The role of precipitation and biosorption in the abiotic removal of manganese with crab-shell chitin

Mary Ann Robinson-Lora, Rachel A. Brennan

Research output: Chapter in Book/Report/Conference proceedingConference contribution

Abstract

This study evaluated manganese removal using crab-shells (SC-20) under abiotic, anoxic conditions. Tests were conducted to assess the contributions of each of the components of SC-20 (chitin, proteins, and minerals) to the observed changes. Manganese removal due to precipitation was evaluated in closed-system tests using raw or deproteinized SC-20. Manganese removal due to adsorption onto the organic components of SC-20 (chitin and protein) was evaluated under different pH conditions using sorption isotherms. In closed-system precipitation tests with a contact time of 72 h and an initial manganese concentration (Mno) of 10 - 250 mg/L, removals of ~60 to >95% were obtained. Manganese removal decreased with increasing Mno and could be attributed to the precipitation of rhodochrosite (MnCO3) and/or MnHPO4. Significant increases in pH (from pH 3 to pH 7.7 - 9.9) and alkalinity (from 0 to 55 - 525 mg CaCO3/L) were also observed as a result of the dissolution of chitinassociated minerals. These changes appear to be promoted by the relatively large surface area and distinct composition of SC-20, including phosphates and soluble organic compounds. The equilibrium of adsorption was well described by the Langmuir model. The maximum sorption capacity (qm) depended greatly on the system's pH, with negligible sorption at pH < 5. At higher pH regimes, qm ranged from 0.165 to 0.981 for chitin. When both chitin and protein were present, qm increased 5 - 7 times, suggesting that chitin-associated proteins offer additional sorption sites for manganese. Results demonstrate that Mn removal with SC-20 is achieved by a combination of the reactivity of chitin-associated minerals and the sorption capacity of chitin and its associated proteins. These characteristics could be easily exploited in polishing systems for the removal of the historically difficult Mn in mine impacted waters.

Original languageEnglish (US)
Title of host publicationJoint Mining Reclamation Conf. 2010 - 27th Meeting of the ASMR, 12th Pennsylvania Abandoned Mine Reclamation Conf. and 4th Appalachian Regional Reforestation Initiative Mined Land Reforestation Conf.
PublisherAmerican Society of Mining and Reclamation
Pages828-846
Number of pages19
ISBN (Print)9781617820526
DOIs
StatePublished - 2010
EventJoint Mining Reclamation Conference 2010 - 27th Annual Meeting of the ASMR, 12th Annual Pennsylvania Abandoned Mine Reclamation Conf. and 4th Annual Appalachian Regional Reforestation Initiative Mined Land Reforestation Conf. - Pittsburgh, PA, United States
Duration: Jun 5 2010Jun 11 2010

Publication series

NameJoint Mining Reclamation Conf. 2010 - 27th Meeting of the ASMR, 12th Pennsylvania Abandoned Mine Reclamation Conf. and 4th Appalachian Regional Reforestation Initiative Mined Land Reforestation Conf.
Volume2

Other

OtherJoint Mining Reclamation Conference 2010 - 27th Annual Meeting of the ASMR, 12th Annual Pennsylvania Abandoned Mine Reclamation Conf. and 4th Annual Appalachian Regional Reforestation Initiative Mined Land Reforestation Conf.
CountryUnited States
CityPittsburgh, PA
Period6/5/106/11/10

All Science Journal Classification (ASJC) codes

  • Geochemistry and Petrology
  • Geotechnical Engineering and Engineering Geology

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    Robinson-Lora, M. A., & Brennan, R. A. (2010). The role of precipitation and biosorption in the abiotic removal of manganese with crab-shell chitin. In Joint Mining Reclamation Conf. 2010 - 27th Meeting of the ASMR, 12th Pennsylvania Abandoned Mine Reclamation Conf. and 4th Appalachian Regional Reforestation Initiative Mined Land Reforestation Conf. (pp. 828-846). (Joint Mining Reclamation Conf. 2010 - 27th Meeting of the ASMR, 12th Pennsylvania Abandoned Mine Reclamation Conf. and 4th Appalachian Regional Reforestation Initiative Mined Land Reforestation Conf.; Vol. 2). American Society of Mining and Reclamation. https://doi.org/10.21000/jasmr10010828