title: Effects of natural organic matter on the coprecipitation of arsenic with iron.
abstract: 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.
authors.affiliation: Department of Bioactive Material Sciences, Chonbuk National University, 567 Baekje-daero, Deokjin-gu, Jeonju, Jeollabukdo, 561-675, Republic of Korea.
authors.forename: Eun Jung
authors.initials: EJ
authors.lastname: Kim
authors.affiliation: Department of Environmental Engineering, Chonbuk National University, 567 Baekje-daero, Deokjin-gu, Jeonju, Jeollabukdo, 561-675, Republic of Korea.
authors.forename: Bo-Ram
authors.initials: BR
authors.lastname: Hwang
authors.affiliation: Department of Bioactive Material Sciences, Chonbuk National University, 567 Baekje-daero, Deokjin-gu, Jeonju, Jeollabukdo, 561-675, Republic of Korea. kbaek@jbnu.ac.kr.|Department of Environmental Engineering, Chonbuk National University, 567 Baekje-daero, Deokjin-gu, Jeonju, Jeollabukdo, 561-675, Republic of Korea. kbaek@jbnu.ac.kr.
authors.forename: Kitae
authors.initials: K
authors.lastname: Baek
mesh_terms: D000327:Adsorption; D001151:Arsenic / Q000737:chemistry*; D004785:Environmental Pollutants / Q000737:chemistry*; D005290:Ferric Compounds / Q000737:chemistry; D006812:Humic Substances; D006863:Hydrogen-Ion Concentration; D007501:Iron / Q000737:chemistry*
chemical_list: D004785:Environmental Pollutants; D005290:Ferric Compounds; D006812:Humic Substances; C092844:ferric oxyhydroxide; D007501:Iron; D001151:Arsenic
keywords: Arsenic; Coprecipitation; Iron; Natural organic matter