摘要
为了提高活性炭对水中的砷酸盐的去除能力,采用共沉淀法制备了2种负载铁锰氧化物的改性活性炭(FM-GAC-1,FM-GAC-2).测定了2种改性活性炭表面的零点电荷、酸碱官能团以及金属溶出量.研究2种改性活性炭去除五价砷的吸附等温线和反应动力学,考察pH值、水中共存离子对其去除五价砷的影响.结果表明,FM-GAC-1和FM-GAC-2表面的零点电荷分别为6.7、6.0;酸性官能团的含量分别为2mmol·g-1、1.667mmol·g-1,碱性官能团的含量分别为1.3mmol·g-1、2.06mmol·g-1;pH值在近中性时金属溶出率最低.在25℃时,FM-GAC-1和FM-GAC-2对五价砷的吸附容量分别为28.87mg·g-1和30.32mg·g-1,随着温度的升高,吸附容量略有下降.吸附速率采用拟二级反应动力学拟合效果最好,化学反应步骤是改性活性炭除砷的限速步骤.pH值偏酸性有利于吸附的进行,水体中SiO32-、PO43-对两者吸附砷酸盐有显著影响.
In order to improve arsenate removal capacity on activated carbon,two kinds of granular activated carbon（GAC） impregnated with Fe-Mn oxide,FM-GAC-1 and FM-GAC-2 were prepared with coprecipitation method.The pH of zero point charge（pHzpc）,acidity and basic function groups and the dissolved metal amount of the both modified GAC were measured.Experiments were performed to investigate arsenate adsorption isotherm,reaction kinetics and different solution conditions,such as pH and co-existing anions.The results showed that pHzpc were 6.7 and 6.0,the acidity function groups were 2 mmol·g^-1 and 1.667 mmol·g^-1,and the basic function groups were 1.3 mmol·g^-1 and 2.06 mmol·g^-1 respectively.When pH was near neutral,the dissolved metal amount was the minimum.Adsorption capacity of FM-GAC-1 and FM-GAC-2 were 28.87 mg·g^-1 and 30.32 mg·g^-1 at 25℃,respectively.Adsorption capacity decreased with temperature increasing.The adsorption kinetics could be predicted well by applying pseudo-second order rate equation and the chemical reaction process was the limited velocity reaction for both modified GAC.Removal was favored at lower pH.SiO32-and PO43-had negative influence on FM-GAC-1 and FM-GAC-2.
出处
《哈尔滨工业大学学报》
EI
CAS
CSCD
北大核心
2010年第8期1317-1322,共6页
Journal of Harbin Institute of Technology
基金
水体污染控制与治理科技重大专项资助(2008ZX07425-007)
关键词
砷酸盐
活性炭
吸附
arsenate
activated carbon
adsorption
