Removal of humic acids from water by advanced oxidation processes

Prisustvo huminskih kiselina u vodama je nepoželjno zbog njihove kemijske reaktivnosti s mnogim tvarima, čime se širi onečišćenje vode. Upotrebom ozoniranja uz prisustvo jakih oksidacijskih sredstava poboljšana je degradacija organskih onečišćivača do CO2 i H2O. U radu je otopina huminske kiseline obrađivana ozonom, Fentonovim procesom, kombiniranjem ozona i vodikovog peroksida te kombiniranjem ozona i Fe2+ iona. Ozoniranjem otopine huminske kiseline uklonjeno je 85-94% tvari mjerenih pri 254 nm uz potpuno uklanjanje obojenja, dok je uklanjanje izračunato preko izmjerenih vrijednosti TOC bilo 3,%. Također je dokazano da dodatak vodikovog peroksida ili Fe2+ iona odvojeno ne pospješuju uklanjanje huminskih kiselina ozoniranjem niti sami imaju oksidacijsko djelovanje na njih. Kod Fentonovog procesa, najbolji učinak smanjenja TOC je postignut kod otopine Fe2+ koncentracije 0,1 mmol/L i kod omjera Fe2+: H2O2 1:5.Occurrence of organic matter in water is undesirable because it can react with many compounds in water thus spreading the water pollution. Degradation of organic pollutants to CO2 and H2O has been improved by the use of ozonation in the presence of strong oxidative agents. In this work, solutions of humic substances were treated by ozonation, Fenton’s process, combination of ozone and hydrogen peroxide and combining ozone and ferrous ion. By ozonation of humic acids, 85-94 % removal was achieved when they were measured at 254 nm along with complete removal of colour, while 37% removal was calculated from the measured TOC concentration. It has also been shown that the addition of hydrogen peroxide or Fe2+ separately does not improve the removal of humic acids by ozonation or have an oxidation effect on them.With the Fenton process, the highest effect in the reduction of TOC was achieved using a solution of Fe2+ 0,1 mmol/L concentration and with a 1:5 rate of Fe2+: H2O2