Lee, Hongkyun Shim, Eunjung Yun, Hyun-Shik Park, Young-Tae Kim, Dohyeong Ji, Min-Kyu Kim, Chi-Kyung Shin, Won-Sik Choi, Jaeyoung 2024-01-20T05:04:46Z 2024-01-20T05:04:46Z 2021-09-03 2016-01 0944-1344 https://pubs.kist.re.kr/handle/201004/124580 Immobilized microalgae using silica (IMS) from Micractinium reisseri KGE33 was synthesized through a sol-gel reaction. Green algal waste biomass, the residue of M. reisseri KGE33 after oil extraction, was used as the biomaterial. The adsorption of Cu(II) on IMS was tested in batch experiments with varying algal doses, pH, contact times, initial Cu(II) concentrations, and temperatures. Three types of IMSs (IMS 14, 70, and 100) were synthesized according to different algal doses. The removal efficiency of Cu(II) in the aqueous phase was in the following order: IMS 14 (77.0 %) < IMS 70 (83.3 %) < IMS 100 (87.1 %) at pH 5. The point of zero charge (PZC) value of IMS100 was 4.5, and the optimum pH for Cu(II) adsorption was 5. Equilibrium data were described using a Langmuir isotherm model. The Langmuir model maximum Cu(II) adsorption capacity (q (m)) increased with the algal dose in the following order: IMS 100 (1.710 mg g(-1)) > IMS 70 (1.548 mg g(-1)) > IMS 14 (1.282 mg g(-1)). The pseudo-second-order equation fitted the kinetics data well, and the value of the second-order rate constant increased with increasing algal dose. Gibbs free energies (Delta GA degrees) were negative within the temperature range studied, which indicates that the adsorption process was spontaneous. The negative value of enthalpy (Delta HA degrees) again indicates the exothermic nature of the adsorption process. In addition, SEM-energy-dispersive X-ray spectroscopy (EDS), Fourier transform infrared (FT-IR), and X-ray photoelectron spectroscopy (XPS) analyses of the IMS surface reveal that the algal biomass on IMS is the main site for Cu(II) binding. This study shows that immobilized microalgae using silica, a synthesized biosorbent, can be used as a cost-effective sorbent for Cu(II) removal from the aqueous phase. English SPRINGER HEIDELBERG HEAVY-METAL IONS WASTE-WATER TREATMENT AQUEOUS-SOLUTIONS ALGAL BIOMASS REMOVAL ADSORPTION ALGINATE SORPTION GREEN COPPER(II) Biosorption of Cu(II) by immobilized microalgae using silica: kinetic, equilibrium, and thermodynamic study Article 10.1007/s11356-015-4609-1 1 ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH, v.23, no.2, pp.1025 - 1034 ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH 23 2 1025 1034 scie scopus 000368200200009 2-s2.0-84954396522 Environmental Sciences Environmental Sciences & Ecology Article; Proceedings Paper HEAVY-METAL IONS WASTE-WATER TREATMENT AQUEOUS-SOLUTIONS ALGAL BIOMASS REMOVAL ADSORPTION ALGINATE SORPTION GREEN COPPER(II) Adsorption Silica Microalgae Copper Biosorbent Micractinium reisseri KGE33