Naturally abundant and renewable macromolecular polysaccharides are now considered as green and sustainable adsorbent material for toxic effluent treatment. However, to deal with complex wastewater, the need for efficient amphoteric adsorbent is still a challenge. Herein a three-dimensional (3D) composite aerogel is prepared from dodecyl amine modified clay (kaolinite) enriched chitosan/alginate via freeze drying method and a post ionic crosslinking. The aerogel was characterized by Fourier transform infrared spectroscopy (FT-IRS), scanning electron microscopy (SEM), energy dispersive X-ray (EDX), thermogravimetric analysis (TGA), X-ray diffraction (XRD), solubility test and adsorption studies. The thermal stability of aerogel was significantly higher than that of chitosan/alginate polymer matrix and substantially increased upon gradual addition of modified clay. The aerogel has ordered fishing net-like microstructure, and interconnected pores for dyes and metal ions adsorption. The adsorption capacities of composite aerogel on methylene blue, acid black and hexavalent chromium [Cr (VI)] ions was reached around 73.1, 71.5, and 62.4 mg/g respectively. The adsorption mechanism was electrostatic interaction and the mass ratio of chitosan and modified clay to alginate regulate the adsorption capacities for the anionic and cationic dyes. As a novel amphoteric adsorbent, the chitosan/alginate/modified clay composite aerogel showed the potential to remove both cationic, anionic dyes and metal ions from wastewaters. Moreover, the prepared biobased aerogel showed high adsorption efficiency in both acidic and basic media even after four cycles. The study demonstrated a high performance, low cost, with materials locally available, recyclable and promising candidate for industrial waste water treatment.

天然丰富且可再生的大分子多糖现在被认为是用于有毒污水处理的绿色可持续吸附材料。然而，为了处理复杂的废水，对高效两性吸附剂的需求仍然是一个挑战。在此，三维（3D）复合气凝胶是由富含十二胺改性粘土（高岭石）的壳聚糖/海藻酸盐通过冷冻干燥法和离子后交联制备的。通过傅里叶变换红外光谱 (FT-IRS)、扫描电子显微镜 (SEM)、能量色散 X 射线 (EDX)、热重分析 (TGA)、X 射线衍射 (XRD)、溶解度测试和吸附研究对气凝胶进行了表征. 气凝胶的热稳定性显着高于壳聚糖/藻酸盐聚合物基质的热稳定性，并且随着改性粘土的逐渐加入而显着增加。气凝胶具有有序的渔网状微观结构，以及用于吸附染料和金属离子的互连孔。复合气凝胶对亚甲基蓝、酸性黑和六价铬 [Cr (VI)] 离子的吸附能力分别达到 73.1、71.5 和 62.4 mg/g 左右。吸附机制是静电相互作用，壳聚糖和改性粘土与海藻酸盐的质量比调节阴离子和阳离子染料的吸附能力。作为一种新型的两性吸附剂，壳聚糖/藻酸盐/改性粘土复合气凝胶显示出从废水中去除阳离子、阴离子染料和金属离子的潜力。而且，即使经过四个循环，制备的生物基气凝胶在酸性和碱性介质中均显示出高吸附效率。该研究展示了一种高性能、低成本、材料在当地可用、可回收和有前途的工业废水处理候选材料。