Adsorption of Cr(VI) in Aqueous Solution Using a Surfactant-Modified Bentonite

Table 4

Points for the validation of the experimental design.

Adsorbent amount (g)	pH	Cr(VI) removal, (%)		Error (%)
		Experimental	Calculated
0.45	5.5	79.01 ± 0.83	82.78	4.78
0.35	3.0	91.17 ± 1.02	90.45	0.79
0.44	3.4	91.85 ± 0.92	93.60	1.75