engleski

Treatment of waters contaminated with diesel fuel by electrocoagulation

Electrocoagulation (EC) is one of the promising contaminated water treatments, where impurities are removed by coagulation and flotation, while coagulant is added in situ by electrochemical oxidation of the suitable anode material. EC is possible alternative to the metal salts or polymers and polyelectrolyte addition, for the stable emulsion breaking, adsorption, as well as the metal, colloids and soluble inorganic impurities removing. In this work, efficiency of electrocoagulation process for hydrocarbon removing from the water emulsion was investigated. As model solution, emulsion of diesel fuel in distillate water with addition of sorbitan monooleate as the emulsifier was used. Process was conducted in the batch reactor with the aluminum electrodes, with addition of the NaCl for the increase of electrical conductivity of the emulsion. Inlet parameters were NaCl and diesel fuel concentrations in emulsion, current density and reaction time. Outlet parameters were total organic carbon (TOC), filtrate volume and mass loss of the anode material. Experiments were conducted in two sets, each with 16 treatments, settled by two level factorial design (TLFD) method. Quantitative influence of each factor, inlet parameters and their interactions on the main responses were calculated, and presented with mathematical correlations. Obtained results indicated very high efficiency of the electrocoagulation process, for the hydrocarbon removal from water emulsion, ranging from 98.9 to 99.5 %, calculated in respect to the total organic carbon content in water, while current efficiency was in the range from 17 to 78 %. Water phase after the EC process was odorless, tasteless and colorless. As expected, it is proven that the current efficiency is increasing with increase of the electric conductivity of the emulsion and with decrease of the current density. High TOC removal was obtained even for the short periods of reaction time (5 minutes), meaning that higher current efficiencies are possible with lower current densities at prolonged reaction times.

water; diesel fuel; emulsion; electrocoagulation; modeling

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