Applications of nanoadsorbent technology in treatment of industrial wastewater: a review

Abstract

Water pollution and freshwater contamination are one of the global problems that directly affect the lives of organisms that one way or the other rely on water for their livelihood. To alleviate these challenges, various treatment methods such as membrane filtration, ion exchange, coagulation as well as adsorption have been adopted to reduce wastewater generated and improve qualities of effluent discharged from industries to meet specified minimum permissible limits. Among all, adsorption is considered to be more efficient in terms of cost, ease of handling, and re-use for water treatment. Furthermore, adsorption technology exhibits excellent removal efficiency using adsorbents prepared from raw or waste materials or nanoparticles synthesized from wastes. Nano-materials exhibit outstanding properties such as small particle size, catalytic potential, large surface area, and a great number of active sites, hence allowing high removal efficiency. The nano-material in this context referred to as “new generation nano-adsorbent” is capable of removing pollutants even at low concentrations. Numerous pathways of synthesizing nanoparticles fall under two approaches namely: bottom-up and top-down approaches. Different materials have been adopted for bulk and nano-based adsorbent with their efficiency varying for different wastewater sources, nature of the adsorbents, adsorbent dosage, and experimental conditions. This study has reviewed the advancement of wastewater treatment using waste and nano-based materials as an adsorbent from 2015 till 2021 and convincingly establishes the potential of nano-adsorbents for wastewater treatment.