Elimination of persistent emerging micropollutants in a suspended-bed photocatalytic reactor: influence of operating conditions and combination with aerobic biological treatment

Abstract

A larger, lab-scale photocatalytic suspended-bed reactor using TiO sol-gel-coated expanded clay granules as a bed material was evaluated for oxidative removal of the persistent pharmaceuticals doxycycline, prednisolone, amoxicillin, and sulfamethizole, as well as their mixture, in ppm concentrations. The photocatalytic degradation potential of drug molecules increases as their adsorption affinity increases towards TiO-containing coatings. The performance of the photocatalytic reactor in the removal of drugs was improved by optimizing the fluidization process parameters. The reactor operation at high bed loadings is determined by the abrasion resistance of the catalyst coating. The long-term stability of the coated bed was enhanced by optimal loading, achieving a higher removal rate while placing moderate mechanical stress on the coated granules. The photocatalytic pretreatment decreased the toxicity of doxycycline solutions to several bacterial strains, including the environmental bacterium Pseudomonas putida and bacterial strains freshly isolated from the activated sludge. The treatment of doxycycline-containing water with a combination of photocatalytic treatment and bio-oxidation resulted in 98% removal of the target in the bioreactor outlet, with no deterioration in the operation of the biological process.

Técnicas De Remoção De Micropoluentes Emergentes Presentes Na Água: Uma Revisão Sistemática

“…A técnica de Fotocatalização foi utilizada em escala laboratorial, seja por meio de nanocompósitos enriquecido de ouro e óxido de titânio (Pronina et al, 2016;Nil et al, 2018), seja por meio do uso do fosfato de prata imobilizado (Petala et al, 2019) em estudo com fluxo contínuo, também em escala laboratorial. Pronina et al (2016) baseou-se em reator fotocatalítico protegido da irradiação UVA com leito suspenso em escala laboratorial usando grânulos de argila expandida revestidos por sol-gel de TiO2 como material de leito.…”

“…Os antiinflamatórios (G14) presentes na análise de 14 artigos do PB foi avaliado em 15 técnicas de remoção em oito MPE, com realce para as técnicas de fotólise, adsorção, ozonização e oxidação, o que resultou em 87.5% de todas análises do grupo G14, com taxa de remoção superior a 90% (Piai et al, 2020;Thiebault et al, 2016;Mojiri et al, 2019;Pronina et al, 2016;Trapido et al, 2014;Mura et al, 2018;Wang et al, 2020;Iovino et al, 2016;Chang et al, 2017;Boucherie et al, 2010;Shu et al, 2013;Nagy et al, 2014;Acero et al, 2010;Liu et al, 2019). Observou-se que os antibióticos (G08) foram aplicados em 16 técnicas de remoção em estudo de 16 MPE, com registro em 55% desses estudos e taxa de eficiência  90%, com destaque para a ozonização e fotólise (Zhang e Jiang, 2021Pronina et al, 2016Trapido et al,2014;Petala et al, 2019;Nil et al, 2018;Tiwari et al, 2018;Boucherie et al, 2010;Tomara et al, 2019;Chen et al, 2016;Acero et al, 2010;Liu et al, 2019;Sturini et al, 2015).…”