摘要
采用农林废弃物核桃壳作为吸附剂处理水中的Mn2+,研究固体投加量、吸附时间、溶液初始质量浓度以及pH值等因素对吸附效果的影响;并进行动力学、热力学研究。结果表明,最佳投加量为50g/L;最佳吸附时间为90min;溶液初始质量浓度为0.32—2.17mg/L时,随着初始浓度的增加,水中Mn2+的去除率也增加;pH值为7—9时去除率可达80%以上。核桃壳对Mn2+的吸附过程符合准二级反应动力学方程。这说明初始阶段核桃壳对Mn2+的吸附受界面扩散控制,之后吸附受粒子内扩散控制。Freundlich等温线模型与实验数据的符合程度比其他的等温线模型要好,这表明发生的是物理吸附。而且对于Freundlich常数n,1/n<1,说明吸附过程较易进行,对于Mn2+来说核桃壳是一种适宜的吸附剂。
The sorption of Mn2＋ onto walnut shell is investigated by batch experiments.The recycle of walnut shell as main agriculture and forestry wastes in the wastewater treatment is estimated.The effects of factors,including soil/water ratio,sorption time,initial concentration of Mn2＋,and pH value on the sorption of Mn2＋ onto walnut shell are carried out.Furthermore,the dynamics and thermodynamics of the sorption are discussed.The results show that the optimal ratio of soil（g） to water（L） is 50：1.And the optimal sorption time is 90min.When the initial concentration of Mn2＋ is in the range of 0.32mg/L-2.17mg/L,the removal rate of Mn2＋ in water increases with increasing initial concentration of Mn2＋.Above 80% of Mn2＋ is sorbed onto walnut shell,when pH value is between 7 and 9.The sorption of Mn2＋ onto walnut shell fits in pseudo-second-order kinetics equation.The fact suggests that the initial sorption is controlled by interfacial diffusion,following by intraparticle diffusion.In addition,the sorption of Mn2＋ onto walnut shell fits better with Freundlich equation with higher R2 value.For the Freundlich constant,1/n is less than 1.It is indicated that the sorption energy decreases with increasing initial concentration of Mn2＋.The sorption of Mn2＋ onto walnut shell likely occurs.In general,the walnut shell is a cost-efficient sorbent for Mn2＋.
出处
《科技导报》
CAS
CSCD
北大核心
2012年第9期49-52,共4页
Science & Technology Review
基金
环保公益性行业科研基金重大项目(201009009)
关键词
核桃壳
吸附
锰离子
动力学
热力学
walnut shell
sorption
manganese ion
dynamics
thermodynamics
