Succinate-bonded pullulan: An efficient and reusable super-sorbent for cadmium-uptake from spiked high-hardness groundwater  

作　　者：Azhar Abbas Muhammad Ajaz Hussain Muhammad Amin Muhammad Sher Muhammad Nawaz Tahir Wolfgang Tremel 

机构地区：[1]Department of Chemistry, University of Sargodha [2]Institute of Inorganic and Analytical Chemistry, Johannes Guttenberg University

出　　处：《Journal of Environmental Sciences》2015年第11期51-58,共8页环境科学学报（英文版）

基　　金：the Higher Education Commission, Pakistan, for funding under the scheme "HEC Indigenous 5000 Fellowships" with grant number PIN 074-1392-Ps4-584

摘　　要：Chemically modified pullulan was evaluated for its sorption efficiency and selectivity to remove cadmium（Cd） from spiked high-hardness groundwater（GW）. Pullulan esterified with succinic anhydride using dimethylaminopyridine showed a fairly high degree of substitution value as confirmed by1 H NMR spectroscopy. Pullulan succinate（Pull-Suc） was converted into the sodium salt（Pull-Suc-Na）. The effect of contact time（5–200 min） and p H（2–8） on Cd-uptake by the sorbent（Pull-Suc-Na） was investigated. The sorbent showed more than 90% Cd-removal in first 15 min from distilled water（DW） and GW solution,respectively. Comparison of Pull-Suc-Na with other polysaccharidal sorbents suggested its high efficiency（DW 476.2 mg/g and GW 454.5 mg/g） and selectivity for the removal of Cd by an ion exchange mechanism, which is further supported by the negative Gibbs free energy values calculated from Langmuir isotherms. A Langmuir isotherm kinetic model provided the best fit for the sorption of Cd using Pull-Suc-Na. The sorbent showed a negligible decrease in Cd-uptake over three regeneration cycles. The thermal stability testing of the sorbents indicated that Pull-Suc-Na（sorbent） is more stable than Pull-Suc.Chemically modified pullulan was evaluated for its sorption efficiency and selectivity to remove cadmium（Cd） from spiked high-hardness groundwater（GW）. Pullulan esterified with succinic anhydride using dimethylaminopyridine showed a fairly high degree of substitution value as confirmed by1 H NMR spectroscopy. Pullulan succinate（Pull-Suc） was converted into the sodium salt（Pull-Suc-Na）. The effect of contact time（5–200 min） and p H（2–8） on Cd-uptake by the sorbent（Pull-Suc-Na） was investigated. The sorbent showed more than 90% Cd-removal in first 15 min from distilled water（DW） and GW solution,respectively. Comparison of Pull-Suc-Na with other polysaccharidal sorbents suggested its high efficiency（DW 476.2 mg/g and GW 454.5 mg/g） and selectivity for the removal of Cd by an ion exchange mechanism, which is further supported by the negative Gibbs free energy values calculated from Langmuir isotherms. A Langmuir isotherm kinetic model provided the best fit for the sorption of Cd using Pull-Suc-Na. The sorbent showed a negligible decrease in Cd-uptake over three regeneration cycles. The thermal stability testing of the sorbents indicated that Pull-Suc-Na（sorbent） is more stable than Pull-Suc.

关 键 词：Adsorption Cadmium Modified pullulan Succinylation Thermal stability 

分 类 号：X523[环境科学与工程—环境工程]