活性炭中孔结构对双组分染料的竞争吸附

为探讨GAC(颗粒活性炭)的V_mes(中孔孔容)对双组分染料吸附行为的影响,对GAC进行改性,得到V_mes分别为0.16、0.25、0.30、0.50 cm3/g下的中孔GAC,并对MB(亚甲基蓝)、CV(结晶紫)、MO(甲基橙)进行了单组分和双组分体系的吸附试验.结果表明:①单组分体系中,随着V_mes的增加,各染料的饱和吸附量均增大,MB从88.98 mg/g增至226.69 mg/g；CV从56.04 mg/g增至105.17 mg/g；MO从64.87 mg/g增至129.66 mg/g.②在由MB和MO组成的分子量接近的双组分体系中,两种染料表现为拮抗作用；随着V_mes的增加拮抗作用增强,并且对MB的拮抗作用大于对MO的作用.③在由MB和CV组成的分子量相差较大的双组分体系中,对于分子量较小的染料MB表现出拮抗作用,随着V_mes的增加,拮抗作用逐渐减小；对于分子量较大的染料CV来说,随着V_mes的改变吸附行为发生改变,当V_mes小于0.25 cm3/g时表现为协同作用,大于0.30 cm3/g转变为拮抗作用,并且随着V_mes的增大逐渐增强.研究显示,染料分子的物理形态对双组分物质竞争吸附的影响起到决定性作用,而吸附剂V_mes的增加促进了对单双组分染料分子的吸附容量增加. 

Competitive Adsorption of Two Component Dyes onto Activated Carbon with Different Mesopore Volumes

Abstract: The adsorption behavior of methylene blue(MB)and crystal violet(CV) or MB and methyl orange(MO) from binary solutions on granular active carbon(GAC) with different mesopore volumes from 0.16 to 0.50 cm³/g was studied.The results showed that the adsorption capacities of MB,CV and MO on GAC in single dye solution increased with V_mes of GAC, which increased from 88.98 to 226.69 mg/g, from 56.04 to 105.17 mg/g and from 64.87 to 129.66 mg/g, respectively. Competitive adsorption of MB and MO with similar molecular weights from binary solutions on the mesopore GAC was shown.Competitive adsorption effect increased with mesopore volume of GAC. The adsorption behavior of MB and CV with different molecular weights from binary solutions was more complicated. The competitive adsorption of MB from binary solutions showed that the effect of competitive adsorption of MB decreased when V_mes of GAC increased. Synergy adsorption of CV from binary solutions showed when V_mes was below 0.25 cm³/g. Competitive adsorption of CV from binary solutions showed when V_mes was more than 0.30 cm³/g. The study showed that the molecular weight and structure of dye play important roles in the competitive adsorption of binary solutions. The adsorption capacity of dyes in single or binary solutions increased when V_mes of GAC increased.