铝盐改性膨润土对竹浆绿液中硅酸盐的吸附动力学研究

Kinetics of adsorption of silicate in bamboo pulp green liquor by aluminum salts modified bentonite

以钠基膨润土作为原料,通过添加铝盐为改性剂制得了一种新型高效绿液除硅剂——铝盐改性膨润土(ALMB),并全面研究了ALMB对绿液中硅酸盐的吸附动力学行为.结果表明,ALMB可以有效地吸附硅酸盐,在10min内即可完成除硅反应,且对绿液pH、总碱量等的影响较小,其最佳ALMB用量为20g/L,此时的除硅率可达79.3%.通过ALMB对绿液(硅含量分别为1g/L、2g/L、3g/L、4g/L)的吸附动力学研究,可知其吸附过程符合二级动力学模型,是物理吸附和化学吸附的共同作用.在2g/L硅浓度下的动力学模型中,其相关参数最大(R2=0.999 78),可得出最大吸附量为101.833 0 mg/g,与实验室中得出的最大吸附量100.583 3mg/g相符.

A variety of novel and efficient silicate‐aluminum salts modified bentonite（ALMB） removal agent was prepared by adding the modifier of aluminum salts as the Na‐bentonite used as the raw material .And the kinetics of adsorption of silicate in green liquor by ALMB was studied .The results indicate that the ALMB can adsorb silicate effectively .The desilica‐tion reaction could be accomplished in 10 min ,and had a little effect on the green liquor pH and total alkali content .The optimum ALMB dosage was 20 g/L ,and the desilication rate could exceed 79 .3% .Study on the adsorption kinetics of green liquid （1 g/L ,2 g/L ,3 g/L ,4 g/L） by ALMB ,the kinetic mode of silicate adsorption were indicated that the whole adsorp‐tion process was suitable to the pseudo‐second‐order kinetic model embracing physical and chemical adsorption .The parameters of the kinetic model of 2 g/L silicate concentration were the largest （R2 =0 .999 78） ,the maximum adsorption capacity was 101 .833 0 mg/g coinci‐ding with the experimental adsorption capacity of 100 .583 3 mg/g .