Evaluation of parameters in the removal of azo Red 40 dye using electrocoagulation

Abstract

The objective of the present investigation was to evaluate the parameters that affect the efficiency of electrocoagulation in a batch system to remove the azo-benzoic dye Red 40 present in synthetic wastewater by determining the effect of the operational parameters of voltage and treatment time. A 12×6 cm iron electrode holder was constructed with PVC pipes and screws separated by 2 cm, and a 1 L beaker was used as the electrocoagulation cell. Synthetic wastewater samples of red 40 were characterized, where UV–VIS was used to measure absorbance before and after being treated in the electrocoagulation cell. The effects of voltages (10, 15, and 20 V) and treatment times up to 60 min were evaluated. As a result, a higher removal of 93.85 % was obtained at 60 min when a voltage of 10 V was used with a lower change in temperature and energy consumption of only 14.08 kJ. The increase in conductivity and pH by values greater than 1600 µs/cm and 11, respectively, indicate the presence of diluted iron at the end of treatment; therefore, if complemented with other treatment methods such as filtration to remove excess iron produced, can be used in treatment plants and reduce their environmental impact, for this research the FTIR analysis showed that the sludge has a dye composition with hydroxides of metals along with a slight trace of dye degradation.