氯化锌催化活化制备中孔活性炭及其对Cr6＋的吸附性能

Preparation of Mesoporous Active Carbon via Catalytic Activation by Zinc Chloride and Evaluation of Its Adsorption Capacity towards Hexavalent Chromium in Wastewater

为进一步提高活性炭对废水中Cr^(6+)的吸附能力,采用氯化锌对市售微孔活性炭粉进行催化活化,制成了中孔活性炭,并研究了中孔活性炭对Cr^(6+)的吸附性能。通过单因素试验优选了中孔活性炭吸附Cr^(6+)的工艺参数;研究了中孔活性炭吸附Cr^(6+)的吸附动力学和吸附等温线,并进行了再生吸附试验。结果表明:向100 mL Cr^(6+)初始浓度为100 mg/L的重铬酸钾溶液中投加0.1 g中孔活性炭,控制温度为35℃,pH=2,3 h即可达吸附平衡,此时吸附效果最佳,最大吸附量达93.7 mg/g;中孔活性炭对Cr^(6+)的吸附遵循二级动力学规律,符合Langmuir吸附等温式;吸附/再生循环2次后,中孔活性炭吸附能力保持不变,循环5次后,活性炭对Cr^(6+)的吸附量为初始吸附量的75%,碳损失率为6.5%。

Mesoporous active carbon was prepared from commercially available active carbon under the catalytic activation by zinc chloride, and its adsorption capacity for Cr6+ was evaluated. The processing parameters for the adsorption of Cr6+ were optimized based on single factor test, and the adsorption kinetics and adsorption isotherm were also investigated. Moreover, the adsorption performance of the adsorbent after recycling and regeneration was examined as well. As the results, the optimal processing parameters for the adsorption of Cr + in 100 mL of potassium chromate solution(Cr6+ initial concentration of 100 mg/L) by the raesoporous active carbon were suggested as mesoporous active carbon dosage of 0. 1 g, temperature of 35 t,pH value of 2,and adsorption time of 3 h. The maximum adsorption amount of 93. 7 mg/g was obtained under the optimized condition. The adsorption of Cr6 +by the mesoporous active carbon followed the pseudo-second-order kinetic equation and conformed to the Langmuir adsorption isotherm model Moreover, after being recycled and regenerated twice, the mesoporous active carbon retained unchanged adsorption capacity,while its adsorption capacity was reduced to 75 % in association with 6.5% of carbon loss after 5 cycles of recycling and regeneration