五种作物秸秆生物炭对重金属Pb^(2+)的吸附性的比较

Adsorbability Comparison of Some Crop Straw Biochar to Heavy Metal Pb^(2+)

为探讨小麦、玉米、水稻、花生壳和稻壳制备生物炭的差异,本文对这些植物纤维在不同预成型压力下制备的生物质炭的结构和性能进行了测定和分析,并研究了其对铅离子(Pb^(2+))的吸附性。结果表明:玉米、小麦和水稻三种秸秆生物质炭对溶液中Pb^(2+)的吸附性能较好,且在不同初始浓度下对Pb^(2+)的吸附符合Langmuir等温吸附模型,吸附量分别为141.310、121.226和122.753mg·g^(-1)。而花生壳和稻壳生物炭对Pb^(2+)的吸附性能较差,吸附量分别为62.914和51.037mg·g^(-1)。玉米秸秆生物质炭的-OH、-C-H、C=C等表面官能团较多,可通过表面官能团的络合作用吸附溶液中的Pb^(2+)。小麦和水稻秸秆制备生物炭由于含有较高的碳酸盐、磷酸等无机矿物形成化学沉淀。不同初始压力下制备生物质炭对溶液中Pb^(2+)的吸附影响较小。

Biochar was prepared from 5kinds of plant fibers (wheat,maize,rice,peanut hull and rice husk)by drying,fragilization and press formation under varied pressure.The property and structure of the biochar were characterized and adsorbability to Pb^2+was compared.The results show that,the biochar of straws of corn,wheat and rice have better adsorption performance to Pb^2+ in solution.Their adsorption to Pb^2+at different initial concentrations conforms to the Langmuir isothermal adsorption model,and the adsorptive capacity are 141.310mg·g^-1 121.226mg·g^-1.122.753mg·g^-1respectively.MeanwhiIe,the adsorption performance of the biochar prepared from speanut hull and rice husk are relatively poor,of which the adsorption capacity are 62.914mg·g^-1,51.037mg·g^-1.The biochar from corn straws has a large number of surface functional groups such as -OH,-C-H and C=C,and the Pb^2+in solution can be absorbed by complexation of those surface functional groups.Due to the presence of high carbonate, phosphoric acid and other inorganic minerals,the biochar from wheat and rice straws have formed the chemical precipitation.The initial pressure condition for the preparation of biochar has a little effect on their adsorption performance of Pb^2+in the solution.