Chen Xiaohong, Deng Wenyang, Miao Luwei, Gao Ming, Ao Tianqi, Chen Wenqing, Ueyama Tetsuro, Dai Qizhou
College of Architecture and Environment, Sichuan University, Chengdu, People's Republic of China.
Institute for Disaster Management and Reconstruction, Sichuan University-The Hong Kong Polytechnic University, Chengdu, PR People's Republic of China.
Environ Technol. 2023 Apr;44(10):1505-1517. doi: 10.1080/09593330.2021.2005689. Epub 2021 Nov 23.
Capacitive deionization (CDI) is an environmentally friendly desalination technique with low energy consumption. However, unmodified carbon electrode materials have poor sulfate selectivity and adsorption capacity. In this work, to improve sulfate selectivity, we prepared activated carbon materials loaded with different amino contents by grafting amino groups via acid treatment for different times. In the competitive ion adsorption experiments, the sulfate selectivity of AC was only 0.64 and the amino-modified AC increased by 1.98-2.52 times due to the formation of stronger hydrogen bonds between the amino group and sulfate. AC-NH-4 had the best selectivity and the sulfate selective coefficient was 2.25. The desorption of sulfate was 92.46% within one hour. In addition, the surface of the amino-modified activated carbon showed significantly improved electrochemical properties and better capacitance. The specific capacitance of amino-modified AC in different electrolyte solutions was consistent with the competitive adsorption results. The specific capacitance of amino-modified AC in NaSO electrolyte solution was the highest. The modified electrode material also had the advantages of a higher adsorption capacity and excellent regeneration performance after continuous electric adsorption-desorption cycles. Therefore, it may have development potential to selectively adsorb sulfate in practical applications.
电容去离子化（CDI）是一种环保型低能耗脱盐技术。然而，未经改性的碳电极材料对硫酸盐的选择性和吸附容量较差。在本工作中，为提高硫酸盐选择性，我们通过不同时间的酸处理接枝氨基制备了负载不同氨基含量的活性炭材料。在竞争离子吸附实验中，活性炭对硫酸盐的选择性仅为0.64，而氨基改性的活性炭由于氨基与硫酸盐之间形成更强的氢键，其选择性提高了1.98 - 2.52倍。AC - NH - 4具有最佳选择性，硫酸盐选择系数为2.25。硫酸盐在一小时内的解吸率为92.46%。此外，氨基改性活性炭的表面电化学性能显著改善，电容更好。氨基改性活性炭在不同电解质溶液中的比电容与竞争吸附结果一致。氨基改性活性炭在NaSO电解质溶液中的比电容最高。改性电极材料还具有较高的吸附容量以及在连续电吸附 - 解吸循环后优异的再生性能等优点。因此，其在实际应用中选择性吸附硫酸盐可能具有发展潜力。
