Metal oxide nanoparticles in removing residual pharmaceutical products and pathogens from water and wastewater
Abstract Residual pharmaceutical products from hospitals, pharmaceutical companies, animal farms, and through human excreta are deposited in wastewater and reach environmental niches instigating potential ecological toxicity, genotoxicity, and endocrine disruption. Antibiotics and other pharmaceutical products like analgesics and antiinflammatory drugs, contraceptives, beta blockers, lipid regulators, phenols, herbicides, pesticides, and neuroactive compounds may form highly toxic derivatives with chlorine in postchlorinated effluents. Their effects in low concentrations necessitate highly sensitive and specific techniques for their detection. Removal of the residual antibiotics and other pharmaceutical compounds in wastewater and water is beyond the capacities of conventional wastewater treatment plants (WWTPs) Metal oxides are able to form diverse oxide compounds, which due to their structural geometries can exhibit metallic, semiconductor, or insulator characteristics. Nanoscale metal oxides are promising alternative effective adsorbents for the removal of heavy metals, organic derivatives, and radionuclides. Ferric oxide nanomaterials (FO NM) like magnetite, maghemite, hematite, and nanoactivated carbon have been used for efficient removal of a range of other antibiotics from water including sulfamethoxazole as well as phenol and phenol related pharmaceuticals. The combination of iron oxide NM and biochars allows the removal of both pharmaceuticals and microbial contaminants and may become a cheap and effective removal process. The potential of zinc oxide nanoparticles (nZnO) and titanium dioxide nanoparticles (TiO2 NPs) has also been explored for the efficient removal of organic and inorganic pharmaceutical contaminants from wastewater. Doped metal oxide nanoparticles (MONs) are showing higher photocatalytic activity than undoped due to factors including small grain size, high crystallinity, high specific surface area, and decrease in the band gap energy. The doped MONs with additional metals can remove a wide range of pharmaceuticals and personal care products, as well as pathogens from water in a more effective way than the undoped ones, while doping with transition metal ions like Fe2+ Mn2+ Cu2+ Zn2+ among others has been appraised positively for best activity. Several advantages have been attributed to the use of NMs based on the cost implication, ease of use, and flexibility with an assurance of removal of toxic pharmaceutical nanocontaminants from water and the wastewater for reuse. The guidelines of the Inter organization Programme for the Sound Management of Chemicals (developed as a cooperative agreement of UNEP, ILO, FAO, WHO, UNIDO, UNITAR, and OECD) which contain reports, identification, risk, analysis, and preliminary guidance on the use of nanoparticles, should be considered in utilizing MON or any other NMs. This chapter will briefly overview the different types of metal oxides nanomaterials used for the monitoring/removal of the pharmaceutical compounds and personal care products (PPCPs) prevalent in wastewater. Further, the feasibility, challenges, and future perspective of the application of these MONs in the development of efficient wastewater treatment processes will be explored.