花生壳生物炭的制备、表征及其吸附性能

Preparation, Characterization and Adsorption Properties of Peanut-shells-derived Biochar

选择花生壳作为原材料,采用限氧升温炭化法在200、450、700℃温度下制备生物炭,在对其元素组成和表面性质进行分析的基础上,重点考察生物炭对邻苯二甲酸酯的吸附性能。结果表明,花生壳生物炭的元素含量由高到低为C>O>H>N,热解温度的升高使碳元素含量显著增高,芳香性增强且极性减弱;花生壳生物炭的比表面积、总孔面积、微孔面积和微孔孔容均随热解温度的升高而增加,平均孔隙宽度随之减小;花生壳生物炭含有丰富的表面官能团,热解温度升高使羟基数量大幅减少,烃基逐渐消失,芳香化程度增强;花生壳生物炭对DEP、DBP的吸附符合Freundlich方程,吸附能力随热解温度的升高而增强,高温生物炭的吸附过程呈现明显的非线性特征。

With peanut shell as the precursors, biochar was prepared by sustainable temperature oxygen limited method at three different pyrolysis temperatures （200℃, 450℃, 700℃）. On the basis of analyzing elemental composition and surface properties of biochars, the paper focuses on the investigation of adsorption properties of phthalate esters by peanut-shells-derived biochars. The results showed that the element content of peanut-shells-derived biochar was in the order of C〉O〉H〉 N. The increasing pyrolysis temperature caused the higher C content, the strengthening aromatic properties and the weaker polarity of biochar. As pyrolysis temperature raised, the specific surface area, total pore surface area, micropore surface area and micropore volume of biochar increased obviously, while average pore width decreased gradually. There were rich functional groups on the surface of the carbonized peanut shell. With a rise in pyrolysis temperature, the quantities of hydroxyl dropped sharply, the alkyl disappeared gradually and the aromatic degree was enhanced. The adsorption of DEP and DBP by peanut-shells-derived biochar fitted well with the Freundlich equation. With raised pyrolysis temperature, the adsorption capacity of biochar increased obviously and the absorption process showed typical nonlinear characteristics.