Progress in porous carbon-based adsorbents for the removal of dyes from single and binary systems and their adsorption mechanism – a review

Abstract

The textile industry is responsible for producing vast amounts of wastewater, which may include a variety of dye compounds. As a result, this dye mixture effluent presents a significant environmental risk to ecosystems. Recently, there has been growing interest among researchers in the removal of dyes from binary mixtures rather than single systems, as real wastewater contains many different types of dyes. Many adsorbents have been developed to remove these dyes from water. The high adsorption properties of porous carbon-based adsorbents have led to their extensive research in various water treatment applications. Most published reviews focus on removing dye from single systems using various adsorbents, rather than from binary systems. However, no recent reviews have been identified that critically address the removal of dye from these systems using porous carbons. Therefore, this review addresses the advancements made in removing dye mixtures from aqueous solutions using various porous carbons. The calculations and isotherm theory for dye removal from single and binary mixtures are discussed. The surface properties and adsorption behaviors of various porous carbons used to remove dye from single and binary mixtures are discussed. Additionally, the adsorption mechanisms of the various interactions between dye and adsorbents that govern their interaction are thoroughly investigated. This review determined that biochar and modified multi-walled carbon nanotubes (MWCNTs) exhibit superior performance in removing dyes from both systems compared with other porous carbon-based adsorbents. Furthermore, the directions for research and development in the fields of porous carbon-based adsorbents for treating wastewater at natural pH and conducting further binary and/or ternary adsorption studies of carbons and/or carbonized adsorbents are addressed. Furthermore, this review discusses the challenges and prospects of using porous carbons to remove dyes from binary systems. Environmentalists working on the removal of dyes from binary systems through the use of carbon-based adsorbents may find this review useful.