The concept of generating an oscillatory electroosmotic flux inside the porous particle to enhance the intra-particle mass transport was presented and a new kind of electrochromatography carried out in a five-compartment electrolyzer were developed. The adsorbent was packed in the central compartment, while the neighboring compartments were used as the elution compartments and the electrode compartments, respectively. Chromatographic separations of human serum albumin on Blue Sepharose Fast Flow, bovine serum albumin (BSA) on DEAE–Sepharose Fast Flow, and BSA on ydroxyapatite were carried out, respectively. The adsorption isotherms were shown to be independent of electric field, while the increase in the electric field strength resulted in a linear increase in the magnitude of electroosmotic flux and the improvement of the breakthrough behavior in all cases. The experiment results have demonstrated the effectiveness of the oscillatory electroosmosis in enhancing intra- and inter-particle mass transport and its high potential to large-scale hromatography.

A temperature stimuli-responsive polymer, dextran-grafted-PNIPAAm (DGP), was prepared by radical polymerization using cerium nitrate as the initiator. The structure and the grafting ratio of DGP were determined by FT-IR and elemental analysis. The temperature-stimuli responsive behavior of DGP and the size of the DGP self-assemblies at different temperatures were determined by transmittance and dynamic light scattering, respectively. The use of DGP as an artificial chaperone to assist protein refolding in vitro was demonstrated using hen egg white lysozyme (lysozyme) and carbonic anhydrase bovine (CAB) as model proteins. It was shown that the hydrophobic interaction between DGP and the protein being refolded gave a significant reduction in the rate of protein aggregation and a slight reduction in the refolding rate, and consequently gave an improved refolding yield. Moreover, the refolding of lysozyme and CAB at a temperature gradient starting above the LCST of DGP and ending at a lower temperature, which make DGP change from hydrophobic to hydrophilic, gave a significant increase in the refolding yield compared to that carried out at a constant temperature. The process mechanism of DGP assisted protein refolding was presented and the importance of controlling the hydrophobicity of the solution environment for protein refolding was discussed.

The effects of a weak electric field on the growth and metabolic behavior of Enterobacter dissolvens were investigated using glucose as the sole carbon source. A direct current (DC) was applied using salt bridge electrodes and platinum electrodes. The best stimulating effects in terms of cell growth and the dehydrogenase activity (DHA) were obtained when a DC of 10mA was applied for 12 h via the platinum electrodes. In this case, the electrolysis of water was the major electrode reaction, as determined by cyclic voltammetry. The presence of the hydrogen generated a strong reductive environment and led to a reduction of NAD/NADH ratio from 7 to 3. The specific activity of dehydrogenase and glucose consumption increased 2- and 1.5-fold, respectively. The application of the DC via the platinum electrodes also led to accelerated cell death during the later stationary phase. This is possibly due to the presence of anodic intermediates including H2O2, OH• and O2•. These results provide more details for understanding the effect of a DC on E. dissolvens, a strain with potential application in the electro-remediation of PAHs contaminated soil.

Removal of hydrophobic organic contaminants (HOCs) from soil of low permeability by electroremedia-tion was investigated by using phenanthrene and kaolinite as a model system. Tween 80 was added into the purging solution in order to enhance the solubility of phenanthrene. The effects of pH on the assorption of phenanthrene and Tween 80 on kaolinite and he magnitude of S-potential of kaolinite were examined. respectively. The effects of electric field strength indicated by electric current on the electroremediation investigated. respectively Incase of an electric field of 25mA applied for 72 hours, overs 90% of phenanthrene was removed from 424g (dry mass) of kaolinite at an energy consumption of 0.148 kW.h. The experimental results described in prcsent study show that the addition of surfactant into purging solution greatlky enhances the removal of HOCs by electroremediation.

Introducing an electric field into chromatography on hydroxyapatite (HAP) was attempted in order to enhance mass transfer and separation performance. A membrane spaced multicompartment electrolyzer was developed for electrochromatography on HAP. The high performance of liquid transport by electroosmotic flux was identified and described in terms of dynamic electroosmotic pressure. The application of the electric field resulted in an improved adsorption of bovine serum albumin as shown by the breakthrough curve as function of the electric field. An improved elution was also obtained in the presence of the electric field. The results show that electroosmosis is a powerful tool of liquid transport and dispersion in a packed bed of fine particles and has potential in the large-scale chromatography of biological molecules.