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为了解狭叶香蒲(Typha angustifolia L.)活性炭的吸附性能及其机理,采用磷酸一步活化法制备了狭叶香蒲活性炭,并对其理化性质进行了表征;通过静态实验,研究了溶液起始pH、Cd~(2+)和Pb~(2+)浓度、吸附时间、温度、活性炭剂量对狭叶香蒲活性炭吸附水溶液中Cd~(2+)和Pb~(2+)的影响。狭叶香蒲活性炭对Cd~(2+)和Pb~(2+)的吸附量随溶液起始pH与温度的增加而增加,吸附平衡时间约为10 min;热力学分析表明,吸附过程自发而且吸热,吸附动力学实验结果符合拟二级动力学模型,Langmuir吸附等温模型能更好地拟合狭叶香蒲活性炭对Cd~(2+)的吸附,Pb~(2+)的平衡吸附量与Freundlich模型的拟合性更好。25℃条件下,由Langmuir线性模型拟合得到的Cd~(2+)和Pb~(2+)最大吸附量Qm分别为83.33和116.28 mg/g。狭叶香蒲活性炭的理化性质分析表明,活性炭表面凹凸不平、多孔,比表面积为780.42 m2/g、孔容23.29 m L/g、平均孔径3.14 nm;活性炭含有羟基、磷酸基、CC键等,等电点为3.3。结果表明,狭叶香蒲活性炭是Cd~(2+)和Pb~(2+)吸附的有效吸附剂,吸附过程包括静电吸附、离子交换等。
In order to understand the adsorption properties and the mechanism of Typha angustifolia L. activated carbon, the activated carbon from Typha angustifolia L. was prepared by phosphoric acid one-step activation method and its physicochemical properties were characterized. By static experiments, the initial pH , Cd 2+ and Pb 2+ concentration, adsorption time, temperature and activated carbon dose on the Cd 2+ and Pb 2+ in the aqueous solution of cattail cattail activated carbon. The adsorption capacity of Cd 2+ and Pb 2+ increased with the initial pH and temperature of the solution, and the equilibrium time of adsorption was about 10 min. The thermodynamic analysis showed that the adsorption process spontaneously and absorbed The experimental results of heat and adsorption kinetics fit the pseudo-second-order kinetic model. The Langmuir adsorption isotherm model can better fit the adsorption of Cd 2+ by the activated carbon of Typha angustifolia, and the equilibrium adsorption capacity of Pb 2+ Freundlich model fitting better. Under 25 ℃, the maximum adsorption capacity of Cd 2+ and Pb 2+ by Langmuir model was 83.33 and 116.28 mg / g, respectively. The physicochemical properties of Acanthopanax angustifolia active carbon showed that the surface of Activated Carbon was rugged and porous with a specific surface area of 780.42 m2 / g, a pore volume of 23.29 m L / g and an average pore diameter of 3.14 nm. Activated carbon contained hydroxyl groups, phosphoric acid groups and CC bonds , Isoelectric point of 3.3. The results show that the cattail Acanthopanax catharanthus is an effective adsorbent for Cd 2+ and Pb 2+ adsorption. The adsorption process includes electrostatic adsorption and ion exchange.