Adsorption of cephalexin: A decade of progress in adsorbent development and mechanistic insights
Clint Sutherland
Abstract
Cephalexin (CEX) is ubiquitous in wastewater effluent and an emerging contaminant due to its potential to cause antibiotic resistance, carcinogenic effects, and mutagenesis in microorganisms. This article's principal objective is to help facilitate the progress of CEX-removal development by consolidating scattered research on CEX adsorption from the past decade. Focusing on recent research advancements ensures that the review reflects the latest findings, offers a succinct overview of influencing factors, and highlights the latest methodologies employed across studies. The reviewed literature indicated that modifying adsorbents by functionalising parent materials effectively enhanced the surface area and pore volume, extended the range of operable pH, and raised their capacity and reaction rates. CEX adsorption capacities as significant as 1667.0 mg/g were attainable by adsorption and, in more than 50% of the reviewed cases, in the zwitterionic form. Adsorbent pHpzc played a crucial role in elucidating mechanisms and is suggested as a fundamental research tool. Despite the numerous strides, most studies are currently at the laboratory batch-scale, using single-contaminant and at concentrations far higher than encountered in the environment. The conclusions drawn from this study and suggestions for future work have potential value for forthcoming research initiatives on CEX removal.