MgB-A promoted the growth of Zea mays L.and Lolium perenne L.Overall,this study suggested that MgB could realize a win-win outcome of struvite biochar-based fertiliser production and wastewater treatment.

Occurrence and risk assessment of typical PPCPs and biodegradation pathway of ribavirin in wastewater treatment plants

A large number of pharmaceuticals and personal care products(PPCPs)persist in wastewater,and the consumption of PPCPs for COVID-19 control and prevention has sharply increased during the pandemic.This study investigated the occurrence,removal efficiency,and risk assessment of six typical PPCPs commonly used in China in two wastewater treatment plants(WWTPs).Ribavirin(RBV)is an effective pharmaceutical for severely ill patients with COVID-19,and the possible biodegradation pathway of RBV by activated sludge was discovered.The experimental results showed that PPCPs were detected in two WWTPs with a detection rate of 100%and concentrations ranging between 612 and 2323 ng L^(-1).The detection frequency and concentrations of RBV were substantially higher,with a maximum concentration of 314 ng L^(-1).Relatively high pollution loads were found for the following PPCPs from influent:ibuprofen>ranitidine hydrochloride>RBV>ampicillin sodium>clozapine>sulfamethoxazole.The removal efficiency of PPCPs was closely related to adsorption and biodegradation in activated sludge,and the moving bed biofilm reactor(MBBR)had a higher removal capacity than the anoxic-anaerobic-anoxicoxic(AAAO)process.The removal efficiencies of sulfamethoxazole,ampicillin sodium,ibuprofen,and clozapine ranged from 92.21%to 97.86%in MBBR process and were relatively low,from 61.82%to 97.62%in AAAO process,and the removal of RBV and ranitidine hydrochloride were lower than 42.96%in both MBBR and AAAO processes.The discrepancy in removal efficiency is caused by temperature,hydrophilicity,and hydrophobicity of the compound,and acidity and alkalinity.The transformation products of RBV in activated sludge were detected and identified,and the biodegradation process of RBV could be speculated as follows:first breaks into TCONH_(2) and an oxygen-containing five-membered heterocyclic ring under the nucleosidase reaction,and then TCONH_(2) is finally formed into TCOOH through amide hydrolysis.Aquatic ecological risks based on risk quotient(RQ)assessment showed that PPCPs had high and medium risks in the influent,and the RQ values were all reduced after MBBR and AAAO treatment.Ranitidine hydrochloride and clozapine still showed high and medium risks in the effluent,respectively,and thus presented potential risks to the aquatic ecosystem.

Preparation of electrically enhanced forward osmosis(FO)membrane by two-dimensional MXenes for organic fouling mitigation

In this work,a conductive thin film composite forward osmosis(TFC-FO)membrane was firstly prepared via vacuum filtering MXenes nanolayer on the outer surface of polyethersulfone membrane followed by interfacial polymerization in the other side.Moreover,its feasibility of mitigating organic fouling under electric field was evaluated.Results indicated that the addition of MXenes greatly reduced the electric resistance of membrane from 2.1×10^(12)Ωto 46.8Ω,enhanced the membrane porosity and promoted the membrane performance in terms of the ratio of water flux to reverse salt flux.The modified TFC-FO membrane presented the optimal performance with 0.47 g/m^(2)loading amount of MXenes.Organic fouling experiments using sodium alginate(SA)and bovine serum albumin(BSA)as representative demonstrated that the introduction of MXenes could effectively enhance the anti-fouling ability of TFC-FO membrane under the electric field of 2 V.The interelectron repulsion hindered organic foulants attaching into membrane surface and thus effectively alleviated the membrane fouling.More importantly,the modified TFC-FO membrane showed good stability during the fouling experiment of 10 h.In all,our work proved that introducing MXenes into the porous layer of support is feasible to alleviate organic fouling of FO membrane.

Distribution,characteristics and daily fluctuations of microplastics throughout wastewater treatment plants with mixed domestic-industrial influents in Wuxi City,China

In wastewater treatment plants(WWTPs),microplastics(MPs)are complex,especially with mixed domestic–industrial influents.Conventional random grab sampling can roughly depict the distribution and characteristics of MPs but can not accurately reflect their daily fluctuations.In this study,the concentration,shape,polymer type,size,and color of MPs were analyzed by micro-Raman spectroscopy(detection limit of 0.05 mm)throughout treatment stages of three mixed domestic–industrial WWTPs(W1,W2,and W3)in Wuxi City,China,and the daily fluctuations of MPs were also obtained by dense grab sampling within 24 h.For influent samples,the average MP concentration of 392.2 items/L in W1 with 10%industrial wastewater was much higher than those in W2(71.2 items/L with 10%industrial wastewater)and W3(38.3 items/L with 60%industrial wastewater).White polyethylene granules with a diameter less than 0.5 mm from plastic manufacturing were the most dominant MPs in the influent of W1,proving the key role of industrial sources in MPs pollution.In addition,the daily dense sampling results showed that MP concentration in W1 influent fluctuated widely between 29.1 items/L and 4617.6 items/L within a day.Finally,few MPs(less than 4.0 items/L)in these WWTPs effluents were attributed to the effective removal of wastewater treatment processes.Thus,further attention should be paid to regulating the primary sources of MPs.

Determination of Aroclor 1254 in Water Samples Using Polystyrene-Divinylbenzene Solid-Phase Extraction and Gas Chromatography

A method was developed for the determination of Aroclor 1254 in water samples using polystyrene-divinylbenzene(PS-DVB)solid-phase extraction(SPE)and gas chromatography(GC).The PS-DVB sorbent demonstrated good recoveries of Aroclor 1254 when sulfuric acid(1:1,v:v)was added to the samples.Sample quantification was performed using gas chroma-tography with a parallel column and dual electron capture detector.Factors in extraction method procedures were optimized,including sample pH,elution solvent,eluting volume and breakthrough volume.With the 1000 ml sample acidified to pH 1.0,a 6.0 ml n-hexane/ethyl acetate(1:1,v:v)elution solvent,and gas chromatographic determination,the recoveries of Aroclor 1254 in spiked water samples ranged from 90.6 to 104%.Across testing days,repeatability ranged from 4.7 to 7.6%.The method detection limit was 0.053μg/L.PS-DVB exhibited a broader pH stability range,satisfactory recoveries,and good repeatability for Aroclor 1254 extraction.The results indicate that these methods can be used to analyze trace amounts of Aroclor 1254,and represent a new analytical approach for determining polychlorinated biphenyls in water samples.

Photocatalytic thin film composite forward osmosis membrane for mitigating organic fouling in active layer facing draw solution mode

As a high-flux operation mode of thin film composite-forward osmosis(TFC-FO)membrane,active layer facing draw solution(AL-DS)mode suffers from the severe membrane fouling tendency,which is not addressed well.Here,we introduced a photocatalyst(Anatase titanium dioxide,A-TiO_(2))onto the support layer of TFC-FO membrane via the bonding of polydopamine(PDA)and polytetrafluoroethylene(PTFE),and prepared two photocatalytic membranes,A-TiO_(2)/PDA@TFC and A-TiO_(2)/PTFE@TFC.Compared with the pristine TFC-FO membrane,both A-Ti O_(2)/PDA@TFC and A-TiO_(2)/PTFE@TFC had an improved water permeability(10.5 L m^(-2)h^(-1)and 9.5 L m^(-2)h^(-1),respectively)and reduced reverse Na Cl flux salt(0.8 g m^(-2)h^(-1)and 0.7 g m^(-2)h^(-1),respectively)in the AL-DS mode using 1 mol/L Na Cl as draw solution and pure water as feed solution.Moreover,in the 16 h fouling experiment using 200 ppm bovine serum albumin(BSA)solution as a representative pollutant,the flux decline rate of both photocatalytic membranes was dramatically alleviated from 39.7%and 21.7%in the darkness to 8.5%and 9.7%under UV irradiation,respectively,indicating a significant anti-fouling capacity of photocatalytic effect.In all,the presence of A-TiO_(2)endowed membrane with high permeability,high rejection efficiency and excellent anti-fouling capacity under UV spotlight.As bonding agent,PTFE provided the modified membrane with a high photocatalytic effect and high self-cleaning capacity,while PDA increased the membrane permeability and protected membrane against photocatalytic damage.This work provides a simple and feasible method to improve the anti-fouling capacity of TFC-FO membrane in AL-DS mode.

Simultaneously recovering electricity and water from wastewater by osmotic microbial fuel cells： Performance and membrane fouling

Since the concept of the osmotic microbial lhcl ceil （OsMFC） was introduced in 2011, it has attracted growing interests for its potential applications in wastewater treatment and energy recovery. However, lbrward osmosis （FO） membrane fouling resulting in a severe water flux decline remains a main obstacle. Until now, the lbuling mechanisms of FO membrane especially the development of biofouling layer in the OsMFC are not yet clear. Here, the fouling behavior of FO membrane in OsMFCs was systematically investigated. The results indicated that a thick fouling layer including biofouling and inorganic fouling was existed on the FO membrane sur｜hce. Compared to the inorganic fouling, the biofouling played a more important role in the development of the fouling layer. Further analyses by the confocal laser scanning microscopy （CLSM） implied that the growth of biofouling layer oll the FO membrane surface in the OsMFC could be divided into three stages. Initially, microorganisms associated with β-D-glucopyranose polysaccharides were deposited on the FO membrane surface. After that, the microorganisms grew into a biofilm caused a quick decrease of water flux. Subsequently, some of microorganisms were dead due to lack of nutrient source, in the meantime, polysaccharidc and proteins in the biofotiling layer werc decomposed as nutrient source, thus leading to a slow development of the biofouling layer. Moreover, the microorganisms played a significant role in the fon＇nation and development of the biotbuling layer, and further studies are needed to mitigate the deposition of microorganisms on FO membrane surfaces in OsMFCs.