改性花生壳对重金属Cr(VI)的吸附性能研究

1.北京市密云县公安消防支队,北京 101500; 2.阿克苏高级技工学校 化学系,新疆 阿克苏 843000; 3.西安石油大学 化学化工学院,陕西 西安 710065

花生壳; 改性; 吸附剂; 动力学; 热力学

Adsorptive properties of modified peanut shell to heavy metal Cr(VI)
GAO Li-da1,CAO Lin-yi2,WANG Shan-shan3,TANG Ying3

(1.Fire Brigade of Miyun County,Beijing 101500,China; 2.Dept.of Chemistry,Senior Technical School of Aksu,Aksu 843000,China; 3.College of Chemistry and Chemical Engineering,Xi'an Petroleum University,Xi'an 710065,China)

peanut shell; modification; adsorption; isotherm; kinetics

DOI: 10.13800/j.cnki.xakjdxxb.2014.0514

备注

为了解决处理含铬等重金属废水时成本高和效率低等问题,采用吸附法去除Cr(VI),筛选廉价且吸附性能较好的吸附剂成为研究中的热点问题。而纤维素类农作物废弃物是廉价吸附剂的重要来源,文中选用花生壳为吸附剂原料,采用盐酸对其表面进行酸化改性。考察了pH值、温度、Cr(VI)初始浓度、改性花生壳投加量和吸附时间对铬离子吸附效果的影响。结果 表明,最佳吸附条件为pH=1,温度为50 ℃,铬离子浓度为50 mg/L,吸附剂投加量为10 g/L,吸附时间为140 min.通过考察反应动力学过程,发现改性花生壳吸附符合准二级反应动力学方程,Freundlich等温吸附模型也能较好地描述改性花生壳对铬离子溶液的等温吸附过程。经过分析研究和实验验证,改性花生壳对吸附废水中的Cr(VI)是可行有效的。

In order to solve the problem of high cost and low efficiency to remove the heavy metals such as chromium in wastewater,adsorption with low cost and simple operation has been explored,whose core technology is the selection of excellent adsorbent.Screening of low cost adsorbent is the hot point in the study of removing Cr(VI).Crops stem which was rich in cellulose becomes an important source of low-cost adsorbent.A great effort has been carried out on the modified peanut shell for their property to absorb Cr(VI).The effects of pH value,initial concentrate ration of Cr(VI),contact time,temperature and modified peanut shell dosage on adsorption had been investigated.The results indicated that modified peanut shell had good adsorption to Cr(VI).Under the condition of 50 ℃,10 g/L modified peanut shell,50 mg/L Cr(VI)solution,the initial pH = 1 and contact time 140 min,the adsorption rate of Cr(VI)is up to 99.6%.The Langmuir and Freundlich adsorption models were used to represent the experimental data and equilibrium data fitted well to Freundlich and Langmuir isotherm mode.Pseudo-second-order model was found to explain the kinetics of Cr(VI)adsorption most effectively.Through analysis and experiments,the modified peanut shell for the adsorption of Cr(VI)in wastewater is feasible and effective.