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Lv T.,Dalian University of Technology | Ma W.,Dalian University of Technology | Xin G.,Dalian University of Technology | Wang R.,Dalian University of Technology | And 4 more authors.
Journal of Hazardous Materials | Year: 2012

The present study explores the potential of Mg-Ca-Al (NO3) hydrotalcite-like compounds (MgCaAlNO3-HTlcs) for the removal of fluoride from protein solutions. In this study, the Mg3-xCaxAlNO3-HTlcs (x=0-3, x is the mol.% of Ca) were synthesized and characterized by SEM, XRD, FTIR, BET, ICP-AES and pHzpc analysis. The sorption experiments were conducted in protein systems of bovine serum albumin (BSA) and lysozyme (LSZ). The batch experiment results showed that the NO3-HTlc with Mg/Ca/Al molar ratio of 2.5/0.5/1 had remarkable fluoride sorption ability with maximum sorption capacities of 82.35mg/g and 72.69mg/g at pH 5.0 and 40°C in BSA and LSZ system, respectively. Moreover, the loss of BSA of 0.71% was low and there was no loss of LSZ. It was evident that the Mg2.5Ca0.5AlNO3-HTlc could selectively adsorb fluoride from protein solutions. The equilibrium sorption data fitted well to the Langmuir model and the kinetic data conformed to the pseudo-second-order model. Thermodynamic parameters (ΔG°, ΔH° and ΔS°) were evaluated and revealed that the sorption process was spontaneous and endothermic in nature. Furthermore, the results from Antarctic krill processing wastewater study confirmed the feasibility and practicality of the Mg2.5Ca0.5AlNO3-HTlc for fluoride removal in fluoride bearing protein system. © 2012 Elsevier B.V.


Ma W.,Dalian University of Technology | Lv T.,Dalian University of Technology | Song X.,Dalian University of Technology | Cheng Z.,Dalian University of Technology | And 4 more authors.
Journal of Hazardous Materials | Year: 2014

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 pHpzc. The fluoride removal efficiency (RF) and protein recovery ratio (RP) 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 RF of 92.1% and 94.8% at the CPLDH-Ca dose of 2.0g/L in LSZ and BSA system, respectively. The RP in both systems of LSZ and BSA were more than 90%. Additionally, the RP of CPLDH-Ca increased with the increase of ionic strengths, and it almost can be 100% with more than 93% RF. 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. © 2014 Elsevier B.V.


Ma W.,Dalian University of Technology | Cheng Z.,Dalian University of Technology | Liu X.,Dalian University of Technology | Gao Z.,Dalian University of Technology | Liu F.,Dalian Ocean Fishery Group of Corporations
Proceedings - 2012 International Conference on Biomedical Engineering and Biotechnology, iCBEB 2012 | Year: 2012

In this study, a modified chitosan transparent thin membrane (MCTTM) was prepared and used for transition metal ions removal from aqueous solutions. The physical and chemical characteristics of the MCTTM were characterized by X-ray diffraction (XRD) and Thermal Gravity Analysis (TGA). The characterization of color changes of the MCTTM after adsorption shows that the MCTTM has the potential to detect some transition metal ions in aqueous solutions rapidly. © 2012 IEEE.


Ma W.,Dalian University of Technology | Gao L.L.,Dalian University of Technology | Cheng Z.H.,Dalian University of Technology | Wang R.,Dalian University of Technology | And 3 more authors.
Applied Mechanics and Materials | Year: 2014

Since commercial chitosan powder may dissolve in water to some degree and demands to be modified chemically to create its own exclusive pore canal we have synthetized two different modified chitosan beads in this investigation by using glutaraldehyde as crosslinking agent, significantly, novel porogen silica sol and methanol, and analysis means SEM, FTIR and BET demonstrated that the surface area and pore size improved signally. Moreover, the adsorption conditions pH and ionic strength have been considered, and the maximum adsorption capacity of nickel ions was 32.40 mg/g at the optimum condition. Furthermore, the main model equations on isotherm and kinetics have been deliberated and the results clearly revealed that Freundlich, external mass transfer, intra particle diffusion and pseudo second order model fitted better to the experimental data (R2 > 0.99, all). It is expected that this results would be serviceable to remove metals from wastewater using chitosan and its derivatives. © (2014) Trans Tech Publications, Switzerland.

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