A comprehensive study on modified-pillared clays as an adsorbent in wastewater treatment processes

Pillared clays are special kinds of modified clays with significant and permanent porosity, produced by embedding columns or pillars between the layers of clay. However, these materials are very wellknown for their catalytic properties; their adsorptive characteristics in wastewaters towards different classic and growing contaminants need to be studied comprehensively. The present work is performed to introduce different methods for clays' pillaring, the main steps of the process, comparison of various pillaring agents, etc. During recent years, several investigations have been carried out to find a way for pillared clays' modification (by introducing active chemical functional groups, doping, heat treatment, etc.) to achieve selective adsorbents towards specific pollutants. Therefore, the main modification techniques including surfactant modification, metal doping, etc. are introduced and classified in the present work. Furthermore, adsorptive applications of (modified) pillared clays towards organic, pharmaceutical, and metal ions pollutants, the relationship between physicochemical properties and adsorption performance of pillared clays, adsorption mechanisms, and quantitative comparison of pillared clays' ability for pollutants removal are the other issues that have been considered in the present work. (C) 2020 Institution of Chemical Engineers. Published by Elsevier B.V. All rights reserved.

Automated summary

Pillared clays are special modified clays with significant and permanent porosity, known for their catalytic properties and adsorptive characteristics towards different contaminants. Various methods for pillaring clays, comparison of pillaring agents, and modification techniques to enhance selective adsorption towards specific pollutants have been studied. These materials show potential for adsorptive applications towards organic, pharmaceutical, and metal ions pollutants.