Source Management of Pharmaceutical Compounds Using Novel Magnetic Nanocomposites in Photocatalytic Reactors

Effluent discharges from hospitals and pharmaceutical manufacturing units contain significant amounts of pharmaceutical compounds. Human consumption as well as veterinary prescription of pharmaceuticals including antibiotics is also on the increase. Not all of the consumed pharmaceutical is metabolised by the body and a good proportion is excreted as parent compounds or as metabolites that enter the sewage system and into the environment. Treatment at Wastewater Treatment Plants (WwTPs) are usually energy intensive and are unable to cope with the increasing loads of pharmaceuticals as a result of which they get released into the environment. Presence of pharmaceuticals, particularly antibiotics, in the environment is leading to the development of antimicrobial resistant (AMR) bacteria. According to WHO data fact, in 2016 490, 000 people world-wide developed multidrug resistant diseases such as TB, HIV, malaria, influenza. Therefore, there is demand for development of environmentally friendly technologies to treat the influent streams at point sources before pharmaceuticals reach WwTPs. This will be one of the measures of tackling antimicrobial resistance.
In this PhD proposal we aim to develop photocatalytic reactors using novel magnetic semiconductor nanoparticles that can be deployed in influent streams at point sources such as hospital discharges for the degradation of pharmaceutical compounds. Novel magnetic nano hybrid composites will be synthesised for use as catalysts in photocatalytic reactors which will be tested in influent streams for the photocatalytic degradation of select model pharmaceutical compounds. The magnetic nano catalysts would enable retrieval and re-use of the photocatalysts by application of magnetic field thus preventing the loss of nanoparticles into the environment.
Photocatalytic reactor technique proposed in this work offers the advantages of effective degradation of pollutants, reduced waste generation and reuse of the photocatalysts. This technique has advantages over conventional adsorption techniques where reuse of adsorbent and disposal of adsorbed material will be a problem. The novel semiconductor nanomaterials proposed in this work will utilise a new class of biodegradable materials which would promote circular economy.
The specific objectives of the project are, (i) to synthesise the novel hybrid nanocomposites for use as photocatalysts, (ii) Engineering design of photocatalytic reactor, (iii) use of Liquid chromatography Tandem Mass spectrometry (LC-MS/MS) and Gas Chromatography Mass Spectrometry (GC-MS) techniques for analysis of pharmaceutical compounds and degradation products, (iv) testing of the developed photocatalytic reactor in field effluents.
The James Hutton Institute (JHI) has recently acquired LC-MS/MS and GC-MS instruments which will be used for the analysis of the pharmaceutical compounds and their degradation products. JHI has considerable expertise in pharmaceutical analysis and in the area of analytical method development. JHI has got access to effluent samples containing pharmaceutical compounds that can be used for initial trial studies. The design of the photocatalytic reactor will be carried out at the School of Engineering at The Robert Gordon University. JHI has collaborations with Health Boards and Scottish Water for the field testing of the built Photocatalytic reactor system.