不同生物炭的理化性质及其对重金属的吸附

Physicochemical properties of different biochars and their adsorption on heavy metals

为了探明不同生物炭材料对水中重金属的吸附效果,于500℃条件下制备农作物秸秆生物炭,并分别在制备的不同生物炭材料中添加重金属溶液,于25℃恒温振荡培养箱下220 r·min-1分别振荡培养1 h、1 d和5 d,过滤后测定滤液中重金属Cr、Cd、Pb、Zn、Hg的含量。结果表明:三种生物炭均为碱性,三种生物炭对重金属Cr、Cd、Pb、Zn、Hg均有不同程度的吸附效果。对重金属Cr而言,培养5 d后芦苇杆、木薯杆、水稻杆生物炭对Cr的吸附量均表现出最高,分别为260.33、250.56、248.69μg·g-1;对重金属Zn、Cd而言,培养1 h后水稻杆生物炭对其吸附量均达到最大,分别为190.80、333.58μg·g-1;对重金属Pb、Hg而言,在培养5 d后,木薯杆生物炭对其吸附量达到最大,分别为312.75、75.32μg·g-1,其中三种生物炭材料对Hg的吸附均随着培养时间的增加而增加。综合三种生物炭对重金属的吸附作用可推断,生物炭对水中重金属的吸附受吸附时间及生物炭性质而出现了不同的变化。

In order to find out the adsorption effect of different biochar materials on heavy metals in water,crop straw biochar was prepared at 500℃,and heavy metal solution was added to the prepared biochar materials respectively.The biochar was cultured for 1 h,1 d and 5 d in 220 r·min-1 in constant temperature oscillation incubator at 25℃,and the content of heavy metals Cr,Cd,Pb,Zn and Hg in the filtrate was determined after filtration.The results show that the three biochar are alkaline,and they have different adsorption effects on heavy metals Cr,Cd,Pb,Zn and Hg.For heavy metal Cr,the adsorption capacity of reed stem,cassava stem and rice stem biochar was the highest(260.33,250.56,248.69μg·g-1)after 5 days of culture;for heavy metal Zn and Cd,the adsorption capacity of rice stem biochar was the highest(190.80μg·g-1 and 333.58μg·g-1)after 1 hour of culture;for heavy metal Pb and Hg,the adsorption capacity of cassava stem biochar was the highest(190.80μg·g-1 and 333.58μg·g-1)after 5 days of culture The adsorption capacity of biochar is 312.75μg·g-1 and 75.32μg·g-1,respectively.The adsorption of Hg by three kinds of biochar materials increases with the increase of culture time.Based on the adsorption of heavy metals by three kinds of biochar,it can be concluded that the adsorption time and properties of biochar for heavy metals in water have different changes.