Adsorption, degradation, and mineralization of emerging pollutants (pharmaceuticals and agrochemicals) by nanostructures: a comprehensive review

This review discusses a fresh pool of research findings reported on the multiple roles played by metal-based, magnetic, graphene-type, chitosan-derived, and sonicated nanoparticles in the treatment of pharmaceutical- and agrochemical-contaminated waters. Some main points from this review are as follows: (i) there is an extensive number of nanoparticles with diverse physicochemical and morphological properties which have been synthesized and then assessed in their respective roles in the degradation and mineralization of many pharmaceuticals and agrochemicals, (ii) the exceptional removal efficiencies of graphene-based nanomaterials for different pharmaceuticals and agrochemicals molecules support arguably well a high potential of these nanomaterials for futuristic applications in remediating water pollution issues, (iii) the need for specific surface modifications and functionalization of parent nanostructures and the design of economically feasible production methods of such tunable nanomaterials tend to hinder their widespread applicability at this stage, (iv) supplementary research is also required to comprehensively elucidate the life cycle ecotoxicity characteristics and behaviors of each type of engineered nanostructures seeded for remediation of pharmaceuticals and agrochemicals in real contaminated media, and last but not the least, (v) real wastewaters are extremely complex in composition due to the mix of inorganic and organic species in different concentrations, and the presence of such mixed species have different radical scavenging effects on the sonocatalytic degradation and mineralization of pharmaceuticals and agrochemicals. Moreover, the formulation of viable full-scale implementation strategies and reactor configurations which can use multifunctional nanostructures for the effective remediation of pharmaceuticals and agrochemicals remains a major area of further research.