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Baoyu Gao - One of the best experts on this subject based on the ideXlab platform.

  • application of enteromorpha polysaccharides as Coagulant Aid in the simultaneous removal of cuo nanoparticles and cu2 effect of humic acid concentration
    Chemosphere, 2018
    Co-Authors: Yuanxia Luo, Baoyu Gao, Qinyan Yue
    Abstract:

    Humic acid (HA) influences the aggregation and stability of nanoparticles (NPs), which determine the removal performance of NPs in coagulation. Consequently, in this study, the impact of HA concentration on the simultaneous removal of CuO NPs, Cu2+, and natural organic matter (NOM) was investigated. Enteromorpha polysaccharides (Ep), as the novel recycling Coagulant Aid, were integrated with polyaluminum chloride (PAC) to treat composite contaminants in this coagulation process. Removal performance, floc properties, zeta potential, scanning electron microscope (SEM) images, and Fourier Transform Infrared Spectra (FT-IR) were measured and analyzed. Results showed that PAC with Ep (PAC-Ep) was more beneficial for improving removal performances than PAC alone. Further, the coagulation performance became better with the increase in HA concentration. When the HA concentration was 10 mg/L (used PAC-Ep), the removal efficiencies of CuO NPs and Cu2+ were both more than 80%; and in particular, the highest removal efficiency of turbidity was 98%. However, excessive HA (more than 10 mg/L) reduced the removal efficiency of Cu by more than 31%. Smaller and denser flocs with better recoverability were formed as the HA concentration increased. Furthermore, because of affluent functional groups, HA was easily adsorbed on the surface of NPs and combined with dissociative Cu2+, thereby forming a composite contaminant. During the coagulation process, the colloidal system was destabilized preferentially by the charge neutralization between composite contaminants and PAC. Furthermore, a chelated reticular structure was formed by the conjunction of carboxyl and hydroxyl groups (from Ep) and Al (III) species (from PAC). Flocs were further enlarged and precipitated by bridging and sweeping of this structure.

  • effects of papermaking sludge based polymer on coagulation behavior in the disperse and reactive dyes wastewater treatment
    Bioresource Technology, 2017
    Co-Authors: Baoyu Gao, Qinyan Yue, Kangying Guo, Huaili Zheng, Yan Wang
    Abstract:

    Abstract In this study, papermaking sludge was used as the raw biomass material to produce the lignin-based flocculant (LBF) by grafting quaternary ammonium groups and acrylamide. LBF was used as a Coagulant Aid with polyaluminum chloride (PAC) to treat reactive and disperse dyes wastewater. Effects of dosing method, pH, hardness and stirring speed on the coagulation behavior and floc properties were studied. Results showed that the superior coagulation efficiency and recovery factor were achieved by PAC + LBF compared with PAC and LBF + PAC. The primary mechanisms of LBF in the treatment of disperse and reactive dye solutions were charge neutralization and bridging effect, respectively. In the dual-coagulation, the impact of pH on the coagulation efficiency was weak during pH range of 5–9. Moderate hardness could enhance the floc properties due to the decrease of electrostatic repulsion and the chelation of Ca(II) and LBF. Besides, flocs coagulated by PAC + LBF had a stronger anti-crush ability.

  • synthesis characterization of a novel lignin based polymer and its behavior as a Coagulant Aid in coagulation ultrafiltration hybrid process
    International Biodeterioration & Biodegradation, 2016
    Co-Authors: Baoyu Gao, Qinyan Yue, Jianzhang Sun, Yan Wang
    Abstract:

    A novel lignin-based flocculant was introduced in recycling of the biomass existing in papermaking sludge. The product, lignin-diallyl dimethyl ammonium chloride-acrylamide (LDA) was characterized as a cationic macromolecule polymer with broad structure. To demonstrate its efficiency, LDA was used as Coagulant Aid with polyferric chloride (PFC) and polyaluminum chloride (PAC) to remove humic acid by coagulation–ultrafiltration processes. Results showed that coagulation Aid effect of LDA was not affected by the type of metal salts and removal ratios of dissolved organic carbon were maximum 15.1% and 11.9% larger than single PFC and PAC coagulation, respectively. More concentrated flocs with larger size and open structure as well as low fractal dimension were formed by dual-Coagulants. In PFC coagulation system, LDA could absorb negative charge on the surface of Fe(III) coagulated flocs efficiently and achieve the maximum floc strength accordingly. In the ultrafiltration experiment, cake layer fouling was demonstrated to be the foremost fouling mechanism. PAC combined used with LDA resulted in the minimum membrane fouling due to the formation of looser flocs as well as more concentrated floc size distribution. Overall, LDA brought in charge neutralization and absorption bridging effect and played a positive role in coagulation–ultrafiltration processes.

  • polyacrylamide as Coagulant Aid with polytitanium sulfate in humic acid kaolin water treatment effect of dosage and dose method
    Journal of The Taiwan Institute of Chemical Engineers, 2016
    Co-Authors: Xin Huang, Baoyu Gao, Shenglei Sun, Yan Wang, Yu Zhao, Qiyan Yue
    Abstract:

    Abstract This study focused on the application of polyacrylamide (PAM) as a Coagulant Aid of polytitanium sulfate (PTS) in humic acid-kaolin water treatment. Coagulation performance and floc properties were all measured in terms of dose amount and dose sequence of PAM and PTS which is meaningful for the practical application. Results showed that PTS-PAM (PTS dosed firstly) attained better natural organic matter (NOM) removal and PAM-PTS (PAM dosed firstly) attained better turbidity removal. Floc size was significantly enhanced by the PTS-PAM, while floc size of PAM-PTS attained similar size as that of PTS alone. Floc strength and recovery ability were also significantly improved by PTS-PAM. Moreover, PTS-PAM floc had a looser structure than that of PTS, while PAM-PTS floc and PTS floc had similar and more compact structure. The effect of PAM on the sludge reuse process was also studied. Results showed that the addition of PAM had a positive effect on the photocatalytic activity of sludge prepared TiO2.

  • application of enteromorpha as a new kind of Coagulant Aid in municipal sludge treatment
    Desalination and Water Treatment, 2016
    Co-Authors: Shuang Zhao, Baoyu Gao
    Abstract:

    AbstractThe large-scale blooms of Enteromorpha disrupts normal ecosystem functioning and brought serious environmental problems in past years. This study focused on the recycling of it with the aim of “treating waste by waste.” In this paper, Enteromorpha polysaccharide (Ep) was applied as a new Coagulant Aid in sludge treatment process. Initially, orthogonal test was conducted and then the effect of Ep on coagulation behavior was studied and coagulation performance was evaluated in terms of solid content, turbidity, filtrate rate, capillary suction time, and resistance to filtration. Zeta potential and scanning electron microscopic (SEM) were also measured to investigate coagulation mechanism. In addition, cost analysis of sludge treatment was also discussed in this paper. Results of orthogonal test showed that coagulation efficiency was significantly affected by hydraulic conditions. Sludge treatment efficiency could be apparently improved by Ep addition and the optimum polyacrylamide (PAM) and Ep dosag...

Qinyan Yue - One of the best experts on this subject based on the ideXlab platform.

  • application of enteromorpha polysaccharides as Coagulant Aid in the simultaneous removal of cuo nanoparticles and cu2 effect of humic acid concentration
    Chemosphere, 2018
    Co-Authors: Yuanxia Luo, Baoyu Gao, Qinyan Yue
    Abstract:

    Humic acid (HA) influences the aggregation and stability of nanoparticles (NPs), which determine the removal performance of NPs in coagulation. Consequently, in this study, the impact of HA concentration on the simultaneous removal of CuO NPs, Cu2+, and natural organic matter (NOM) was investigated. Enteromorpha polysaccharides (Ep), as the novel recycling Coagulant Aid, were integrated with polyaluminum chloride (PAC) to treat composite contaminants in this coagulation process. Removal performance, floc properties, zeta potential, scanning electron microscope (SEM) images, and Fourier Transform Infrared Spectra (FT-IR) were measured and analyzed. Results showed that PAC with Ep (PAC-Ep) was more beneficial for improving removal performances than PAC alone. Further, the coagulation performance became better with the increase in HA concentration. When the HA concentration was 10 mg/L (used PAC-Ep), the removal efficiencies of CuO NPs and Cu2+ were both more than 80%; and in particular, the highest removal efficiency of turbidity was 98%. However, excessive HA (more than 10 mg/L) reduced the removal efficiency of Cu by more than 31%. Smaller and denser flocs with better recoverability were formed as the HA concentration increased. Furthermore, because of affluent functional groups, HA was easily adsorbed on the surface of NPs and combined with dissociative Cu2+, thereby forming a composite contaminant. During the coagulation process, the colloidal system was destabilized preferentially by the charge neutralization between composite contaminants and PAC. Furthermore, a chelated reticular structure was formed by the conjunction of carboxyl and hydroxyl groups (from Ep) and Al (III) species (from PAC). Flocs were further enlarged and precipitated by bridging and sweeping of this structure.

  • effects of papermaking sludge based polymer on coagulation behavior in the disperse and reactive dyes wastewater treatment
    Bioresource Technology, 2017
    Co-Authors: Baoyu Gao, Qinyan Yue, Kangying Guo, Huaili Zheng, Yan Wang
    Abstract:

    Abstract In this study, papermaking sludge was used as the raw biomass material to produce the lignin-based flocculant (LBF) by grafting quaternary ammonium groups and acrylamide. LBF was used as a Coagulant Aid with polyaluminum chloride (PAC) to treat reactive and disperse dyes wastewater. Effects of dosing method, pH, hardness and stirring speed on the coagulation behavior and floc properties were studied. Results showed that the superior coagulation efficiency and recovery factor were achieved by PAC + LBF compared with PAC and LBF + PAC. The primary mechanisms of LBF in the treatment of disperse and reactive dye solutions were charge neutralization and bridging effect, respectively. In the dual-coagulation, the impact of pH on the coagulation efficiency was weak during pH range of 5–9. Moderate hardness could enhance the floc properties due to the decrease of electrostatic repulsion and the chelation of Ca(II) and LBF. Besides, flocs coagulated by PAC + LBF had a stronger anti-crush ability.

  • synthesis characterization of a novel lignin based polymer and its behavior as a Coagulant Aid in coagulation ultrafiltration hybrid process
    International Biodeterioration & Biodegradation, 2016
    Co-Authors: Baoyu Gao, Qinyan Yue, Jianzhang Sun, Yan Wang
    Abstract:

    A novel lignin-based flocculant was introduced in recycling of the biomass existing in papermaking sludge. The product, lignin-diallyl dimethyl ammonium chloride-acrylamide (LDA) was characterized as a cationic macromolecule polymer with broad structure. To demonstrate its efficiency, LDA was used as Coagulant Aid with polyferric chloride (PFC) and polyaluminum chloride (PAC) to remove humic acid by coagulation–ultrafiltration processes. Results showed that coagulation Aid effect of LDA was not affected by the type of metal salts and removal ratios of dissolved organic carbon were maximum 15.1% and 11.9% larger than single PFC and PAC coagulation, respectively. More concentrated flocs with larger size and open structure as well as low fractal dimension were formed by dual-Coagulants. In PFC coagulation system, LDA could absorb negative charge on the surface of Fe(III) coagulated flocs efficiently and achieve the maximum floc strength accordingly. In the ultrafiltration experiment, cake layer fouling was demonstrated to be the foremost fouling mechanism. PAC combined used with LDA resulted in the minimum membrane fouling due to the formation of looser flocs as well as more concentrated floc size distribution. Overall, LDA brought in charge neutralization and absorption bridging effect and played a positive role in coagulation–ultrafiltration processes.

  • impacts of organic Coagulant Aid on purification performance and membrane fouling of coagulation ultrafiltration hybrid process with different al based Coagulants
    Desalination, 2015
    Co-Authors: Qinyan Yue, Baoyu Gao
    Abstract:

    Effects of polydimethyldiallylammonium chloride (PD) on coagulation behaviors of different Al-based Coagulants were investigated in coagulation-ultrafiltration (C-UF) hybrid process, regarding the impurity removal efficiency, floc properties and membrane foulings. Floc characteristics, including floc size, compact degree, strength and re-growth ability were studied using a laser diffraction particle sizing device. Resistance analyses were implemented to explore the membrane fouling mechanisms. The results indicated that PD Aid could increase the purification efficiency of C-UF, especially at low Coagulant doses. PD-alum/PD-PACl contributed to large flocs, while alum-PD/PACl-PD gave rise to flocs with high R-f and D-f values. The results of ultrafiltration experiments showed that conventional Coagulant, i.e,, alum led to a flux reduction of 52%; while the reductions for alum-PD and PD-alum were 53% and 34%, respectively. The flux reductions for PACl, PACl-PD and PD-PACl were 60%, 57% and 39%. Flux declines became more severe when the coagulated suspensions were exposed to increased shears and the suspensions coagulated by aluminum plus PD resulted in the least reductions in fluxes. (C) 2014 Elsevier B.V. All rights reserved.

  • study of enteromorpha polysaccharides as a new style Coagulant Aid in dye wastewater treatment
    Carbohydrate Polymers, 2014
    Co-Authors: Shuang Zhao, Baoyu Gao, Qinyan Yue, Yan Wang, Hongyu Dong, Han Yan
    Abstract:

    Abstract Enteromorpha is one of the common fouling green algae, which has brought serious environmental problems in past years. This study was aimed to apply it in water treatment process. Enteromorpha polysaccharides (Ep) were used as a new-style Coagulant Aid to assess its effect on coagulation behavior and floc characteristics. Color removal was used to evaluate coagulation effects and floc properties were investigated by Photometric Dispersion Analyzer (PDA). Results showed that when Ep was used in combination with aluminum chloride (AC), color removal could be apparently improved, and the optimal solution pH ranged 6.0–8.0. The growth rate and average size of flocs formed by AC–Ep were larger than those by AC in steady-state after floc growth phase, and meanwhile the distribution of floc size had a wider range. Besides, floc recoverability could be significantly improved when Ep was used as Coagulant Aid.

Shuang Zhao - One of the best experts on this subject based on the ideXlab platform.

  • application of sodium alginate as a Coagulant Aid for mitigating membrane fouling induced by humic acid in dead end ultrafiltration process
    Separation and Purification Technology, 2020
    Co-Authors: Xin Liu, Shuang Zhao, Xiaoxiao Zhang, Wenlin Jia, Zhangjian Zou, Qian Wang
    Abstract:

    Abstract Ultrafiltration (UF) is one of the most promising technologies for surface water treatment, but severe membrane fouling is a significant obstacle for its widespread application. In this study, sodium alginate (SA) was used as a Coagulant Aid of polyaluminum chloride (PAC) in a pre-coagulation process prior to UF to mitigate UF membrane fouling. The influence of SA addition on water treatment efficiency, flocs characteristics and membrane fouling were examined. Results showed that SA dosed after PAC improved coagulation and UF efficiency due to its bridge role and gel network formation. UV254 and DOC removal from UF effluent were over 97% and 70%, respectively, when SA dosage ≥0.3 mg/L. In addition, UF membrane normalized flux was improved from 0.19 to 0.47. The membrane fouling alleviating mechanism of SA application was the formation of a porous cake layer by flocs with looser structures. In addition, these flocs were much larger than membrane pores (flocs sizes >450 μm), which also alleviate pore blocking degree of UF membrane.

  • enteromorpha prolifera polysaccharide based Coagulant Aid for humic acids removal and ultrafiltration membrane fouling control
    International Journal of Biological Macromolecules, 2020
    Co-Authors: Shuang Zhao, Qianshu Sun, Weihua Yang, Yun Chen, Jing Lin, Mengyao Dong, Haoyan Cheng, Zhanhu Guo
    Abstract:

    Abstract Polyacrylamide (PAM) has been used as a Coagulant Aid in water treatment process for past decades, but it has caused great damages to human nervous system. Developing new Coagulant Aid with high biological safety is urgently demanded. This study provides a natural biomacromolecule Coagulant Aid with good biosecurity-Enteromorpha prolifera polysaccharide (Ep). Its Coagulant Aid efficiency and mechanism were investigated in terms of organics removal, floc properties and membrane fouling degree. In addition, contrast experiments were conducted with PAM to evaluate its potential of industrial applications. Results showed that organics removal could be increased by 23% when 0.3 mg/L Ep was used, which exhibited comparable Aid effects to PAM. Due to the bridging-sweep Aid role of Ep, flocs sizes, growth rate and recovery factor reached 470 μm, 62.6 μm/min and 0.492, respectively, while only 170 μm, 14.0 μm/min and 0.326 were obtained by PAM. Additionally, flocs exhibited more porous and multi-branched structures when Ep was applied, which caused less ultrafiltration membrane fouling (eventual J/J0 value = 0.52). As a result, Ep could be considered as a potential substitute of PAM, since better biosecurity, higher organics removal and lower membrane fouling could be obtained simultaneously by Ep addition.

  • application of enteromorpha polysaccharides as a new Coagulant Aid to remove silver nanoparticles role of dosage sequence and solution ph
    RSC Advances, 2019
    Co-Authors: Shuang Zhao, Qianshu Sun, Wenlin Jia, Feng Wang, Zhangjian Zou
    Abstract:

    Silver nanoparticles (AgNPs) in surface water cause a serious threat to the health of humans and aquatic organisms. However, it is difficult to remove AgNPs completely since they could adsorb onto the surface of humic acid (HA) and meanwhile release Ag+ into water. In this paper, Enteromorpha polysaccharides (Ep) were applied as a Coagulant Aid with polyaluminum chloride (PAC) to solve this problem. The influences of Ep dosage, dosing sequence and solution pH on the coagulation efficiency, kinetics and removal mechanism of AgNPs were discussed systematically. Results showed that when Ep was applied, AgNPs could be removed effectively due to charge neutralization of PAC hydrolysate and the bridging-sweeping role of Ep gel network. When Ep was added 30 s after PAC dosing, the coagulation efficiency was about 10–20% higher than that of the reverse order. Under this condition, flocs sizes achieved 450 μm when the solution pH was 6.0, which is much larger than that using Ep–PAC. Additionally, Ep showed an ability to promote the re-aggregation of broken flocs, and AgNP–HA flocs exhibited larger sizes, better shear resistance, higher recovery ability and denser structure at pH 6.0. Factorial analysis results indicated that PAC dosage had the greatest impact on HA and AgNP removal, while Ag+ removal is more sensitive to Ep dosage.

  • application of enteromorpha as a new kind of Coagulant Aid in municipal sludge treatment
    Desalination and Water Treatment, 2016
    Co-Authors: Shuang Zhao, Baoyu Gao
    Abstract:

    AbstractThe large-scale blooms of Enteromorpha disrupts normal ecosystem functioning and brought serious environmental problems in past years. This study focused on the recycling of it with the aim of “treating waste by waste.” In this paper, Enteromorpha polysaccharide (Ep) was applied as a new Coagulant Aid in sludge treatment process. Initially, orthogonal test was conducted and then the effect of Ep on coagulation behavior was studied and coagulation performance was evaluated in terms of solid content, turbidity, filtrate rate, capillary suction time, and resistance to filtration. Zeta potential and scanning electron microscopic (SEM) were also measured to investigate coagulation mechanism. In addition, cost analysis of sludge treatment was also discussed in this paper. Results of orthogonal test showed that coagulation efficiency was significantly affected by hydraulic conditions. Sludge treatment efficiency could be apparently improved by Ep addition and the optimum polyacrylamide (PAM) and Ep dosag...

  • coagulation performance and floc characteristics of aluminum sulfate with cationic polyamidine as Coagulant Aid for kaolin humic acid treatment
    Colloids and Surfaces A: Physicochemical and Engineering Aspects, 2015
    Co-Authors: Bo Guo, Hongyan Rong, Baoyu Gao, Hongyu Dong, Shuang Zhao
    Abstract:

    Abstract In this study, novel cationic polyamidine (Pa) was synthesized and used as Coagulant Aid with aluminum sulfate (AS) for kaolin-humic acid simulated water treatment. The effects of Pa on coagulation performance and floc properties were investigated. Results showed that Pa addition significantly enhanced the removal of turbidity, ultraviolet absorbance at 254 nm wavelength (UV 254 ) and dissolved organic carbon (DOC). AS–Pa exhibited high coagulation efficiency at border pH range and increased floc size and growth rate significantly. Floc recovery ability was also improved, while floc fractal dimension was lower with Pa addition. This would be attributed to high cationic charge density and long chain of Pa, which could enhance the effect of charge neutralization and adsorption bridging.

Yan Wang - One of the best experts on this subject based on the ideXlab platform.

  • effects of papermaking sludge based polymer on coagulation behavior in the disperse and reactive dyes wastewater treatment
    Bioresource Technology, 2017
    Co-Authors: Baoyu Gao, Qinyan Yue, Kangying Guo, Huaili Zheng, Yan Wang
    Abstract:

    Abstract In this study, papermaking sludge was used as the raw biomass material to produce the lignin-based flocculant (LBF) by grafting quaternary ammonium groups and acrylamide. LBF was used as a Coagulant Aid with polyaluminum chloride (PAC) to treat reactive and disperse dyes wastewater. Effects of dosing method, pH, hardness and stirring speed on the coagulation behavior and floc properties were studied. Results showed that the superior coagulation efficiency and recovery factor were achieved by PAC + LBF compared with PAC and LBF + PAC. The primary mechanisms of LBF in the treatment of disperse and reactive dye solutions were charge neutralization and bridging effect, respectively. In the dual-coagulation, the impact of pH on the coagulation efficiency was weak during pH range of 5–9. Moderate hardness could enhance the floc properties due to the decrease of electrostatic repulsion and the chelation of Ca(II) and LBF. Besides, flocs coagulated by PAC + LBF had a stronger anti-crush ability.

  • synthesis characterization of a novel lignin based polymer and its behavior as a Coagulant Aid in coagulation ultrafiltration hybrid process
    International Biodeterioration & Biodegradation, 2016
    Co-Authors: Baoyu Gao, Qinyan Yue, Jianzhang Sun, Yan Wang
    Abstract:

    A novel lignin-based flocculant was introduced in recycling of the biomass existing in papermaking sludge. The product, lignin-diallyl dimethyl ammonium chloride-acrylamide (LDA) was characterized as a cationic macromolecule polymer with broad structure. To demonstrate its efficiency, LDA was used as Coagulant Aid with polyferric chloride (PFC) and polyaluminum chloride (PAC) to remove humic acid by coagulation–ultrafiltration processes. Results showed that coagulation Aid effect of LDA was not affected by the type of metal salts and removal ratios of dissolved organic carbon were maximum 15.1% and 11.9% larger than single PFC and PAC coagulation, respectively. More concentrated flocs with larger size and open structure as well as low fractal dimension were formed by dual-Coagulants. In PFC coagulation system, LDA could absorb negative charge on the surface of Fe(III) coagulated flocs efficiently and achieve the maximum floc strength accordingly. In the ultrafiltration experiment, cake layer fouling was demonstrated to be the foremost fouling mechanism. PAC combined used with LDA resulted in the minimum membrane fouling due to the formation of looser flocs as well as more concentrated floc size distribution. Overall, LDA brought in charge neutralization and absorption bridging effect and played a positive role in coagulation–ultrafiltration processes.

  • polyacrylamide as Coagulant Aid with polytitanium sulfate in humic acid kaolin water treatment effect of dosage and dose method
    Journal of The Taiwan Institute of Chemical Engineers, 2016
    Co-Authors: Xin Huang, Baoyu Gao, Shenglei Sun, Yan Wang, Yu Zhao, Qiyan Yue
    Abstract:

    Abstract This study focused on the application of polyacrylamide (PAM) as a Coagulant Aid of polytitanium sulfate (PTS) in humic acid-kaolin water treatment. Coagulation performance and floc properties were all measured in terms of dose amount and dose sequence of PAM and PTS which is meaningful for the practical application. Results showed that PTS-PAM (PTS dosed firstly) attained better natural organic matter (NOM) removal and PAM-PTS (PAM dosed firstly) attained better turbidity removal. Floc size was significantly enhanced by the PTS-PAM, while floc size of PAM-PTS attained similar size as that of PTS alone. Floc strength and recovery ability were also significantly improved by PTS-PAM. Moreover, PTS-PAM floc had a looser structure than that of PTS, while PAM-PTS floc and PTS floc had similar and more compact structure. The effect of PAM on the sludge reuse process was also studied. Results showed that the addition of PAM had a positive effect on the photocatalytic activity of sludge prepared TiO2.

  • cuo nanoparticle humic acid cuonp ha composite contaminant removal by coagulation ultrafiltration process the application of sodium alginate as Coagulant Aid
    Desalination, 2015
    Co-Authors: Yan Wang, Han Yan, Nan Xue, Yongbao Chu, Yangyang Sun, Qi Han
    Abstract:

    Abstract In order to remove CuO nanoparticle–humic acid composite contaminant (CuONP–HA) and reduce the membrane fouling in coagulation/ultrafiltraion process, sodium alginate (SA) was used as a Coagulant Aid of polyaluminum chloride (PAC) to pre-treat CuONP–HA in synthetic water. The effect of SA on floc properties and membrane fouling was investigated by a laser diffraction instrument and ultrafiltration fouling model. The results showed that SA, as Coagulant Aid, could improve the removal efficiency of CuONP–HA by coagulation/ultrafiltration process. CuONP was completely removed, and the removal efficiency of HA was over 80% at PAC dosage = 3.0 mg/L and SA dosage ≥ 0.2 mg/L. Besides, PAC with SA (PAC + SA) could form larger flocs with better recoverability than PAC alone. The average size of CuONP–HA flocs formed by PAC + SA exceeded 1000 um which was about 66% larger than flocs formed by PAC, and the small CuONP–HA aggregation also increased to about 280 um. Moreover, membrane fouling was effectively reduced by pre-treating of SA, and membrane fouling index (MFI) was decreased with the dosage of SA increasing.

  • study of enteromorpha polysaccharides as a new style Coagulant Aid in dye wastewater treatment
    Carbohydrate Polymers, 2014
    Co-Authors: Shuang Zhao, Baoyu Gao, Qinyan Yue, Yan Wang, Hongyu Dong, Han Yan
    Abstract:

    Abstract Enteromorpha is one of the common fouling green algae, which has brought serious environmental problems in past years. This study was aimed to apply it in water treatment process. Enteromorpha polysaccharides (Ep) were used as a new-style Coagulant Aid to assess its effect on coagulation behavior and floc characteristics. Color removal was used to evaluate coagulation effects and floc properties were investigated by Photometric Dispersion Analyzer (PDA). Results showed that when Ep was used in combination with aluminum chloride (AC), color removal could be apparently improved, and the optimal solution pH ranged 6.0–8.0. The growth rate and average size of flocs formed by AC–Ep were larger than those by AC in steady-state after floc growth phase, and meanwhile the distribution of floc size had a wider range. Besides, floc recoverability could be significantly improved when Ep was used as Coagulant Aid.

Nigel Graham - One of the best experts on this subject based on the ideXlab platform.

  • evaluation of ferrate as a Coagulant Aid oxidant pretreatment for mitigating submerged ultrafiltration membrane fouling in drinking water treatment
    Chemical Engineering Journal, 2016
    Co-Authors: Yunjia Yang, Nigel Graham
    Abstract:

    Abstract Although pre-coagulation can mitigate ultrafiltration (UF) membrane fouling in the treatment of surface waters for drinking water supply, biological activities (‘biofouling’) can induce a continuous increase in membrane fouling. To meet this challenge, potassium ferrate, K 2 FeO 4 , a combined oxidant and Coagulant, was evaluated as a pre-treatment chemical for controlling submerged UF membrane fouling in water treatment. Ferrate use as an alternative to- (phase 1: ∼23 days), and in combination with- (phase 2: ∼30 days), conventional FeCl 3 , have been studied using parallel continuous bench-scale submerged membrane systems, using FeCl 3 as the reference. The poorer performance of ferrate (alone) as a pre-treatment compared to FeCl 3 (phase 1) was the result of a lower coagulation efficiency, which outweighed the beneficial impact of the ferrate on bacterial inactivation. The net reduction in pre-treatment performance led to an increase in the concentration of residual, active bacteria in the membrane tank, and bacteria associated large molecular weight (MW) organic substances, such as extracellular polymeric substances (EPS) or biopolymers, which were the principal cause of the higher rate of membrane fouling observed. In contrast, ferrate performed best as a Coagulant Aid/oxidant (FeCl 3 /K 2 FeO 4 ) (phase 2), with the rate of membrane fouling (increase in transmembrane pressure) 4.5 times lower than conventional FeCl 3 pre-treatment. This pre-treatment arrangement resulted in less bacteria (and EPS) and suspended solids in the membrane tank, and less accumulation of materials in the cake layer and within the membrane pores. The results indicated clearly the potential benefit of applying ferrate as a Coagulant Aid/oxidant with a Coagulant, in UF pre-treatment, with the control of bacteria and EPS a key factor in reducing membrane fouling.

  • the pre treatment of submerged ultrafiltration membrane by coagulation effect of polyacrylamide as a Coagulant Aid
    Journal of Membrane Science, 2013
    Co-Authors: Huijuan Liu, Nigel Graham
    Abstract:

    Abstract The application of polyacrylamide (PAM) as a Coagulant Aid before membrane ultrafiltration was investigated to examine its potential benefit and impact on membrane fouling. The benefit of PAM with alum coagulation was found to depend on the dose and the time of addition during the flocculation process. The optimal conditions, corresponding to the lowest rate of TMP increase, were at a PAM dosage of 0.2 mg/L, applied 5 min after the start of flocculation; a higher PAM dosage of 1 mg/L led to a significant increase in the rate of TMP increase. Since NOM removal was nearly the same for all the pre-treatments, the character of the flocs was the main reason for the variation in fouling. Dynamic light scattering indicated that nano-scale particles (