水蒸气活化制备竹质成型活性炭及其对二硫化碳的吸附性能

Preparation of bamboo molding activated carbon by steam activation and its adsorption performance on carbon disulfide

竹材是重要的林业可再生资源,以竹材代替木材制备活性炭可节省大量木材。以竹粉为原料,经磷酸活化成型后进行水蒸气二次活化,在不同工艺条件下制备了高吸附性能活性炭。通过碘吸附值、亚甲基蓝吸附值、N_2吸附-脱附等温线、二硫化碳动态吸附量等对所制活性炭的性能进行表征。结果表明:在磷酸浸渍比1.2∶1、活化时间20 min、活化温度450℃,水蒸气活化温度875℃、活化时间1 h、流量3.0 m L/min条件下,制得的活性炭BET比表面积为1 264.60 m^2/g、总孔容积为1.227 cm^3/g、平均孔径为3.88 nm、碘吸附值为1 452.96 mg/g、亚甲基蓝吸附值为307.5 mg/g、强度为91.76%、得率为30.42%;在动态干燥和30%相对湿度条件下,对二硫化碳的单位质量吸附量分别为0.416和0.390 g/g。活性炭对CS2的吸附能力主要与活性炭的孔结构有关,微孔发达、平均孔径小、碘吸附值高的活性炭更有利于CS2的吸附。由于竹材表观密度相对较低,且受到竹材自身组分的限制,所制活性炭的强度低于椰壳活性炭。

As one of the important forestry renewable resources,bamboo is grown without pesticides or chemical fertilizers,and plays a critical role in the balance of oxygen and carbon dioxide in the atmosphere.It grows rapidly and can be harvested in 3-5 years,which produces 35%more oxygen than an equivalent volume of trees.Bamboo can be used to prepare activated carbon instead of wood,which would save precious wood resources.In this study,the activated carbon with high adsorption performance was prepared from bamboo flour by the phosphoric acid activation and molding before the steam activation.The properties of the activated carbon were characterized by the iodine adsorption value,methylene blue adsorption value,N2adsorptiondesorption isotherm,carbon disulfide dynamic adsorption capacity,et al.The results showed that the optimum preparation condition was the phosphoric acid impregnation ratio of1.2〖DK〗∶1,activation time of 20 min,activation temperature of 450℃,steam activation temperature of 875℃,activation time of 1 h and flow rate of 3.0 mL/min.Under these conditions,the activated carbon had the BET specific surface area of 1 264.60 m2/g,total pore volume of 1.227 cm3/g,average pore size of 3.88 nm,iodine adsorption value of1 452.96mg/g,methylene blue adsorption value of 307.5 mg/g,strength of 91.76%and yield of 30.42%.Under the dynamic drying and 30%relative humidity conditions,the unit mass adsorption of activated carbon on carbon disulfide were 0.416 g/g and 0.390 g/g,respectively.The adsorption capacity of the activated carbon on carbon disulfide was mainly related to the pore structure of the activated carbon.The activated carbon with high micropores,small average pore diameter and high iodine adsorption value were more favorable for the adsorption of carbon disulfide.Due to the relatively low apparent density of bamboo,the strength of the prepared activated carbon was inferior to the coconut shell activated carbon.