Sequestration of Pb(II) and Cr(VI) from aqueous environment using low-cost immobilised tannin resin

摘要: The present study was conducted to optimise the process parameters for extraction of tannin (adsorbent raw material) while minimising waste with aid response surface methodology and application immobilised as a mob metal ions. Based on reduced second-order polynomial quadratic model, optimised conditions maximum (tannin): material mass 6 g, pH 7, 37.5 °C, 22.5 min 50 mL water is required. adsorbents; magnetite (MTR) sulphur doped resins (S-MTR), were characterised by XRD, FT-IR, TGA, SEM, EDS, BET an elemental analyser. influences pH, contact time, temperature initial ion concentration adsorption performance MTR S-MTR evaluated. Equilibrium data assessed fitness into four isotherms kinetic models. capacities Pb(II) observed at optimum 4 534.8 mg/g 15.1 mg/g, respectively. However, Cr(VI) 813.0 mg/g, 709.2 mg/g 2, obtained from uptake ions best fit Langmuir Freundlich isotherms. Whereas, sorption fits pseudo-first order pseudo-second-order model. Thermodynamic revealed feasible, spontaneous endothermic MTR; however, incorporation thiourea improves both solution but reduces feasibility spontaneity process.