Fe 3 O 4 @nSiO 2 @mSiO 2 was prepared successfully and characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), vibrating sample magnetometer (VSM), infrared spectrometer (FT-IR), BET surface area measurements and Zeta potential analysis techniques. The contact time, initial concentration of congo red, temperature and pH on adsorption capacity were studied. The adsorbent shows highly efficient adsorption properties, with maximum adsorption capacity of 1428 mg g − 1 for congo red, which is much higher than the other adsorbents (normally below 300 mg g − 1 ). The adsorption kinetics and isotherm of congo red on Fe 3 O 4 @nSiO 2 @mSiO 2 were systematically investigated and found that the adsorption kinetics and isotherm were well fitted by pseudo-second-order kinetic and Langmuir isotherm model.
Allura red (AR) is a water-soluble synthetic colorant often used as an additive in the food industry, but excess AR can be harmful to human health. In this work, we report the development of a new removal method for AR by using amino-functionalized microspheres with Fe 3 O 4 cores and twolayer shells composed of SiO 2 particles and perpendicularly aligned mesoporous SiO 2 (designated Fe 3 O 4 @nSiO 2 @mSiO 2 –NH 2 ). The material exhibits good dispersibility in aqueous solutions and a high saturation magnetization of 45.68 emu g − 1 , and can be magnetically separated efficiently with an external magnet. Importantly, the material has great adsorption capacity of 29.6 mg g − 1 for AR and the capacity for reuse with a simple treatment. The adsorption process is very fast and the kinetics data are consistent with a pseudo-second order model. Based on these, a rapid and efficient method for extraction and analysis of AR in water and soft drinks has been established.
Gang Qu,Yuxin Zhao,Qiaoli Zhang,Ji Na Wu,Xiao Sen Li,Yang Yang,Shi-Lei Liu
Rapid and accurate detection of hydrolyzed products of organophosphorus nerve agents (OPNAs) is an important method to confirm the use of organophosphorus nerve agents effectively. OPNAs are rapidly hydrolyzed to methyl phosphonates (MPs), which act as environmental traceability marker for OPNAs. In this study, magnetic mesoporous materials combined with real-time in-situ mass spectrometry were used to achieve high throughput detection of MPs. A novel magnetic mesoporous nanoparticles Fe3O4@nSiO2@mSiO2 were synthesized through co-condensation of tetraethyl orthosilicate (TEOS) and cetyltrimethylammonium bromide (CTAB) on the surface of nonporous silica-coated Fe3O4 at alkaline conditions, CTAB templates were removed by the reflux of ethanol (0.0375 mM ammonium nitrate) to form a mesoporous SiO2, which has a large specific surface area of 549 m2/g and an excellent magnetization strength of 59.6 emu/g. A quick cheap, effective, rugged and safe magnetic preparation method (M-QuEChERS) was established with magnetic mesoporous nanoparticles (Fe3O4@nSiO2@mSiO2) as adsorption materials for real-time direct analysis and tandem mass spectrometry (DART-MS/MS) of MPs in environmental samples. The method exhibits a good linearity (R2 > 0.992) in the range of 20.0 ng/mL-4.00 µg/mL, the limits of detections (LODs) were less than 5.00 ng/mL, the limits of quantifications (LOQs) were less than 20.0 ng/mL, the extraction recoveries were 70.2%-98.1%, with relative standard deviation (RSD) ranged from 1.97 to 10.6%. In addition, the method analysis of 70 environmental samples could be completed within 20 min. What’ more, it was applied to the 52nd OPCW environmental spiled samples analysis, the accuracy ranged from 95.2-116%, and the RSD ranged from 1.16-7.83%. The results demonstrated that Fe3O4@nSiO2@mSiO2 based on QuEChERS method can quickly and efficiently remove the matrix of environmental samples and coupled with the DART-MS/MS technique can achieve the throughput determination of MPs in environmental samples.
危险品化学品经营许可证（带存储）