Tan Yunfeng, Wang Jinxia, Zhan Lingling, Yang Hongjun, Gong Yinchun
College of River and Ocean Engineering, Chongqing Jiaotong University, Chongqing, 400074, China.
College of Resources and Safety, Chongqing Vocational Institute of Engineering, Chongqing, 402260, China.
Sci Rep. 2024 Feb 28;14(1):4853. doi: 10.1038/s41598-024-55520-9.
Chromium (Cr(VI)) pollution has attracted wide attention due to its high toxicity and carcinogenicity. Modified biochar has been widely used in the removal of Cr(VI) in water as an efficient and green adsorbent. However, the existing biochar prepared by chemical modification is usually complicated in process, high in cost, and has secondary pollution, which limits its application. It is urgent to explore modified biochar with simple process, low cost and environmental friendliness. Therefore, ball milling wheat straw biochar (BM-WB) was prepared by ball milling technology in this paper. The adsorption characteristics and mechanism of Cr(VI) removal by BM-WB were analyzed by functional group characterization, adsorption model and response surface method. The results showed that ball milling effectively reduced the particle size of biochar, increased the specific surface area, and more importantly, enhanced the content of oxygen-containing functional groups on the surface of biochar. After ball milling, the adsorption capacity of Cr(VI) increased by 3.5-9.1 times, and the adsorption capacity reached 52.21 mg/g. The adsorption behavior of Cr(VI) follows the pseudo-second-order kinetics and Langmuir isotherm adsorption model rate. Moreover, the Cr(VI) adsorption process of BM-WB is endothermic and spontaneous. Under the optimized conditions of pH 2, temperature 45 °C, and adsorbent dosage 0.1 g, the removal rate of Cr(VI) in the solution can reach 100%. The mechanism of Cr(VI) adsorption by BM-WB is mainly based on electrostatic attraction, redox and complexation. Therefore, ball milled biochar is a cheap, simple and efficient Cr(VI) removal material, which has a good application prospect in the field of remediation of Cr(VI) pollution in water.
铬（Cr(VI)）污染因其高毒性和致癌性而备受广泛关注。改性生物炭作为一种高效绿色的吸附剂，已被广泛应用于水中Cr(VI)的去除。然而，现有的通过化学改性制备的生物炭通常工艺复杂、成本高且存在二次污染，这限制了其应用。迫切需要探索工艺简单、成本低且环境友好的改性生物炭。因此，本文采用球磨技术制备了球磨小麦秸秆生物炭（BM-WB）。通过官能团表征、吸附模型和响应面法分析了BM-WB对Cr(VI)的吸附特性及机理。结果表明，球磨有效地减小了生物炭的粒径，增加了比表面积，更重要的是提高了生物炭表面含氧官能团的含量。球磨后，Cr(VI)的吸附量提高了3.5 - 9.1倍，吸附量达到52.21 mg/g。Cr(VI)的吸附行为遵循准二级动力学和朗缪尔等温吸附模型速率。此外，BM-WB对Cr(VI)的吸附过程是吸热且自发的。在pH为2、温度为45℃、吸附剂用量为0.1 g的优化条件下，溶液中Cr(VI)的去除率可达100%。BM-WB对Cr(VI)的吸附机理主要基于静电吸引、氧化还原和络合作用。因此，球磨生物炭是一种廉价、简单且高效的Cr(VI)去除材料，在水体Cr(VI)污染修复领域具有良好的应用前景。
