磷酸活化植物基活性炭对水溶液中铅的吸附
Adsorption of lead ions onto activated carbon prepared from bio-plant stems activation with H3PO4
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摘要: 以棉秆与互花米草为原料,采用磷酸活化法制备了低成本的植物基活性炭,通过静态实验研究了其对重金属铅的吸附性能。结果表明,在活化温度为500℃、活化时间为2 h条件下,制备的棉秆和互花米草活性炭比表面积为1 570 m2/g和856 m2/g，含氧酸官能团含量分别为1.43 mmol/g和1.27 mmol/g。在25℃下，两种活性炭对重金属铅的Langmuir最大吸附量分别为119 mg/g和111 mg/g，吸附最佳pH 为4.3,吸附平衡符合Freundlich方程，离子交换在吸附过程中发挥了重要作用。Abstract: Low-cost activated carbons were prepared from cotton stalk and Spartina alterniflora by phosphoric acid activation. Adsorption capacities for lead on the prepared carbons were measured by conducting a series of batch adsorption experiments. The results showed that the carbon prepared from cotton stalk activated at 500 ℃ for 2 h has 1.43 mmol/g acidic surface groups and 1 570 m2/g BET surface area. The activated carbon prepared from Spartina alterniflora under the conditions has 1.27 mmol/g acidic surface groups and 856 m2/g BET surface area. The maximum adsorption capacity for lead onto the two activated carbons calculated from Langmuir isotherm is 119 mg/g and 111 mg/g at 25℃ respectively. The optimum pH for the removal of lead was found to be 4.3, and the Freundlich isotherm model was found to best describe the equilibrium experimental data. It was also found that the ion-exchange mechanism was involved and played an important role in the adsorption.
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Key words:
- activated carbon /
- H3PO4 activation /
- adsorption
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