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Objective In order to avoid the problem of equipment blockage caused by sulfur deposition in the conventional natural gas wet oxidation desulfurization process, an iron-based hollow glass beads(HGB) catalyst modified by amino-phosphate difunctional group was developed for the heterogeneous catalytic oxidation regeneration of desulfurization rich liquid in the desulfurization- regeneration step-by-step scheme. Methods Infrared spectroscopy was used to characterize the structure of the catalyst. The effects of the ratio of silane coupling agent (KH-550), roasting temperature and FeCl2, 6H2. O dosage on the regeneration of desulfurization agent and desulfurization effect were investigated by static desulfurization experiments, and the reusability performance of the catalyst was explored. Results The amino-phosphoric acid modified iron-based HGB catalyst could make the desulfurization rich liquid to be effectively regenerated and remain stable in the acidic desulfurization liquid. Under the conditions of roasting temperature of 300 C for 6 h, mass ratio of HGB to KH-550 of 18 and mass ratio of HGB to FeCl2, 6H2O of 15, the iron-based HGB catalyst prepared had the best catalytic performance, and the desulfurization performance kept basically stable after 3 times of repeated regeneration of desulfurization solution. Infrared spectroscopy analysis showed that the catalyst structure remained intact. Conclusions The amino-phosphoric acid modified iron-based HGB catalyst has a good effect on desulfurization rich liquid regeneration in the field of natural gas wet oxidation desulfurization, which provides a new choice for desulfurization rich liquid regeneration at present. [ABSTRACT FROM AUTHOR] more...

Metallurgical solid wastes, such as metallurgical dust and mud containing iron, are formed during metallurgical sintering. They are composed of complex components and are harmful to the environment. Alongwith the current metallurgical sintering process, NOx emission control is the top priority of pollution control in the steel industry. This paper proposes a new idea of preparing doped low-temperature catalysts using metallurgical dust and mud containing iron. Herein, the metallurgical iron-containing mud was modified by acid leaching, and the products were doped with Ce and Mn by the precipitation method to prepare a new type of catalyst. The prepared Mn–Ce-doped mud-based catalyst (Mn0.05Ce0.1/ADM, the ADM represents the dust and mud from acidolysis) was characterized via X-ray diffraction, nitrogen adsorption/desorption isotherm method, scanning electron microscopy, X-ray photoelectron spectroscopy, temperature-programmed desorption of ammonia, and temperature-programmed reduction of hydrogen. The results showed that Mn0.05Ce0.1/ADM achieveda NOx removal rate of >90% within a wide temperature range from 170 ℃ to 430 ℃. Moreover, itshowed excellent SO2 and H2O resistance. A microstructural analysis revealed that the strong interaction between Fe–Ce–Mn could improve the surface acidity of the catalyst, thus increasing Lewis acid sites. Further, the active components of Mn0.05Ce0.1/ADM prepared by Ce and Mn exhibited good dispersion and an excellent mesoporous structure. In particular, Mn doping could inhibit the crystallization degree on the catalyst surface, improve the dispersed state of the active components in Mn0.05Ce0.1/ADM, and help improve the catalyst SCR (Selective Catalytic Reduction) activity. Combined with theanalysis of the factors influencing the catalyst, the results showed that the Ce–Mn doped catalyst increased the Fe3+ concentration while sacrificing a certain amount of Ce3+ and high-valent Mn+, achieving the most balanced denitration activity. Mn0.05Ce0.1/ADM formed more NO active centers by increasing the Lewis acid content to promote the generation of nitrate species and NO2. Moreover, Mn doping enhanced the Fe–Ce synergy, which makes active species (Mn–Ce–Fe) easier reduction. In particular, the increase in surface oxygen mobility could significantly improve the low-temperature activity of the catalyst. The water and sulfur resistance tests of the three catalysts (Ce0.1/ADM、Mn0.05/ADM、Mn0.05Ce0.1/ADM) showed that Mn0.05Ce0.1/ADM benefited from the excellent water and sulfur resistance of Fe and Ce. The results showed that doping Ce into ADM inhibited the adsorption of H2O molecules on the active component β-MnO2 and also the reaction of SO2 molecules with the component. The results reported herein can provide theoretical references for the high-value-added utilization of metallurgical solid wastes. more...

The hot-pressing sintering experiments were carried out under the conditions of sintering temperature of 950 ℃, holding time of 5 mins and different sintering pressures. The effects of sintering pressure on the properties of three kinds of low liquid phase Fe-based pre-alloyed bit matrix and one traditional Fe-based bit matrix were compared and studied, including the hardness, the bending strength, the relative density, the diamond embedding strength of the matrix, the thermal damage of diamond. as well as the microstructure and the morphology of drill bit matrix. The results show that with the increase of sintering pressure, the indentation hardness, the bending strength and the relative density of blank matrix with low liquid phase gradually increase, but the hardness and the bending strength of traditional Fe-based pre-alloyed blank matrix increase at first and then decrease, and the relative density increases. For the matrix containing diamonds, the bending strength of low liquid phase and traditional Fe-based matrix increases with the increase of sintering pressure. When the sintering pressure is 20 MPa, the bending strength of the diamond containing matrix with low liquid phase tends to be stable, while the bending strength of the traditional Fe-based matrix containing diamond decreases slightly. At the same time, with the increase of sintering pressure, the homogeneity of the low liquid phase matrix is enhanced, but the thermal damage of the diamond is gradually aggravated. According to the analysis of the mechanical properties and the fracture morphology of the matrix, the optimal sintering pressure is 20MPa. At this time, the hardness and the bending strength of the low liquid phase Fe-based pre-alloy matrix can meet the requirements of impregnated diamond bits. more...

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Fe-based magnetic metal organic framework materials （MMOFs） with high selectivity， easy separation and multiple reuse have been widely applied in wastewater treatment. Ferrous magnetic metal organic framework materials （MMOFs） have been widely used in wastewater treatment due to their high selectivity, easy separation and multiple reuse. In this paper, the main synthesis methods of iron based MMOFs in recent years, such as mixed synthesis, in situ growth， layer by layer self-assembly, buffer encapsulation and other synthesis methods, are summarized; At the same time, the application progress of iron based MMOFs materials in the fields of catalysis, such as heterogeneous catalysis, photocatalysis and adsorption， such as the adsorption treatment of heavy metals, the adsorption treatment of organic substances and the phosphate adsorption treatment of landscape water in sewage remediation is summarized; The application characteristics of several representative MMOFs materials, such as specific surface area， pore diameter, magnetic saturation strength, treated pollutants, adsorption capacity and reuse times, were compared. Finally, the future research of iron based MMOFs materials is prospected. It is believed that the research direction of MMOFs materials in the future is to improve the stability and selectivity of MMOFs, expand the application scale of MMOFs, and develop low-cost and simpler preparation methods. [ABSTRACT FROM AUTHOR] more...

In recent years, antibiotic residues are commonly detected in a variety of water bodies, causing serious threat to water ecosystems and human health. The removal of antibiotic contaminants from water based on the advanced oxidation process of activated persulfate has become a hot research topic due to its strong oxidative properties, high selectivity, and wide pH applicability range. Iron-based bimetallic materials with low cost, high stability, and excellent catalytic performance can effectively activate persulfate, which makes up for the defects of being a single iron activator, such as easy deactivation, low efficiency, and producing secondary pollution easily. Three typical Fe-based bimetallic catalysts, namely spinel ferrite, Fe-based layered double hydroxides, and Fe-based Prussian blue analogues, were investigated and analyzed for their activation of persulfate for antibiotic degradation. Several intrinsic mechanisms of persulfate activation by Fe-based bimetallic catalysts are systematically discussed, including the generation of free radicals, singlet oxygen, and high-valent metals; the process of electron transfer; and the direct oxidation process of persulfate. Finally, the general degradation pathways of four typical antibiotics, including fluoroquinolones, sulfonamides, tetracyclines, and β -lactam antibiotics, are summarized to act as a reference for future studies on the application of Fe-based bimetallic catalysts and their modifications, derivatives, and complexes in the activating technology of persulfate. more...