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以废旧汽车轮胎橡胶与城市污水处理厂污泥为原料,采用ZnCl2与H_2SO_4复配活化法,添加黏结剂和Fe_3O_4粉末,在真空管式气氛炉中炭化制备球形磁性活性炭,并测定其物理化学性能。研究球形磁性活性炭添加量、土壤pH值和含水率对球形磁性活性炭吸附重金属Pb的影响。采用火焰法-原子吸收分光光度计测定球形磁性活性炭对Pb的吸附量。结果表明:球形磁性活性炭的比表面积及亚甲基蓝吸附量相比商品活性炭要小,但其抗压强度高,不容易松散,便于回收,酸性官能团总量高,有助于提高球形磁性活性炭的吸附性能和对重金属的亲和力,因此球形磁性活性炭的综合理化性能优于干污泥活性炭和商品活性炭,适合用于土壤中重金属Pb的吸附;随添加量增加,球形磁性活性炭对土壤中Pb的吸附量也增加,当球形磁性活性炭添加质量分数为6%时,达到最优吸附效果;随土壤pH值增加,球形磁性活性炭对土壤中Pb的吸附量也增加,但当pH值超过5时,其吸附量开始下降;当吸附时间达到35 d后,其吸附量基本处于饱和状态;土壤含水率为20%时,吸附达到平衡。在最优工艺参数下,球形磁性活性炭对土壤中Pb的吸附量达到最大,为3.55 mg/g。球形磁性活性炭对土壤中重金属Pb的吸附过程可以用准二级动力学方程较好地解释,而且球形磁性活性炭经过1次再生后用于吸附土壤中Pb时,其吸附量达到2.56 mg/g,再生效率达72.11%,吸附效果良好。
The waste rubber tire and sewage sludge of urban sewage treatment plant were used as raw materials, and spherical magnetic activated carbon was prepared by carbonization in vacuum tube atmosphere furnace with ZnCl2 and H_2SO_4 compound activation method, binder and Fe_3O_4 powder, and the physicochemical properties were determined. The effects of the amount of spherical magnetic activated carbon, soil pH value and water content on the adsorption of heavy metal Pb on spherical magnetic activated carbon were investigated. Determination of Pb Adsorption by Spherical Magnetic Activated Carbon by Flame Method - Atomic Absorption Spectrophotometer. The results show that the specific surface area and methylene blue adsorption capacity of spherical magnetic activated carbon are smaller than that of commercial activated carbon, but their compressive strength is high, so they are not easily loose and easy to be recovered. The total amount of acidic functional groups is high, which helps to improve the adsorption performance of spherical magnetic activated carbon And the affinity for heavy metals, the comprehensive physical and chemical properties of spherical magnetic activated carbon is superior to the dry sludge activated carbon and commercial activated carbon, suitable for the adsorption of heavy metal Pb in the soil; with the added amount, the adsorption capacity of spherical magnetic activated carbon on the soil Pb When the mass fraction of spherical magnetic activated carbon is 6%, the optimal adsorption effect is achieved. With the increase of soil pH, the adsorption amount of Pb by the spherical magnetic activated carbon also increases in the soil, but when the pH value exceeds 5, the adsorption capacity Began to decline; when the adsorption time reached 35 d, the adsorption capacity of the basic saturation; soil moisture content of 20%, the adsorption equilibrium. Under the optimum process parameters, the adsorption capacity of Pb on soil by spherical magnetic activated carbon reached the maximum, which was 3.55 mg / g. The adsorption of heavy metal Pb in the soil by spherical magnetic activated carbon can be well explained by the quasi-second-order kinetic equation. The adsorption capacity of the spherical magnetic activated carbon after it is used for the adsorption of Pb in soil reaches 2.56 mg / g, Regeneration efficiency of 72.11%, the adsorption effect is good.