不同EPS组成生物膜对Cu2+吸附的研究

采用自行设计的反应器,通过调节培养液的配比对载体进行挂膜,得到蛋白质和多糖含量比分别为7:1、5:1和10:1的3种生物膜作为吸附剂,用其对Cu2+进行吸附试验,同时对吸附机理进行探讨.结果表明,培养8d后,生物膜可挂膜成熟,在C/N=12时,生物膜上的菌落数较C/N=4和C/N=37条件下多.PN/PS值越小,生物膜对铜的吸附量越高,EPS3对Cu2+的吸附量分别高出EPS1 7.37 %, EPS2 7.62%.在生物膜吸附Cu2+后,溶液中Ca2+、Mg2+、K+含量明显升高,表明离子交换对生物膜吸附Cu2+起主要作用,且Cu2+更易与Ca2+和Mg2+产生离子交换作用.当KNO3浓度在0.1~0.6mol/L之间,随着离子强度的增加,生物膜吸附Cu2+的量迅速减少,当KNO3浓度大于0.6mol/L时,生物膜对Cu2+吸附量的变化趋于平缓,说明生物膜对Cu2+的吸附同时包括离子交换吸附和化学吸附.

The research on biofilm composed by different EPS to adsorb Cu2+

The biofilm were cultured in a self-designed reactor by adjusting the ratio of nutrients in order to get 3different biofilms as adsorbents for Cu2+, in which the proportion of protein and polysaccharide were 7:1, 5:1and 10:1respectively. This paper had a study on the adsorption of 3different bilfilms to Cu2+. Besides, the adsorption mechanism was discussed. The results showed that the biofilm became mature after 8days. When the value of C/N was 12, the biofilm grew better than that C/N was 4and 37, and the number of bacteria on it was more than the the number of bacteria on C/N =4and C/N=37. PN/PS value was smaller, and the adsorption capacity of Cu2+ was higher. The amount of Cu2+ adsorbed on EPS3is higher than EPS1(7.37%) and EPS2(7.62%). Cu2+ was absorbed on the biofilm, the concentration of Ca2+, Mg2+, K+ was significantly increased in the solution, demonstrating ion exchange play a main role during the adsorption and Cu2+ prefer to exchange with divalent Ca2+ and Mg2+. As the concentration of KNO3was from 0.1to 0.6mol/L, along with the increase of ionic strength, the Cu2+ content adsorbed on biofilm decreased rapidly. However, the concentration of KNO3is greater than 0.6mol/L, the change of Cu2+content adsorbed by biofilm trended to be gentle, the phenomenon showed that Cu2+ adsorption mechanism include ion exchange and chemical adsorption.