The contagious SARS-CoV-2 virus responsible for COVID-19 disease has infected over 27 million people across the globe within a few months. While literature on SARS-CoV-2 indicates that its transmission may occur predominantly via aerosolization of virus-laden droplets, the possibility of alternate routes of transmission and reinfection through environmental factors require considerable scientific attention. This review aims to collate information on possible transmission routes of this virus, to ascertain its fate in the environment. Concomitant with the presence of SARS-CoV-2 viral RNA in faeces and saliva of infected patients, studies also indicated its occurrence in raw wastewater, primary sludge and river water. Therefore sewerage system could be a possible route of virus outbreak, a possible tool to assess viral community spread and future surveillance technique. Hence, this review looked into detection, occurrence and fate of SARS-CoV-2 during primary, secondary, and tertiary wastewater and water treatment processes based on published literature on SARS-CoV and other enveloped viruses. The review also highlights the need for focused research on occurrence and fate of SARS-CoV-2 in various environmental matrices. Utilization of this information in environmental transmission models developed for other enveloped and enteric viruses can facilitate risk assessment studies. Preliminary research efforts with SARS-CoV-2 and established scientific reports on other coronaviruses indicate that the threat of virus transmission from the aquatic environment may be currently non-existent. However, the presence of viral RNA in wastewater provides an early warning that highlights the need for effective sewage treatment to prevent a future outbreak of SARS-CoV-2.

No abstract

No abstract

No abstract

No abstract

Heterogeneous photocatalysis employing semiconductor nanoparticles, especially TiO 2 nanoparticles, has attained considerable research interest in recent years. [1] TiO 2 is known to exist in three polymorphic forms, viz. anatase, rutile, and brookite. [2] Often, anatase TiO 2 is considered to be the most photocatalytically active due to high adsorption affinity for organic molecules even at low concentration [3] and low recombination of charge carriers, owing to inherently present oxygen vacancies. [4] However, the inability to utilize visible light limits the practical application of TiO 2 for photocatalysis. [5] Therefore, in recent years, synthesis and application of photocatalytic heterostructures based on TiO 2 and other semiconductors/noble metals have emerged as a strategy to facilitate visible light activity. [6-9] Nanocomposites made of two of the most versatile semiconductor oxides, viz. TiO 2 and ZnO have drawn considerable attention for photocatalytic processes. [10] TiO 2-ZnO nanocomposites have shown good potential for degradation of a variety of organic pollutants, [11,12] and activity under visible irradiation was feasible due to favorable alignment of energy states of both TiO 2 and ZnO. [12-14] Heterostructures comprising of anatase TiO 2 and other metal oxides, [15] and anatase with other TiO 2 phases, such as rutile, [10] are reported to be active under visible irradiation. Their superior photocatalytic activity was attributed to the presence of anatase or a favorable anatase/rutile ratio. The superior photocatalytic activity of anatase TiO 2 is well established. [16] According to literature reports, anatase exhibits an indirect bandgap in addition to its direct bandgap, which enhances charge carrier lifetime. [17] Anatase TiO 2 , being a quasi-stable polymorph, is susceptible to formation of defects and, hence, midgap defect states. [18] On the other hand, pure rutile phase of TiO 2 is reported to be photocatalytically inferior to anatase phase. [3] Contrary to such theories, recent studies have suggested that phase transformations were controlled by the addition of ZnO, such that, at optimal Ti:Zn molar ratios, a unique mix of various TiO 2 , ZnO, and zinc titanate phases coexisted which helped in tailoring the bandgap. This facilitated visible light activity even when anatase was present in negligible amounts or even absent. [19] Interestingly,

No abstract

No abstract