Combined Coagulation and Electrochemical Process to Treat and Detoxify a Real Textile Effluent
2016
Aquino, José M. | Pereira, Gabriel F. | Rocha-Filho, Romeu C. | Bocchi, Nerilso | Biaggio, Sonia R.
Combined coagulation and electrochemical treatment processes were used to mineralize the organic load and detoxify a real textile effluent. The coagulation step was investigated for distinct pH values (4 to 11) and Al₂(SO₄)₃ concentrations (0.25 to 9.00 g L⁻¹). Complete turbidity and partial total organic carbon (TOC) removals were attained at pH 5, using 0.50 g L⁻¹Al₂(SO₄)₃. Moreover, the coagulation process totally removed the initial toxicity (100 % mortality) of the effluent, assessed by toxicity tests with the crustacean Artemia salina. The remaining TOC was mineralized by the electrochemical step in a flow cell with a boron-doped diamond (BDD) anode, when the investigated parameters were the BDD boron-doping level (100, 500, 2500 ppm), pH (3, 7, 11, no control), and current density (10, 20, 30 mA cm⁻²). No significant differences in TOC removal were observed when the BDD anode or pH value was changed; however, as the system was under mass transport limitation, mineralization attained at low current densities led to a reasonable current efficiency (∼40 %) and low energy consumption (∼16 kW h m⁻³). The use of the electrochemical method solely led to poor TOC and turbidity removals, thus not being recommended.
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