title: Heterogeneous selenite reduction by zero valent iron steel wool.
abstract: Mine drainage from the low-sulfur surface coal mines in southern West Virginia, USA, is circumneutral (pH > 6) but contains elevated selenium (Se) concentrations. Removal of selenite ions from aqueous solutions under anoxic condition at pH 6-8.5 by zero valent iron steel wool (ZVI-SW) was investigated in bench-scale kinetic experiments using wet chemical, microscopic and spectroscopic techniques (X-ray photoelectron spectroscopy). ZVI-SW could effectively and efficiently remove SeIVfrom solution with pH 6-8.5. A two-step removal mechanism was identified for SeIVreduction by ZVI-SW. The proposed mechanism was electrochemical reduction of SeIVby Fe0in an initial lag stage, followed by a faster heterogeneous reduction, mediated by an FeII-bearing phase (hydroxide or green rust). Solution pH was a critical factor for the kinetic rate in the lag stage (0.33 h-1for pH > 8 and 0.10 h-1for pH 6-8). The length of lag stage was 20-30 min as determined by the time for dissolved FeIIconcentration to reach 0.30 ± 0.04 mg L-1which was critical for induction of the faster stage. About 65% of the initial SeIVwas reduced to Se0, the primary reductive product in both stages.
authors.affiliation: College of Natural Resources and Environment, Northwest Agriculture and Forestry University, 3# Taicheng Rd., Yangling, Shaanxi 712100, China and Key Laboratory of Plant Nutrition and the Agri-environment in Northwest China, Ministry of Agriculture, Yangling, China E-mail: dlynnhuang@nwsuaf.edu.cn.
authors.forename: Ziyan
authors.initials: Z
authors.lastname: Li
authors.affiliation: College of Natural Resources and Environment, Northwest Agriculture and Forestry University, 3# Taicheng Rd., Yangling, Shaanxi 712100, China and Key Laboratory of Plant Nutrition and the Agri-environment in Northwest China, Ministry of Agriculture, Yangling, China E-mail: dlynnhuang@nwsuaf.edu.cn.
authors.forename: Donglin
authors.initials: D
authors.lastname: Huang
authors.affiliation: Division of Plant and Soil Sciences, West Virginia University, P.O. Box 6108, Morgantown, WV 26506, USA.
authors.forename: Louis M
authors.initials: LM
authors.lastname: McDonald
mesh_terms: D003032:Coal Mining; D055664:Electrochemical Techniques; D006863:Hydrogen-Ion Concentration; D007501:Iron / Q000737:chemistry*; D056951:Photoelectron Spectroscopy; D020887:Selenious Acid / Q000032:analysis* / Q000737:chemistry; D012643:Selenium / Q000032:analysis; D013232:Steel / Q000737:chemistry*; D014874:Water Pollutants, Chemical / Q000032:analysis* / Q000737:chemistry; D014903:West Virginia
chemical_list: D014874:Water Pollutants, Chemical; D013232:Steel; D007501:Iron; D020887:Selenious Acid; D012643:Selenium