Effect of modified peanut shell on the removal of Cu(II) in aqueous solution

Abstract

The effective resource utilization of agricultural and forestry waste has always been a core issue in the field of environmental protection. In this study, nitric acid-potassium hydroxide (HNO3-KOH) was used to modify the peanut shell, and the effects of different adsorption time, initial concentration and exogenous Cr(III) addition on the adsorption of Cu(II) were investigated. The results show that the adsorption of Cu(II) on peanut shell raw material (HS-YL) and acid-base modified peanut shell (HS-SJ) was in accordance with the pseudo-second-order kinetic model. Isotherm study shows that HS-YL fitted Langmuir adsorption model, mainly exhibiting monomolecular and chemical adsorption. HS-SJ conformed to the Freundlich adsorption model, which was mainly controlled by multi-layer adsorption. Additionally, when Cr(III) and Cu(II) coexisted, HS-SJ could simultaneously adsorb two heavy metals in a large amount, showing stronger adsorption performance compared to HS-YL. Therefore, the acid-base combined modification method is one of the important ways to recycle peanut shells.