Pb, Zn and Cu were determined in 35 Preserved Egg (PE) samples, 25 Salted Egg (SE) samples and 40 Egg Preserved in Rice Wine (EPRW) samples collected from Jiangxi province by ICP-MS. The corresponding health risk for consumers was assessed by the target hazard quotients (THQ) and hazard index (HI). Average Pb, Zn and Cu content in all samples was 0.125 mg/kg, 10.939 mg/kg and 2.094 mg/kg, respectively. Average Pb content in PE was significantly higher than in SE and EPRW. THQ and HI values were less than 1, indicating that intake of heavy metals from PE, SE and EPRW will not pose a significant hazard risk to humans. However, more attention should be paid to control the ingestion by PE, which is the main source of Pb, Zn and Cu for consumers among these three egg products.
Photolysis of N-benzoyl-S,S-diphenylsulfilimine or N-benzoyl dibenzothiophene sulfilimine produces PhNCO and also benzoylnitrene. Direct observation of the triplet nitrene, energetic differences between the singlet and triplet state of the nitrene, and oxygen quenching experiments suggest that the triplet nitrene derives from the triplet excited state of the sulfilimine precursors, rather than through equilibration of nearby singlet and triplet states of the nitrene itself. In acetonitrile, the formation of an ylide, followed by cyclization to the corresponding oxadiazole, is the predominant nitrene chemistry, occurring on the time scale of a few microseconds and few tens of microseconds, respectively. Trapping experiments with substrates such as cis-4-octene suggest that reactivity of the nitrene is mainly through the singlet channel, despite a fairly small energy gap between the singlet ground state and the triplet.
Pure nanometals have poor adsorption capacity due to their agglomeration in aqueous solution. In this study, biochar (Bc) prepared by the pyrolysis of rosin and coated on bentonite (Bt) was designed to support and disperse nanoscale α-Fe2O3 (Bt/Bc/α-Fe2O3). The generation of α-Fe2O3 nanoparticles and the pyrolysis of rosin on the surface of Bt were accomplished in a one-step heating route. Fourier transform infrared spectroscopy (FTIR) and X-ray diffraction (XRD) analysis confirmed the pyrolysis of rosin into biochar and the production of α-Fe2O3 in the composite. Besides, scanning electron microscopy (SEM) images showed good dispersion of α-Fe2O3 nanoparticles on the biochar surface. This adsorbent demonstrated fast Cr(VI) adsorption property with a Cr(VI) removal efficiency of 95% within one minute and high Cr(VI) adsorption capacity with a maximum Cr(VI) removal up to 81.7 mg g−1 based on the Langmuir model. The remarkable improvement of Cr(VI) adsorption on Bt/Bc/α-Fe2O3 was attributed to the good dispersion of α-Fe2O3 nanoparticles by the biochar network in comparison with other similar adsorbents. In addition, Bt/Bc/α-Fe2O3 maintained high Cr(VI) adsorption capacity under both acidic and basic conditions. This indicated that Bt/Bc/α-Fe2O3 can be used for fast Cr(VI) removal from wastewater or emergent Cr(VI) leakage due to its facile preparation and high efficiency in a wide range of pH.
Abstract Dyes and heavy metals pollute the environment. Biochar-based hydrogel is an excellent adsorbent, but the competitive adsorption mechanism associated with the removal of pollutants using biochar is yet to be understood in detail. Biochar was prepared following the process of high-temperature lysis of marine green tide ( Enteromorpha prolifera ). The prepared biochar was cross-linked with water-soluble chitosan and compounded with nano-Fe 3 O 4 to synthesize magnetically-modified Enteromorpha prolifera -based biochar hydrogel (MM-EBC-HD). The competitive removal performance of the hydrogel was studied, and the pollutant removal mechanism was analyzed against a binary system consisting of common environmental pollutants (methyl orange [MO] and hexavalent chromium [Cr (VI)]. The physical and chemical properties of the composites were studied before and after contaminant removal, and the associated pollutant removal mechanisms were analyzed by SEM, EDS, FTIR, XRD, and XPS techniques. The effects of pH, temperature and initial pollutant concentration on the adsorption performance of the materials were examined. The maximum adsorption of MO on MM-EBC-HD was 71.18 mg g −1 , and adsorption equilibrium was attained at approximately 60 min. Electrostatic forces, hydrophobic bonds, and hydrogen bonds were exploited for MO adsorption. And the maximum adsorption amount of Cr (VI) was recorded to be 115.41 mg g −1 , and equilibrium was attained in approximately 10 min. Electrostatic and ion exchange effects were exploited to adsorb Cr (VI) efficiently. The MO and Cr (VI) adsorption processes could be explained by the second-order kinetic model and Langmuir adsorption isotherms, respectively. The adsorption performance recorded for the binary adsorption system was poorer than that recorded for the single adsorption system for both pollutants. MO and Cr (VI) adsorption decreased from 74.88% to 47.65% and from 62.33% to 42.4%, respectively. Competition between MO and Cr (VI) in the dual system can be attributed to the presence of amino and hydroxyl groups. The MO–Cr complex, which was more compact in structure than a single contaminant, was formed, allowing few reactive groups to be exposed to the surface of the hydrogel. Additionally, MM-EBC-HD nanocomposites presented a recovery rate of 87% after 5 cycles and thus could be used to avoid adsorbents-caused environmental hazards. Graphical Abstract
In this study,imidazole-2-carboxylic acid butyl ester( ICABE) was ultrasonically extracted from Aconitum pendulum Busch. Three influencing parameters,namely ratio of solvent to solid,extraction time and extraction temperature,were optimized using response surface methodology( RSM). The optimum conditions were as follows: the ratio of solvent to solid was 23 mL /g,extraction temperature was 58 ℃ and extraction time was 51 min. The predicted value of extraction rate of ICABE was 0. 081% under the optimum conditions,and the experimental value was 0. 079%. The validation test showed that the ultrasonic-assisted extraction process of ICABE was successfully optimized by RSM.
Traditional image acquisition system has the faults of complex, bulky and inconvenient to carry. The embedded image processing system integrates all the functions of image capturing, displaying and processing as well as takes the advantages of small size and low power consumption. According to the need of modern security monitoring system, a kind of image acquisition system based on ARM and Linux was designed. The system takes S3C2410(ARM9) as the core to construct the image acquisition and processing system with USB camera, monitor and memory, and builds necessary peripherals and communication interfaces to complete the design of the hardware platform. Then drivers were composed and embedded Linux operating system was transplanted, eventually the functions of image data collection, display and storage were realized. The test results show that images acquisition were clear and the system turns out to meet the requirement.
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