Particular attention is paid towards photocatalysis using nanocatalysts in this review, due to their effectiveness towards POP degradation, technological feasibility, and energy and cost-efficiency. This review focuses on existing POPs and the types of remediation processes available for their removal. To address the safe disposal and clean-up of such chemicals, new, and especially cost-effective, remediation technologies for POPs are urgently required. Although POPs are banned in several countries, many chemicals have been proposed as POP candidates to be added to the existing compounds as defined by the United Nations Stockholm Convention committee. The release of persistent organic pollutants (POPs) into the environment is an issue of global concern, as the chemicals are stable over a prolonged period resulting in their accumulation in many animals and plants. This review will serve as an updated survey, yet touching also the fundamentals of the antimicrobial activity, with vital information for researchers planning to embark on the development of superior antimicrobial nanomaterials for wastewater treatment applications. The direction of future work was found to be in the development of antimicrobial nanocomposites, since they provide more stability for antimicrobial metal and metal oxides NPs in water, thereby increasing their activity. Nanosilver (nAg) was the most studied and moderately understood metal NPs with proven antimicrobial activity followed by ZnO (among antimicrobial metal oxide NPs) which outperformed titania (in the absence of light) in efficacy due to its better solubility in aqueous condition. Our review shows that there are only a few eligible candidate nanoparticles (NPs) (metal and metal oxide) that can adequately serve as an antimicrobial agent. Studies involving fabrication and testing of antimicrobial nanomaterials for wastewater treatment were gathered, critically reviewed, and analyzed. In this paper, we present a critical review on antimicrobial nanomaterials with demonstrated potential for application as a disinfection technology in wastewater treatment. Some of the main material focuses are zero-valent iron, iron oxides, spinel ferrites, natural and waste-based biosorbents. This review highlights, discusses and reports on the state-of-the-art of these two promising routes to adsorp-tion and provides indications as to what are the optimum materials for utilization and insight into their efficiency, reusability and practicality for the removal of pollutants from wastewater streams. On the other hand, biosorbents have a synergistic effect with their efficient adsorption capacity to remove contaminants, high abundance and participation in waste minimization, helping alleviate ecological and environmental problems. Magnetic nanomaterials act as efficient adsorbents due to their ease of removal of contaminants from wastewater using an applied magnetic field but also their advantageous surface charge and redox activity characteristics. Two methods that have shown promising results and gained significant interest is that of magnetic nanomaterials and biosorbents due to their effective, safe, eco-friendly, low cost and low-energy intensive material properties. However, there are many challenges to adsorption processes such as reducing the high cost, through means of separation of suspending adsorbents to be used again, as well as the ease to synthesize. In this approach, many adsorbents have been synthesized, tested and used for the elimination and separation of the contaminants such as radionuclides, heavy metals, dyes and pharmaceutical compounds both at lab and industrial scale. Adsorption to date is the most effective and utilized technology globally to remove several pollutants in wastewater.
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