Removal of Cd(II) and Cu(II) from Aqueous Solution by Na⁺-Modified Pisha Sandstone

Figure 6

Experimentally interpolated (symbols) and calculated (surface) isotherms for sorption in Cd-Cu systems. The adsorption amounts of (a) Cd(II) by PS, (b) Cd(II) by Na-PS, (c) Cu(II) by PS, and (d) Cu(II) by Na-PS, respectively. The Y-axis is the individual metal adsorption amount, the X-axis is the concentration of Cd(II), and the Z-axis is the concentration of Cu(II). PS means Pisha sandstone; Na-PS means Pisha sandstone modified with Na⁺.

(a)

(b)

(c)

(d)