氮掺杂TiO_2对水中Cr(Ⅵ)的吸附  

Adsorption of Cr(Ⅵ) from aqueous solution by N-doped TiO_2

作　　者：李道荣[1] 王霞[1] 张坤峰[1] 刘畅[1] 方宝岭[1] 

机构地区：[1]河南工业大学化学化工学院,郑州450001

出　　处：《环境工程学报》2013年第1期185-190,共6页Chinese Journal of Environmental Engineering

基　　金：河南省科技攻关项目(0624210001);河南省重点科技攻关项目(07210220001)

摘　　要：以四氯化钛、尿素为原料,采用简单的溶胶-凝胶法制得了氮掺杂TiO2,其比表面积(BET)为106.48 m2/g。系统研究了该吸附剂对Cr(Ⅵ)的吸附性能。结果表明,对于初始浓度为100 mg/L的Cr(Ⅵ)溶液,吸附剂用量为5 g/L,在pH=5时,25℃下吸附180 min即能达到满意的吸附效果,其吸附效率可达97%以上。氮掺杂TiO2对Cr(Ⅵ)的吸附平衡符合Langmuir方程,升高温度,平衡吸附量增大;在温度为55℃时,Cr(Ⅵ)的饱和吸附量高达29.906 mg/g。吸附动力学可用拟二级速率方程很好地描述。氮掺杂后TiO2的吸附能力比纯TiO2明显增强。即对于Cr(Ⅵ),氮掺杂TiO2是一种优良吸附剂。此外,从氮掺杂TiO2吸附Cr(Ⅵ)前后的FTIR图可知,氮掺杂TiO2吸附Cr(Ⅵ)的过程中,N—H键参与了吸附过程。由于氮掺杂TiO2制备简单、原料廉价易得、吸附Cr(Ⅵ)效果良好,故可用于工业化生产。N-doped TiO2 was prepared by a simple sol-gel method using titanium tetraehloride and urea. The result shows that the BET surface reaches 106.48 m2/g. The Cr（ Ⅵ ） adsorption properties of N-doped TiO2 were systematically investigated. The results show that the adsorption efficiency is higher than 97% at Cr（Ⅵ） initial concentration of 100 mg/L, temperature of 25℃ , amount of adsorbent of 5 g/L, adsorption time of 180 min and pH of 5. The adsorption of Cr（Ⅵ） follows Langmuir isotherm, and the adsorption capacity increases with an increase in temperature. The maximum adsorption capacity is 29.9136 mg/g at 55℃. The Cr（Ⅵ） adsorption kinetics data can be well described by the pseudo-second-order reaction model. The adsorption efficiency of N-doped TiO2 is significantly higher than that of pure TiO2 under the given experimental conditions. Therefore, N-doped TiO2 is an attractive adsorbent in treatment of chromium-containing wastewater. In addition, N-H bonds were involved in the adsorption process from the FIIR spectrum of N-doped TiO2 and Cr（Ⅵ） loaded N-doped TiO2. The simple synthesis method, wide raw material resources and high Cr（Ⅵ） adsorption capacity of N- doped TiO2 make it possible to apply in large-scale industry process.

关 键 词：尿素 氮掺杂TiO2 六价铬离子 吸附 四氯化钛 

分 类 号：X703.1[环境科学与工程—环境工程]