Nanoparticles and Significance of Photocatalytic Nanoparticles in Wastewater Treatment: A Review

Background: In the present situation where there is a water shortage globally, nanoparticles can play a vital role in treating wastewater to make it usable for several processes. Industrial wastewater contains numerous heavy metals and associated wastes that enter our food chain by one means or other. This article provides a review of applications of nanoparticles in wastewater treatment and highlights the significance of photocatalytic nanoparticles in general. Methods: Online journals and books related to wastewater treatment using nanoparticles are reviewed to compile their essentials findings. General mechanisms, applications, limitations, and comparison of photocatalytic nanoparticles are reviewed as well. Results: A study of photocatalytic nanoparticles shows that TiO2 and ZnO nanoparticles have excellent photocatalytic capabilities as compared to other nanoparticles due to their bandgap properties; however, the usage of these nanoparticles is limited since there is higher recombination rate of electrons and holes in photocatalysis. Further, individual limitations also exist as TiO2 is inoperable in the visible light region. So, their heterostructures with other nanoparticles have been developed to overcome their limitations. Other nanoparticles, like noble metals, and those like CuO, CeO2, SnO2 have potential in carrying out photocatalytic degradation of contaminants of wastewaters. Conclusion: Several contaminants can be eliminated from wastewater bodies using photocatalytic nanoparticles. The efficiency of photocatalytic nanoparticles can be enhanced by coupling them with suitable species. Research in this area can prevent the water shortage of upcoming years.