Iron-impregnated activated carbons precursor to rice hulls and areca nut waste in the remediation of Cu(II) and Pb(II) contaminated waters: a physico-chemical studies

摘要

The aim of this study is to exploit the abundantly available rice hulls and areca nut waste in obtaining the activated carbons which is further impregnated with a low dose of iron to obtain the iron-impregnated activated carbon (IIAC) samples. The solids are characterized by the IR and XRD analytical tools whereas the surface morphology is discussed with the SEM images of these solids. BET specific surface area which was obtained for these materials showed that the impregnation of iron did not significantly affect the specific surface area of these solids. Further, the materials were employed in the removal of two different heavy metal toxic ions viz. Cu(II) and Pb(II) under the batch and column reactor operations. The batch data were collected for various physico-chemical parametric studies, viz. effect of solution pH, sorptive concentration, contact time, electrolyte concentrations, etc. The mechanism involved at solid/solution interface was discussed with the help of these studies. Moreover, the equilibrium state sorption data and the time dependence data were utilized to conduct the adsorption isotherm and kinetic modeling studies, respectively. The pseudo-second-rate equation was fitted well to the sorption of these two cations; hence, the sorption capacity was estimated to be 1.770 and 1.926 mg/g (for Cu(II)) and 3.507 and 3.439 mg/g (for Pb(II)), respectively for IIAC-R and IIAC-N. The removal of these two cations was also performed under the dynamic experimentations under column studies. The column data were utilized obtaining the breakthrough curves and hence the breakthrough volumes were obtained. Further, the breakthrough data were utilized to simulate it with Thomas equation and, hence, the loading capacity of the columns was estimated to be 2.746 and 3.057 mg/g (for Cu(II)) and 6.957 and 6.505 mg/g (for Pb(II)), respectively for IIAC-R and IIAC-N samples.