Enhancement of selective adsorption of Cr species via modification of pine biomass

DOI: 10.1016/j.scitotenv.2020.143816

Authors: Jingjing Zhao (Universitat Autònoma de Barcelona) , Roberto Boada (Universitat Autònoma de Barcelona) , Giannantonio Cibin (Diamond Light Source) , Cristina Palet (Universitat Autònoma de Barcelona)
Co-authored by industrial partner: No

Type: Journal Paper
Journal: Science Of The Total Environment

State: Published (Approved)
Published: November 2020
Diamond Proposal Number(s): 18561

Abstract: Pine biomass (Pine), pine gasification biochar (PG) and pine biomass loaded with TiO2 (Pine/TiO2) were used as sorbent materials to remove Cr(III) or Cr(VI) ions from aqueous solutions. Our results showed that Pine/TiO2 had an improved adsorption capacity respect to Pine being the adsorption capacity for Cr(VI), 12.8 mg/g, much larger than for Cr(III), 1.23 mg/g. On the other hand, PG showed much higher adsorption for Cr(III), 12.4 mg/g, than Pine/TiO2, and negligible adsorption for Cr(VI). To understand this species-dependent adsorption behavior, the adsorption mechanisms, sorbents morphology and functional sites were characterized using a multi-technique approach. The chemical state and local coordination structure of the adsorbed Cr species was studied by X-ray absorption spectroscopy (XAS). Our results show that the adsorption of Cr(III) occurred mainly through cation exchange with mineral elements in PG biochar, whereas the Cr(III) adsorption by functional groups (carboxyl and hydroxyl groups) dominate in the biomass sorbent. The enhancement of Cr(VI) adsorption in Pine/TiO2 can be explained by the presence of TiOH2+ groups present in the surface of theTiO2 microparticles. X-ray absorption spectroscopy (XAS) results reveal that Cr(VI) reduces to Cr(III) after being adsorbed by the sorbent materials.

Journal Keywords: XAS; Chromium species; adsorption mechanism; biomass/biochar; water remediation

Subject Areas: Chemistry, Environment


Instruments: B18-Core EXAFS

Added On: 02/12/2020 09:23

Discipline Tags:

Desertification & Pollution Earth Sciences & Environment Chemistry Inorganic Chemistry

Technical Tags:

Spectroscopy X-ray Absorption Spectroscopy (XAS)