Removal of Cr(III), Mn(II), Fe(III), Ni(II), Cu(II), Zn(II), and Pb(II) from Water Solutions Using Activated Carbon Based on Cherry Kernel Shell Powder

In this work, a method for preparing activated carbon based on cherry kernel shell (AC-CKS) was investigated using two consecutive steps: chemical activation with H۲SO۴ agent and thermal activation in air. For the first time, AC-CKS product is used for the removal of numerous metal ions such Cr(III), Mn(II), Fe(III), Ni(II), Cu(II), Zn(II), and Pb(II) from water solutions. The AC-CKS was characterized using EA, FTIR, SEM, EDX, and XRF techniques. The AC-CKS obtained by heating at ۶۰۰ °C showed products with higher iodine numbers and invariably micro-size pores compared to those obtained by heating at ۵۵°C and ۴۰۰°C. The adsorption capacity of AC-CKS۶۰۰ was tested in the removal of previously mentioned metal ions. The essential parameters affecting the removal of metal ions were studied. The results showed maximum adsorption of ۹۹.۰% for Cr(III), ۹۱.۷% for Fe(III), ۶۲.۰% for Cu(II), ۵۹.۳% for Pb(II), ۴۲.۰% for Zn(II), ۲۸.۰% for Ni(II), and ۲۶.۹% for Mn(II). The adsorption data of most metal ions fitted well with Langmuir model. The maximum adsorption capacity followed the sequence: Cr(۱۰.۷۵mg/g)>Fe(۱۰.۱۵mg/g)>Cu(۷.۵۸mg/g)>Pb(۷.۳۶mg/g)>Zn(۶.۰۸mg/g)>Ni(۲.۸۳g/g)>Mn(۲.۲۹ mg/g). The adsorption kinetics was tested for the pseudo-first order and pseudo-second order. The rate constants of adsorption for all studied metal ions were calculated. Good correlation coefficients (R۲>۰.۹۹۷۲) were obtained for the pseudo-second-order kinetic model showing that all metal ions uptake processes followed the pseudo-second-order rate expression. Desorption studies showed the quantitative recovery of metal ions in the range of ۸۹.۴% for Pb(II) to ۹۴% for Cr(III). According to the adsorption model applied in this work, AC-CKS۶۰۰ product could be recommended for the removal of Cr(III), Fe(III), Cu(II), Pb(II), and Zn(II) from aqueous solutions.

کلیدواژه ها:

Activated Carbon ، Adsorption ، cherry kernel shell ، Metal ions