Figure 1. Variation of Fe2+-ions concentration versus contact time at room temperature during Fe(II) adsorption onto the composite FeOOH-coated brick: (a) With brick previously washed in a 1 M HCl solution for 24 h; (b) With brick previously pre-activated in a 6 M HCl solution at 90°C for 6 h. Co represented the initial concentration of iron(II) in the medium, and Ct was the Fe(II) content at the adsorption time, t.