Thu Dau Mot University Journal of Science


UTILIZATION OF HYDROXYAPATITE/CRAB SHELL CHITOSAN COMPOSITES IN REMOVAL OF AQUEOUS CONGO RED: INFLUENCE FACTORS, ADSORPTION KINETICS AND ISOTHERM

By Nguyen Trung Hieu, Ha Tuan Anh
DOI: 10.37550/tdmu.EJS/2025.02.627

Abstract

Due to the limitations of traditional adsorbents for dyeing wastewater, this study combined natural adsorbent (CS, chitosan) and hydroxyapatite (HAp) to form a composite for enhancing the adsorption of aqueous Congo red (CR). The chitosan was prepared from crab shells (Somanniathelphusa sinensis) with a deacetylation degree of about 89%. The HAp and HAp-CS composites were prepared by precipitation in high pH (~10) with the help of concentrated ammonia water (25%). The crab shell chitosan and chitin were characterized by the FTIR method, and the HAp and HAp-CS composites were analyzed using the SEM method. The CR adsorption experiments were carried out in batch form and sampled once for each condition. The results showed that the characteristic peaks in the FTIR spectrum confirmed the success of the crab shell chitosan preparation. The HAp and HAp-CS composites possess porous structures and seem to have a high surface area. The CR adsorptions reached optimal after 5-15 min. contacting, the adsorption efficiency tended to decrease with the initial concentration of CR and increase with the adsorbent dosage. The initial pH of the solution affected the adsorption efficiency for the 70%HAp-CS and 30%HAp-CS composites but had almost no effect on the adsorption capacity of 0%HAp-CS and 50%HAp-CS. The 50%HAp-CS composite had the best adsorption capacity among the synthesized composites (qmax = 769.2mg/g). The adsorption isotherm and kinetics best fit the Langmuir isotherm and pseudo-second-order kinetics model.


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Publication Information

Publisher

Thu Dau Mot University, Viet Nam

Editor-in-Chief

Assoc. Prof. Nguyen Van Hiep
Thu Dau Mot University

Editorial Board

Assoc. Prof. Le Tuan Anh
Thu Dau Mot University
PhD. Nguyen Quoc Cuong
Thu Dau Mot University

PhD. Doan Ngoc Xuan
Thu Dau Mot University
PhD. Nguyen Khoa Truong An
Thu Dau Mot University

Assoc. Prof. Nguyen Thanh Binh
Thu Dau Mot University
PhD. Le Thi Thuy Dung
Thu Dau Mot University

PhD. Ngo Hong Diep
Thu Dau Mot University
PhD. Nguyen Duc Dat Duc
Ho Chi Minh City University of Industry and Trade

Assoc. Prof. Nguyen Van Duc
Animal Husbandry Association of Vietnam
PhD. Nguyen Thi Nhat Hang
Department of Education and Training of Binh Duong Province

PhD. Nguyen Thi Cam Le
Vietnam Aviation Academy
PhD. Trần Hạnh Minh Phương
Thu Dau Mot University

M.A. Pham Van Thinh
Thu Dau Mot University
PhD. Nguyen Thi Lien Thuong
Thu Dau Mot University

Prof. Le Quang Tri
Can Tho University
Prof. Banh Quoc Tuan
Thu Dau Mot University