RSC Advances
·
2016
·Vol. 6
·期 76
·72479-72486
·
IF 3.289
Chunrong Ren,Xingeng Ding,Huiqin Fu,Cheng Meng,Wenqi Li,Hui Yang
Amino-functionalized nanocomposites with a magnetic CoFe2O4 core and an amorphous SiO2 shell have been designed and synthesized. The core–shell structure was characterized by SEM, EDS, TEM, FTIR and XPS. CoFe2O4@SiO2–NH2 with a high saturated magnetization (28.09 emu g−1) can be easily separated under a moderate external magnetic field within one minute. In addition, the adsorption capacity of the CoFe2O4@SiO2–NH2 for Cu(II), Cd(II) and Mn(II) was 170.829, 144.948 and 110.803 mg g−1, respectively. The removal efficiency was increased from 12 to 85% with an increase in the pH from 4 to 6.5. The adsorbent can be recycled for at least four cycles with a feasible removal efficiency (85.41%). The adsorption process was fitted by pseudo-second-order kinetics and a Langmuir isotherm model. Based on the data of the present investigation, CoFe2O4@SiO2–NH2 could find potential applications in heavy metal ion wastewater treatment.
研究领域:
材料科学
·
环境工程
·
纳米技术
✓ 已验证
产品关联
DOI
高影响因子
Nanomaterials
·
2019
·Vol. 9
·期 3
·455
·
IF 4.034
Yuhao Zhao,Kai Xia,Zhenzong Zhang,Ziming Zhu,Yongfu Guo,Zan Qu
In order to avoid using toxic or harmful operational conditions, shorten synthesis time, enhance adsorption capacity, and reduce operational cost, a novel magnetic nano-adsorbent of CoFe2O4@SiO2with core–shell structure was successfully functionalized with polypyrrole (Ppy). The physical and chemical properties of CoFe2O4@SiO2-Ppy are examined by various means. The as-prepared CoFe2O4@SiO2-Ppy nanomaterial was used to adsorb Hg2+from water. During the process, some key effect factors were studied. The adsorption process of Hg2+onto CoFe2O4@SiO2-Ppy was consistent with the pseudo-second-order kinetic and Langmuir models. The Langmuir capacity reached 680.2 mg/g, exceeding those of many adsorbents. The as-prepared material had excellent regeneration ability, dispersibility, and stability. The fitting of kinetics, isotherms, and thermodynamics indicated the removal was endothermic and spontaneous, and involved some chemical reactions. The application evaluation of electroplating wastewater also shows that CoFe2O4@SiO2-Ppy is an excellent adsorbent for Hg2+ions from water.Keywords:adsorbent;polypyrrole;heavy metal;mercury;modification
研究领域:
环境科学
·
材料科学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
OPTICAL MATERIALS
·
2021
·
IF 3.08
Yanlin Li,Xuegang Lu,Sen Yang
Fluorescence detection is actually available on measuring substances by using metal-based micro or nano structures which produce a great surface enhanced fluorescence (SEF) effect in quick response to endless diseases and environmental problems recently. However, traditional SEF substrates are expensive, as well as inefficient due to single-component detection mode. Therefore, SEF substrates with controllable fluorescence enhancement formed by magnetically responsive CoFe 2 O 4 @SiO 2 @Ag colloidal photonic crystals were designed in this work. The fluorescence spectra were enhanced selectively at different wavelength owing to photonic band gap adjusted by magnetic field so as to detect Rhodamine B (RB) and fluorescein isothiocyanate (FITC) which had quite different fluorescence emission wavelength. As-prepared composites showed that the highest enhancement factors were 12.6 and 17.6 fold for RB and FITC, respectively, only when the tunable photonic band gap matched with the fluorescence emission wavelength of fluorescent molecules. The mechanism of significant fluorescence enhancement was explained in detail. The CoFe 2 O 4 @SiO 2 @Ag substrates were confirmed to be reliable, sensitive and reproducible in detecting a variety of fluorescent molecules. The results played an important role in effective fluorescence detection, such as chemical analysis, biological sensing and cell imaging .
研究领域:
材料科学
·
生物医学检测
·
光学
✓ 已验证
产品关联
DOI
高影响因子
Nanomaterials
·
2019
·Vol. 9
·期 11
·1532
·
IF 4.034
Kai Xia,Yongfu Guo,Qijun Shao,Qu Zan,Renbi Bai
In order to reduce the difficulty and risk of operation, decrease the preparation time and improve the adsorption performance of magnetic nano-silicon adsorbent with core-shell structure, a carboxylated CoFe2O4@SiO2was prepared by EDTA-functionalized method using a safe, mild and simple hydrothermal method. The results show that the prepared material of CoFe2O4@SiO2-EDTA has a maximum adsorption capacity of 103.3 mg/g for mercury ions (Hg(II)) at pH = 7. The adsorption process of Hg(II) is a chemical reaction involving chelation and single-layer adsorption, and follows the pseudo-second-order kinetic and Langmuir adsorption isotherm models. Moreover, the removal of Hg(II) is a spontaneous and exothermic reaction. The material characterization, before and after adsorption, shows that CoFe2O4@SiO2-EDTA has excellent recyclability, hydrothermal stability and fully biodegradable properties. To summarize, it is a potential adsorption material for removing heavy metals from aqueous solutions in practical applications.Keywords:magnetic material;adsorption;heavy metal;mercury;EDTA functionalization
研究领域:
环境科学
·
材料科学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
RSC Advances
·
2017
·Vol. 7
·期 12
·6911-6921
·
IF 3.108
Chunrong Ren,Xingeng Ding,Huiqin Fu,Wenqi Li,Huating Wu,Hui Yang
To remove heavy metals from aqueous solutions, amino-functionalized superparamagnetic CoFe2O4@SiO2 (CoFe2O4@SiO2–NH2) core–shell nanospheres were designed and constructed. In particular, well-defined CoFe2O4 nanoparticles (NPs) were synthesized by reverse co-precipitation. The shell of the CoFe2O4 NPs was composed of amorphous silica (SiO2), which had a thickness of ∼35 nm. Monodisperse CoFe2O4@SiO2 nanospheres grafted with more amino groups had a greater adsorption capacity and higher removal efficiency for heavy metal ions (Cd(II): 199.9 mg g−1, 99.96%; Cu(II): 177.8 mg g−1, 88.05%; Pb(II): 181.6 mg g−1, 90.79%). The effects of the pH, initial concentrations, reaction temperature and time on the adsorption of heavy metal ions by CoFe2O4@SiO2–NH2 were analyzed systematically. The adsorption process on the nanospheres was well described by the Langmuir model. The adsorption kinetics can be best fitted by the pseudo-second-order kinetics model. Analysis of a thermodynamic study of Cu(II) showed that the process of adsorption is spontaneous and endothermic in nature. Owing to the superparamagnetic properties with a high saturation magnetization value (32.92 emu g−1) of CoFe2O4@SiO2–NH2, the metal-loaded nanospheres can be quickly removed from an aqueous solution (30 s) by magnetic separation. Moreover, the nanospheres exhibited good reusability for up to five cycles. The results confirm that the monodisperse amino-functionalized CoFe2O4@SiO2 magnetic nanospheres could be a potential adsorbent for the effective and regenerable removal of heavy metals from aqueous solutions.
研究领域:
材料科学
·
环境科学
✓ 已验证
产品关联
DOI
高影响因子
CERAMICS INTERNATIONAL
·
2023
·
IF 5.2
Chunhao Wan,Rong Yan,Shansheng Yu,Xiaoyi Wang,Hongwei Tian
The development of functional materials with dual characteristics of microwave absorption and low infrared emissivity is vital for protection against magnetic-wave contamination. Currently, both microwave protection and infrared protection technologies are developing rapidly, but simultaneous integration of both has not been extensively investigated. Herein, a new ternary core-shell CoFe 2 O 4 @SiO 2 @ZAO composite dual-functional material was designed and fabricated. The process consisted of coating CoFe 2 O 4 microspheres with ZAO based on SiO 2 middle layer prepared through hydrolysis and sol-gel methods. The introduction of ZAO and SiO 2 was found conducive to dielectric loss and impedance matching, thereby improving wave absorption. The nano-flower ZAO coating provided low infrared emissivity with a lamellar structure and high carrier concentration in the resulting ternary structure. The rise in ZAO content first enhanced the wave absorption of CoFe 2 O 4 @SiO 2 @ZAO and then decreased while the infrared emissivity declined. Among prepared samples, CoFe 2 O 4 @SiO 2 @ZAO exhibited a minimum reflection loss (RL min ) of −59.31 dB at 10.96 GHz, conducive to effective absorption bandwidth (EAB) of 4 GHz at 2 mm thickness with an infrared emissivity of 0.71 in 8–14 μm waveband. In sum, the novel CoFe 2 O 4 @SiO 2 @ZAO core-shell structure showed attractive properties in terms of compatibility of wave absorption and infrared emissivity, promising for future syntheses of dual-functional materials with improved performance.
研究领域:
材料科学
·
电磁材料
·
复合材料
✓ 已验证
产品关联
DOI
高影响因子
危险品化学品经营许可证（带存储）