Water purification

Pharmaceutical substances get into municipal sewage together with urine (containing their free and metabolized forms) or by pouring unused or expired preparations into the water supply system. The degradation of these substances in wastewater is a demanding, complex process and most of the currently functioning wastewater treatment systems are not properly prepared for their effective removal. The discharge of untreated sewage into the waters causes the widespread spread of persistent pollutants in the aquatic ecosystem.

Residues of plant protection products and pharmaceuticals used in animal husbandry in free form and in biologically active metabolic forms migrate to surface and underground waters on an uncontrolled scale.
Current legislation on the protection of aquatic ecosystems as well as water and wastewater quality standards increasingly addresses this problem.

The basic legal acts in this respect are, at the level of the European Union, the Water Framework Directive (Directive 2000 / 60 / EC of the European Parliament and of the Council of 23 October 2000 establishing a framework for Community action in the field of water policy, as amended) and Polish Water Law Act (currently applicable Act of 20 July 2017, Journal of Laws 2017, item 1566), together with the regulations resulting therefrom.

At present, these provisions specify the 45 list of chemical compounds that are priority substances in the field of water policy in the European Union. 21 of them were classified as priority hazardous substances. Plant protection products constitute a large proportion of the compounds listed on the list.

In the form of an implementing decision, the European Commission has also established an observation list for substances for which data on water quality monitoring is to be collected, covering the entire Union. The current watch list, from 5 June 2018, lists (among other plant protection products) 5 substances of pharmaceutical origin: 17-alpha-ethinylestradiol (EE2), 17-beta-estradiol (E2), estrone (E1), amoxicillin and ciprofloxacin .

In response to the needs of developing efficient, available technologies for water and wastewater treatment, the scientific team headed by prof. Krzysztof Szczubiałka from the Faculty of Chemistry of the Jagiellonian University developed a photochemically active catalytic system composed of expanded polymer microspheres coated with TiO2. This photocatalyst has a controllable density, which means that it can float on the surface of treated water or sewage for a sufficiently long time, controlled by its manufacturer. Floating the photocatalyst on the water surface provides the light access necessary for the process, and at the same time facilitates its removal from the cleaned tank.

The presence of the described photocatalytic system ensures degradation of residues of commonly used drugs, including antibiotics: cephalotin, amoxicillin, sulfamethoxazole, as well as the most popular nonsteroidal anti-inflammatory drug, ibuprofen. Additional research also confirmed the degradation of phenol, which is a representative of the most common industrial pollutants.

Until now, TiO2-polymer hybrid systems have been rarely used due to the incompatibility of these components. The previously used photocatalytic systems based on TiO2 in the form of a suspension also have restrictions regarding, among others low rate of particle deposition and the resulting low light transmission of the resulting solution and the necessary processes for separating suspended particles.

The technology developed at the Faculty of Chemistry of the Jagiellonian University has been covered by a patent application to the Patent Office of the Republic of Poland.

Author: Agata Błaszczyk-Pasteczka - agata.blaszczyk-pasteczka@uj.edu.pl

Project Manager in the area of ​​water and air protection since 2006, Technology Broker at CITTRU for one year, responsible for commercialization of technology from the Faculty of Chemistry.

The article was prepared as part of the ProBio Małopolska project