Study Of Clay Minerials On The Loadings Of Bovine Serum Albumin

It was mainly studied that the loadings of bovine serum albumin (BSA) loaded by sodium montmorillonite, attapulgite and layered double hydroxides. Sodium montmorillonite and attapulgite were purified by natural sedimentation method. The purified sodium montmorillonite and attapulgite were modified by sodium chloride and hydrochloric acid. Layered double hydroxides were prepared by method of thermal crystallization of water-phase precipitation. The aims of this study are to investigate the effect of pH value, initial concentration of BSA and concentration of couple agents (glutaraldehyde andγ-methyl-propenoyl-silane) on the loadings of BSA and the structure of the three clay minerals which loaded BSA showed by XRD and FT-IR.The XRD and TEM showed that the impurities of the sodium montmorillonite and attapulgite were reduced significantly. The XRD of layered double hydroxides showed that the phase is single, the crystal structure is same, the order degree of crystal face is high and the crystallinity is also good.The loadings of BSA loaded by sodium montmorillonite reduced when the pH value increased, but the loadings of BSA increased when the pH value increased from 7.0 to 8.0. The change of loadings of BSA divided into three stages when initial concentration of BSA increased. The first stage was that the loadings of BSA increased rapidly. The second stage was that the loadings of BSA did not change. The third stage was that the loadings of BSA continue to increase, but the rate is slow. The effect of concentration of couple agents on the loadings of BSA was obvious. The loadings of BSA achieved maximum when the concentration of glutaraldehyde andγ-methyl-propenoyl-silane was 6% and 2%. The XRD showed that d001 of sodium montmorillonite increased from 1.25 nm to 3.4 nm. The FT-IR showed that sodium montmorillonite loaded BSA had the protein amides absorption peaks of the supernatant. The XRD and FT-IR showed that BSA was intercalated into montmorillonite interlayer, it caused changes in the structure of sodium montmorillonite.The loadings of BSA loaded by attapulgite reduced when the pH value increased, the loadings of BSA achieved maximum when the pH value was 3.8, the maximum was 132.45 mg·g-1. The equilibrium time is 6 h. The loadings of BSA increased rapidly when initial concentration of BSA increased from 0 to 6.0 g·L-1, but the loadings was not change when initial concentration of BSA surpassed 12 g·L-1. The loadings of BSA were 79.26 mg·g-1 and 83.21 mg·g-1 when the concentration of glutaraldehyde andγ-methyl-propenoyl-silane was 2%. The XRD showed that the structure of attapulgite was not change. The FT-IR showed that attapulgite loaded BSA had small changes, the loading behaviors occurred mainly in the surface of attapulgite.The maximum loadings of BSA loaded by layered double hydroxides was 56.82 mg·g-1 when the pH value is 6.2. The equilibrium time is 6 h. The loadings of BSA increased rapidly when initial concentration of BSA increased from 0 to 6.0 g·L-1, but the loadings was not change when initial concentration of BSA surpassed 9.0 g·L-1. The two coupling agents (y-methyl-propenoyl-silane and glutaraldehyde) made the loadings increase, but the effect of KH570 was greater. The XRD showed that the layered structure of layered double hydroxides did not change. The FT-IR showed that layered double hydroxides loaded BSA had small changes, the loading behaviors occurred mainly in the surface of layered double hydroxides.The loadings of BSA loaded by sodium montmorillonite and attapulgite reached maximum when the pH value is 3.8. However, The loadings of BSA loaded by layered double hydroxides reached maximum when the pH value is 6.2. Comparison of the three kinds of clay minerals on the loadings of BSA, The loadings of BSA loaded by sodium montmorillonite was largest. When initial concentration of BSA was 20.0 g·L-1, The loadings of BSA loaded by sodium montmorillonite, attapulgite and layered double hydroxides were 907.36 mg·g-1,167.83 mg·g-1, 74.52 mg·g-1. Sodium montmorillonite on the loadings of BSA was 5.4 times that of attapulgite, was 12 times that of layered double hydroxides. Compared with sodium montmorillonite, attapulgite and layered double hydroxides on the loadings of BSA were very small.