We demonstrate herein the synthesis and modification of magnetic nanoparticles and its use in the immobilization of the lipase. Magnetic Fe 3 O 4 nanoparticles (MNPs) were prepared by simple co-precipitation method in aqueous medium and then subsequently modified with tetraethyl orthosilicate (TEOS) and 3-aminopropyl triethylenesilane (APTES). Silanization magnetic nanoparticles (SMNP) and amino magnetic nanomicrosphere (AMNP) were synthesized successfully. The morphology, structure, magnetic property and chemical composition of the synthetic MNP and its derivatives were characterized using transmission electron microscopy (TEM), Fourier transform infrared spectroscopy (FT-IR) analysis, X-ray diffraction, superconducting quantum interference device (SQUID) and thermogravimetric analyses (TGA). All of these three nanoparticles exhibited good crystallization performance, apparent superparamagnetism, and the saturation magnetization of MNP, SMNP, AMNP were 47.9 emu/g, 33.0 emu/g and 19.5 emu/g, respectively. The amino content was 5.66%. The AMNP was used to immobilize lipase, and the maximum adsorption capacity of the protein was 26.3 mg/g. The maximum maintained activity (88 percent) was achieved while the amount of immobilized lipase was 23.7 mg g −1. Immobilization of enzyme on the magnetic nanoparticles can facilitate the isolation of reaction products from reaction mixture and thus lowers the cost of enzyme application.

To meet the environmental requirements, kerosene, as the major component of jet fuel, is necessary for deep desulfurization. An electrochemical oxidation−extraction method was proposed to reduce the sulfur content in kerosene in this work. First, the electrochemical oxidation of kerosene was carried out in NaCl solution. Then, N-methyl-2-pyrrolidone (NMP) was used as an extractant to remove the oxidized organic sulfides. Gas chromatography−flame photometric detector (GC−FPD), gas chromatography−mass spectrometry (GC−MS), Fourier transform infrared (FTIR) spectroscopy, and ion chromatography were used to determine 1-heptyl mercaptan, one of the main organic sulfides in kerosene, and its products after electrochemical oxidation. The results showed that 1-heptyl mercaptan was effectively oxidized to diheptyl disulfide, 1-heptanesulfonyl chloride, and sulfate in electrochemical oxidation and removed after extraction. After electrochemical oxidation−extraction, the sulfur content of kerosene decreased from 180.0 to 13.2 μg/g and the desulfurization efficiency reached 92.67%. By gas chromatography−flame ionization detector (GC−FID) analysis of kerosene, the electrochemical oxidation process has no impact on the properties of kerosene. On the basis of these experimental results, a mechanism of electrochemical oxidative desulfurization was proposed.

Heterometallic Pb-Ag iodometallates [Ln(DMF)8]2Pb3Ag10I22 [Ln = Ce(1), Pr(2)] were prepared by the reactions of PbI2, AgNO3 and KI in dimethylformamide (DMF) templated by [Ln(DMF)8](3+) complexes formed in situ by stirring LnCl3 in DMF. The same reactions in the absence of AgNO3 or PbI2 afforded iodoplumbate [Pr(DMF)9]2[Pr(DMF)8]Pb11I31 (3), and iodoargentates [Ln(DMF)8]Ag6I9 [Ln = Ce(4), Pr(5)], respectively. Compounds 1 and 2 contain a ternary one-dimensional polymeric [Pb3Ag10I22](6-) anion self-assembled from five AgI4, one PbI6 and one PbI4 primary units via edge- and face-sharing. Twelve PbI6 octahedra are interlinked via sharing of common faces to generate a 1D zigzag [Pb11I31(9-)]n chain in 3, which represents a new member of iodoplumbate aggregates. In 4 and 5, three AgI4 tetrahedra connect through common edges to form the [Ag6I12](6-) building block. The [Ag6I12](6-) blocks are further interlinked by sharing common edges, resulting in the 1D [Ag6I9(3-)]n chain. Optical absorption spectra showed that the synthesized Ag-iodoplumbate and iodoplumbate have potential for being used as semiconductors. Our results show that heterometallic halometallate properties can be tuned by combining structural units with different symmetries, enabling the synthesis of specific functional materials.

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