TY - JOUR

T1 - Recyclable high-affinity arsenate sorbents based on porous Fe2O3/La2O2CO3 composites derived from Fe-La-C frameworks

AU - Huo, Jiang Bo

AU - Gupta, Kiran

AU - Lu, Changyong

AU - Bruun Hansen, Hans Chr

AU - Fu, Ming Lai

PY - 2020/1/20

Y1 - 2020/1/20

N2 - Efficient removal of aqueous arsenic is still a great challenge in particular for producing clean drinking water and for waste water treatment. To this end, a novel magnetic porous Fe-La composite, comprising La2O2CO3 and Fe2O3, was fabricated via a self-sacrificing template method based on bimetallic (Fe, La)-MOFs calcined at 550 °C. Batch adsorption results demonstrated that Fe-LaXY (X and Y represent the feeding mole ratio of Fe and La precursors) exhibited a maximum adsorption capacity of As(V) (241, 251 and 410 mg g−1 for Fe-La51, Fe-La21 and Fe-La11, respectively), and they also showed satisfactory adsorption kinetics, which can be ascribed to a strong coordination between La and arsenate species. Coexisting sorbates including carbonate, silicate, sulfate, and humic acid had a slight influence on adsorption performance of arsenate, while phosphate isostructural to arsenate gave severe interference. More importantly, the Fe-La11 could be easily separated from water due to its magnetism (7.0 emu g−1), and it also exhibited excellent recyclability (above 80% of removal efficiency at the fifth cycle) as well as stability in terms of release of Fe and La ions (< 0.5 mg L−1 at pH 4.0–10.0). Based on results from X-ray photoelectron spectroscopy (XPS), Powder X-ray diffraction (PXRD) and Raman spectroscopy, it is demonstrated that ligand exchange of surface hydroxyl groups and the formation of inner-sphere surface complexes are main responsible for the As(V) removal mechanism. Combining the magnetic properties, the absorption properties and the recyclability make Fe-LaXY derived from bimetallic MOFs promising sorbents for arsenate removal.

AB - Efficient removal of aqueous arsenic is still a great challenge in particular for producing clean drinking water and for waste water treatment. To this end, a novel magnetic porous Fe-La composite, comprising La2O2CO3 and Fe2O3, was fabricated via a self-sacrificing template method based on bimetallic (Fe, La)-MOFs calcined at 550 °C. Batch adsorption results demonstrated that Fe-LaXY (X and Y represent the feeding mole ratio of Fe and La precursors) exhibited a maximum adsorption capacity of As(V) (241, 251 and 410 mg g−1 for Fe-La51, Fe-La21 and Fe-La11, respectively), and they also showed satisfactory adsorption kinetics, which can be ascribed to a strong coordination between La and arsenate species. Coexisting sorbates including carbonate, silicate, sulfate, and humic acid had a slight influence on adsorption performance of arsenate, while phosphate isostructural to arsenate gave severe interference. More importantly, the Fe-La11 could be easily separated from water due to its magnetism (7.0 emu g−1), and it also exhibited excellent recyclability (above 80% of removal efficiency at the fifth cycle) as well as stability in terms of release of Fe and La ions (< 0.5 mg L−1 at pH 4.0–10.0). Based on results from X-ray photoelectron spectroscopy (XPS), Powder X-ray diffraction (PXRD) and Raman spectroscopy, it is demonstrated that ligand exchange of surface hydroxyl groups and the formation of inner-sphere surface complexes are main responsible for the As(V) removal mechanism. Combining the magnetic properties, the absorption properties and the recyclability make Fe-LaXY derived from bimetallic MOFs promising sorbents for arsenate removal.

KW - Adsorbent

KW - Arsenic

KW - Bimetallic MOFs

KW - Fe-La composite

KW - Magnetic

U2 - 10.1016/j.colsurfa.2019.124018

DO - 10.1016/j.colsurfa.2019.124018

M3 - Journal article

AN - SCOPUS:85073118366

VL - 585

SP - 1

EP - 10

JO - Colloids and Surfaces A: Physicochemical and Engineering Aspects

JF - Colloids and Surfaces A: Physicochemical and Engineering Aspects

SN - 0927-7757

M1 - 124018

ER -