Study on Treatment of Cr (VI)-Containing Wastewater with Nitric Acid Modified Activated Carbon

After activated carbon is oxidized and modified with nitric acid (1:1), its cation exchange capacity can amount to 1.840 mmol • g-1. The modified activated carbon is used as adsorbent for the treatment of Cr (Ⅵ)-containing wastewater at room temperature, and its removal mechanism is discussed in this paper. It is shown that: when the pH value of the aqueous solution being 2.5-3.0;the adsorption time being 3.0h, the removal rate of Cr (Ⅵ) in the aqueous solution can reach 97% and its adsorption capacity can amount to 45.66 mg • g-1. From the results, it can be also seen that the adsorption curve to chromium in wastewater by the modified activated carbon better meets the Freundlich isotherm, and ion exchange adsorption mainly does its work.