Nitrogen rich core-shell magnetic mesoporous silica as an effective adsorbent for removal of silver nanoparticles from water

Xiaoye Zhang; Yao Zhang; Xiaodan Zhang; Siqi Li; Yuming Huang

doi:10.1016/j.jhazmat.2017.04.053

Nitrogen rich core-shell magnetic mesoporous silica as an effective adsorbent for removal of silver nanoparticles from water

J Hazard Mater. 2017 Sep 5:337:1-9. doi: 10.1016/j.jhazmat.2017.04.053. Epub 2017 May 1.

Authors

Xiaoye Zhang¹, Yao Zhang¹, Xiaodan Zhang¹, Siqi Li¹, Yuming Huang²

Affiliations

¹ Key Laboratory of Eco-environments in Three Gorges Reservoir Region (Ministry of Education), College of Chemistry and Chemical Engineering, Southwest University, Chongqing 400715, China.
² Key Laboratory of Eco-environments in Three Gorges Reservoir Region (Ministry of Education), College of Chemistry and Chemical Engineering, Southwest University, Chongqing 400715, China. Electronic address: ymhuang@swu.edu.cn.

PMID: 28501638
DOI: 10.1016/j.jhazmat.2017.04.053

Abstract

The production and increasing use of silver nanoparticles (AgNPs) obviously results in their release into the environment, leading to a risk to the environment due to their toxic effects. Thus, the removal of AgNPs from water is highly needed. Here, we demonstrate that nitrogen rich (∼10% nitrogen content) core-shell magnetic mesoporous silica is a promising adsorbent for the removal of AgNPs. For this, the poly(ethylenimine) functionalized core-shell magnetic mesoporous silica composites (Fe₃O₄@SiO₂-PEI) were prepared, and characterized by TEM, FT-IR, XRD, TG and N₂ adsorption-desorption. The removal of AgNPs by Fe₃O₄@SiO₂-PEI as a function of contact time, concentration of AgNPs, solution pH and ionic strength were studied. The adsorption kinetic data could be described by the pseudo-second-order rate model. Both Langmuir and Freundlich models fitted the adsorption data well. The adsorption capacity for AgNPs is 909.1mg/g, which is 5-181 times higher than that of the previously reported adsorbents for AgNPs. Interestingly, the silver adsorbed onto Fe₃O₄@SiO₂-PEI exhibits highly catalytic activity for 4-nitropheol (4-NP) reduction with a rate constant of 0.072min^-1, which is much higher than those by other AgNPs reported before. The silver-loaded Fe₃O₄@SiO₂-PEI promises good recyclability for at least five cycles, showing great potential in practical applications.

Keywords: Adsorption; Nitrogen rich core–shell magnetic mesoporous silica; Poly(ethylenimine); Removal; Silver nanoparticle.