Solid Phase Extractive Pre-Concentration of Uranium(VI) from Liquid Waste onto Peach Stone Steam Pyrolysis Activated Carbon

摘要

Drinking water contaminants, especially heavy metals and uranium, have been recognized as a worldwide problem pose a serious threat to human health. Among several treatment technologies applied for contaminant removal, adsorption methods have been studied extensively and proven to offer satisfactory results with high selectivity. In this study, steam pyrolysis activated carbons from biomass were synthesized with characterizations giving a higher capacity for uranium and other heavy metal contaminants. In this study, a batch equilibration pre-concentration of uranium(VI) was carried out in the pH range (2-10), adsorbent dosage (0.166-0.833 g L~(-1)), sorption time (5 min to 24 h), temperatures (25, 50 and 70 °C), different types of activated carbon precursor, uranium initial concentration (50-500 mg L~(-1)) and different interfering ions (cations: Cr, Pb, Fe, K and anions: NO3~-, Cl~-, SO4~(2-). HPO4~(2-)). The equilibrium data fitted well to the Freundlich and Langrauir equilibrium models in the studied concentration range and temperatures. The kinetics of the adsorption process followed a second-order adsorption and intra-particle diffusion is not the only rate determining step. 0.25 M H2SO4 was effective in uranium recovery. The results indicated that the conversion of naturally abundant peach stone of the nuisance value to valuable material exhibited considerable potential for application in pre-concentration and separation of uranium from aqueous solution.