氮炭化核桃壳对Cr(Ⅵ)的吸附特性与机理  

Nitrogen carbonized walnut shell for Cr(Ⅵ) adsorption: Behaviors and mechanisms

作　　者：鲁秀国[1] 段建菊 黄林长 杨凌焱 

机构地区：[1]华东交通大学土木建筑学院,南昌330013

出　　处：《环境工程学报》2017年第6期3446-3452,共7页Chinese Journal of Environmental Engineering

基　　金：国家自然科学基金资助项目(51168013);"十二五"国家科技支撑计划项目(2014BAC04B03)

摘　　要：采用新疆核桃壳为原材料,将其在氮气氛围下炭化,制备氮炭化核桃壳吸附剂,利用静态吸附法研究了其对模拟废水中低浓度Cr(Ⅵ)的吸附性能,并采用SEM和FTIR技术对该吸附剂进行表征。结果表明,Langmuir等温吸附方程可以更好地拟合氮炭化核桃壳对Cr(Ⅵ)的吸附过程,说明Cr(Ⅵ)在氮炭化核桃壳上的吸附属于单分子层吸附,25℃时,当pH为2.0、吸附剂用量为16 g·L^(-1)、吸附时间为180 min、转速为200 r·min^(-1)时,Cr(Ⅵ)的去除率达到99.1%,饱和吸附容量为8.751 mg·g^(-1)。吸附动力学分析结果表明,该动态吸附平衡遵循拟二级动力学方程。表征结果显示,氮炭化核桃壳表面较粗糙,孔隙轮廓更清晰,更有利于对Cr(Ⅵ)的吸附,吸附过程中Cr(Ⅵ)主要与氮炭化核桃壳表面的O—H、CO、N—H、C—O—C等活性基团发生了作用。Xinjiang walnut shell which carbonized in the nitrogen atmosphere to prepare adsorbent. The adsorp- tion capability of the nitrogen-carbonized walnut shell for Cr（ VI ） in simulated low-concentration wastewater was studied using the static adsorption process and the walnut shell before and after carbonization was characterized using SEM and FTIR. The results indicated that the equilibrium was described well by the Langmuir isotherm, predicting that the adsorption of Cr（ VI ） onto the nitrogen-carbonized walnut shell was a monolayer adsorption. When the pH was 2.0, temperature was 25 ℃ , dosage of nitrogen-carbonized walnut shells was 16 g . L-1 , rotating speed was 200 r . min-1 , and adsorption time was approximately 180 rain, the removal rate of Cr（ VI ） was 99.1% and the maximum adsorption capacity was 8. 751 mg. g-1. Moreover, the equilibrium kinetic adsorption data fit the pseudo-second-order kinetic equation. The characterization results showed that the surface of the nitro- gen-carbonized walnut shell after carbonization was rougher and the pore outline was clearer, which made it more favorable for Cr（VI） adsorption. Active groups including O-H, C =O, N-H, C-O-C, etc. were involved in the Cr（VI） adsorption.

关 键 词：氮炭化核桃壳 Cr(Ⅵ) 吸附 等温线 动力学 

分 类 号：X703.1[环境科学与工程—环境工程]