Fast and Selective Adsorption of Au (III) from the Waste Printed Circuit Boards Using a Low-Cost Adsorbent: Optimization by Central Composite Design Based on Response Surface Methodology

Figure 7

Effect of competing metals in the waste PCB on Au (III) adsorption. The initial concentration of metals in the solution at pH = 2 (Au = 30.12, Ag = 6, Al = 8423, Ba = 133, Ca = 1160, Co = 2, Cr = 59, Cu = 8196, Fe = 744, Mg = 71, Mn = 13.6, Mo = 1, Ni = 176, Pb = 16.3, Si = 7, W = 0.3, and Zn = 40 ), volume of solution = 5 mL, adsorbent mass = 23 mg, temperature = 303 K, and contact time = 30 min.