A Comparing Study on Copper Adsorption on Nanoscale Carbon Black Modified by Different Kinds of Acid

Considerable attention has been focused on the nanoscale carbon black development and application in wastewater treatment. But the CB is a hydrophobic and nonpolar adsorbent, and it has strong adsorption ability to nonpolar organic compounds and poor adherence to heavy metal ions. The nanoscale carbon black modified by appropriate physical and chemical treatments could improve their adsorption capacities for heavy metal ions. In this study, a surface-modified nanoscale carbon black was prepared by oxidizing the carbon black with 65% HNO3 (B), 0.05 mol⋅L-1HAc (C), 20% HNO3+ 1.58% K2MnO4 (D) and 50% H2SO4 (E), respectively. Batch experiments showed that the adsorption quantities of Cu(II) on the nanoscale carbon black modified by different kind of acids (MCBs) were significantly increased compared with those on the parent one, and the maximum adsorption quantities of Cu(II) were 48.92 mg⋅g-1 (D), 30.15 mg⋅g-1 (B), 12.33 mg⋅g-1 (A), 13.51 mg⋅g- (C) and 5.47 mg⋅g-1 (E), respectively. The Langmuir isotherm provided a better fit to the experimental data of the parent one and the MCBs fitted well into Freundlich adsorption isotherm. The adsorption kinetic model of Cu(II) on all sorbents followed pseudo second order model well. It is clear from this work that the nanoscale carbon black modified by 65% HNO3 (B) and 20% HNO3+ 1.58% K2MnO4 (D) had very good adsorption properties for the metal ions.