煤矸石-污泥基活性炭对苯酚的吸附

Adsorption of Phenol by ZnCl_(2) modified coal gangue-sludge based activated carbon

以煤矸石和污泥为原料、ZnCl_(2)为活化剂,制备了煤矸石-污泥基活性炭(CSAC)吸附剂,考察该吸附剂对溶液中苯酚的吸附去除效果。实验结果表明:在苯酚质量浓度为50 mg/L、CSAC投加量为7 g/L、初始pH为7~8、温度为(25±1)℃的条件下,当吸附时间为10 min时,CSAC对苯酚的吸附基本达到平衡,相应的吸附量为5.87 mg/g,苯酚去除率为83%;在其他条件相同、市售颗粒活性炭(AC)投加量为30 g/L的条件下,当吸附时间为120 min时,AC对苯酚的吸附达到平衡,相应的吸附量为1.05 mg/g,苯酚去除率仅63%。CSAC吸附苯酚的过程包含物理吸附和化学吸附,属于单层吸附,该过程是吸热的、熵增加的过程。表征结果显示:CSAC表面粗糙,由不定型的小颗粒紧密排列而成,比表面积和孔体积分别为258.74 m2/g和0.19 cm^(3)/g;CSAC中含有C=C、C=O、—OH、π-π基团等多种官能团,具有较好的吸附小分子有机物的能力。

Coal gangue-sludge based activated carbon(CSAC)adsorbent was prepared using coal gangue and sludge as raw materials and ZnCl_(2) as activator.Its adsorption effect on phenol in solution was studied.The experimental results show that:Under the conditions of phenol mass concentration 50 mg/L,CSAC amount 7 g/L,pH 7-8,temperature(25±1)℃and adsorption time 10 min,the adsorption of phenol on CSAC nearly reaches equilibrium,with a corresponding adsorption amount of 5.87 mg/g and a phenol removal rate of 83%;As a comparison,under the conditions of granular activated carbon(AC)amount 30 g/L,adsorption time 120 min and other same conditions,the adsorption of phenol on AC reaches equilibrium with a corresponding adsorption amount of 1.05 mg/g and a phenol removal rate of 63%only.The adsorption of CSAC to phenol is single-layer adsorption including physical adsorption and chemical adsorption,and the process is an endothermic and entropy increasing reaction process.The characterization results indicate that:the surface of CSAC is rough,consisting of closely arranged amorphous small particles,and the specific surface area and pore volume of CSAC is 258.74 m2/g and 0.19 cm^(3)/g,respectively;The various functional groups of CSAC,such as C=C,C=O,—OH,π-πgroups,endow it with good adsorption ability to small molecule organic compounds.