Kim Eun Jung, Hwang Bo-Ram, Baek Kitae
Department of Bioactive Material Sciences, Chonbuk National University, 567 Baekje-daero, Deokjin-gu, Jeonju, Jeollabukdo, 561-675, Republic of Korea.
Department of Environmental Engineering, Chonbuk National University, 567 Baekje-daero, Deokjin-gu, Jeonju, Jeollabukdo, 561-675, Republic of Korea.
Environ Geochem Health. 2015 Dec;37(6):1029-39. doi: 10.1007/s10653-015-9692-1. Epub 2015 Mar 10.
Natural organic matter (NOM) can affect arsenic speciation and mobility in the environment. In this study, the effects of NOM on the coprecipitation of arsenic with iron were investigated in order to better understand the fate and transport of arsenic in natural environments. The coprecipitation of arsenic with iron was studied in the presence and absence of NOM under various arsenic-to-iron molar ratios (As/Fe) and pH conditions. The addition of humic acid (HA) hindered the As-Fe coprecipitation under high pH and high As/Fe conditions by forming a soluble As-Fe-HA complex. The X-ray diffraction and Fourier transform infrared studies showed that the As-Fe-coprecipitated solid phase was highly affected by pH and As/Fe. The arsenic was coprecipitated with iron as an amorphous ferric arsenate phase at a low pH level or high As/Fe conditions, while the formation of ferrihydrite phase and the arsenic incorporation to the ferrihydrite by adsorption was predominant at high pH levels or low As/Fe conditions. The HA affected the As-Fe-coprecipitated solid phase depending on the As/Fe molar ratio under neutral and alkaline conditions.
天然有机物（NOM）会影响环境中砷的形态和迁移性。在本研究中，研究了NOM对砷与铁共沉淀的影响，以便更好地了解自然环境中砷的归宿和迁移。在不同的砷铁摩尔比（As/Fe）和pH条件下，研究了有无NOM时砷与铁的共沉淀情况。在高pH和高As/Fe条件下，腐殖酸（HA）的添加通过形成可溶性As-Fe-HA络合物阻碍了As-Fe共沉淀。X射线衍射和傅里叶变换红外研究表明，As-Fe共沉淀固相受pH和As/Fe的影响很大。在低pH水平或高As/Fe条件下，砷与铁以无定形砷酸铁相共沉淀，而在高pH水平或低As/Fe条件下，主要形成水铁矿相且砷通过吸附作用掺入水铁矿中。在中性和碱性条件下，HA根据As/Fe摩尔比影响As-Fe共沉淀固相。
