Open Access

ARTICLE

Chitosan and Carboxymethylchitosan as High Turbidity Water Biocoagulants

by Raimundo N. Lima Júnior, João L. I. O. Almeida, Jones de Andrade, Flávia O. M. S. Abreu

1 Natural Sciences Program, State University of Ceará-UECE, Fortaleza, CE 60714-903, Brazil
2 Physical-Chemistry Department, Institute of Chemistry, Federal University of Rio Grande do Sul-UFRGS, Porto Alegre, RS 91501-970, Brazil

* Corresponding Author: Flávia O. M. S. Abreu. Email:

(This article belongs to the Special Issue: 15th Brazilian Polymer Conference (15th CBPol))

Journal of Renewable Materials 2020, 8(11), 1489-1504. https://doi.org/10.32604/jrm.2020.011629

Received 20 May 2020; Accepted 09 July 2020; Issue published 28 September 2020

Abstract

Biocoagulants emerges as a promising technology in water treatment, in order to exploit renewable and biodegradable materials. The present work aims to study the coagulant action of chitosan and carboxymethylchitosan on water with very high turbidity (above 300 NTU), contrasting the physicochemical results with those obtained for aluminum sulphate. Carboxymethylchitosan was produced by the Williamson’s ethers synthesis and characterized by potentiometric titration, FTIR and ¹ H-NMR. The coagulant tests were performed using synthetic water in a Jar-test equipment, through the induction of high and low velocity gradients, followed by sedimentation. The results showed turbidity and color removal efficiencies above 99% for the biocoagulants, by applying dosages much lower than those used for aluminum sulphate; the volume of sedimentable solids obtained at the end of the water treatment process was much lower when chitosan and carboxymethylchitosan were used as coagulants (reduction of 25% when compared to aluminum sulphate). In summary, carboxymethylchitosan is a non-toxic, renewable, biodegradable material with high efficiency as a coagulant for waters with very high turbidity, showing promise for in natura applications.

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