An overview of chlorophenols as contaminants and their removal from wastewater by adsorption: A review

In this review article, a significant number of published articles (over three decades) were consulted in order to provide comprehensive literature information about chlorophenols, their sources into the environment, classification, and toxicity, various wastewater treatment methods for their removal as well as the characteristics of their adsorption by various adsorbents. Organizing the scattered available information on a wide range of potentially effective adsorbents in the removal of chlorophenols is the principal objective of this article. Various adsorbents such as natural materials, waste materials from industries, agricultural by-products and biomass-based activated carbon in the removal of various chlorophenols have been compiled and discussed here. Crucial factors like temperature, solution pH, contact time and initial solution concentration are also reported and discussed here. The π-π dispersion interaction mechanism, hydrogen bonding formation mechanism, and the electron donor-acceptor complex mechanism were proposed for the chlorophenols adsorption onto various adsorbents with the help of current literature. Conclusions have been drawn proposing a few suggestions for future research on mitigating the effect of chlorophenols in the environment. [Display omitted] •The review considers studies on chlorophenols and their removal from waste water by adsorption over the past three decades.•Studies on chlorophenols removal from real effluents under wide range of operating conditions are limited.•Proposed mechanisms are π-π dispersion interaction, hydrogen bonding formation and electron donor–acceptor complex.•More economical and environmentally friendly methods for improved adsorption rate of chlorophenols are needed.