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Xing D.Y.,Harbin Institute of Technology | Xing D.Y.,Shenzhen Key Laboratory of Water Resource Utilization and Environmental Pollution Control | Dong W.Y.,Harbin Institute of Technology | Dong W.Y.,Shenzhen Key Laboratory of Water Resource Utilization and Environmental Pollution Control | Chung T.-S.,National University of Singapore
Industrial and Engineering Chemistry Research | Year: 2016

In this work, we have examined and compared the interactions between cellulose acetate and different ionic liquids at a molecular level and explored their effects on dope rheology, hollow fiber morphology, and performance. Ionic liquid, 1-ethyl-3-methylimidazolium acetate ([EMIM]OAc), was found to interact with cellulose acetate (CA) more closely with intensive hydrogen bonds than 1-ethyl-3-methylimidazolium thiocyanate ([EMIM]SCN). Thus, the CA/[EMIM]OAc solution exhibits a more pronounced charge-ordered network than the CA/[EMIM]SCN solution. In addition, the former does not obey the Cox-Merz rule, whereas the latter obeys the rule with its shear viscosity η identical to its complex viscosity |η∗| at the equivalent shear rate and angular frequency. These dissimilar factors have contributed to an instantaneous liquid-liquid demixing and resulted in a dense outer skin surface and a porous cross-sectional structure comprising macrovoids for the CA/OAc membrane. In contrast, the CA/SCN membrane has a looser interconnected nodular structure resulting from the delayed liquid-liquid demixing. The effects of spinning conditions on membrane properties have been determined. The higher dope flow rate and take-up speed result in smaller pore size. [EMIM]OAc is a more practical solvent than [EMIM]SCN to fabricate CA hollow fibers with a broader choice of spinning parameters. The newly developed CA/OAc membranes have PWP values of 230 and 260 L/(m2 bar h) and pore sizes of 10-27 nm. This work may provide useful insights to develop polymeric membranes using ionic liquids as solvents and facilitate a greener fabrication method in the membrane industry. © 2016 American Chemical Society.


Tian F.,Harbin Institute of Technology | Zhu R.,Harbin Institute of Technology | Zhu R.,Shenzhen Key Laboratory of Water Resource Utilization and Environmental Pollution Control | He Y.,Harbin Institute of Technology | And 2 more authors.
International Journal of Hydrogen Energy | Year: 2014

A series of rare earth (RE) ions (La3+, Ce3+, Gd 3+, Er3+ or Y3+) modified ZnIn 2S4 photocatalysts (RE-ZnIn2S4) were prepared using the hydrothermal method and characterized by various analysis techniques, such as UV-Vis diffusive reflectance spectroscopy, X-ray diffraction, scanning electron microscopy, Brunauer-Emmett-Teller surface analyzer, photoluminescence spectroscopy and X-ray photoelectron spectroscopy. The results indicated that the RE element exists as the oxide RE 2O3 and their modification can reduce ZnIn 2S4 crystallite size, inhibit ZnIn2S 4 grain growth, promote ZnIn2S4 crystallite self-organization into a micro-sphere flower-like morphology, increase ZnIn 2S4 surface area and total pore volume, and bring rich defects to ZnIn2S4. The photocatalytic activities of RE-ZnIn2S4 were evaluated based on photocatalytic hydrogen production from water under visible-light irradiation and the hydrogen production efficiency increased by 46%, 53%, 61%, 69%, and 106% after adding 2.0 wt% of Y, Gd, Er, Ce and La, respectively. The relationship between the photocatalytic activity of RE-ZnIn2S4 and the RE properties was discussed. Copyright © 2014, Hydrogen Energy Publications, LLC. Published by Elsevier Ltd. All rights reserved.


Han Q.,Harbin Institute of Technology | Dong W.,Harbin Institute of Technology | Dong W.,Shenzhen Key Laboratory of Water Resource Utilization and Environmental Pollution Control | Wang H.,Harbin Institute of Technology | And 7 more authors.
Separation and Purification Technology | Year: 2013

In this study, the effects of anions on the decolorization reaction by potassium ferrate(VI) were investigated for the first time and a comparative investigation between potassium ferrate(VI) and potassium permanganate was carried out. Anions such as Cl-, SO42-, and NO3- showed favorable effects on color removal, while, CO32- and PO43- displayed inhibitory effects. The effects of the oxidant concentration, initial solution pH, dye concentration and temperature on color removal were studied, and the removal efficiencies of chemical oxygen demand (COD) and total organic carbon (TOC) were also examined. The decolorizing capacity of ferrate(VI) was better than potassium permanganate. When dye concentration was 100 mg/L, oxidants were both 150 mg/L, 100% color removal was achieved by K2FeO4 treatment while only 62.04% by KMnO4. Ferrate(VI) has stably high decolorizing efficiency up to 85% in a wide pH range from 4.0 to 9.0. However, potassium permanganate only had better efficiency under acidic solution (100% color removal at pH 3.0, while only 78.05% at pH 9.0). At the temperature of 60 °C, approximately 80% decolorizing efficiency was achieved by ferrate(VI) while potassium permanganate only 59.37%. Ferrate(VI) acquired 58.33% COD and 24.15% TOC removal while potassium permanganate only 42.86% and 9.94% respectively. The oxidizing order was that color > COD > TOC both for K2FeO4 and KMnO4.© 2013 Elsevier B.V. All rights reserved.


Han Q.,Harbin Institute of Technology | Wang H.,Harbin Institute of Technology | Wang H.,Shenzhen Key Laboratory of Water Resource Utilization and Environmental Pollution Control | Dong W.,Harbin Institute of Technology | And 4 more authors.
Separation and Purification Technology | Year: 2013

To investigate the feasibility of minimizing the bromate formation with ferrate(VI) during ozonation process, the batched experiments were carried out under several operating variables, such as ferrate(VI) dose (0-5.0 mg/L), initial bromide concentration (100-1500 μg/L), ozone concentration (1.5, 2.5 and 4.0 mg/L), pH (3.0-11.0), temperature (278 K, 298 K and 313 K) and reaction time (0-60 min). Compared with ozone oxidation, ferrate(VI)-ozone process can effectively inhibit the bromate formation. Bromate formation can be completely inhibited under the following conditions: ferrate(VI) dose of 1.0 or 2.0 mg/L, [O3] ≤ 2.5 mg/L, [Br-] ≤ 200 μg/L, pH ≤ 9.0 and temperature ≤ 313 K. The inhibiting mechanism took effect by the produced intermediates of ferrate(VI), such as Fe(III), Fe(II), H2O 2 and the hydroxides of Fe(III), which had reduction or flocculation effects on BrO3- or HBrO/BrO- that resulted in less bromate formation, and it was further proved by the effect of radical scavenger (t-BuOH). The pH effect study revealed that ferrate(VI) could depress the concentration of bromate below the drinking water standard (10 μg/L) in the wide pH range of 3.0-11.0. High ambient temperature also showed a positive effect on the inhibition of bromate formation in ferrate(VI)-ozone process. © 2013 Published by Elsevier B.V.


Han Q.,Harbin Institute of Technology | Wang H.,Harbin Institute of Technology | Wang H.,Shenzhen Key Laboratory of Water Resource Utilization and Environmental Pollution Control | Dong W.,Harbin Institute of Technology | And 4 more authors.
Chemical Engineering Journal | Year: 2014

A series of batch experiments were conducted to investigate the effects of ferrate(VI) on bromate formation in a ferrate(VI)-ozone oxidation system under different conditions with varying ozone dosage (1.5-4.0. mg/L), initial bromide concentration (100-1500. μg/L), temperature (5-40. °C), alkalinity (25-250. mg/L) and NOM (0.1-10. mg/L) content of water being treated. The range of ferrate(VI) dosage used was 0-5.0. mg/L. Comparisons with other methods capable of controlling bromate formation (e.g. suppression of pH, addition of ammonia, as well as other ozone-based technologies) were also made. Compared with sole ozonation process, the addition of ferrate(VI) was demonstrated an effective suppression of bromate formation in ferrate(VI)-ozone oxidation process. The required ferrate(VI) dosage to achieve 100% diminishing of bromate formation was 2.0. mg/L, at the conditions of ozone dosage ≤2.5. mg/L, initial bromide concentration ≤200. μg/L, pH. ≤. 9.0 and temperature ≤40. °C. The possible mechanisms responsible for the diminished bromate formation in the ferrate(VI)-ozone oxidation process were speculated to be the combined effects induced by the ferrate(VI) intermediates, such as low valent Fe species and hydrogen peroxide. The additional cost for treating per ton bromide bearing water was only 0.0003-0.006 $ at ferrate(VI) dosage of 0.1-2.0. mg/L. © 2013 Elsevier B.V.


Li T.,Harbin Institute of Technology | Wang H.,Harbin Institute of Technology | Wang H.,Shenzhen Key Laboratory of Water Resource Utilization and Environmental Pollution Control | Dong W.,Harbin Institute of Technology | And 6 more authors.
Chemical Engineering Journal | Year: 2014

A coagulant dosed pre-anoxic activated sludge reactor is proposed to configure prior to the BAF reactor to reduce the contents of phosphorus and suspend solids in wastewater, efficiently utilize the carbon source for denitrification, and avoid the problems caused by direct addition of coagulant into BAF reactor. A series of laboratory experiments were carried out to examine the feasibility and suitability of using Fe(II) as a coagulant. The performance on phosphorus removal and dinitrification, the determination of an optimal Fe(II), and any adverse effect brought by dosing Fe(II) are of interests. Base on the results of the continuously operated experiment, it was observed that dosing Fe(II) in the proposed pre-anoxic reactor demonstrated fair effectiveness in phosphorous removal and simultaneous denitrification. Enhanced denitrification efficiency was observed in the presence of Fe(II), probably resulting from the increased returned sludge amount and the promoted denitrification related to microbial Fe(II)-dependent nitrate reduction after dosing Fe(II). Overdosing Fe(II) would however result in suppressed TSS, TCOD and TP removal in the settling tank effluent due to the formation of fine microbial flocs. A Fe(II) dose with Fe:P molar ratio of 2-2.2:1 was selected as an optimal dose, which showed good performance in phosphorus removal, denitrification, and COD reduction, as well as, avoided the adverse effects caused by Fe(II) overdosing. Besides enhancing wastewater treatment in pre-anoxic reactor, dosing Fe(II) also improved sludge sedimentation and dewaterability, which were beneficial for the subsequent operation of dealing with excessive sludge. © 2014 Elsevier B.V.


Lv X.-M.,Harbin Institute of Technology | Lv X.-M.,Shenzhen Key Laboratory of Water Resource Utilization and Environmental Pollution Control | Shao M.-F.,Harbin Institute of Technology | Shao M.-F.,Shenzhen Key Laboratory of Water Resource Utilization and Environmental Pollution Control | And 8 more authors.
Microbes and Environments | Year: 2014

Denitrifying phosphorus removal is an attractive wastewater treatment process due to its reduced carbon source demand and sludge minimization potential. Two lab-scale sequencing batch reactors (SBRs) were operated in alternating anaerobic-anoxic (A-A) or anaerobic-oxic (A-O) conditions to achieve denitrifying enhanced biological phosphate removal (EBPR) and traditional EBPR. No significant differences were observed in phosphorus removal efficiencies between A-A SBR and A-O SBR, with phosphorus removal rates being 87.9% and 89.0% respectively. The community structures in denitrifying and traditional EBPR processes were evaluated by high-throughput sequencing of the PCR-amplified partial 16S rRNA genes from each sludge. The results obtained showed that the bacterial community was more diverse in A-O sludge than in A-A sludge. Taxonomy and β-diversity analyses indicated that a significant shift occurred in the dominant microbial community in A-A sludge compared with the seed sludge during the whole acclimation phase, while a slight fluctuation was observed in the abundance of the major taxonomies in A-O sludge. One Dechloromonas-related OTU outside the 4 known Candidatus “Accumulibacter” clades was detected as the main OTU in A-A sludge at the stationary operation, while Candidatus “Accumulibacter” dominated in A-O sludge. © 2014 Microbes Environ. All rights reserved.


Wang H.,Harbin Institute of Technology | Wang H.,Shenzhen Key Laboratory of Water Resource Utilization and Environmental Pollution Control | Dong W.,Harbin Institute of Technology | Dong W.,Shenzhen Key Laboratory of Water Resource Utilization and Environmental Pollution Control | And 3 more authors.
Bioresource Technology | Year: 2014

A series of laboratory-scale experiments for examining the feasibility and suitability of using Fe2+ as the precipitant dosed in the pre-denitrification stage of a modified BAF process employing simultaneous chemical precipitation of TSS and phosphorus were carried out. The effects of dosing Fe2+ on effluent quality and sludge characteristics of the pre-denitrification stage were assessed with comparing to the cases of no additional chemical dosing and dosing Fe3+. Results obtained demonstrated a sound performance of synergistic denitrification and chemical precipitation in pre-denitrification of the modified BAF process when dosing Fe salts, which showed enhanced by using Fe2+ as the dosed precipitant in increasing the denitrification loading rate, exhibiting a better controlling of the residual phosphorus in pre-denitrification effluent, and improving sludge settleability. Dosing Fe salt showed no adverse impact in removing COD, but resulted in a relatively higher SS content in the pre-denitrification effluent. © 2013 Elsevier Ltd.


Xia X.,Harbin Institute of Technology | Shao M.-F.,Harbin Institute of Technology | Shao M.-F.,Shenzhen Key Laboratory of Water Resource Utilization and Environmental Pollution Control | Lyu X.-M.,Harbin Institute of Technology | And 3 more authors.
Research of Environmental Sciences | Year: 2014

In the present study, denitrifying phosphorus removal sludges with acetate, glycerol and propionate as the sole carbon sources were acclimatized in three sequencing reactors (SBRs) operated under strict anaerobic-anoxic conditions, and the sludges with different carbon sources were systematically investigated by high-throughput sequencing. Stable operation showed that propionate was the optimal carbon source, followed by acetate and glycerol, with average effluent phosphorus concentrations of 0.29, 0.79 and 0.98 mg/L, corresponding to removal rates of 93.4%, 82.5% and 79.2%, respectively. The seed sludge from WWTP had the richest microbial diversity, followed by sludge fed with glycerol, acetate and propionate. Moreover, the two Volatile Fatty Acids (VFAs) feeding sludge (acetate and propionate) exhibited similar bacterial diversity and community structure. At the class level, β-Proteobacteria was most abundant for all the sludge samples. At the order level, Rhodocyclales that most phosphorus removal bacteria belonged to was the most dominant order for the samples from SBRs. Sequence local BLAST (Basic Local Alignment Search Tool) showed that the Ca. Accumulibacter-like PAO abundances of sludge with propionate, acetate and glycerol as carbon sources were 41.5%, 9.5% and 8.0% respectively during the stable operation; propionate feeding sludge had the highest abundance. Compared with acetate and glycerol, propionate showed priority for the enrichment of phosphorus removing bacteria in anaerobic-anoxic system, and the best carbon source for the EBPR.


Lv X.,Harbin Institute of Technology | Shao M.,Harbin Institute of Technology | Shao M.,Shenzhen Key Laboratory of Water Resource Utilization and Environmental Pollution Control | Li C.,Harbin Institute of Technology | And 6 more authors.
Journal of Industrial Microbiology and Biotechnology | Year: 2014

Operation performances of phosphorus removal sludge with different electron acceptors in three parallel SBRs were firstly compared in the present study, and the effect of post-aeration on denitrifying phosphorus removal was also studied. Moreover, community dynamics of different phosphorus removal sludge was systematically investigated with high-throughput sequencing for the first time. TP removal rates for nitrate-, nitrite-, and oxygen-based phosphorus removal sludge were 84.8, 78.5, and 87.4 %, with an average effluent TP concentration of 0.758, 0.931, and 0.632 mg/l. The average specific phosphorus release and uptake rates were 20.3, 10.8, and 21.5, and 9.43, 8.68, and 10.8 mgP/(gVSS h), respectively. Moreover, electron utilization efficiency of denitrifying phosphorus removal sludge with nitrate as electron acceptor was higher than nitrite, with P/e- were 2.21 and 1.51 mol-P/mol-e-, respectively. With the assistance of post-aeration for nitrate-based denitrifying phosphorus removal sludge, settling ability could be improved, with SVI decreased from 120 to 80 and 72 ml/g when post-aeration time was 0, 10, and 30 min, respectively. Moreover, further phosphorus removal could be achieved during post-aeration with increased aeration time. However, the anoxic phosphorus uptake was deteriorated, which was likely a result of shifted microbial community structure. Post-aeration of approximately 10 min was proposed for denitrifying phosphorus removal. Nitrate- and nitrite-based denitrifying phosphorus removal sludge exhibited similar community structure. More phosphorus accumulating organisms were enriched under anaerobic-aerobic conditions, while anaerobic-anoxic conditions were favorable for suppressing glycogen-accumulating organisms. Significant differences in pathogenic bacterial community profiles revealed in the current study indicated the potential public health hazards of non-aeration activated sludge system. © 2014 Society for Industrial Microbiology and Biotechnology.

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