Ecotoxicity testing og organic pollutants degradation products in Water after the treatment with advanced oxidation processes.

[M. D. Marković]

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Hemija - Hemija životne sredine / Chemistry - Environmental Chemistry

U okviru ove disertacije ispitana je degradacija 4CP (para-hlorfenol), reaktivnih azo boja i ibuprofena primenom unapređenih oksidacionih procesa (eng. Advanced Oxidation Processes, AOP) kao što su Fentonov reagens, DBD reaktor (eng. Dielectric Barrier Discharge) i elektrohemijske degradacije. Efikasnost degradacija zagađujućih organskih supstanci optimizovana je dodatkom homogenog katalizatora (Fe2+ ili H2O2) u reaktor, primenom različitih elektrodnih materijala ili variranjem vremena tretmana. Dekolorizacija (%) je praćena UV-VIS tehnikom, efikasnost degradacije je praćena jonskom hromatografijom (IC) i HPLC tehnikom. Identifikacija glavnih proizvoda degradacije, kao i mehanizmi degradacije određeni su LC-MS (TOF) tehnikom. Efikasnost mineralizacije je određena preko TOC vrednosti. Tretman netermalnom plazmom (eng. non-thermal plasma NTP) u DBD reaktoru je ispitan tokom degradaciji 4CP do biodegradabilnijih i manje toksičnih intermedijera. Eksperimentalni rad je organizovan u tri sistema za degradaciju 4CP: DBD, DBD/H2O2 i DBD/Fe2+. Praćena je efikasnost degrdacije 4CP u funkciji broja prolaza kroz DBD reaktor, kao i količini unete energije po jedinici zapremine rastvora (gustina energije, kJ/L). Koncentracija 4CP, kao i koncentracija pojedinih proizvoda degradacije merena je nakon svakog prolaza. Koncentracije proizvoda degradacije 4CP kao što su sirćetna, mravlja ili oksalna kiselina, bile su niže u sistemu gde je kao katalizator upotrebljeno gvožđe DBD/Fe2+ u poređenju sa sistemom gde je kao katalizator primenjen vodonik-peroksid DBD/H2O2. Koncentracija hlorida u sva tri sistema je rasla tokom procesa degradacije. Najviša koncentracija hlorida, zabeležena je u sistemu sa dodatkom Fe2+ kao katalizatora. Procena toksičnosti početnog rastvora 4CP, kao i rastvora tretiranih u sva tri sistema ispitana je pomoću A.salina. U odnosu na početni (netretirani) rastvor 4CP, nakon tretmana DBD/Fe2+ porcenat preživelih larvi A. salina se povećao za 95%. Degradacija reaktivnih azo boja (RG15, RY125 i RB52) je ispitana primenom EAOP (eng. Eletrochemical Advance Oxidation Processes) tehnika u nepodeljenoj dvoelektrodnoj ćeliji, gde je kao anoda primenjena Fišerova platinska elektroda, a kao katoda korišćena je Pd, Zr ili C elektroda. Najefikasniji sistem za degradaciju RG15 i RY125 je bio Pt-Pd sistem, dok je za RB52 to bio Pt-Zr sistem. Ekotoksikološki efekat za boje RG15 i RY125 bio je najniži ili nije detektovan u rastvoru boje nakon Pt-Pd tretmana. U slučaju RB52, uočeno je da se ekotoksikološki efekat uvećava i na A.salina i na V.fischeri nakon EAOP tretmana. U slučaju degradacije ibuprofena, nakon 15 min tretmana dodatak homogenog katalizatora je poboljšao NTP tretman i doprineo efikasnosti degradacije ibuprofena (99%), kao i mineralizaciji zagađujuće supstance u odnosu na DBD i Fentonov proces (oko 80%). U svim tretmanima analizom masenih spektara, identifikovano je 12 proizvoda degradacije ibuprofena: pet aromatičnih i sedam alifatičnih proizvoda. Nakon DBD/Fe2+ tretmana detektovane su samo 4 alifatične karboksilne kiseline. Ekotoksikološki efekat tretiranih rastvora ibuprofena u DBD reaktoru nije detektovan, kao ni u slučaju kada je gvožđe korišćeno kao katalizator. U odnosu na A.salina, V.fischeri je pokazao veću osetljivost na proizvode degradacije koji su nastali tokom Fenton tretmana. Toksični efekat rastvora ibuprofena nakon Fenton tretmana kategorisan je kao klasa III, tj. “toksičan”. Najviši procenat degradacije ibuprofena primenom EAOP- a je postignut tretmanom rastvora u Pt - Pd sistemu - 98%, pri jačini struje od 100 mA i pH od 3. Toksični efekat mortalitet (%) A. salina izazvan rastvorom ibuprofena tretiranog u Pt-Pd sistemu bio je ispod 30% pri najvišoj testiranoj koncentraciji od 100% (c, v/v). V.fischeri se pokazao kao osetljiviji model za procenu toksičnog efekta proizvoda degradacije ibuprofena nakon Pt-Pd tretmana u odnosu na A.salina.

In this thesis the degradation of 4CP (para-chlorophenol), reactive azo dyes and ibuprofen was studied using the Advanced Oxidation Processes (AOP) such as Fenton's reagent, Dielectric Barrier Discharge (DBD) reactor and electrochemical degradation. The efficiency of degradation was optimized by addition of a homogenous catalyst (Fe2+ or H2O2) to the reactor and also by applying different electrode materials or by varying the duration of the treatment. The decolorization (%) of reactive azo dyes was monitored by UV-VIS technique and the efficiency of degradation was monitored by ion chromatography (IC) and HPLC. Identification of the main degradation products as well as the degradation mechanisms were determined by LC-MS (TOF) technique. The mineralization efficiency was determined through the value of TOC. Treatment by non-thermal plasma (NTP) in the DBD reactor was studied during the degradation of 4CP to biodegradable and less toxic intermediates. Experimental work was organized into three systems for 4CP degradation: DBD, DBD/H2O2 and DBD/Fe2+ . The efficiency of 4CP degradation was evaluated by the number of passing of the solution through the DBD reactor, as well as the amountn of the introduced energy density (kJ/L). The concentration of 4CP, as well as the concentration of the individual degradation products were measured after the each pass. The concentrations of the 4CP degradation products such as acetic, formic or oxalic acid were lower in the system where the iron was used as the catalyst (DBD/Fe2+) in comparison to the system with hydrogen peroxide as the catalyst (DBD/H2O2). The concentration of chloride in all three systems increased during the degradation process. The highest concentration of chlorides was recorded in the system with the addition of Fe2+ as a catalyst. The toxicity assessment of initial solution of 4CP as well as the solution which has been treated in all three systems was performed using A.salina. In comparison to untreated solution of 4CP the solution treated in DBD/Fe2+ system had increased percentage of larval survival by 95%. Degradation of reactive azo dyes (RG15, RY125 or RB52) was studied using the EAOP (Eletrochemical Advance Oxidation Processes) techniques in undivided twoelectrode cell, where the Fisher platinum electrode was applied as anode and the Pd, Zr or C electrodes were applied as cathode. The most effective system for the degradation of RG15 and RY125 was Pt-Pd system, while for the RB52 the Pt-Zr system was more applicable. Ecotoxicological effect of reactive dyes RG15 and RY125 was the lowest or not detected in the dye solution after the Pt-Pd treatment. In the case of RB52 ecotoxicological effect increased for both A.salina and V.fischeri after the EAOP treatment. In the case of ibuprofen degradation, the NTP treatment (15 min) was improved by addition of a homogeneous catalyst, which contributed to the efficiency of degradation (99%) and the mineralization of polluting substances in comparison to DBD and the Fenton process (about 80%). After all treatments, by analysis of mass spectra 12 degradation products of ibuprofen were identified: five aromatic and seven aliphatic products. In the solution after the DBD/Fe2+ treatment only 4 aliphatic carboxylic acids were detected. Ecotoxicological effect of the ibuprofen solution treated in the DBD reactor as well as in the DBD/Fe2+ system was not detected. In relation to A.salina, V. fischeri has shown greater sensitivity to degradation products which appeared during the Fenton treatment. The toxic effect of ibuprofen solution after the Fenton treatment was categorized as class III, that is "Toxic". The highest degradation percentage of ibuprofen was achieved by application of EAOPs in the Pt - Pd system (98%), with the current of 100 mA and at the pH value of 3. The toxic effect expressed as the mortality (%) of A. saline was less than 30% at the highest tested concentration 100% (c, v/v) of ibuprofen solution treated in the Pt-Pd system. The V.fischeri was the more sensitive model for the assessment of the ibuprofen degradation products toxic effect after the Pt-Pd treatment in comparison to A.salina.

ekotoksikologija, para-hlorfenol, azo boje, ibuprofen, AOP, neravnotežna plazma, DBD, elektrohemijska degradacija, homogeni katalizatori, HPLC, LC-MS (TOF), A. salina, V. fischeri

ecotoxicology, para-chlorophenol, azo dyes, ibuprofen, AOP, non-thermal plasma, electrochemical degradation, homogeneous catalysts, HPLC, LC-MS (TOF), Artemia salina, V. fischeri

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