Heterogeneous photocatalysis for removal of microbes from water

Abstract

Increasing water pollution by microbes has become a source of serious health concern across the globe. Production of potentially carcinogenic disinfection byproducts has marred credibility of traditional water purification techniques like chlorination. Photocatalysis has emerged as a promising alternative technique for the disinfection of water with minimal risk of harmful by-products. The process involves a wide band gap semiconductor material which, upon irradiation of light, produces electrons and holes with high redox potential to degrade organic contaminants and microbes. In this review, we analyze the research trends in photocatalytic inactivation of water borne microorganisms. This report analyzes the major factors that affect the disinfection efficiency using this process. The discussion also includes plausible mechanisms of microbial degradation as well as a kinetic model of the inactivation process. Different approaches, like doping of semiconductors or energy band engineering or plasmon coupling, have been reported for the enhancement and utilization of ambient solar light. Photocatalysis could be a cost-effective and environmentally friendly water purification technique though further research is required to enhance its efficiency with the use of solar light.

A review of graphene‐TiO2 and graphene‐ZnO nanocomposite photocatalysts for wastewater treatment

“…The credibility of traditional water purification processes such as chlorination is lost by the carcinogenic disinfection by-products production. Therefore, in order to cope such impurities, photocatalysis has come to the picture as an emerging substitute method for disinfection of water with lower risks of harmful by-products (Mahmood et al, 2012). Many photocatalysts show remarkable antimicrobial effects and retards microbial growth (Yadav et al, 2016).…”

Environmental chemistry is most relevant to study coronavirus pandemics

“…These suggest the potential role of climate change on occurrence and the fate of the virus. Environmental chemistry research on the fate of pollutants in air (Kfoury et al 2016;Yu 2019;Gopinath and Kadirvelu 2018), water (Gopinath and Kadirvelu 2018; Mahmood et al 2012;Rodgers et al 2019;Wen et al 2019) and wastewater (Padervand et al 2020;Simas et al 2019;Villaseñor and Ríos 2018;) is therefore highly relevant to the study of pathogenic microbes. Future detailed investigations about the physiochemical role of environmental parameters of air might therefore address the control of future outbreaks or pandemics with greater efficiency.…”

Chlorination disadvantages and alternative routes for biofouling control in reverse osmosis desalination

“…141 showing almost 99% microbial removal from water, which was used to develop portable water purification system. Similarly, 142 have reviewed the heterogeneous photocatalytic inactivation of water borne microorganisms, including plausible mechanisms of microbial degradation as well as a kinetic model of the inactivation process and analyzed various factors involved in the photo catalytic process, such as light intensity, pH and water quality. The photocatalytic properties of ZnO nano rods have also been investigated against marine micro and macro fouling organisms in laboratory, 143 mesocosm 144 , and field experiments.…”