Change search
CiteExportLink to record
Permanent link

Direct link
Cite
Citation style
  • apa
  • harvard1
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf
Sorption performances of TiO(OH)(H2PO4)·H2O in synthetic and mine waters
Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Chemical Engineering.ORCID iD: 0000-0002-4533-3920
Tananaev Institute of Chemistry and Technology of Rare Elements and Mineral Raw Materials, Kola Science Center, Russian Academy of Sciences.
Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Chemical Engineering.
Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Chemical Engineering.ORCID iD: 0000-0003-1067-7990
Number of Authors: 42017 (English)In: RSC Advances, ISSN 2046-2069, E-ISSN 2046-2069, Vol. 7, no 4, p. 1989-2001Article in journal (Refereed) Published
Abstract [en]

¨The sorption properties toward Cu2+, Zn2+, Ni2+, Mn2+ and Co2+ ions, in synthetic and industrial waters with pH of 3.9–7.2, and the chemical stability of a titanium phosphate ion-exchanger synthesized at mild conditions and containing solely –H2PO4 groups, TiO(OH)(H2PO4)·H2O (TiP1) are investigated. TiP1 displays the highest Na+ uptake (6.3 meq. g−1) among TiP ion-exchangers and a maximum sorption capacity of ca. 1.55 mmol g−1 (i.e. 3.1 meq. g−1) for the studied ions, which is higher than the ones reported for exchangers composed predominantly of –HPO4 groups. The sorption isotherms were best described by the Temkin model while the Langmuir and the Freundlich models appear to be insufficient in describing all data. TiP1 shows fast kinetics with an equilibrium reached within 10–20 minutes and diffusion processes play a role in the initial period of sorption that is overpowered by chemisorption reactions in the overall rate controlling step. The selectivity order of the metal ions on TiP1 is determined as: Cu2+ > Zn2+ ≫ Mn2+ > Co2+, Ni2+, following the order of stability of MOH+ complexes and the corresponding activation parameters for a water molecule exchange in [M(H2O)6]2+ ions. The surface sorption data are in good correlation with the EDS data for these systems, supporting the idea of chemical sorption with no metal hydroxide precipitation. Additional sorption studies show that the quality of industrial waters after sorption reaches the EU recommendation for drinking water. The faster kinetics and the higher exchange capacity reveal that the presence of –H2PO4 groups strongly enhances the sorption properties of titanium phosphate sorbents.

Place, publisher, year, edition, pages
2017. Vol. 7, no 4, p. 1989-2001
National Category
Physical Chemistry
Research subject
Chemistry of Interfaces
Identifiers
URN: urn:nbn:se:ltu:diva-61629DOI: 10.1039/C6RA25410AISI: 000393748000028Scopus ID: 2-s2.0-85009723957OAI: oai:DiVA.org:ltu-61629DiVA, id: diva2:1068495
Note

Validerad; 2017; Nivå 2; 2017-01-30 (andbra)

Available from: 2017-01-25 Created: 2017-01-25 Last updated: 2018-08-10Bibliographically approved
In thesis
1. Titanium(IV) Phosphates: The Next Generation of Wastewater Sorbents
Open this publication in new window or tab >>Titanium(IV) Phosphates: The Next Generation of Wastewater Sorbents
2018 (English)Doctoral thesis, comprehensive summary (Other academic)
Abstract [en]

Treatment of industrial waters containing heavy metal ions is essential before being discharged into the environment. Consequently, European regulations have been established to control and limit the amount of heavy metals released. There is a need to develop efficient water treatment techniques that can remove contaminants with respect to these EU regulations.

Ion-exchange is one of the processes that is being investigated due to fast kinetics, high treatment capacity and its ability to remove heavy metal ions present in trace amounts. Titanium phosphates (TiP) are a group of inorganic ion-exchangers that have demonstrated to be particularly selective towards transition metal ions in aqueous solutions. Two types of ion-exchange units are present in TiP material, which are –HPO4 and –H2PO4 groups. Their structural characteristic is highly dependent on the synthesis conditions, which include the source of titanium, temperature, reaction time and P2O5:TiO2 ratio. Most of the studies have been performed on amorphous TiP containing a mixture of both exchange units, with –HPO4 groups being predominant; as crystalline TiP and –H2PO4 based TiP  are often obtained in difficult conditions, high temperature (up to 250 °C) and/or long reaction time (up to 30 days) and/or using autoclave. Despite promising properties depicted in batch conditions, very few data in continuous flow systems (fixed-bed columns) have been reported.

In this work, amorphous TiP composed of entirely –H2PO4 ion-exchange units (TiP1) was synthesized at mild conditions using a TiOSO4 solution and HCl/deionized water as post-synthesis treatments. The sorbent was characterized using a range of techniques (solid-state 31P MAS NMR, Raman, XRD, TGA, BET, Elemental analysis, EXAFS and XANES,) and tested in batch and column set-ups towards single and multi-component waters. The chemical formula of TiP1 was established as TiO(OH)(H2PO4)·H2O and it was found that the synthesis of TiP1 was also dependent on the TiO2/H2SO4 content in the primary titanium solution.

The material displayed a high maximum exchange capacity of ca. 6.4 meq.g-1, expressed as the sodium uptake. The actual ion-exchange capacity towards divalent metal ions was calculated to be ca. 3.4 meq.g-1 in batch condition and up to 4.1 meq.g-1 in fixed-bed column, which is to date the highest recorded for TiP materials. Kinetics of the exchange processes have been studied and the equilibrium was reached within 5-20 minutes. Modeling of the breakthrough curves was achieved using the Thomas model, indicating that the rate driving forces of the processes follow second-order reversible kinetics. The TiP1 sorbent has shown to maintain a high selectivity towards heavy metal ions in multi-component systems (including closed-mine waters) when column studies were performed. The sorption behavior of TiP1 in batch experiments correlates very well with data obtained in fixed-bed column conditions, confirming that prediction of the sorption behavior on the basis of batch data is conceivable.

Another important aspect of this work also involves the mild syntheses of crystalline α-TiP, Ti(HPO4)·H2O, and LTP (Linked Titanium Phosphate) composed of α-TiP and TiP1, where the structural characteristics of these materials were investigated using solid-state NMR, XRD, TGA, EXAFS and XANES.

Place, publisher, year, edition, pages
Luleå: Luleå University of Technology, 2018
Series
Doctoral thesis / Luleå University of Technology 1 jan 1997 → …, ISSN 1402-1544
National Category
Chemical Engineering Chemical Sciences Physical Chemistry
Research subject
Chemistry of Interfaces
Identifiers
urn:nbn:se:ltu:diva-70326 (URN)978-91-7790-178-5 (ISBN)978-91-7790-179-2 (ISBN)
Public defence
2018-09-14, E632, Luleå, 09:00 (English)
Opponent
Supervisors
Available from: 2018-08-13 Created: 2018-08-10 Last updated: 2018-08-28Bibliographically approved

Open Access in DiVA

No full text in DiVA

Other links

Publisher's full textScopus

Authority records BETA

Trublet, MyleneRusanova-Naydenova, DanielaAntzutkin, Oleg

Search in DiVA

By author/editor
Trublet, MyleneRusanova-Naydenova, DanielaAntzutkin, Oleg
By organisation
Chemical Engineering
In the same journal
RSC Advances
Physical Chemistry

Search outside of DiVA

GoogleGoogle Scholar

doi
urn-nbn

Altmetric score

doi
urn-nbn
Total: 453 hits
CiteExportLink to record
Permanent link

Direct link
Cite
Citation style
  • apa
  • harvard1
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf