Qing Chang

In recent years, environmental pollution has become more serious, especially the organic pollutants. Metal organic frameworks (MOFs) are promising materials used to degrade pollutants recently. Among them, Materials Institute Lavoisier frameworks (MILs) have been widely engaged due to their good stability and unique structural characteristics. This paper systematically analyses and summarizes the progress of MILs in degradation of organic pollutant by Fenton reaction in recent years. The MILs, especially four types of MILs, including MIL-100, MIL-101, MIL-88, and MIL-53, are first described and classified. Then, the common synthesis methods (hydrothermal synthesis, steam-assisted synthesis, and microwave-assisted synthesis) of MIL are summarized and compared. Modification and activation of MILs to obtain good degradation effect are also introduced and discussed. Finally, the applications of MILs in Fenton reaction are reviewed and their future development is prospected.

In-Situ Construction of La-B Co-Doped g-C3N4 for Highly Efficient Photocatalytic H2 Production and RhB Degradation

A covalent linkage between polyaniline (PANI) and Si nanoparticles in PANI-encapsulated Si nanocomposites was proposed and achieved by a facile and economical synthetic strategy, in which NH₂-grafted Si was first obtained via a chemical modification of Si surface and the polymerization of aniline initiated at NH₂ group surface was readily accomplished to get PANI shell. The characterizations suggested that NH₂ groups were successfully introduced onto Si surface and PANI-encapsulated Si nanocomposites with a core/shell structure were fabricated. Electrochemical tests showed that our proposed Si nanocomposites delivered a high initial specific capacity of 2135[ ]mAh/g and retained 848[ ]mAh/g after 100 charge/discharge cycles at a current density of 0.1[ ]A/g, which were superior than that of the normal PANI-encapsulated Si nanocomposites with the absence of chemical bonds in the interface. The enhanced electrochemical performance was ascribed to the surface chemical modification and the introduction of chemical bond in the interface. NH₂ group function of Si could improve the homogeneity of encapsulated PANI shell. Additionally, PANI was tightly anchored to Si nanoparticles via a covalent bond between silicon and PANI, which would greatly inhibit the separation of PANI from Si surface during the expansion/contraction of Si particles. Thus, the structural integrity was maintained. Besides, PANI layer with a unique structure promoted the transport of both electrons and lithium ions.

Iron-carbon (Fe/C) magnetic nanocubes were synthesized by direct pyrolysis of Prussian blue nanocubes under an inert gas atmosphere. They are shown to possess intrinsic peroxidase mimicking activity to catalyze the oxidation of peroxidase substrate N,N-diethyl-p-phenylenediamine sulfate salt to form a purple colored product in the presence of H₂O₂. The values for K_m and V_max are 74 μM and 46 nmol s⁻¹, respectively. Steady-state kinetic analysis also indicates that the catalysis reaction follows a ping-pong mechanism. Based on these findings, an ultrasensitive colorimetric H₂O₂ assay was worked. Absorbance (best value measured at 550 nm) increases linearly in the 10 nM to 0.2 mM H₂O₂ concentration range, and the limit of detection is 1.5 nM. The method was also applied to the quantification of glucose, which is oxidized by glucose oxidase in the coexistence of H₂O₂. The response covers the 0.1 to 500 μM glucose concentration range, and the limit of detection is 16 nM. The method was applied to the determination of H₂O₂ in rainwater samples. The glucose assay was used to analyze serum samples, and satisfactory results were obtained. Other attractive features include good chemical activity, low cost, easy storage, and high catalytic efficiency.

Graphene oxide/Fe₃O₄ (GO/Fe₃O₄) nanoparticles were synthesized by an ultrasonic-assisted reverse co-precipitation method, and then horseradish peroxidase (HRP) was covalently immobilized onto GO/Fe₃O₄ with 1-ethyl-3-(3-dimethyaminopropyl)carbodiimide (EDC) as a cross-linking agent. In order to enhance the phenol removal efficiency and prevent the inactivation of the enzyme, the polyethylene glycol with highly hydrophilicity was added in this reaction, because the adsorption capacity for the polymer by degradation was stronger than the HRP. The results showed that the immobilized enzyme removed over 95% of phenol from aqueous solution. The catalytic condition was extensively optimized among the range of pH, mass ratio of PEG/phenol as well as initial concentration of immobilized enzyme and H₂O₂. The HRP immobilized on GO/Fe₃O₄ composite could be easily separated under a magnetic field from the reaction solution and reused.