Effect of Environmental Factors on Mn2+ Release of δ-MnO2 In Water
Manganese dioxide (MnO2) is one of the important sewage treating agents for adsorption of trace heavy metals due to its outstanding structural flexibility and novel chemical and physical properties.The δ-MnO2 is characterized by low points of zero charge,high negative charge and large surface areas.It is active in various chemical reactions,which leads to a high adsorption capacity.In addition,the phenomenon of the release of Mn2+ during the adsorption of certain heavy metal ions onto δ-MnO2 has been followed with interest by researchers.Herein,the effects of different environmental factors on Mn2+ release of δ-MnO2 in water have been investigated.The results showed that the amounts of Mn2+ release was related with initial electrolyte,chelating agent,initial pH,temperature and other coexisted heavy metals.The amounts of Mn2+ release was decreased as electrolyte concentration increasing in the presence of NaCl.It appeared that cation was the main factor influencing the release of Mn2+ in the relevant electrolyte solution.The objective of the effect of chelating agents on the Mn2+ release by δ-MnO2 was to determine the effect of EDTA and NTA respectively.The amount of Mn2+ release promoted by EDTA was much higher than NTA.Mn2+ was released to achieve balance after 100 mg·L-1 of EDTA and NTA individually.In addition,the amount of Mn2+ release decreased sharply with the increase of pH (1-3.5) in system,and then decreased gradually as system pH increased.In comparison,the ranging amounts of Mn2+ released were narrow as the increasing of temperature.It appeared that temperature had a less effect on release behavior.Adsorption of heavy metals such as Pb2+,Cr3+ or Co2+ on δ-MnO2 by different mechanisms caused different amount of Mn2+ released,the influence order of the three heavy metals on Mn2+ released at the same concentration was as follows:Cr3+>Co2+>pb2+.
δ-MnO2 environmental factors Mn2+ released
Feng Bi Li-jun Zhu Jie-chen Qian
College of Forest Resources and Environment,Nanjing Forestry University,Nanjing,China College of Science,Nanjing Forestry University,Nanjing,China
国际会议
3rd International Conference on Pollution Ecology(第三届污染生态学国际会议(3rd ICPE))
天津
英文
16-20
2012-11-06（万方平台首次上网日期，不代表论文的发表时间）