The Experts below are selected from a list of 23214 Experts worldwide ranked by ideXlab platform
Aimin Li - One of the best experts on this subject based on the ideXlab platform.
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enhanced removal of trace antibiotics from turbid water in the coexistence of natural organic matters using phenylalanine modified chitosan Flocculants effect of Flocculants molecular architectures
Chemical Engineering Journal, 2018Co-Authors: Hongwei Du, Zhen Yang, Ziqi Tian, Menglu Huang, Weiben Yang, Limin Zhang, Aimin LiAbstract:Abstract Removal of two typical antibiotics (norfloxacin and tylosin) at trace level in turbid water simultaneously containing natural organic matters (NOMs) was conducted using two phenylalanine (Phe)-modified-chitosan Flocculants (CHS-Phe and CHS-PPhe) with different molecular architectures. Response surface methodology (RSM) was applied for interactive effects evaluation and optimization of various parameters. CHS-Phe with linear molecular architecture displays higher removal efficiencies of antibiotics than commercial Flocculants. By contrast, CHS-PPhe, owning the same Phe functional groups but comb-like architecture (polyPhe polymer branches grafted on chitosan backbone), shows poor performance. Deep mechanism investigations indicated that, for hydrophilic and flexible CHS-Phe linear molecules, bridging and sweeping flocculation for antibiotics were enhanced by electrostatic attraction, π-electron-containing interaction, and H-bond between introduced Phe groups and antibiotic molecules. However, for comb-like CHS-PPhe, excessively hydrophobic polyPhe branches aggregated to coils. This phenomenon caused fewer exposed flocculation sites outwards, although the interactions of Phe-antibiotic still existed. 3D response surfaces of CHS-Phe generated by RSM exhibited that, concentrations of coexisting kaolin and HA, as well as pH and flocculant dosage, can be controlled to obtain desired performance. This work enriches the knowledge of effect of molecular architecture of Flocculants on contaminant removal, and provides guidance for flocculation parameter control.
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evaluation of the starch based Flocculants on flocculation of hairwork wastewater
Science of The Total Environment, 2017Co-Authors: Qing Du, Aimin Li, Hu YangAbstract:China is the world's largest producer of wigs, and the manufacturing generates large quantities of hairwork effluents. Coagulation/flocculation is an important step in the water treatment process. In this study, two versions of starch-based Flocculants were successfully prepared through etherification and graft copolymerization, respectively. Starch-3-chloro-2-hydroxypropyl triethyl ammonium chloride (St-CTA-DQ) and starch-graft-poly[(2-methacryloyloxyethyl) trimethyl ammonium chloride] (St-g-PDMC-DQ) both contain strongly cationic quaternary ammonium salt groups, but have differing cationic contents, specifically, the degree of substitution (DS) and grafting ratio (G). Furthermore, the additional functional groups were distributed on different chain sites (the starch backbone for St-CTA-DQ, and the branch chains for St-g-PDMC-DQ). These two Flocculants demonstrated superior efficiency for turbidity and UV254 removal in hairwork wastewater as well as better floc properties compared to polyaluminum chloride. The effects of pH, flocculant dose, and cationic group contents (DS and G) were systematically investigated. Consequently, it was determined that a higher cationic content in both the Flocculants led to better flocculation performance as well as increased removal rates of both turbidity and UV254. This was primarily due to improved charge neutralization, which highlighted the preference towards a lower optimal dose. In addition, flocculation performance worsened as the pH level increased. Overall, St-g-PDMC-DQ exhibited similar flocculation performance to St-CTA-DQ. However, the wastewater treated by St-g-PDMC-DQ showed lower residual turbidity than when treated by St-CTA-DQ. This was attributed to the distinct branch chain architecture of St-g-PDMC-DQ, which was beneficial for coagulating the uneasily flocculated contaminants in water, such as smaller-sized colloids and water-soluble organic substances. Flocculant structural factors, specifically charge properties and chain architecture, heavily affected the final flocculation performance.
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evaluation of chain architectures and charge properties of various starch based Flocculants for flocculation of humic acid from water
Water Research, 2016Co-Authors: Hu Wu, Hu Yang, Aimin LiAbstract:Three different starch-based Flocculants with various chain architectures and charge properties have been prepared through etherification, graft copolymerization, or their combination. Two of the Flocculants (starch-graft-poly[(2-methacryloyloxyethyl) trimethyl ammonium chloride] and starch-3-chloro-2-hydroxypropyl triethyl ammonium chloride, denoted as STC-g-PDMC and STC-CTA respectively) are cationic, and another one (carboxymethyl starch-graft-poly[(2-methacryloyloxyethyl) trimethyl ammonium chloride], denoted as CMS-g-PDMC) is amphoteric. Those three Flocculants have shown far different flocculation efficiency and floc properties for the removal of humic acid (HA) from water due to their distinct structural features. The effects of pH, flocculant dose, and initial HA concentration have been studied systematically. Accordingly, STC-g-PDMC and CMS-g-PDMC with strongly cationic branch chains have much better flocculation performance than polyaluminum chloride (PAC) and STC-CTA, the latter of which features linear chain architecture and strongly cationic pieces lying on its chain backbone. It indicates that the architecture of cationic branch chains plays an important role in HA flocculation due to their significantly enhanced bridging effects. Moreover, STC-g-PDMC has higher HA removal efficiency and better floc properties than CMS-g-PDMC, suggesting that charge neutralization effects make notable contributions to HA removal and that the additional anionic pieces on CMS-g-PDMC can weaken its flocculation performance. In addition, STC-g-PDMC used as coagulant aid for PAC has also been tried, which observably reduces the optimal dose of the inorganic coagulant.
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synthesis of amphoteric starch based grafting Flocculants for flocculation of both positively and negatively charged colloidal contaminants from water
Chemical Engineering Journal, 2014Co-Authors: Zhen Yang, Hu Wu, Bo Yuan, Mu Huang, Hu Yang, Aimin Li, Rongshi ChengAbstract:Contaminants in real water are normally complicated. Surface charges of suspended colloidal particles can be either negative or positive. In this work, a series of amphoteric starch-based grafting Flocculants (3-chloro-2-hydroxypropyl trimethyl ammonium chloride modified starch-graft-poly(acrylamide-co-acrylic acid)) denoted as SCPAMPAA were successfully synthesized with different grafting ratios and used for the removal of different charged contaminants from water. Various SCPAMPAA Flocculants exhibited remarkably different flocculation performance and obeyed diverse flocculation mechanisms due to the differences in their structural characteristics. Therefore, precise control of the molecular structure of Flocculants is of great significance to obtain the desired flocculation performance. To provide practically operational feasibility for the preparation of a predicted flocculant, a quantitative mathematical correlation between the preparation recipe and the structural features of SCPAMPAA were derived. The final well-designed flocculant demonstrated a high flocculation performance in aspects of optimal dosage, flocculation window and pH sensitivity for the removal of both negatively and positively charged colloidal contaminants from targeted wastewater.
Hu Yang - One of the best experts on this subject based on the ideXlab platform.
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evaluation of the starch based Flocculants on flocculation of hairwork wastewater
Science of The Total Environment, 2017Co-Authors: Qing Du, Aimin Li, Hu YangAbstract:China is the world's largest producer of wigs, and the manufacturing generates large quantities of hairwork effluents. Coagulation/flocculation is an important step in the water treatment process. In this study, two versions of starch-based Flocculants were successfully prepared through etherification and graft copolymerization, respectively. Starch-3-chloro-2-hydroxypropyl triethyl ammonium chloride (St-CTA-DQ) and starch-graft-poly[(2-methacryloyloxyethyl) trimethyl ammonium chloride] (St-g-PDMC-DQ) both contain strongly cationic quaternary ammonium salt groups, but have differing cationic contents, specifically, the degree of substitution (DS) and grafting ratio (G). Furthermore, the additional functional groups were distributed on different chain sites (the starch backbone for St-CTA-DQ, and the branch chains for St-g-PDMC-DQ). These two Flocculants demonstrated superior efficiency for turbidity and UV254 removal in hairwork wastewater as well as better floc properties compared to polyaluminum chloride. The effects of pH, flocculant dose, and cationic group contents (DS and G) were systematically investigated. Consequently, it was determined that a higher cationic content in both the Flocculants led to better flocculation performance as well as increased removal rates of both turbidity and UV254. This was primarily due to improved charge neutralization, which highlighted the preference towards a lower optimal dose. In addition, flocculation performance worsened as the pH level increased. Overall, St-g-PDMC-DQ exhibited similar flocculation performance to St-CTA-DQ. However, the wastewater treated by St-g-PDMC-DQ showed lower residual turbidity than when treated by St-CTA-DQ. This was attributed to the distinct branch chain architecture of St-g-PDMC-DQ, which was beneficial for coagulating the uneasily flocculated contaminants in water, such as smaller-sized colloids and water-soluble organic substances. Flocculant structural factors, specifically charge properties and chain architecture, heavily affected the final flocculation performance.
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evaluation of chain architectures and charge properties of various starch based Flocculants for flocculation of humic acid from water
Water Research, 2016Co-Authors: Hu Wu, Hu Yang, Aimin LiAbstract:Three different starch-based Flocculants with various chain architectures and charge properties have been prepared through etherification, graft copolymerization, or their combination. Two of the Flocculants (starch-graft-poly[(2-methacryloyloxyethyl) trimethyl ammonium chloride] and starch-3-chloro-2-hydroxypropyl triethyl ammonium chloride, denoted as STC-g-PDMC and STC-CTA respectively) are cationic, and another one (carboxymethyl starch-graft-poly[(2-methacryloyloxyethyl) trimethyl ammonium chloride], denoted as CMS-g-PDMC) is amphoteric. Those three Flocculants have shown far different flocculation efficiency and floc properties for the removal of humic acid (HA) from water due to their distinct structural features. The effects of pH, flocculant dose, and initial HA concentration have been studied systematically. Accordingly, STC-g-PDMC and CMS-g-PDMC with strongly cationic branch chains have much better flocculation performance than polyaluminum chloride (PAC) and STC-CTA, the latter of which features linear chain architecture and strongly cationic pieces lying on its chain backbone. It indicates that the architecture of cationic branch chains plays an important role in HA flocculation due to their significantly enhanced bridging effects. Moreover, STC-g-PDMC has higher HA removal efficiency and better floc properties than CMS-g-PDMC, suggesting that charge neutralization effects make notable contributions to HA removal and that the additional anionic pieces on CMS-g-PDMC can weaken its flocculation performance. In addition, STC-g-PDMC used as coagulant aid for PAC has also been tried, which observably reduces the optimal dose of the inorganic coagulant.
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synthesis of amphoteric starch based grafting Flocculants for flocculation of both positively and negatively charged colloidal contaminants from water
Chemical Engineering Journal, 2014Co-Authors: Zhen Yang, Hu Wu, Bo Yuan, Mu Huang, Hu Yang, Aimin Li, Rongshi ChengAbstract:Contaminants in real water are normally complicated. Surface charges of suspended colloidal particles can be either negative or positive. In this work, a series of amphoteric starch-based grafting Flocculants (3-chloro-2-hydroxypropyl trimethyl ammonium chloride modified starch-graft-poly(acrylamide-co-acrylic acid)) denoted as SCPAMPAA were successfully synthesized with different grafting ratios and used for the removal of different charged contaminants from water. Various SCPAMPAA Flocculants exhibited remarkably different flocculation performance and obeyed diverse flocculation mechanisms due to the differences in their structural characteristics. Therefore, precise control of the molecular structure of Flocculants is of great significance to obtain the desired flocculation performance. To provide practically operational feasibility for the preparation of a predicted flocculant, a quantitative mathematical correlation between the preparation recipe and the structural features of SCPAMPAA were derived. The final well-designed flocculant demonstrated a high flocculation performance in aspects of optimal dosage, flocculation window and pH sensitivity for the removal of both negatively and positively charged colloidal contaminants from targeted wastewater.
Joao B P Soares - One of the best experts on this subject based on the ideXlab platform.
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dewatering of oil sands tailings with novel chitosan based Flocculants
Energy & Fuels, 2018Co-Authors: Leonardo Pennetta De Oliveira, Sarang P Gumfekar, F L Motta, Joao B P SoaresAbstract:Mature fine tailings need to be dewatered to reduce the environmental impact caused by oil sands extraction. Polymer Flocculants are commonly used to accelerate this process. In this work, we modified chitosan, a naturally occurring biopolymer, with 3-chloro-2-hydroxypropyltrimethylammonium chloride (Chito-CTA) and also grafted polyacrylamide to chitosan (Chito-g-PAM). We compared the dewatering performance of these two Flocculants with that of a commercial cationic polyacrylamide (C-PAM). Chito-CTA and Chito-g-PAM dewatered tailings at rates of 18.27 and 20.72 m/h, respectively. The dewatering ability of Chito-CTA and Chito-g-PAM, measured in terms of capillary suction time (CST), was below 10 s, whereas the value for C-PAM was 82.3 s at optimum dosage. The turbidity of the supernatant obtained after flocculation with Chito-CTA or Chito-g-PAM was below 10 NTU, while C-PAM produced turbid supernatants. We studied the effect of flocculant microstructure on the specific resistance to filtration of the sedim...
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water soluble polymers for oil sands tailing treatment a review
Canadian Journal of Chemical Engineering, 2015Co-Authors: Diogenes R L Vedoy, Joao B P SoaresAbstract:Efficient dewatering of oil sands tailings is imperative to reduce the environmental footprint of oil sands operators. Currently there is no mature technology capable of effectively treating oil sands tailings and completely eliminating the use of tailings ponds. Consolidated tailings and paste technology are the most extensively used dewatering methods. However, the high concentrations of divalent ions in the water recovered using the consolidated tailings process impedes the re-utilization of this water in the bitumen extraction process. Accumulation of ions does not occur in the case of paste technology; however, this technology, similarly to the consolidated tailings process, recovers only part of the water from tailings and produces high-water content sediments (25–30 wt. % solids) that sill requires special storage. This happens because the sediments produced by polyacrylamide (PAM) Flocculants are not closely packed and require the application of other consolidation technologies (e.g., freeze-thaw, filtration, centrifugation) to obtain dry and self-supportive tailings. This review focuses on examining alternative Flocculants that could potentially replace PAM polymers in mature and new dewatering technologies. Flocculants are a key element of many tailing treatments including paste technology and filtration. The “ideal” flocculant would increase the ability of these technologies to dewater tailings, resulting in higher water recovery and sediment consolidation without affecting water chemistry or increasing operational costs. This review presents a comparison between PAM Flocculants and two promising alternative Flocculants: inorganic-organic hybrid and temperature-sensitive polymers. Each flocculant type is evaluated in terms of its flocculation mechanisms and its dewatering efficacy.
Zhen Yang - One of the best experts on this subject based on the ideXlab platform.
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enhanced removal of trace antibiotics from turbid water in the coexistence of natural organic matters using phenylalanine modified chitosan Flocculants effect of Flocculants molecular architectures
Chemical Engineering Journal, 2018Co-Authors: Hongwei Du, Zhen Yang, Ziqi Tian, Menglu Huang, Weiben Yang, Limin Zhang, Aimin LiAbstract:Abstract Removal of two typical antibiotics (norfloxacin and tylosin) at trace level in turbid water simultaneously containing natural organic matters (NOMs) was conducted using two phenylalanine (Phe)-modified-chitosan Flocculants (CHS-Phe and CHS-PPhe) with different molecular architectures. Response surface methodology (RSM) was applied for interactive effects evaluation and optimization of various parameters. CHS-Phe with linear molecular architecture displays higher removal efficiencies of antibiotics than commercial Flocculants. By contrast, CHS-PPhe, owning the same Phe functional groups but comb-like architecture (polyPhe polymer branches grafted on chitosan backbone), shows poor performance. Deep mechanism investigations indicated that, for hydrophilic and flexible CHS-Phe linear molecules, bridging and sweeping flocculation for antibiotics were enhanced by electrostatic attraction, π-electron-containing interaction, and H-bond between introduced Phe groups and antibiotic molecules. However, for comb-like CHS-PPhe, excessively hydrophobic polyPhe branches aggregated to coils. This phenomenon caused fewer exposed flocculation sites outwards, although the interactions of Phe-antibiotic still existed. 3D response surfaces of CHS-Phe generated by RSM exhibited that, concentrations of coexisting kaolin and HA, as well as pH and flocculant dosage, can be controlled to obtain desired performance. This work enriches the knowledge of effect of molecular architecture of Flocculants on contaminant removal, and provides guidance for flocculation parameter control.
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synthesis of amphoteric starch based grafting Flocculants for flocculation of both positively and negatively charged colloidal contaminants from water
Chemical Engineering Journal, 2014Co-Authors: Zhen Yang, Hu Wu, Bo Yuan, Mu Huang, Hu Yang, Aimin Li, Rongshi ChengAbstract:Contaminants in real water are normally complicated. Surface charges of suspended colloidal particles can be either negative or positive. In this work, a series of amphoteric starch-based grafting Flocculants (3-chloro-2-hydroxypropyl trimethyl ammonium chloride modified starch-graft-poly(acrylamide-co-acrylic acid)) denoted as SCPAMPAA were successfully synthesized with different grafting ratios and used for the removal of different charged contaminants from water. Various SCPAMPAA Flocculants exhibited remarkably different flocculation performance and obeyed diverse flocculation mechanisms due to the differences in their structural characteristics. Therefore, precise control of the molecular structure of Flocculants is of great significance to obtain the desired flocculation performance. To provide practically operational feasibility for the preparation of a predicted flocculant, a quantitative mathematical correlation between the preparation recipe and the structural features of SCPAMPAA were derived. The final well-designed flocculant demonstrated a high flocculation performance in aspects of optimal dosage, flocculation window and pH sensitivity for the removal of both negatively and positively charged colloidal contaminants from targeted wastewater.
Hu Wu - One of the best experts on this subject based on the ideXlab platform.
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evaluation of chain architectures and charge properties of various starch based Flocculants for flocculation of humic acid from water
Water Research, 2016Co-Authors: Hu Wu, Hu Yang, Aimin LiAbstract:Three different starch-based Flocculants with various chain architectures and charge properties have been prepared through etherification, graft copolymerization, or their combination. Two of the Flocculants (starch-graft-poly[(2-methacryloyloxyethyl) trimethyl ammonium chloride] and starch-3-chloro-2-hydroxypropyl triethyl ammonium chloride, denoted as STC-g-PDMC and STC-CTA respectively) are cationic, and another one (carboxymethyl starch-graft-poly[(2-methacryloyloxyethyl) trimethyl ammonium chloride], denoted as CMS-g-PDMC) is amphoteric. Those three Flocculants have shown far different flocculation efficiency and floc properties for the removal of humic acid (HA) from water due to their distinct structural features. The effects of pH, flocculant dose, and initial HA concentration have been studied systematically. Accordingly, STC-g-PDMC and CMS-g-PDMC with strongly cationic branch chains have much better flocculation performance than polyaluminum chloride (PAC) and STC-CTA, the latter of which features linear chain architecture and strongly cationic pieces lying on its chain backbone. It indicates that the architecture of cationic branch chains plays an important role in HA flocculation due to their significantly enhanced bridging effects. Moreover, STC-g-PDMC has higher HA removal efficiency and better floc properties than CMS-g-PDMC, suggesting that charge neutralization effects make notable contributions to HA removal and that the additional anionic pieces on CMS-g-PDMC can weaken its flocculation performance. In addition, STC-g-PDMC used as coagulant aid for PAC has also been tried, which observably reduces the optimal dose of the inorganic coagulant.
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synthesis of amphoteric starch based grafting Flocculants for flocculation of both positively and negatively charged colloidal contaminants from water
Chemical Engineering Journal, 2014Co-Authors: Zhen Yang, Hu Wu, Bo Yuan, Mu Huang, Hu Yang, Aimin Li, Rongshi ChengAbstract:Contaminants in real water are normally complicated. Surface charges of suspended colloidal particles can be either negative or positive. In this work, a series of amphoteric starch-based grafting Flocculants (3-chloro-2-hydroxypropyl trimethyl ammonium chloride modified starch-graft-poly(acrylamide-co-acrylic acid)) denoted as SCPAMPAA were successfully synthesized with different grafting ratios and used for the removal of different charged contaminants from water. Various SCPAMPAA Flocculants exhibited remarkably different flocculation performance and obeyed diverse flocculation mechanisms due to the differences in their structural characteristics. Therefore, precise control of the molecular structure of Flocculants is of great significance to obtain the desired flocculation performance. To provide practically operational feasibility for the preparation of a predicted flocculant, a quantitative mathematical correlation between the preparation recipe and the structural features of SCPAMPAA were derived. The final well-designed flocculant demonstrated a high flocculation performance in aspects of optimal dosage, flocculation window and pH sensitivity for the removal of both negatively and positively charged colloidal contaminants from targeted wastewater.