吸附
化学
解吸
碳纳米管
电化学
表面改性
水溶液
活性炭
洗脱
吸附剂
无机化学
酰胺
化学工程
材料科学
有机化学
色谱法
纳米技术
工程类
电极
物理化学
作者
Mohamed A. Ganzoury,Christina M. Hanna,Nan Zhang,Yichen Wu,Charles‐François de Lannoy
标识
DOI:10.1016/j.jhazmat.2023.132721
摘要
Wastewater generated from e-waste leaching is rich in precious metals including gold, silver and platinum. Conventional precipitation and solvent extraction are chemically intensive separations with concerning environmental externalities. Sorbents, in particular carbon nanotubes, have low chemical consumption, and have shown promise for gold adsorption due to their high specific surface area and chemical functionalization potential. However, regenerating sorbents used to adsorb Au is hazardous requiring strong acids. Herein, we delineate the effect of various functional groups on the sidewalls of multiwall carbon nanotubes (MWCNTs) on gold adsorption, and we introduced an acid-free electrochemical technique for Au elution from MWCNTs. Pristine MWCNTs (P-MWCNTs), carboxylic functionalised MWCNTs (COOH-MWCNTs) and amide functionalised MWCNTs (NH2-MWCNTs) were compared for their affinity for Au adsorption from acidic AuCl4-solutions mimicking acidic e-waste leachate. Au adsorption affinity onto MWCNTs followed the order of P-MWCNT > NH2-MWCNT > COOH-MWCNTs. Au elution from Au-saturated MWCNTs was subsequently achieved up to 65%, using acid-free electrochemical desorption in neutral aqueous brine. The Au electro-desorption was shown to have a direct relationship with both the applied current and the mass of the Au adsorbed on the MWCNTs. This study demonstrates enhanced adsorption-based preconcentration of gold and acid-free regeneration of sorbents.
科研通智能强力驱动
Strongly Powered by AbleSci AI