Efficient Removal of Chromium and Lead from Water Solutions Using Forward Osmosis: A Response Surface Methodology Approach

Global pollution has increased significantly in the last decades due to excessive consumption of heavy metals in the industrial sector. Many solutions have been developed to decrease this pollution; however, novel methods are welcomed in this topic. Two of the most pollutant heavy metals are chromium and lead which cause catastrophic problems to living organisms. Hence, it is crucial to separate these heavy metals from the water. Synthetic feed solution samples of chromium and lead have been prepared in the laboratory with concentrations of 50, 75, and 100 mg/L. The draw solution is magnesium chloride and has been prepared with concentrations of 0.5, 1, and 1.5 mol/L. The variable factors are draw and feed solution concentration and experiment time duration. Regarding these variable factors, the experiment has been designed by response surface methodology and central composite design. The removal efficiency, water flux, and reverse solute flux for chromium and lead under optimum conditions were 94.47% and 99.91%, 17.16 Lm−2 h and 11.03 Lm−2 h, 7.03 gm−2 h, and 7.76 gm−2 h, respectively. Thus, forward osmosis with magnesium chloride as the draw solution is more effective in lead removal. However, the water flux is higher in the chromium removal process.