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Synthesis, Characterization, and Sludge Dewaterability Evaluation of the Chitosan-Based Flocculant CCPAD

School of Energy and Environmental Engineering, University of Science and Technology Bejing, Bejing 100083, China
College of Urban Construction, Nanjing Tech University, Nanjing 211800, China
Jiangsu Key Laboratory of Industrial Water-Conservation & Emission Reduction, College of Environment, Nanjing Tech University, Nanjing 211800, China
Authors to whom correspondence should be addressed.
Polymers 2019, 11(1), 95;
Received: 9 December 2018 / Revised: 27 December 2018 / Accepted: 30 December 2018 / Published: 8 January 2019
(This article belongs to the Special Issue Chitin and Chitosan: Properties and Applications)
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Carboxymethyl chitosan (CMCS), acrylamide, and methacryloxyethyltrimethyl ammonium chloride were used as co-monomers to produce a sludge dewatering agent carboxymethyl chitosan-graft-poly(acrylamide-methacryloxyethyltrimethyl ammonium chloride) (CCPAD) by UV-induced graft polymerization. Single-factor experiments and response surface methodology were employed to investigate and optimize the grafting rate, grafting efficiency, and intrinsic viscosity influenced by the total monomer concentration, CMCS concentration, cationic degree, pH value, and illumination time. The structure, surface morphology, and thermal stability of CCPAD were characterized by infrared spectroscopy, hydrogen nuclear magnetic resonance, X-ray diffraction, scanning electron microscopy, and differential thermal-thermogravimetry. The raw sludge with 97.9% water content was sourced from the concentrated tank of a sewage treatment plant and used in the sludge condition experiments. In addition, CCPAD was applied as the sludge conditioner to investigate the effects of cationic degree, intrinsic viscosity, and pH on the supernatant turbidity, moisture content, specific resistance to filtration, and sludge settling ratio. Moreover, the mechanism of sludge conditioning by CCPAD was discussed by examining the zeta potential and extracellular polymeric substance (EPS) content of the supernatant. The sludge dewatering results confirmed that CCPAD had excellent performance for improving sludge dewaterability. View Full-Text
Keywords: chitosan-based flocculant; graft copolymerization; flocculation; sludge conditioning; dewaterability chitosan-based flocculant; graft copolymerization; flocculation; sludge conditioning; dewaterability

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This is an open access article distributed under the Creative Commons Attribution License which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited (CC BY 4.0).

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Shi, C.; Sun, W.; Sun, Y.; Chen, L.; Xu, Y.; Tang, M. Synthesis, Characterization, and Sludge Dewaterability Evaluation of the Chitosan-Based Flocculant CCPAD. Polymers 2019, 11, 95.

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