High Mn2+ Uptake by a New Polyvinyl Alcohol Derivative: Isotherm Model Analysis

The transformation of Polyvinyl alcohol (PVA) into poly(vinyl phenylthionecarbamate) (PVA-PT) was upgraded to 35 g with 45% yield and 90% conversion degree. PVA-PT has shown high uptakes (93-96%) towards Mn2+ > Cu2+ > Cd2+ after 4 hours stirring at 20 degrees C in a batch procedure, towards 31-1600 mg/L concentration range. The material and its metal ion adducts were characterized by gravimetric analysis, IR, Raman, and SEM/EDS. An experimental design was applied to evaluate the influence of parameters on the Mn2+ removal efficiency by PVA-PT. The best results were achieved after 240 min, at 20 degrees C and concentrations higher than 187 mg/L. The 20 degrees C sorption isotherms were recorded for the PVA-PT/Mn2+ system at different particle sizes and dosages. The best experimental sorption capacity (q(e) = 343.76 mg/g) was reached at the lowest dose (0.05 g in 10 mL solution) and the highest concentration (1809.82 mg/L). Data fit Freundlich isotherm model (R-2 = 0.9462, K-F = 0.8625, N = 0.8271), indicative of a moderate affinity interaction PVA-PT/Mn+2. The kinetic isotherm models demonstrate chemisorption and bulk diffusion-controlled absorption into the material after 7 min.