蜂巢石改性及其对Mn^(2+)吸附试验研究

Experimental research on modification of pumice and its adsorption performance to Mn^(2+)

为探讨硫酸对蜂巢石吸附材料改性的影响因素,以及改性蜂巢石对Mn^(2+)的吸附特性,采用正交试验法研究了硫酸改性条件对蜂巢石比表面积、孔容、孔径的影响;对改性蜂巢石和未改性蜂巢石做了SEM和XRD对比分析;通过静态吸附试验探讨了硫酸改性蜂巢石对Mn^(2+)的最佳吸附条件。试验结果表明,硫酸浓度为0.50mol/L,改性时间为30 min,温度为35℃时改性最佳,改性后蜂巢石比表面积、孔容分别达到21.15 m2/g、0.053cm3/g左右,平均孔径为5 nm;SEM和XRD对比分析发现,改性后蜂巢石表面变得粗糙蓬松,微孔增加,空隙率和孔道通透性提高,出现了Ca SO4·2H2O单斜晶体;改性蜂巢石投加量和溶液的p H值是影响吸附效果的重要因素,当溶液p H值为5,改性蜂巢石投加量为4 g/L,Mn^(2+)初始质量浓度为5 mg/L时,对Mn^(2+)的去除率达85%以上,吸附量超过10.0 mg/g。

In order to investigate the effect of sulfuric acid on modification of pumice and the adsorption property of the modified pumice to Mn2＋, the influence of sulfuric acid modification condition on specific surface area, pore volume and pore diameter of the pumice were studied through orthogonal test. The modified pumice and unmodified pumice were analyzed contrastively by SEM and XRD. The optimal adsorption conditions of sul- furic acid modified pumice to Mn2＋ were studied by static adsorption test. The results showed that, the optimal conditions for pumice modification was as follows： the mass concentration of sulfuric acid was 0.50 mol/L, the modi- fication time was 30 min, the temperature was 35℃. The specific surface area and pore volume of the modified pumice were about 21.15 m2/g and 0.053 cm3/g respectively, the average pore diameter was 5 nm. The results of SEM and XRD comparative analysis showed that, the surface of the modified pumice became rough and fluffy, the micropores increased, the porosity and the permeability of the pores increased, and CaSO4·2H2O monoclinic crystals appeared. Modified pumice dosage and solution pH value were key factors affecting adsorption perfor- mance, when the solution pH value was 5, the modified pumice dosage was 4 g/L, the initial mass concentration of Mn2~ was 5 mg/L, the removal rate of Mn2＋ reached above 85%, the adsorption capacity was over 10.00 mg/g.