氯化钙对棉秆炭理化性质的影响

Effect of CaCl2on Physicochemical Properties of Cotton Straw Carbon

以棉花秸秆(棉秆)为原料,研究了不同温度下添加无水氯化钙对热解产物棉秆炭理化特性的影响。通过同步热分析(TG/DSC)、X射线衍射(XRD)、拉曼光谱(Raman)、扫描电子显微镜(SEM)、透射电子显微镜(TEM)和N2吸附-脱附分析表征了其微观形貌和结构。TG分析显示热解温度达到500℃后,样品失重较少,故选择550~750℃为热解温度范围;试验结果表明直接热解和氯化钙活化这两种热解法制备的样品均是无定形炭结构,在550~750℃时,直接热解法制备的样品拉曼分析参数I_(D)/I_(G)约为0.93,最大比表面积2.09 m^(2)/g,最大平均孔径为7.21 nm,氯化钙活化法制备样品I_(D)/I_(G)约为0.85,最大比表面积487.68 m^(2)/g,最大平均孔径为5.97 nm。活化法制备的样品在石墨化程度、比表面积大小、孔径数量等方面优于直接热解法制得的样品,而直接热解法制得的样品孔径较大、无序化程度高、稳定性较好。

The effects of anhydrous calcium chloride on the physicochemical properties of cotton straw based porous biochar were studied with cotton straw as raw material under different temperature.The morphology and structure were characterized by simultaneous thermal analysis(TG-DSC),X-ray diffraction(XRD),Raman spectroscopy(Raman),scanning electron microscopy(SEM),transmission electron microscopy(TEM)and N2 adsorption-desorption analysis.The TG results showed when the pyrolysis temperature reached 500℃,the weight loss of the samples was less,so 550-750℃was selected as the pyrolysis temperature range.The experimental results showed that the samples prepared by the two pyrolysis methods(direct pyrolysis and CaCl_(2)activation)were amorphous carbon structure.During 550-750℃,for direct pyrolysis,the I_(D)/I_(G)values of Roman analysis were about 0.93,the maximum specific surface area was 2.09 m^(2)/g and the average pore size was 7.21 nm;for CaCl_(2)activation,the I_(D)/I_(G)values were about 0.85,the maximum specific surface area was 487.68 m^(2)/g and the average pore size was 5.97 nm.And the samples prepared by the activation method are better than the samples prepared by the direct pyrolysis method in the degree of graphitization,specific surface area and pore size,while the samples prepared by the direct pyrolysis method had larger pore size,high degree of disorder and good stability.