Fast adsorption of Cd²⁺ and Pb²⁺ by EGTA dianhydride (EGTAD) modified ramie fiber.
In this study, the removal of Cd(2+) and Pb(2+) from aqueous solutions was investigated using a novel chelating material. The first part described the synthesis of ethylene glycol-bis(2-aminoethylether)-N,N,N',N'-tetraacetic acid dianhydride (EGTAD), mercerization treatment of ramie fiber (MRF), and the MRF was then reacted with EGTAD to prepare the new material (ERF). The obtained material was characterized by weight gain, SEM, FTIR, and elemental analysis. The results of FTIR and elemental analysis confirmed that ester bond, carboxyl and amine groups were introduced onto ERF. The adsorption capacity of metals on ERF was evaluated at different contact times, pH values, initial metal concentrations, and temperatures in the second part. The adsorption equilibrium was reached within 5 min for Cd(2+) and Pb(2+). Adsorption isotherm could be well fitted by the Langmuir model, and the maximum adsorption capacities were 159.11 and 273.78 mg g(-1) for Cd(2+) and Pb(2+) at 298 K, respectively. Thermodynamic analysis showed that the adsorption process was spontaneous and endothermic. The molar ratio of adsorbed cation to grafted EGTA is close to 1.8:1, which confirmed that the adsorption was chemical process involving both surface chelation reaction and ion exchange. In addition, the absorbent was successfully regenerated using HCl and ultrasonic treatment.
['Sun|Zhichao|Z|', 'Liu|Yunguo|Y|', 'Huang|Yuanqing|Y|', 'Tan|Xiaofei|X|', 'Zeng|Guangming|G|', 'Hu|Xinjiang|X|', 'Yang|Zhongzhu|Z|']
D000327:Adsorption D032402:Boehmeria D002104:Cadmium D002614:Chelating Agents D004533:Egtazic Acid D007854:Lead D008958:Models, Molecular D013816:Thermodynamics D014874:Water Pollutants, Chemical D018508:Water Purification
Adsorption EGTA dianhydride Modified ramie fiber Mercerization Adsorption isotherm Regeneration Heavy metals