Activated Carbon Based on Cherry Kernel Shell and a New Composite of Lacunary K۱۰P۲W۱۷O۶۱/Activated Carbon for Removal of Cd(II) from Aqueous Solutions

There is still an urgent need to develop new materials for removing heavy metal elements from polluted water bodies. In the present study, a new composite of activated carbon-loaded lacunary phosphotungstate (LPW) was produced for removing Cd(II) from aqueous solutions. The Activated Carbon (AC) was prepared based on Cherry Kernel Shell (CKS) treated with concentrated H۲SO۴ (۹۸%) followed by thermal activation at ۸۰۰°C. The ACCKS and LPWAC were characterized in terms of ash content, bulk density, and moisture content. The functional groups, morphology, and surface area of the produced materials were studied using FT-IR, SEM-EDX, and BET techniques, respectively. LPWAC was prepared as an ultrafine powder (<۱ μm) containing ۳.۳% of the LPW. The LPWAC consisted of carbon (۵۳.۸۷%), tungsten (۲۸.۴۰%), and oxygen (۱۱.۴۱%), while ACCKS contained a major amount of carbon (۷۲.۸۷%) and oxygen (۱۶.۸۸%). The kinetic study of Cd(II) adsorption on both LPWAC and ACCKS materials followed pseudo-second-order. The Cd(II) adsorption data fitted well with the Langmuir model. The maximum adsorption capacity for LPWAC and ACCKS alone at ۱۰۰ mg Cd(II)/mL and ۲۵°C was ۸.۷۳۴ mg/g and ۷.۵۹۳ mg/g, respectively, while these values were ۹.۹۳۱ mg/g and ۸.۵۰۷ mg/g at ۸۰°C, respectively. Positive values of ΔHo and ΔSo showed the endothermic nature and increased randomness of the Cd(II) adsorption process. The negative values of ∆G° ​​for LPWAC composite indicated the spontaneous reaction, while the positive ∆G° values ​​for ACCKS indicated the existence of an energy barrier during the adsorption process. The adsorption of Cd(II) on ACCKS and LPWAC materials was a physicochemical process. The desorption ability of Cd(II) ions from both materials was obtained using HNO۳ ≥ ۰.۵M. According to these results, both LPWAC composite and ACCKS alone could have potential applications in removing Cd(II) ions from aqueous solutions.

کلیدواژه ها:

Activated Carbon ، Adsorption ، Cd(II) ، cherry kernel shell ، Composite ، Kinetics