engleski

Removal of reactive dye from wastewater by electrocoagulation method

The industrial growth is accompanied by an increase in water consumption, with simultaneous increase of environmental pollution, including water. Solution of the problem is a reasonable use of water by longer retention in the system for water management and multiple usages trough recovery and recycling, because all forms of water present a valuable resource which is necessary to be evaluated and used according to the quality. We investigated the possibility of processing wastewater contaminated with reactive dye by electrocoagulation. Electrocoagulation is a complex process where a separation of pollutants by electrolysis, coagulation and flotation takes place. The advantage of electrocoagulation over conventional methods of treatment of contaminated water is generation of a coagulant in situ by electrochemical oxidation of anode. Thus, additional burden of water and the need for neutralization of excess chemicals are prevented, as in the case of direct addition of coagulant, i.e. chemical coagulation. Its additional advantage is the possibility to process water loaded with different types of pollutants and design in the scale of smaller, local systems for water treatment that may be preferable to large, centralized systems that require transport to the distance, as well as the additional costs regarding energy, infrastructure, etc. Processes are carried out in batch reactor with a pair of iron electrodes. Processes are performed at different current densities. Influence of initial pH and duration of the process on the effectiveness of electrocoagulation are examined. The total organic carbon (TOC) and the absorption, i.e. the concentration of dye in solution after treatment, were used as performance indicators. Treatment of contaminated solution resulted with a high efficiency of removal of dye and decrease of the TOC. The best values are achieved for the initial pH = 3, wherein the color removal of 99.8% was achieved, and TOC reduction of 92-95%.

electrocoagulation; wastewater; reactive dye

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