Study on behavior and kinetics of sorption of Ag+ by Shenfu3−1 coal

Shenfu3−1 coal has been used for the adsorption of Ag ion from aqueous solution, over a range of initial Ag+ concentrations (3240-21600 mg l−1), temperatures (18, 20, 60 and 80 °C), pH values (1.5-10) etc. The Ag+ adsorption on Shenfu3−1 coal increased with an increase in initial concentration of Ag+ and with an increase in temperature. The process of uptake follows the Langmuir isotherm model. RL (0 < RL < 1) factor revealed the favorable nature of adsorption isotherm of the Ag+-coal system. The applicability of Lagergren and empirical kinetic models has also been investigated. Intraparticle diffusion studies revealed the Ag+ sorption interaction was complex and intraparticle diffusion was not the only rate limiting step. At pH 4.5 of Ag+-coal aqueous system,the adsorbent Shenfu3−1 coal yielded maximum Ag+ adsorption. The coal powders were characterized using Infrared spectroscopy and XRD before and after adsorption.