Developments in Adsorption Technologies for Removal of Heavy Metals, Dyes, and Xenobiotics

Anthropogenic activities have led to widespread pollution in aquatic bodies due to extensive dissemination of refractory contaminants such as heavy metals, dyes, and xenobiotics. Adsorption is well recognized as a suitable technology for the removal of these pollutants. The major objective of this book chapter is to summarize recent advancement in this field. Accordingly, the book chapter starts with a brief introduction explaining the potential of the technology as compared to other competitive operations, followed by the identification of thrust areas to work on and the construction of a “template” to evaluate the progress in the technology. Next, recent developments in the preparation of various types of adsorbents (activated carbon-based traditional adsorbents, zeolites and clay minerals, adsorbents of biological origin, composite adsorbents having nanoparticles impregnated in a suitable matrix) have been elaborated. The chapter then focuses on how different process parameters may affect the efficiency of these adsorbents in removal of heavy metals, dyes, and xenobiotics. Finally, a comprehensive discussion has been made about how different mathematical models have been applied in recent times to fit experimental equilibrium and kinetic data obtained from the batch adsorption experiments, along with a critical evaluation of frequently used models. The chapter ends with a recommendation regarding future trends in adsorption technology.

Keywords: Adsorption, Biochar, Isotherms, Models, Nanomaterials