Faculty of Science, Engineering and Built Environment, Deakin University, Victoria 3216, Australia.
Department of Civil Engineering, Xi'an Jiaotong-Liverpool University, Suzhou 215123, China.
Sci Total Environ. 2022 Feb 10;807(Pt 1):150606. doi: 10.1016/j.scitotenv.2021.150606. Epub 2021 Sep 27.
Contamination of the aquatic ecosystem by heavy metals is a growing concern that has yet to be addressed with an efficient, cost-effective and environmentally-friendly solution. Heavy metals occur naturally in the earth's crust and also result from anthropogenic activities. Due to the rapid increase in industrialization, there is an increase in consumer demands across various industries such as metal processing, mining sector, agricultural activities, etc. and this has led to an increase in heavy metal concentrations in the aqueous environment. Cellulose-based aerogels are a novel third-generation of aerogels that have recently attracted a lot of attention due to their high adsorption efficiency, eco-friendly prospects and cost effectiveness. In this review, recent literature on cellulose-based aerogel adsorbents used for the removal of heavy metals from aqueous solution has been compiled. The preparation of cellulose-based aerogels, adsorption mechanisms, effects of experimental factors such as pH, temperature, contact time, initial metal concentration and adsorbent dose have been discussed. In addition, cost analysis of cellulose-based adsorbents and some challenges in this research field along with recommendations of improvements have been presented. It can be concluded that functionalizing of cellulose-based aerogels with amine groups, thiol groups, other compounds such as nanobentonite and chitosan results in very high adsorption capacities. The adsorption studies revealed that pseudo-second-order kinetic model was the most commonly encountered adsorption kinetic model, and the most commonly encountered adsorption isotherm model was the Langmuir isotherm model. The main adsorption mechanisms were electrostatic interaction, complexation and ion exchange.
重金属对水生态系统的污染是一个日益严重的问题，但目前还没有找到一种高效、经济且环保的解决方案。重金属在地球地壳中自然存在，也源自人为活动。由于工业化的迅速发展，各个行业（如金属加工、采矿部门、农业活动等）的消费需求不断增加，这导致了水环境中重金属浓度的增加。纤维素基气凝胶是一种新型的第三代气凝胶，由于其高吸附效率、环保前景和成本效益，最近引起了广泛关注。在本综述中，编译了最近关于用于从水溶液中去除重金属的纤维素基气凝胶吸附剂的文献。讨论了纤维素基气凝胶的制备、吸附机制、pH、温度、接触时间、初始金属浓度和吸附剂剂量等实验因素的影响。此外，还介绍了纤维素基吸附剂的成本分析以及该研究领域的一些挑战和改进建议。可以得出结论，用胺基、硫醇基、纳米膨润土和壳聚糖等化合物对纤维素基气凝胶进行功能化处理，可获得非常高的吸附容量。吸附研究表明，伪二级动力学模型是最常见的吸附动力学模型，而最常见的吸附等温线模型是朗缪尔等温线模型。主要的吸附机制是静电相互作用、络合和离子交换。
