Comparative analysis of coagulants for selective removal of iron and aluminum from galvanic wastewater: A practical and effective approach

This research aimed to evaluate three coagulants (aluminum sulfate, polyaluminum chloride, and ferric chloride) for the selective removal of iron and aluminum from wastewater generated during the pickling process in the galvanic industry. Jar tests were conducted at pH levels of 5.5 and 11, adjusted using lime. Results indicated that aluminum sulfate was the most effective coagulant, achieving a 97.91% removal of iron and a 93.09% removal of aluminum at pH 5.5 with specific dosages. The study established that optimal metal removal occurs at pH 5.5, with a necessary lime concentration of 7.5%. Statistical analyses, including MANOVA and ANOVA, confirmed significant relationships between metal removal efficiency, coagulant type, dosage, concentration, and pH. The Tukey-HSD test indicated distinct behaviors among coagulants, while the Mahalanobis Distance test highlighted specific relationships among the study variables. Overall, aluminum sulfate and polyaluminum chloride are recommended for effective wastewater treatment in the electroplating industry.