期刊
SCIENCE OF THE TOTAL ENVIRONMENT
卷 421, 期 -, 页码 260-266出版社
ELSEVIER
DOI: 10.1016/j.scitotenv.2012.01.010
关键词
Fe nanoparticles; SiO2 coating; Core-shell; One-step synthesis; Cr (VI) reduction
资金
- National Natural Science Foundation of China [40971254, 41173102]
- National Youth Science Foundation of China [20907023]
A facile one-step method was developed to fabricate mono-dispersed Fe nanoparticles (Fe NPs) coated with SiO2 shell by aqueous reduction method combined with modified Stober method. Borohydride was acted not only as a reductant for iron salt but also as a catalyst for hydrolysis and polycondensation reaction of tetraethylorthosilicate (TEOS), and more importantly, there was no need to use surface primer for the generation of Fe NPs and catalyst NH4OH for SiO2. Both the Fe NPs agglomeration and SiO2 shell thickness can be controlled through the synthetic conditions. Lower potassium borohydride (KBH4) injection speed was preferable to assemble Fe NPs. The SiO2 shell thickness increased gradually with the increase of TEOS amount. Under the condition of TEOS amount of 0.1 mL and KBH4 injection speed of 5 mL/min, 25 nm single Fe NP was coated with SiO2 shell with thickness of about 9 nm. The resulting nanoporous SiO2 shell was proved to allow reactant to reach the Fe NPs while at the same time protect them from aggregation. The reactivity characterization of the SiO2-coated Fe nanoparticles (Fe@SiO2) showed that both TEOS concentration and KBH4 injection speed had effect on Cr (VI) degradation ability. The highest removal capacity of Fe@SiO2 can reach 467 mg Cr/g Fe at an initial Cr (VI) concentration of 70 mg/L under pH 6.0 +/- 0.1. XPS and TEM results showed that Cr (VI) was converted to nontoxic Cr (III) and the reaction product was completely adsorbed to SiO2 shell. (C) 2012 Elsevier B.V. All rights reserved.
作者
我是这篇论文的作者
点击您的名字以认领此论文并将其添加到您的个人资料中。
推荐
暂无数据