Tian Zeyuan, Feng Yong, Guan Yiyi, Shao Binbin, Zhang Yalei, Wu Deli
State Key Laboratory of Pollution Control and Resources Reuse, College of Environmental Science & Engineering, Tongji University, Shanghai, 200092, P.R. China.
Department of Civil Engineering, The University of Hong Kong, Pokfulam Road, Hong Kong, China.
Sci Rep. 2017 Dec 5;7(1):17015. doi: 10.1038/s41598-017-17108-4.
Freshly prepared carbonate structural Fe(II) (CSF) was used to immobilize As(III) and As(V) in wastewater under oxic and anoxic conditions. Dissolved oxygen was found to exert opposite effects on these two arsenic species. The sorption density of As(III) was higher under oxic conditions, whereas that of As(V) was higher under anoxic conditions. X-ray diffraction and infrared spectroscopic analyses indicated that crystalline parasymplesite (Fe(II)(AsO)·8HO) was formed when As(V) was removed under anoxic conditions, while an amorphous Fe-As-containing precipitate was formed when As(III) was removed under oxic conditions. The distribution of arsenic and iron between the solution and sediments suggested that the oxidation of structural Fe(II) promoted coprecipitation process and inhibited surface complexation. X-ray photoelectron spectroscopic analyses revealed that more As(III) was oxidized under oxic condition, which contributed to a higher sorption capacity for As(III). The formation of parasymplesite through surface complexation/precipitation was proposed to be more effective for the removal of As(V) by CSF, while As(III) was more efficiently removed through coprecipitation. Together, the results suggest that CSF may be an effective material for sequestering both As(III) and As(V). In addition, attention should be paid to the dissolved oxygen content when remediating different arsenic species.
使用新制备的碳酸结构铁（II）（CSF）在有氧和无氧条件下固定废水中的As（III）和As（V）。发现溶解氧对这两种砷物种有相反的影响。As（III）的吸附密度在有氧条件下较高，而As（V）的吸附密度在无氧条件下较高。X射线衍射和红外光谱分析表明，在无氧条件下去除As（V）时形成了结晶副磷铁矿（Fe（II）（AsO）·8H₂O），而在有氧条件下去除As（III）时形成了无定形含Fe-As沉淀。溶液和沉积物之间砷和铁的分布表明，结构Fe（II）的氧化促进了共沉淀过程并抑制了表面络合。X射线光电子能谱分析表明，在有氧条件下更多的As（III）被氧化，这有助于提高对As（III）的吸附容量。通过表面络合/沉淀形成副磷铁矿被认为对CSF去除As（V）更有效，而As（III）通过共沉淀更有效地被去除。总之，结果表明CSF可能是一种有效螯合As（III）和As（V）的材料。此外，在修复不同砷物种时应注意溶解氧含量。
