College of Resources and Environment, Southwest University, Chongqing 400715, PR China.
College of Resources and Environment, Southwest University, Chongqing 400715, PR China.
J Colloid Interface Sci. 2022 Jul 15;618:386-398. doi: 10.1016/j.jcis.2022.03.097. Epub 2022 Mar 23.
Currently, simultaneous removal of anionic and cationic pollutants from combined pollution wastewater is a challenging subject. Here, a novel composite adsorbent which can simultaneously adsorb anionic azo dye and heavy metal cations was developed by flocculation inspired assembly of MgAl layered double hydroxides (LDH) and fulvic acid (FA). The results show that the negatively charged macromolecule FA is firmly intertwined with the positively charged LDH through electrostatic attraction and adsorption bridging. This composite adsorbent (MgAl LDH-FA) can effectively capture anionic Orange II by anion exchange adsorption derived from LDH component with the maximum adsorption capacity of 604 mg/g. MgAl LDH-FA also exhibits good adsorption performance for heavy metals due to the complexation with FA and surface precipitation on LDH. The adsorption isotherms of heavy metals coincided with Langmuir model or Freundlich model, and the adsorption capacities for Pb, Cu, Ni, Cd could reach up to 661.5 mg/g, 116.3 mg/g, 117.3 mg/g, 235.2 mg/g respectively. Particularly, MgAl LDH-FA can simultaneously uptake Orange II and heavy metals from the stimulated combined pollution wastewater, moreover it shows higher adsorption capacity for each pollutant than that in the single pollutant case as the result of the synergistic adsorption effect between LDH and FA.
目前，同时去除混合污染废水中的阴离子和阳离子污染物是一个具有挑战性的课题。在这里，通过絮凝诱导组装镁铝层状双氢氧化物（LDH）和富里酸（FA），开发了一种可以同时吸附阴离子偶氮染料和重金属阳离子的新型复合吸附剂。结果表明，带负电荷的大分子 FA 通过静电吸引和吸附桥接与带正电荷的 LDH 牢固地交织在一起。这种复合吸附剂（MgAl LDH-FA）可以通过 LDH 组分的阴离子交换吸附有效地捕获阴离子橙 II，最大吸附容量为 604mg/g。由于与 FA 的络合作用以及在 LDH 上的表面沉淀，MgAl LDH-FA 对重金属也表现出良好的吸附性能。重金属的吸附等温线符合 Langmuir 模型或 Freundlich 模型，对 Pb、Cu、Ni、Cd 的吸附容量分别高达 661.5mg/g、116.3mg/g、117.3mg/g、235.2mg/g。特别是，MgAl LDH-FA 可以同时从模拟的混合污染废水中摄取橙 II 和重金属，而且由于 LDH 和 FA 之间的协同吸附作用，其对每种污染物的吸附容量都高于单一污染物情况下的吸附容量。
