화학공학소재연구정보센터
Journal of Hazardous Materials, Vol.268, 166-176, 2014
Characteristics of selective fluoride adsorption by biocarbon-Mg/Al layered double hydroxides composites from protein solutions: Kinetics and equilibrium isotherms study
In the study, two novel applied biocarbon-Mg/Al layered double hydroxides composites (CPLDH and CPLDH-Ca) were successfully prepared and characterized by TEM, ICP-AES, XFS, EDS, FTIR, XRD, BET and pH(pzc). The fluoride removal efficiency (R-F) and protein recovery ratio (R-p) of the adsorbents were studied in protein systems of lysozyme (LSZ) and bovine serum albumin (BSA). The results showed that the CPLDH-Ca presented remarkable performance for selective fluoride removal from protein solution. It reached the maximum R-F of 92.1% and 94.8% at the CPLDH-Ca dose of 2.0 g/L in LSZ and BSA system, respectively. The R-p in both systems of LSZ and BSA were more than 90%. Additionally, the R-p of CPLDH-Ca increased with the increase of ionic strengths, and it almost can be 100% with more than 93% R-F. Fluoride adsorption by the CPLDH-Ca with different initial fluoride concentrations was found to obey the mixed surface reaction and diffusion controlled adsorption kinetic model, and the overall reaction rate is probably controlled by intra-particle diffusion, boundary layer diffusion and reaction process. The adsorption isotherms of fluoride in BSA system fit the Langmuir-Freundlich model well. The BSA has synergistic effect on fluoride adsorption and the degree increased with the increase of the initial BSA concentration. (C) 2014 Elsevier B.V. All rights reserved.