| Sažetak | Prekomjerna i kontinuirana primjena pesticida dovela je do onečišćenja vode, tla i zraka. Visoka stabilnost onečišćivala prema toplini, svjetlu i oksidansima, te dobra topljivost u vodi rezultiralo je njihovom prekomjernom akumulacijom u okoliš. Prisustvo pesticida u vodenom sustavu predstavlja zdravstveni rizik za ljude budući da su mnogi pesticidi endokrini disruptori te djeluju štetno na način da oponašaju ili antagoniziraju hormone u tijelu. Konvencionalne metode tretiranja otpadnih voda poput koagulacije, sedimentacije i filtracije nisu dovoljno učinkovite u uklanjanju svih onečišćivala iz vode, stoga je potrebno istražiti alternativna rješenja. Kao najperspektivnija iz skupine naprednih oksidacijskih procesa, ističe se heterogena fotokataliza uporabom poluvodičkog katalizatora, metoda kojom se organske molekule potpuno razgrađuju djelovanjem svjetlosti i kisika iz zraka. U okviru ovog rada provedeno je 15 eksperimenata fotokatalitičke razgradnje acetamiprida u vodenoj otopini s ciljem ispitivanja utjecaja triju nezavisnih varijabli na odziv sustav. Kao ulazne varijable izabrane su volumen reakcijske otopine (100 mL, 150 mL i 200 mL), tip katalizatora (2, 5 i 10 dana) te izvor zračenja (UVA-LED 20 W, UVA-LED 30 W i pen-ray lampa), a kao odziv praćena je promjena koncentracije acetamiprida, tj. konverzija. Eksperimenti su provedeni u čaši koja je predstavljala kotlasti reaktor s recirkulacijom reakcijske smjese. Kao heterogeni fotokatalizator izabran je TiO2 modificiran UV-C zračenjem i imobiliziran na abrazivni materijal. Eksperimentalni rezultati pokazali su da od tri ispitivane varijable, na brzinu i učinkovitost fotokatalitičke razgradnje acetamiprida, najviše utječe izvor zračenja. Najbolji rezultati postignuti su prijemnom UV-LED modula snage 30 W dok su najlošije konverzije dobivene primjenom pen-ray lampe. |
| Sažetak (engleski) | Excessive and continuous application of pesticides has led to water, soil, and air pollution. High stability towards heat, light, and oxidizing agents, as well as good solubility in water, has led to their persistence and accumulation in the environment. The presence of pesticides in the water system poses a health risk to humans as many pesticides are known endocrine disruptors and have a detrimental effect by mimicking or antagonizing hormones in the body. Conventional water treatment methods such as coagulation, sedimentation, and filtration are not able to successfully eliminate all contaminants from water, so alternative solutions need to be explored. Advanced oxidation processes, specifically semiconductor photocatalysis is becoming a very promising alternative because it uses sustainable solar energy and oxygen from air to remove pollutants. In this study, 15 experiments of photocatalytic degradation of acetamiprid in an aqueous solution were performed to investigate the effect of three independent variables on the systems' response. The volume of the reaction solution (100 mL, 150 mL, and 200 mL), the type of catalyst (2, 5, and 10 days), and the source of radiation (UVA-LED 20 W, UVA-LED 30 W, and pen-ray lamp) were chosen as input variables. and in response, a change in acetamiprid concentration, i.e. conversion, was monitored. The experiments were carried out in a 250 mL batch reactor with recirculation of the reaction mixture. TiO2, UV-C modified and immobilized on abrasive material was used as the heterogeneous photocatalyst. Experimental data showed, that of the three examined variables, source of radiation has the greatest effect on the rate and efficiency of photocatalytic degradation of acetamiprid. Highest conversion rates were achieved using UV-LED 30 W, while using pen-ray lamp showcased low conversion rates. |
