ADSORPTION OF Pb(Ⅱ) FROM AQUEOUS SOLUTION BY PEANUT SHELL POWDER

摘要

In this paper, two kinds of peanut shell powder, natural peanut shell powder (NPSP) and modified peanut shell powder (MPSP), were chosen to treat Pb(Ⅱ)-containing aqueous solution. The influence of various factors including pH value, reaction time, dosage of peanut shell powder and the initial concentration of Pb(Ⅱ) were also investigated. The results showed that pH 5.0 was the prime pH condition for the adsorption of Pb (Ⅱ) by NPSP and MPSP. With the increase of reaction time and decrease of peanut shell powder dosage, the adsorption amount of Pb(Ⅱ) by peanut shell powder exerted a gradual increase. Adsorption capacity of NPSP and MPSP were 37.5, 57.6 mg/g, respectively. MPSP had higher adsorption capacity than NPSP under the same experimental conditions, which can be attributed to the different surface structures between these two biosorbents. The adsorption process was described well by the Langmuir model due to the higher coefficient compared to Freundlich model. Both pseudo-first-order and pseudo-second-order equations were able to describe properly the kinetics of Pb(Ⅱ) adsorption. Based on the FT-IR analysis, it was supposed that chelation process took place between functional groups and Pb(Ⅱ) ions.