enhanced al and zn removal from coal mine drainage during rapid oxidation and precipitation of fe oxides at near neutral ph

Accepted Manuscript Enhanced Al and Zn removal from coal-mine drainage during rapid oxidation and precipitation of Fe oxides at near-neutral pH Jill E Burrows, Charles A Cravotta, III, Stephen C Peters PII: S0883-2927(16)30603-5 DOI: 10.1016/j.apgeochem.2016.12.019 Reference: AG 3784 To appear in: Applied Geochemistry Received Date: March 2016 Revised Date: 23 September 2016 Accepted Date: 22 December 2016 Please cite this article as: Burrows, J.E., Cravotta III., , C.A., Peters, S.C., Enhanced Al and Zn removal from coal-mine drainage during rapid oxidation and precipitation of Fe oxides at near-neutral pH, Applied Geochemistry (2017), doi: 10.1016/j.apgeochem.2016.12.019 This is a PDF file of an unedited manuscript that has been accepted for publication As a service to our customers we are providing this early version of the manuscript The manuscript will undergo copyediting, typesetting, and review of the resulting proof before it is published in its final form Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain ACCEPTED MANUSCRIPT Enhanced Al and Zn Removal from Coal-Mine Drainage during Rapid Oxidation and Precipitation of Fe Oxides at Near-Neutral pH Jill E Burrowsa*, Charles A Cravotta IIIb, Stephen C Petersa Department of Earth and Environmental Sciences, Lehigh University, W Packer Ave., RI PT a Bethlehem, PA 18015 b U.S Geological Survey, Pennsylvania Water Science Center, 215 Limekiln Road, New SC Cumberland, PA 17070 AC C EP TE D M AN U (* author for correspondence, email: burrowsjille@gmail.com, Tel: 1-484-893-0673) ACCEPTED MANUSCRIPT Abstract Net-alkaline, anoxic coal-mine drainage containing ~20 mg/L FeII and ~0.05 mg/L Al and Zn was subjected to parallel batch experiments: control, aeration (Aer 12.6 mL/s; Aer RI PT 16.8 mL/s; Aer 25.0 mL/s), and hydrogen peroxide (H2O2) to test the hypothesis that aeration increases pH, FeII oxidation, hydrous FeIII oxide (HFO) formation, and trace-metal removal through adsorption and coprecipitation with HFO During 5.5-hr field experiments, pH increased SC from 6.4 to 6.7, 7.1, 7.6, and 8.1 for the control, Aer 1, Aer 2, and Aer 3, respectively, but decreased to 6.3 for the H2O2 treatment Aeration accelerated removal of dissolved CO2, Fe, Al, M AN U and Zn In Aer 3, dissolved Al was completely removed within hour, but increased to ~20% of the initial concentration after 2.5 hours when pH exceeded 7.5 H2O2 promoted rapid removal of all dissolved Fe and Al, and 13% of dissolved Zn Kinetic modeling with PHREEQC simulated effects of aeration on pH, CO2, Fe, Zn, and TE D Al Aeration enhanced Zn adsorption by increasing pH and HFO formation while decreasing aqueous CO2 available to form ZnCO30 and Zn(CO3)22- at high pH Al concentrations were inconsistent with solubility control by Al minerals or Al-containing HFO, but could be simulated EP by adsorption on HFO at pH