Remediation of Antiseptic Components in Wastewater by Photocatalysis Using TiO₂ Nanoparticles

Abstract

Environmental awareness in both the public and regulatory sectors has necessitated proper treatment of medicinal components-rich pharmaceutical effluents. Even the presence of trace antiseptic may cause adverse health effects including development of "product resistant microbes" in the aquatic environment. The present study involves photomineralization of chlorhexidine, which belongs to the class of antiseptic drug components. This study details investigations on photocatalytic degradation of chlorhexidine in a slurry batch reactor using titanium dioxide photocatalyst. Emphases were given to study the effects of operating parameters on the degradation behavior of the targeted compound and characterization of degraded products. About 68.14% removal of chlorhexidine digluconate (CHD) was found after 1 h at 25 °C with a substrate-to-catalyst ratio of 2.5:1 under UV intensity of 50 μW•cm −2 at pH 10.5. Though the product profile illustrates several degraded products, toxicological analysis on Bacillus subtilis exhibited no inhibition zone, suggesting the eco-friendly nature of the degraded products.

Development of a mathematical model to predict different parameters during pharmaceutical wastewater treatment using TiO2 coated membrane

“…At constant time interval, aliquot sample was collected from permeate line to analyses the degradation of CHD using PMR. The details of analysis protocols of CHD have been provided in earlier works by the same research group (Das et al, 2014;Sarkar et al, 2014a).…”

“…The immobilization of TiO 2 on membrane surface makes the process economically feasible in terms of catalyst recycle and reuse. Moreover, adsorption tendency of CHD on TiO 2 surface has been observed (Das et al, 2014), thus the thickness of 'polarized layer' formation on the TiO 2 coated membrane surface will be very less. The developed model involved in this study is very pragmatic and comprehensive in nature, as it considers reactor design aspects i.e.…”

“…Finally, a proper mathematical modelling is essential to predict as well as to understand different process parameters related to membrane separation process, as well as photocatalytic reaction. The current research group has already established that photocatalysis in presence of TiO 2 nano particle in suspension mode is very much effective in removal of anti-biotic, like chlorhexidine digluconate (CHD) and the details of regarding photomineralisation of CHD have been described elsewhere (Das et al, 2014, Sarkar et al, 2014a. In this study, CHD has been used as target material to model and understand photomineralisation behavious in presence of TiO 2 immobilised photo-membrane reactor.…”

Engineered nanomaterials for water treatment and remediation: Costs, benefits, and applicability

“…With sufficient investment other Me/MeO ENM compounds may reach similar prices, although this estimate may not hold true for more exotic formulations (e.g., [43]) as titanium is the 9th most abundant element in the Earth's crust [485] and is cheaply available. Since photocatalysts are not degraded in the production of oxidizing radicals, the possibility of regeneration and reuse exists and has indeed been proven for these materials [282,404,486,487], which has the potential to further decrease the overall costs associated with using photocatalytic Me/MeO ENMs in water treatment.…”

Nanomaterials for the Abatement of Pharmaceuticals and Personal Care Products from Wastewater

“…Moreover, a TiO2 photocatalyst-based process showed a good ability to remove up to 68% chlorhexidine digluconate (CHD, an antiseptic compound), in 1 h at 25 °C with a substrate-to-catalyst ratio of 2.5:1 under UV light at basic pH [45].…”