CONTINUOUS FOAM SEPARATION OF HEAVY METAL IONS FROM ELECTROPLATING INDUSTRIAL EFFLUENT

Abstract

Process industries generate a large amount of waste materials during either production or downstreaming operations. Among many methods available for their separation, foam separation plays a major role, especially when the concentration of undesirable components involved is very low. The success of this technique depends on the stability and characteristics of the foam. This operation is simple with less maintenance as there are no moving parts. In the present study, simultaneous removal of metal ions such as chromium (VI), copper (II), and zinc (II) from electroplating industrial effluent was carried out with sodium lauryl sulfate (SLS) as surfactant in continuous foam column. Enrichment ratios of 3.94, 4.05, and 7.96 with a percentage removal of 59.0%, 63.0%, and 99.2% were obtained for chromium (VI), copper (II), and zinc (II) ions respectively at the optimum operating parameters of 23 cm liquid pool height in column, 0.1 liter per minute (Lpm) of airflow rate, feed flow rate of 4 liters per hour (Lph), 0.1% (w/v) of SLS concentration, pH of 6.0, and at feed concentrations of 32.5, 27.0, and 23.0 ppm for chromium (VI), copper (II), and zinc (II) ions respectively. Enrichment ratio was found to increase with an increase in feed flow rate. With a decrease in concentration of the bulk solution, the separation factor was found to increase. The study indicates the feasibility of continuous foam separation for treating industrial effluents.