Removal of Pharmaceutical Contaminants in Wastewater Using Nanomaterials: A Comprehensive Review

Abstract

Background: The limitless presence of pharmaceutical contaminants in discharged wastewater has emerged as a threat to aquatic species and humans. Their presence in drinking water has although raised substantial concerns, very little is known about the fate and ecological impacts of these pollutants. As a result, these pollutants are inevitably introduced to our food chain at trace concentrations. Unfortunately, the conventional wastewater treatment techniques are unable to treat pharmaceuticals completely with practical limitations. The focus has now been shifted towards nanotechnology for the successful remediation of these persistent pollutants. Thus, the current review specifically focuses on providing readers brief yet sharp insights into applications of various nanomaterials for the removal of pharmaceutical contaminants. Methods: An exhaustive collection of bibliographic database was done with articles having high impact and citations in relevant research domains. An in-depth analysis of screened papers was done through standard tools. Studies were categorized according to the use of nanoscale materials as nano-adsorbents (graphene, carbon nanotubes), nanophotocatalysts (metal, metal oxide), nano-filtration, and ozonation for promising alternative technologies for the efficient removal of recalcitrant contaminants. Results: A total of 365 research articles were selected. The contemporary advancements in the field of nanomaterials for drinking and wastewater treatment have been thoroughly analyzed along with their future perspectives. Conclusion: The recommendations provided in this article will be useful to adopt novel strategies for on-site removal of the emerging contaminants in pharmaceutical effluents and related industries.

Current Trends in the Application of Nanomaterials for the Removal of Emerging Micropollutants and Pathogens from Water

“…Owing to their unique characteristics, and in particular their high adsorption capacity, they are favorable nanoadsorbents for pharmaceuticals and personal care products, with π-π and n-π interactions thought to be the principal mechanisms for the abatement of organic compounds. Moreover, hydrogen bonding has a significant role in the adsorption of organic compounds on carbon based materials, and also Lewis acid-base interactions may facilitate their high adsorption [53]. As it concerns their antimicrobial properties, severe damage of cell membrane and contact of CNTs with bacterial cells has been identified as one of the main inactivation mechanisms; oxidation stress is another possible mechanism of action [54].…”

“…Interestingly, pristine g-C 3 N 4 has very good antibacterial and antiviral activities under visible-light irradiation, supporting its application in water disinfection [55]. In their review, Chauhan et al (2018) presented the gC 3 N 4 /ZnO nanocomposite as an example of heterojunction-type photocatalytic system. The movement of the excited electrons from the higher energy potential CB of g-C 3 N 4 to the lower energy potential CB of ZnO, results in the degradation of the pollutants by reduction.…”

New trends in nanofibers functionalization and recent applications in wastewater treatment

“…Furthermore, nanofiltration and ozonation are good advanced avenues for the effective remediation of solid and stable contaminants. 91 Another study focused on the nanofibers synthesized from the root extract of Mondia whitei for the remediation of 13 antiretroviral and other relevant drugs in wastewaters. Here, these nanofibers showed a good adsorption potential for these pharmaceuticals compounds; however, the adsorption capacity was studied through the following parameters: concentration, pH, contact time, dosages, and temperature.…”

The Use of Surface-Modified Nanocrystalline Cellulose Integrated Membranes to Remove Drugs from Waste Water and as Polymers to Clean Oil Sands Tailings Ponds

“…For systems that adsorb and remove pollutants, it is preferable for the adsorbate to have high surface areas to maximize direct adsorption, and to be inexpensive and biodegradable. Considerable attention has been paid to the potential use of nanomaterials in environmental remediation science due to the high surface area to volume ratio, easily functionalized surfaces for specific trapping Polymers 2021, 13, 3899 2 of 21 and easy transport [4,5]. Cellulose, and in particular nanocellulose, is such a material and has the added advantage of being easily surface derivatized to create surfaces for specific adsorbing purposes [6].…”