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

• Published in: Journal of environmental sciences (China) Vol. 37; no. 11; pp. 51 - 58
• Main Authors: Abbas, Azhar, Hussain, Muhammad Ajaz, Amin, Muhammad, Sher, Muhammad, Tahir, Muhammad Nawaz, Tremel, Wolfgang
• Format: Journal Article
• Language: English
• Published: Netherlands Elsevier B.V 01-11-2015
• Subjects: Adsorption; Cadmium; Cadmium - chemistry; Cadmium - isolation & purification; Glucans - chemistry; Groundwater - chemistry; Hydrogen-Ion Concentration; Kinetics; Modified pullulan; Succinic Acid - chemistry; Succinylation; Temperature; Thermal stability; Thermodynamics; Water Pollutants, Chemical - chemistry; Water Pollutants, Chemical - isolation & purification; Water Purification; 可重复使用; 吸收剂; 地下水; 普鲁兰多糖; 热稳定性试验; 琥珀酸酐; 镉吸收; 高硬度; Cadmium; Succinylation; Adsorption; Thermal stability; Modified pullulan
• ISSN: 1001-0742; 1878-7320
• DOI: 10.1016/j.jes.2015.04.013

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.