Figure 6

Dual effects of input variables on Cr(VI) removal efficiency (3D plot): (a) pH and initial concentration effect; (b) pH and dosing amount effect; (c) pH and adsorption time effect; (d) pH and temperature effect; (e) initial concentration and dosing amount effect; (f) dosing amount and adsorption time effect; (g) predicted and actual values of model on Cr(VI) removal efficiency; (h) independent effects of five variables A, B, C, D and E on Cr(VI) removal.