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Fei YH, Deng H, Wu G, Luo M, Chen Y, Wang X, Ye H, Liu T. Insight into adsorption process and mechanisms of Cr(III) using carboxymethyl cellulose- g-poly(acrylic acid- co-acrylamide)/attapulgite composite hydrogel. ENVIRONMENTAL TECHNOLOGY 2023; 44:4173-4187. [PMID: 35611631 DOI: 10.1080/09593330.2022.2082325] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/17/2022] [Accepted: 05/15/2022] [Indexed: 06/15/2023]
Abstract
Cr(III) as one of the most concerned potentially toxic elements, is discharged from relevant industries and Cr(VI) reduction. Hydrogel-based adsorption could be one of the promising approaches for Cr(III) removal. Featured with environmental friendliness and low cost, carboxymethyl cellulose (CMC) was employed for the hydrogel synthesis, and attapulgite (APT) could be used to strengthen its stability. However, the adsorption performance and mechanisms need to be examined. In the present study, carboxymethyl cellulose-g-poly(acrylic acid-co-acrylamide)/ attapulgite (CMC-g-p(AA-co-AM)/APT) was synthesised via in situ copolymerisation. Its efficacy for removing Cr(III) from an aqueous solution was investigated using batch adsorption experiments. Results showed that the introduction of APT enhanced the thermal stability but decreased the swelling performance of the hydrogel. The prepared hydrogel could strongly adsorb Cr(III) at a wide pH range of 3.0-7.0. Cr(III) can be efficiently removed by the composite hydrogel within 1-2 h. At low concentration, CMC-g-p(AA-co-AM)/APT could slightly adsorbed more Cr(III) than CMC-g-p(AA-co-AM). The maximum absorption of CMC-g-p(AA-co-AM) and CMC-g-p(AA-co-AM)/APT were 74.8 and 47.7 mg/g at 298 K, respectively. The negative value of ΔHo and ΔGo indicated the adsorption of Cr(III) onto the two studied hydrogels is an exothermic and spontaneous process. Ion exchange and complexation, as implied by EDS, FT-IR and XPS, combining with electrostatic attraction are the possible adsorption mechanisms for Cr(III) onto the prepared hydrogels. All the results above suggests that the composite hydrogel CMC-g-p(AA-co-AM)/APT can be a promising candidate for the removal of Cr(III) from waste water.
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Affiliation(s)
- Ying-Heng Fei
- School of Environmental Science and Engineering, Guangzhou University, Guangzhou, People's Republic of China
| | - Hongmei Deng
- School of Environmental Science and Engineering, Guangzhou University, Guangzhou, People's Republic of China
- Key Laboratory of Water Safety and Protection in Pearl River Delta, Ministry of Education, Guangzhou, People's Republic of China
- Guangdong Provincial Key Laboratory of Radionuclides Pollution Control and Resources, Guangzhou University, Guangzhou, People's Republic of China
| | - Gaoyuan Wu
- School of Environmental Science and Engineering, Guangzhou University, Guangzhou, People's Republic of China
- Key Laboratory of Water Safety and Protection in Pearl River Delta, Ministry of Education, Guangzhou, People's Republic of China
| | - Mengting Luo
- School of Environmental Science and Engineering, Guangzhou University, Guangzhou, People's Republic of China
- Key Laboratory of Water Safety and Protection in Pearl River Delta, Ministry of Education, Guangzhou, People's Republic of China
| | - Yongheng Chen
- Key Laboratory of Water Safety and Protection in Pearl River Delta, Ministry of Education, Guangzhou, People's Republic of China
| | - Xiaohuan Wang
- College of Chemistry and Pharmaceutical Engineering, Nanyang Normal University, Nanyang, People's Republic of China
| | - Hengpeng Ye
- School of Chemistry and Materials, South-Central University for Nationalities, Wuhan, People's Republic of China
| | - Tao Liu
- School of Civil and Engneering, Guangzhou University, Guangzhou, People's Republic of China
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