| Title |
Adsorption of Zinc Ion in Synthetic Wastewater by Ethylenediaminetetraacetic Acid-Modified Bentonite |
| Authors |
정명화 ( Myung-hwa Jeong ) ; 권동현 ( Dong-hyun Kwon ) ; 임연주 ( Yeon-ju Lim ) ; 안종화 ( Johng-hwa Ahn ) |
| DOI |
https://doi.org/10.15681/KSWE.2019.35.2.123 |
| Keywords |
Adsorption; EDTA-modified bentonite; Operation condition; Zinc ion |
| Abstract |
Ethylenediaminetetraacetic acid-modified bentonite (EMB) was used for adsorption of zinc ion (Zn) from aqueous solution, compared with unmodified bentonite (UB). Parameters such as dose (0.750 ~ 3.125 g/L), mixing intensity (10 ~ 150 rpm), contact time (0.17 ~ 30 min), pH (2 ~ 7), and temperature (298 ~ 338 K), were studied. Zn removal efficiency for EMB was 20 ~ 30 % higher, than that for UB, in all experiments. Thermodynamic studies demonstrated that adsorption process was spontaneous with Gibb’s free energy (ΔG) values, ranging between -5.211 and -7.175 kJ/mol for EMB, and -0.984 and -2.059 kJ/mol for UB, and endothermic with enthalpy (ΔH) value of 9.418 kJ/mol for EMB and 7.022 kJ/mol for UB. Adsorption kinetics was found to follow the pseudo-second order kinetics model, and its rate constant was 3.41 for EMB and 2.00 g/mg min for UB. Adsorption equilibrium data for EMB were best represented by the Langmuir adsorption isotherm, and calculated maximum adsorption capacity was 2.768 mg/g. It was found that the best conditions for Zn removal of EMB within the range of operation used, were 3.125 g/L dose, 90 rpm intensity, 10 min contact time, pH 4, and 338 K. Therefore, EMB has good potential for adsorption of Zn. |