Removal of anthraquinone dyes from aqueous solutions by adsorption, electrochemical oxidation and advanced oxidation processes

U radu je ispitivana mogućnost uklanjanja ili razgradnje antrahinonskih boja C.I. kiselo plavo 111 (AB111) i C.I. kiselo ljubičasto 109 (AV109) adsorpcijom, elektrohemijskom oksidacijom i višim oksidacionim procesima. Tokom ispitivanja uklanjanja ispitivanih antrahinonskih boja iz vodenih rastvora, korišćene su čestice na bazi aluminijum-oksida dopovane različitim masenim udelom gvožđe(III)-oksida (4 i 13 mas. %) termički obrađene na temperaturama 700, 800 i 900 ℃. Karakterizacija termički obrađenih čestica korišćenih tokom ispitivanja vršena je SEM-EDS i XRD analizama. Ispitan je uticaj početne koncentracije adsorbenta i boje, početne vrednosti pH, vrste adsorbenta i temperature na efikasnost uklanjanja boja i kinetiku adsorpcije. Takođe, određeni su i termodinamički modeli i parametri adsorpcije antrahinonske boje AB111. Ispitivanje obezbojavanja rastvora i razgradnje ispitivanih antrahinonskih boja elektrohemijskom oksidacijom u zavisnosti od mehanizma procesa podeljeno je na dve celine: direktnu i indirektnu elektrohemijsku oksidaciju. Tokom ispitivanja korišćena je IrOX anoda, određena je zavisnost efikasnosti obezbojavanja rastvora od jačine struje, koncentracije elektrolita i početne vrednosti pH rastvora. U radu je određen specifični utrošak električne energije u zavisnosti od primenjene jačine struje. Ispitivanje obezbojavanja rastvora i razgradnje molekula boja višim oksidacionim procesima obuhvata primenu Fenton, foto-Fenton i elektro-Fenton (elektroasistirani-Fenton) procesa. Tokom svih ispitivanja utvrđen je uticaj početne koncentracije vodonik-peroksida, Fe2+ jona i vrednosti pH rastvora na efikasnost svih procesa, a tokom elektro-Fenton procesa ispitivan je i uticaj anode (IrOX i Pt) i jačine struje na efikasnost i kinetiku obezbojavanja rastvora. Ispitan je i uticaj 2-propanola, hlorida i sulfata na efikasnost obezbojavanja rastvora Fenton i elektro-Fenton procesima. U cilju sagledavanja isplativosti procesa, izračunati su mogući troškovi obezbojavanja rastvora ovim procesima. Metoda UV-Vis spektrofotometrije je korišćena da bi se pratila promena koncentracije boje tokom obezbojavanje rastvora. Efikasnost razgradnje boje AB111 elektrohemijskom oksidacijom i višim oksidacionim procesima ispitivana je promenom vrednosti ukupnog organskog ugljenika (TOC analiza). Joni koji su nastali razgradnjom boja detektovani su metodom jonske hromatografije. Karakterizacija proizvoda razgradnje izvršena je FT-IR, HPLC-MS i GC-MS analizama. Ispitivanjem klijanja Mung pasulja, određena su fitotoksikološka svojstva početnog rastvora boje AB111 i rastvora dobijenih posle tretmana Fenton i elektro-Fenton procesima.The removal or degradation of anthraquinone dyes C.I. Acid Blue 111 (AB111) and C.I. Acid Violet 109 (AV109) was studied by adsorption, electrochemical oxidation, and advanced oxidation processes. During the investigation of the anthraquinone dyes’ removal from aqueous solutions, alumina-based particles doped with different mass fractions of iron (III)-oxide (4 and 13 wt %) thermally treated at temperatures of 700, 800, and 900 ℃ were used. The characterization of the heat-treated particles used during the examination was performed by SEM-EDS and XRD analyses. The influence of the initial concentration of adsorbent and dye, initial value of pH, type of adsorbent and temperature on the efficiency of dye removal and adsorption kinetics was investigated. Also, thermodynamic models and adsorption parameters of anthraquinone dye AB111 were determined. The study of the decolorization and degradation of the anthraquinone dyes by electrochemical oxidation depending on the process mechanism was divided into two parts: direct and indirect electrochemical oxidation. During the study, the IrOX anode was used, and the dependence of the solution’s decolorization efficiency on the applied current, electrolyte concentration, and initial pH value of the solution was determined. The specific consumption of electricity depending on the applied current was determined. The study of decolorization and degradation of the dyes by advanced oxidation processes included the application of Fenton, photo-Fenton and electro-Fenton (electro-assisted-Fenton) processes. During the study, the influence of the solution’s initial concentration of hydrogen peroxide, Fe2+ ions and pH values on the efficiency of all processes was determined, and during the electro-Fenton process the influence of the anode (IrOX and Pt) and current on the efficiency and kinetics of the solution’s decolorization were examined. The influence of 2-propanol, chloride and sulfate ions on the decolorization efficiency of the Fenton and electro-Fenton process was also determined. In order to assess the cost-effectiveness of the process, the possible costs of decolorization of the solution by these processes were calculated. The UV-Vis spectrophotometry method was used to follow the change in the dyes’ concentration during the decolorization of the solution. The efficiency of AB111 degradation by electrochemical oxidation and advanced oxidation processes was established by total organic carbon analysis. Ions formed by dye degradation were detected by ion chromatography. The characterization of the degradation products was performed by FT-IR, HPLC-MS and GC-MS analyzes. The phytotoxicological properties of the AB111 dye solution as well as of the solutions after the treatment by Fenton and electro-Fenton processes were determined using the Mung beans