Amine- and thiol-bifunctionalized mesoporous silica material for immobilization of Pb and Cd: Characterization, efficiency, and mechanism

Ni Tang; Xue Liu; Meng-Ru Jia; Xin-Yao Shi; Jing-Wei Fu; Dong-Xing Guan; Lena Q Ma

doi:10.1016/j.chemosphere.2021.132771

Amine- and thiol-bifunctionalized mesoporous silica material for immobilization of Pb and Cd: Characterization, efficiency, and mechanism

Chemosphere. 2022 Mar;291(Pt 1):132771. doi: 10.1016/j.chemosphere.2021.132771. Epub 2021 Nov 2.

Authors

Ni Tang¹, Xue Liu², Meng-Ru Jia³, Xin-Yao Shi³, Jing-Wei Fu³, Dong-Xing Guan⁴, Lena Q Ma⁵

Affiliations

¹ Zhejiang Provincial Key Laboratory of Agricultural Resources and Environment, Institute of Soil and Water Resources and Environmental Science, College of Environmental and Resource Sciences, Zhejiang University, Hangzhou, 310058, China; Institute of Bio- and Geosciences, Agrosphere (IBG-3), Forschungszentrum Jülich GmbH, Wilhelm-Johnen-Straße, 52425, Jülich, Germany.
² Institute of Environment Remediation and Human Health, And College of Ecology and Environment, Southwest Forestry University, Kunming, 650224, China.
³ State Key Lab of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, Nanjing, 210023, China.
⁴ Zhejiang Provincial Key Laboratory of Agricultural Resources and Environment, Institute of Soil and Water Resources and Environmental Science, College of Environmental and Resource Sciences, Zhejiang University, Hangzhou, 310058, China. Electronic address: dxguan@zju.edu.cn.
⁵ Zhejiang Provincial Key Laboratory of Agricultural Resources and Environment, Institute of Soil and Water Resources and Environmental Science, College of Environmental and Resource Sciences, Zhejiang University, Hangzhou, 310058, China. Electronic address: lqma@zju.edu.cn.

PMID: 34740698
DOI: 10.1016/j.chemosphere.2021.132771

Abstract

In this study, a two-step functionalizing strategy by combining co-condensation with grafting procedures was employed to synthesize well-ordered Amino- and Thiol-Bifunctionalized SBA-15 (ATBS) mesoporous silica. Its physicochemical properties, performance, and mechanisms in immobilization of toxic metals Pb and Cd in water and soil were investigated. After bi-functionalization, X-ray diffractometer, transmission electron microscope, and N₂ adsorption-desorption measurements confirmed that the ATBS maintained a highly-ordered mesoporous structure, large surface area and pore volume. The elemental analysis, Fourier transform infrared spectroscopy and X-ray Photoelectron Spectroscopy (XPS) evidenced the successful incorporation of amine and thiol groups into ATBS. These structure and functional characteristics of ATBS benefited Pb and Cd sorption. Sorption isotherms of Pb and Cd were better fit with Sips and Redlich-Peterson models. Sorption kinetics suggested that Pb sorption was mainly regulated by chemical reactions, whereas both diffusion process and chemical reactions were rate-regulating steps in Cd sorption. ATBS showed the maximum sorption capacities for Pb and Cd at 120 and 38 mg g^-1, respectively. The sorption mechanisms revealed by XPS measurements suggested that Cd sorption was mainly attributed to thiol groups while Pb was efficiently bond to both thiol and amino groups. High and stable sorption efficiencies were attained in the pH range of 4-6, with a higher affinity towards Pb than Cd. Furthermore, its ability to immobilize Pb and Cd in soils was examined with an incubation experiment, which showed that ATBS reduced 30-56% of MgCl₂-extractable Pb and Cd in a contaminated soil. The synthesized sorbent via the two-step functionalizing strategy shows high sorption efficiency towards Pb and Cd, and thus it has potential application in remediating Pb and Cd contaminated water and soils.

Keywords: Bi-functionalization; Co-condensation and post-grafting; Contaminated water and soils; Mesoporous silica; Sorption mechanisms; Toxic metals.

MeSH terms

Adsorption
Amines
Cadmium*
Lead*
Silicon Dioxide
Sulfhydryl Compounds

Substances

Amines
Sulfhydryl Compounds
Cadmium
Lead
Silicon Dioxide