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Wu H, Shen W, Zhao Q, Zhang W. Synthesis of chitosan-based flocculant by dielectric barrier discharge modification and its flocculation performance in wastewater treatment. RSC Adv 2024; 14:2410-2421. [PMID: 38223699 PMCID: PMC10785050 DOI: 10.1039/d3ra06265a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2023] [Accepted: 01/04/2024] [Indexed: 01/16/2024] Open
Abstract
As a typical type of organic flocculant, chitosan is limited by its poor water solubility and narrow pH range application. Grafting modification can improve chitosan's solubility and availability through linking macromolecular chains with other types of water-soluble groups or functional side groups. In this study, dielectric barrier discharge (DBD) was used to active the surface of chitosan, then activated chitosan was polymerized with acrylamide to synthesize a chitosan-based flocculant, chitosan-acrylamide (CS-AM). During the synthesis of CS-AM, the optimal conditions were determined as follows: discharge time of 5 min, discharge power of 60 W, total monomer mass concentration of 80 g L-1, polymerization time of 3 h, polymerization temperature of 70 °C, and m(CS) : m(AM) ratio of 1 : 3. The structure and morphological characteristics of CS-AM were investigated and analyzed by Fourier transform infrared (FTIR) spectroscopy, X-ray photoelectron spectroscopy (XPS), thermogravimetric (TG) analysis, scanning electron microscopy (SEM), X-ray diffraction (XRD) and N2 physical adsorption, respectively. The removal efficiency of kaolin suspension and CNTs suspension can reach up to 95.9% and 90.2% after flocculation of CS-AM. Furthermore, the zeta potential of the supernatant from the CS-AM treated kaolin suspension at different pH values was examined, and the flocculation mechanism of CS-AM was analyzed. This study provides new ideas for the preparation and development of modified chitosan and broadens its application in water treatment.
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Affiliation(s)
- Haixia Wu
- College of Urban Construction, Nanjing Tech University Nanjing 211816 China
| | - Wang Shen
- College of Urban Construction, Nanjing Tech University Nanjing 211816 China
| | - Quanfa Zhao
- College of Urban Construction, Nanjing Tech University Nanjing 211816 China
| | - Weiwei Zhang
- College of Urban Construction, Nanjing Tech University Nanjing 211816 China
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Zhao W, Zou W, Liu F, Zhou F, Altun NE. Molecular dynamics simulations of the solubility and conformation change of chitosan grafted polyacrylamide: Impact of grafting rate. J Mol Graph Model 2024; 126:108660. [PMID: 37956531 DOI: 10.1016/j.jmgm.2023.108660] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2023] [Revised: 10/24/2023] [Accepted: 10/24/2023] [Indexed: 11/15/2023]
Abstract
Graft modification is an effective approach to improve the water solubility and molecular weight of chitosan. This work investigated the effect of grafting rate on water solubility of chitosan-grafted polyacrylamide (Chi-g-PAM) using molecular dynamics simulations. The intramolecular and intermolecular interaction between Chi-g-PAM with the grafting rate of 100%-250% and water together with the conformation change were analyzed by radial distribution function (RDF), radius of gyration, solvation free energy (ΔGSFE), mean square displacement, diffusion coefficient and shear viscosity. The results showed that the intramolecular hydrogen bonding of Chi-g-PAM was the dominant factor affecting its water solubility. While the grafting rate of Chi-g-PAM increased from 100% to 250%, the RDF of Chi-g-PAM decreased from 5.39 to 3.57 between O-H at 2.0 Å and 2.60 to 1.30 between N-H at 2.1 Å. The interaction between Chi-g-PAM and water increased with grafting rate as the absolute value of ΔGSFE for Chi-g-PAM increased from 432.917 kcal/mol to 858.749 kcal/mol. The solubility of Chi-g-PAM in acidic solution was much better than that of Chi-g-PAM in aqueous solution. Our work on the fundamental insights into the effect of grafted molecular structure of chitosan-based copolymer on its solubility will benefit the development of environmentally friendly chitosan-based flocculants.
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Affiliation(s)
- Wei Zhao
- State Key Laboratory of High-Efficient Mining and Safety of Metal Mines of Ministry of Education, University of Science and Technology Beijing, Beijing 100083, China; State Key Laboratory of Water Resource Protection and Utilization in Coal Mining, China
| | - Wenjie Zou
- State Key Laboratory of Water Resource Protection and Utilization in Coal Mining, China; School of Civil and Resources Engineering, University of Science and Technology Beijing, Beijing 100083, China.
| | - Fengyang Liu
- School of Civil and Resources Engineering, University of Science and Technology Beijing, Beijing 100083, China
| | - Fang Zhou
- Key Laboratory for Green Chemical Process of Ministry of Education, Wuhan Institute of Technology, Wuhan, 430073, China
| | - N Emre Altun
- Middle East Technical University, Mining Engineering Department, Ankara, Turkey
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Zhao Q, Wu H, Shen W, Han X, Zheng B, Wang Y. Dielectric barrier discharge plasma-modified chitosan flocculant and its flocculation performance. Int J Biol Macromol 2023; 251:126364. [PMID: 37595720 DOI: 10.1016/j.ijbiomac.2023.126364] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2023] [Revised: 07/19/2023] [Accepted: 08/14/2023] [Indexed: 08/20/2023]
Abstract
The flocculation performance of chitosan can be enhanced by grafting modification to overcome its disadvantages of poor water solubility. In this study, chitosan was modified by dielectric barrier discharge plasma and polymerized with acrylamide and aluminum chloride to synthesize a new chitosan-based flocculant, namely, chitosan-acrylamide-aluminum chloride (CA-PAC). After optimizing the synthesis conditions of CA-PAC, the best conditions were as follows: discharge time of 3 min, discharge power of 50 W, polymerization temperature of 60 °C, polymerization time of 3 h, total monomer concentration of 100 g/L, and m(AlCl3):m(CA) ratio of 2:1. Characterization was performed through SEM, XPS, FTIR, XRD, TG and 1H NMR. Results showed that the preparation of CA-PAC was successful. The influences of flocculant dosage, pH, and stirring intensity on flocculation efficiency were investigated. The removal efficiency of turbidity was 94.1 %. The investigation of the flocculation mechanism revealed that CA-PAC mainly relied on charge neutralization or the synergic action of electric neutralization, bridging, and roll-sweep under acidic and neutral conditions, but it depended on the joint action of adsorption bridging and net sweeping under alkaline conditions. This study provides new ideas for the preparation and development of modified chitosan and broadens its application in water treatment.
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Affiliation(s)
- Quanfa Zhao
- College of Urban Construction, Nanjing Tech University, Nanjing 211816, China
| | - Haixia Wu
- College of Urban Construction, Nanjing Tech University, Nanjing 211816, China.
| | - Wang Shen
- College of Urban Construction, Nanjing Tech University, Nanjing 211816, China
| | - Xiao Han
- College of Urban Construction, Nanjing Tech University, Nanjing 211816, China
| | - Bin Zheng
- College of Urban Construction, Nanjing Tech University, Nanjing 211816, China
| | - Yong Wang
- Nanjing Branch of Central & Southern China Municipal Engineering Design and Research Institute Co., Ltd, Nanjing 210012, China
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Wang R, Zhou J, Qu G, Wang T, Jia H, Zhu L. FT-ICR/MS deciphers formation of unknown macromolecular disinfection byproducts from algal organic matters after plasma oxidation. WATER RESEARCH 2022; 218:118492. [PMID: 35489152 DOI: 10.1016/j.watres.2022.118492] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/19/2022] [Revised: 04/19/2022] [Accepted: 04/20/2022] [Indexed: 06/14/2023]
Abstract
Algal organic matter (AOM) is a potential precursor of disinfection byproducts (DBPs) in water treatment. It is a major challenge to identify macromolecular DBPs due to the diversity of AOM. In this study, Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR/MS) was applied to diagnose the AOM diversity after algae removal by plasma oxidation and to recognize the macromolecular DBPs in subsequent chlorination. Significant removal of AOM released by M. aeruginosa, C. raciborskii, and A. spiroies was achieved by plasma oxidation, accompanied by decrease in the proportion of CHNO formulas and increase in CHO formulas. Without plasma treatment, chlorination generated approximately 2486 macromolecular carbonaceous DBPs (C-DBPs) and 1984 nitrogenous DBPs (N-DBPs), with C11HnOmClx and C18HnNmOzClx as the most abundant DBPs. The numbers of C-DBPs and N-DBPs decreased by 63.3% and 62.9%, respectively, if plasma treatment was applied prior to chlorination. Network computational analysis revealed that Cl substitution was the main formation pathway of AOM-derived DBP formation rather than HOCl addition. The precursors of macromolecular DBPs contained a characteristic atomic number of C and O (7 ≤ C ≤ 18; 3 ≤ O ≤ 11). This study firstly disclosed the relationship between AOM diversity and novel macromolecular DBPs during algae-laden water treatment.
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Affiliation(s)
- Ruigang Wang
- College of Natural Resources and Environment, Northwest A&F University, Yangling, Shaanxi 712100, PR China; Key Laboratory of Plant Nutrition and the Agri-Environment in Northwest China, Ministry of Agriculture, Yangling, Shaanxi 712100, PR China
| | - Jian Zhou
- College of Natural Resources and Environment, Northwest A&F University, Yangling, Shaanxi 712100, PR China; Key Laboratory of Plant Nutrition and the Agri-Environment in Northwest China, Ministry of Agriculture, Yangling, Shaanxi 712100, PR China
| | - Guangzhou Qu
- College of Natural Resources and Environment, Northwest A&F University, Yangling, Shaanxi 712100, PR China; Key Laboratory of Plant Nutrition and the Agri-Environment in Northwest China, Ministry of Agriculture, Yangling, Shaanxi 712100, PR China
| | - Tiecheng Wang
- College of Natural Resources and Environment, Northwest A&F University, Yangling, Shaanxi 712100, PR China; Key Laboratory of Plant Nutrition and the Agri-Environment in Northwest China, Ministry of Agriculture, Yangling, Shaanxi 712100, PR China.
| | - Hanzhong Jia
- College of Natural Resources and Environment, Northwest A&F University, Yangling, Shaanxi 712100, PR China; Key Laboratory of Plant Nutrition and the Agri-Environment in Northwest China, Ministry of Agriculture, Yangling, Shaanxi 712100, PR China
| | - Lingyan Zhu
- College of Natural Resources and Environment, Northwest A&F University, Yangling, Shaanxi 712100, PR China; Key Laboratory of Plant Nutrition and the Agri-Environment in Northwest China, Ministry of Agriculture, Yangling, Shaanxi 712100, PR China.
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Xu R, Zou W, Wang T, Huang J, Zhang Z, Xu C. Adsorption and interaction mechanisms of Chi-g-P(AM-DMDAAC) assisted settling of kaolinite in a two-step flocculation process. THE SCIENCE OF THE TOTAL ENVIRONMENT 2022; 816:151576. [PMID: 34774625 DOI: 10.1016/j.scitotenv.2021.151576] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/15/2021] [Revised: 10/22/2021] [Accepted: 11/06/2021] [Indexed: 06/13/2023]
Abstract
Flocculation has been widely employed in treatment of mineral tailings and water management. In this study, a chitosan-graft-poly(acrylamide-dimethyl diallyl ammonium chloride) (Chi-g-P(AM-DMDAAC)) was synthesized in-house. The adsorption and interaction mechanisms of Chi-g-P(AM-DMDAAC) and an anionic polyacrylamide (APAM) in a two-step flocculation process of kaolinite were explored using settlement tests, zeta potential measurement, quartz crystal micro-balance with dissipation (QCM-D) and atomic force microscopy (AFM) technique. The type of primary flocculant was critical for the two-step flocculation process. The treatment of the kaolinite suspension using 1 mg/L of Chi-g-P(AM-DMDAAC) followed by adding 2 mg/L of APAM displayed more efficient flocculation performance. QCM-D results showed that three dissipative layers were assembled on model kaolinite surface after sequentially injecting 3.5 mg/L of Chi-g-P(AM-DMDAAC), 0.05 wt% kaolinite suspension and 2.5 mg/L of APAM. The above total adsorption amount (Δf of -64.9 Hz) was much higher than that of using the two flocculants in reverse order (Δf of -23.1 Hz). This result indicated that the adsorption layer of the positively charged Chi-g-P(AM-DMDAAC) on kaolinite surface provided active adsorption sites for APAM. Further AFM measurement confirmed that the average adhesion between the silicon tip adsorbed Chi-g-P(AM-DMDAAC) and model kaolinite surface in 2.5 mg/L APAM solution increased from 0.25 ± 0.1 nN to 4.2 ± 0.3 nN with the effective interaction range of 700 nm, which was stronger than that measured between a bare silicon tip and silica substrate in single-component-flocculant solutions. The highly efficient two-step flocculation process could be ascribed to the strong electrostatic attraction between the kaolinite and the oppositely charged Chi-g-P(AM-DMDAAC) and APAM. Findings in this study will benefit the development of environmentally friendly flocculant for mineral tailings and water treatment.
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Affiliation(s)
- Ruijing Xu
- Civil and Resource Engineering School, University of Science and Technology Beijing, Beijing 100083, China
| | - Wenjie Zou
- Civil and Resource Engineering School, University of Science and Technology Beijing, Beijing 100083, China.
| | - Ting Wang
- Civil and Resource Engineering School, University of Science and Technology Beijing, Beijing 100083, China
| | - Jun Huang
- Center for Advanced Jet Engineering Technologies (CaJET), Key Laboratory of High-efficiency and Clean Mechanical Manufacture (Ministry of Education), School of Mechanical Engineering, Shandong University, Jinan 250061, China
| | - Zhijun Zhang
- School of Chemical and Environmental Engineering, China University of Mining and Technology, Beijing, China
| | - Chengyan Xu
- Civil and Resource Engineering School, University of Science and Technology Beijing, Beijing 100083, China
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Sun Y, Yu Y, Zhou S, Shah KJ, Sun W, Zhai J, Zheng H. Functionalized chitosan-magnetic flocculants for heavy metal and dye removal modeled by an artificial neural network. Sep Purif Technol 2022. [DOI: 10.1016/j.seppur.2021.120002] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
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Xu K, Zou X, Chang W, Qu Y, Li Y. Microalgae harvesting technique using ballasted flotation: A review. Sep Purif Technol 2021. [DOI: 10.1016/j.seppur.2021.119439] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
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Efficient Bioflocculation of Chlorella vulgaris with a Chitosan and Walnut Protein Extract. BIOLOGY 2021; 10:biology10050352. [PMID: 33919407 PMCID: PMC8143315 DOI: 10.3390/biology10050352] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/21/2021] [Revised: 04/19/2021] [Accepted: 04/19/2021] [Indexed: 11/29/2022]
Abstract
Simple Summary With the increase in population size, global climate changes, and the improvement of living standards, the fossil fuel resources may run out in the future. Microalgae have been considered the next generation of sustainable and renewable feedstock to produce biofuel and a large spectrum of high-value products, such as healthy oils, carotenoids, and proteins. Unlike terrestrial plants, the production of added-value chemicals from microalgal species is not seasonal; they can be grown under climate-independent conditions in bioreactors; can use wastewater as a source of nutrients, contributing to wastewater treatment; and can convert CO2 into organic compounds more efficiently. However, the utilization of microalgal biomass is heavily dependent on microalgal biomass harvesting and concentration technology. Flocculation represents a relatively low-cost and efficient approach for the harvesting of microalgal biomass at a large scale. However, in traditional flocculation, most of the chemical flocculants covalently bind to the microalgal surfaces, contaminating the final product, which significantly limits their application. This study aims to develop an efficient and convenient bioflocculation technique to harvest microalgae. Abstract Bioflocculation represents an attractive technology for harvesting microalgae with the potential additive effect of flocculants on the production of added-value chemicals. Chitosan, as a cationic polyelectrolyte, is widely used as a non-toxic, biodegradable bioflocculant for many algal species. The high cost of chitosan makes its large-scale application economically challenging, which triggered research on reducing its amount using co-flocculation with other components. In our study, chitosan alone at a concentration 10 mg/L showed up to an 89% flocculation efficiency for Chlorella vulgaris. Walnut protein extract (WPE) alone showed a modest level (up to 40%) of flocculation efficiency. The presence of WPE increased chitosan’s flocculation efficiency up to 98% at a reduced concentration of chitosan (6 mg/L). Assessment of co-flocculation efficiency at a broad region of pH showed the maximum harvesting efficiency at a neutral pH. Fourier transform infrared spectroscopy, floc size analysis, and microscopy suggested that the dual flocculation with chitosan and walnut protein is a result of the chemical interaction between the components that form a web-like structure, enhancing the bridging and sweeping ability of chitosan. Co-flocculation of chitosan with walnut protein extract, a low-value leftover from walnut oil production, represents an efficient and relatively cheap system for microalgal harvesting.
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Plasma-enhanced modification of polysaccharides for wastewater treatment: A review. Carbohydr Polym 2021; 252:117195. [PMID: 33183635 DOI: 10.1016/j.carbpol.2020.117195] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2020] [Revised: 09/29/2020] [Accepted: 10/03/2020] [Indexed: 01/23/2023]
Abstract
In this work, novel polysaccharide-based sorbents modified with plasma technologies are discussed. Plasma selectively modifies the surface properties by generating specific moieties, enhancing adsorption performance, and the physical-chemical properties of the material without modifying its bulk properties. Among plasma technologies, cold plasma is more suitable and energy-efficient, since thermal-sensitive materials could be modified using this technology. Besides, atmospheric-pressure plasma systems possess the required features to scale-up plasma technologies for surface modification of sorbents. Moreover, a big challenge is the semi-continuous operation to modify sorbents as it would decrease overall process costs. Due to its low-cost and extensive availability, polysaccharide-based sorbents are promising substrates for plasma-enhanced modification to develop highly efficient adsorbents. The development of polysaccharide-based materials includes modified cellulose, chitosan, or lignocellulosic materials with functionalities that increase adsorption capacity and selectivity towards a specific organic or inorganic pollutant.
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Chen J, Xu X, Nie R, Feng L, Li X, Liu B. Chitosan Modified Cationic Polyacrylamide Initiated by UV-H 2O 2 for Sludge Flocculation and New Insight on the Floc Characteristics Study. Polymers (Basel) 2020; 12:E2738. [PMID: 33218149 PMCID: PMC7698928 DOI: 10.3390/polym12112738] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2020] [Revised: 11/13/2020] [Accepted: 11/16/2020] [Indexed: 11/16/2022] Open
Abstract
In the present study, a novel graft modified flocculant CTS-g-PAMD was synthesized and applied to conduct sludge conditioning and dewatering. CTS-g-PAMD was copolymerized with AM, DMC and chitosan (CTS) under UV-H2O2 initiation. In addition, the effects of single factor experiments on the molecular weight (MW) CTS grafting efficiency (GE) of CTS-g-PAMD were determined and the optimal copolymerization conditions were achieved. The GE of CTS-g-PAMD reached 91.1% and the MW was 4.82 × 106 Da. As revealed from the characterized results of Fourier-transform infrared spectra (FT-IR), 1H/ NMR, X-ray diffraction (XRD), scanning electron microscopic (SEM) and X-ray photoelectron spectroscopy (XPS), the successful synthesis of CTS-g-PAMD was confirmed, which is considered to be conducive to explaining sludge dewatering performance. Under the optimal conditions (pH = 7.0, flocculant dosage = 35 mg/L), the best flocculating performance (FCMC: 73.7%; SRF: 4.7 × 1012 m·kg-1, turbidity: 9.4 NTU) and large and dense sludge flocs (floc size d50 = 379.142 µm, floc fractal dimension Df = 1.58) were formed. The DMC and CTS chain segments exhibiting cationic properties significantly improved the positive charge density and enhanced the electrical patching effect of CTS-g-PAMD. The long molecular chain of CTS-g-PAMD exhibited superior extensibility, which enhanced bridging effect on adsorption. Moreover, the sludge floc after undergoing CTS-g-PAMD conditioning exhibited robust shear resistance and regeneration ability. After the sludge floc was crushed and broken, a large and dense sludge floc was formed, helping significantly reduce the sludge specific resistance (SRF), turbidity and cake moisture content (FCMC) and enhance the sludge dewatering effect. The novel CTS-g-PAMD flocculant shows promising practical applications and high market value.
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Affiliation(s)
- Jie Chen
- Faculty of Environmental Science and Engineering, Kunming University of Science and Technology, Kunming 650500, China; (J.C.); (X.X.); (R.N.)
| | - Xiaojun Xu
- Faculty of Environmental Science and Engineering, Kunming University of Science and Technology, Kunming 650500, China; (J.C.); (X.X.); (R.N.)
| | - Rui Nie
- Faculty of Environmental Science and Engineering, Kunming University of Science and Technology, Kunming 650500, China; (J.C.); (X.X.); (R.N.)
| | - Li Feng
- School of Civil and Transportation Engineering, Guangdong University of Technology, Guangzhou 510006, China; (X.L.); (B.L.)
| | - Xuhao Li
- School of Civil and Transportation Engineering, Guangdong University of Technology, Guangzhou 510006, China; (X.L.); (B.L.)
| | - Bingzhi Liu
- School of Civil and Transportation Engineering, Guangdong University of Technology, Guangzhou 510006, China; (X.L.); (B.L.)
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Flocculation activity and evaluation of chitosan-based flocculant CMCTS-g-P(AM-CA) for heavy metal removal. Sep Purif Technol 2020. [DOI: 10.1016/j.seppur.2020.116737] [Citation(s) in RCA: 31] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
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