化学改性对BA-3活菌体去除Cr(Ⅵ)的影响作用

通过对BA-3活菌体进行多种化学改性,比较了经化学改性后的BA-3菌体对C(rⅥ)的去除效率。结果表明,所试化学改性均会导致BA-3活菌体一定程度的质量减少;无机酸改性及有机溶剂改性均可较大程度提高菌体的C(rⅥ)去除效率,而无机酸改性、有机溶剂改性及盐改性则对菌体吸附Cr的效率有不同程度的提高作用。菌体表面上的H+]及OH-]的分布对于其吸附Cr及还原C(rⅥ)均有重要的影响作用,当溶液中的H+]浓度增加时,会加快菌体还原Cr(Ⅵ)的速率,并促进菌体对Cr的吸附作用;当溶液中OH-]增加时,C(rⅥ)的去除速率会相应降低,而菌体对Cr的吸附效果也有所降低。以盐改性时可提高菌体表面可交换阳离子的活性,并促进菌体表面与C(rⅢ)的离子交换,从而在Cr的吸附后期有利于菌体吸附溶液中的C(rⅢ)。此外,菌体的菌丝球结构及其比表面积也会影响其吸附Cr及还原C(rⅥ)的效率。有机溶剂改性可改善菌体的有效表面积,对菌体去除C(rⅥ)及吸附Cr都是有利的。

Effect of Cr(Ⅵ) Removal by Chemical Modified BA-3

BA-3 bacteria were modified by a variety of chemical reagents and removal efficiency in Cr(Ⅵ)was compared. Experimental results indicated that all the chemical modification could lead to a certain degree of mass reduction of BA-3 living bacteria.Inorganic acid modification and organic solvent modification could improve the bacteria's removal efficiency of C(rⅥ)in a large extent.Inorganic acid modification,organic solvents modification and salt modification could enhance the bacteria's C(rⅥ)absorption efficiency in different extents.It was also found that distribution of H + ] and on the surface of BA-3 bacteria had an important impact on bacterial absorption and deoxidation in Cr(Ⅵ).When H + ] concentration in solution increased,the rate of deoxidation in Cr(Ⅵ) would speed up and it would promote the bacterial absorption of Cr. When concentration in solution increased,the rate of removal in C(rⅥ)would be reduced accordingly and it would decrease the efficiency in bacterial absorption of Cr.Salt modification could improve the activity of exchangeable cations on surface of the bacteria and promote the ion exchange process of Cr(Ⅲ),so it could be advantageous to bacterial absorption of C(rⅢ)in the later period of Cr adsorption.Mycelia pellet structure and specific surface area could also affect the bacterial absorption of Cr and deoxidation of Cr(Ⅵ).Modification with organic solvents could improve the effective surface area of bacteria and it could be advantageous to the removal of C(rⅥ)and bacterial adsorption of Cr.