Science Engineer Laboratory for Energy, ENSAJ, Chouaïb Doukkali University, El Jadida, Morocco.
Innovative Durable Building and Infrastructure Research Center, Center for Creative Convergence Education, Hanyang University-ERICA, 55 Hanyangdaehak-ro, Sangnok-gu, Ansan-si, Gyeonggi-do, 15588, Republic of South Korea.
Environ Sci Pollut Res Int. 2023 Oct;30(49):107772-107789. doi: 10.1007/s11356-023-29896-6. Epub 2023 Sep 23.
Nitrates level in water is a worldwide problem that represents a risk to the environment and people's health; efforts are currently devoted to the development and implementation of new biomaterials for their removal. In this study, chitosan (Ch) from shrimp waste and the related epichlorohydrin-modified crossover chitosan (Ch-EPI) were used to remove nitrates from aqueous solutions. The mechanism of selective nitrate removal was elucidated and validated by theoretical calculations. The physicochemical performance of Ch and Ch-EPI was investigated through the main parameters pH, adsorption capacity, contact time, initial nitrate concentration, coexisting anions, and temperature. The experimental data were fitted to widely used adsorption kinetic models and adsorption isotherms. The maximum percentage of nitrate adsorption was reached at an equilibrium pH of 4.0 at an adsorbent dose of 2.0 g/L after a contact time of 50 min. Competing anion experiments show that chloride and sulfate ions have minimal and maximal effects on nitrate adsorption by Ch-EPI. Experimental adsorption data are best fitted to pseudo-second-order kinetic and isothermal Langmuir models. The maximum adsorption capacities of Ch and Ch-EPI for nitrate removal were 12.0 mg/g and 38 mg/g, respectively.
水中硝酸盐水平是一个全球性问题，对环境和人类健康构成威胁；目前正在努力开发和应用新型生物材料来去除硝酸盐。在这项研究中，使用虾废料中的壳聚糖（Ch）和相关的环氧氯丙烷改性交联壳聚糖（Ch-EPI）从水溶液中去除硝酸盐。通过理论计算阐明并验证了选择性去除硝酸盐的机制。通过主要参数 pH 值、吸附容量、接触时间、初始硝酸盐浓度、共存阴离子和温度来研究 Ch 和 Ch-EPI 的物理化学性能。实验数据拟合了广泛使用的吸附动力学模型和吸附等温线。在吸附剂用量为 2.0 g/L、接触时间为 50 min 后，在平衡 pH 值为 4.0 时达到最大硝酸盐吸附百分比。竞争阴离子实验表明，氯离子和硫酸根离子对 Ch-EPI 吸附硝酸盐的影响最小和最大。实验吸附数据最符合拟二级动力学和等温朗缪尔模型。Ch 和 Ch-EPI 对硝酸盐去除的最大吸附容量分别为 12.0 mg/g 和 38.0 mg/g。
