Publication detail

Oxalic Acid Adsorption on Rutile: Experiments and Surface Complexation Modeling to 150 degrees C

KROUTIL, O. MACHESKY, ML. RIDLEY MOIRA, K. BIRIUKOV, D. PREDOTA, M.

Original Title

Oxalic Acid Adsorption on Rutile: Experiments and Surface Complexation Modeling to 150 degrees C

Type

journal article in Web of Science

Language

English

Original Abstract

Here, we characterize oxalate adsorption by rutile in Oxalate adsorption on rutile NaCl media (0.03 and 0.30 m) and between pH 3 and 10 over a wide temperature range which includes the near hydrothermal regime (10-150 degrees C). Oxalate adsorption increases with decreasing pH (as is typical for anion binding by metal oxides), but systematic trends with respect to ionic strength or temperature are absent. Surface complexation modeling (SCM) following the CD-MUSIC formalism, and as constrained by molecular modeling simulations and IR spectroscopic results from the literature, is used to interpret the adsorption data. The molecular modeling simulations, which include molecular dynamics simulations supported by free-energy and ab initio calculations, reveal that oxalate binding is outer- sphere, albeit via strong hydrogen bonds. Conversely, previous IR spectroscopic results conclude that various types of inner-sphere complexes often predominate. SCMs constrained by both the molecular modeling results and the IR spectroscopic data were developed, and both fit the adsorption data equally well. We conjecture that the discrepancy between the molecular simulation and IR spectroscopic results is due to the nature of the rutile surfaces investigated, that is, the perfect (110) crystal faces for the molecular simulations and various rutile powders for the IR spectroscopy studies. Although the (110) surface plane is most often dominant for rutile powders, a variety of steps, kinks, and other types of surface defects are also invariably present. Hence, we speculate that surface defect sites may be primarily responsible for inner-sphere oxalate adsorption, although further study is necessary to prove or disprove this hypothesis.

Keywords

WATER INTERFACE; ION ADSORPTION; ORGANIC-ACIDS; HYDROUS OXIDES; MELLITIC ACID; NACL MEDIA; OXALATE; TEMPERATURE; SPECIATION; ANATASE

Authors

KROUTIL, O.; MACHESKY, ML.; RIDLEY MOIRA, K.; BIRIUKOV, D.; PREDOTA, M.

Released

18. 6. 2019

Publisher

AMER CHEMICAL SOC

Location

WASHINGTON

ISBN

0743-7463

Periodical

Langmuir

Year of study

35

Number

24

State

United States of America

Pages from

7631

Pages to

7640

Pages count

10

URL

http://apps.webofknowledge.com.ezproxy.lib.vutbr.cz/full_record.do?product=WOS&search_mode=GeneralSearch&qid=1&SID=E6JXvEJHJpsw8EibggE&page=1&doc=1

BibTex

@article{BUT163557,
  author="KROUTIL, O. and MACHESKY, ML. and RIDLEY MOIRA, K. and BIRIUKOV, D. and PREDOTA, M.",
  title="Oxalic Acid Adsorption on Rutile: Experiments and Surface Complexation Modeling to 150 degrees C",
  journal="Langmuir",
  year="2019",
  volume="35",
  number="24",
  pages="7631--7640",
  doi="10.1021/acs.langmuir.8b03982",
  issn="0743-7463",
  url="http://apps.webofknowledge.com.ezproxy.lib.vutbr.cz/full_record.do?product=WOS&search_mode=GeneralSearch&qid=1&SID=E6JXvEJHJpsw8EibggE&page=1&doc=1"
}