14 results about "Urea decomposition" patented technology

According to the preparation method, a co-sintering pretreatment step is added, potassium carbonate and urea are co-sintered at a limited temperature to form a eutectic mixture, so that a nitrogen-containing group (such as NH3) generated by urea decomposition and the potassium carbonate are synergistically embedded into a carbon skeleton precursor, and the carbon skeleton precursor is formed. Meanwhile, urea decomposition provides a nitrogen source, efficient nitrogen doping is achieved, the nitrogen doping efficiency is improved by 50% or above compared with a traditional process, continuous production can be achieved, the production efficiency is improved, continuous activation of the rotary furnace is matched with segmented temperature control, construction of a micropore-dominated hierarchical pore structure (the micropore rate is larger than 85%) is facilitated, and the specific surface area is increased; the capacitance carbon prepared by the method has the advantages of high specific surface area, reasonable pore size distribution and the like, the specific capacitance can reach 220F / g and is increased by 40% compared with that of an undoped sample, the tap density is greater than or equal to 0.4 g / cm, and the specific capacitance is increased by 30%.

A MnO2 catalyst for efficient catalytic purification of acetonitrile x This paper discusses SiO2@CeO2 catalysts and their preparation methods, belonging to the fields of catalysis chemistry and environmental chemistry. It involves using MnO... x MnO was prepared by loading it onto a SiO2@CeO2 core-shell structure support. x / SiO2@CeO2 catalyst. The preparation method is as follows: silica microspheres are prepared using a method similar to [preparation method], followed by SiO2@CeO2 preparation using a urea decomposition and precipitation method. The above steps are repeated to adjust the CeO2 loading. MnO is then impregnated using an impregnation method. x MnO was prepared by loading the sample onto the surface of a core-shell SiO2@CeO2 support and then calcining the sample in a muffle furnace at 450℃ for 3 hours. x / SiO2@CeO2 catalyst. This catalyst features a uniform dispersion of transition metal oxides on the support surface, exhibiting good catalytic purification performance for acetonitrile, and shows significant application potential in the treatment of nitrogen-containing organic pollutants.

This invention relates to a method for preparing a perlite-based adsorbent material, the resulting material, and its applications. The preparation method includes: pretreating expanded perlite particles; mixing polyaluminum chloride and urea in water to obtain an impregnation solution; subjecting the pretreated perlite to vacuum impregnation followed by atmospheric pressure soaking, allowing the impregnation solution to enter the open pores; then subjecting it to staged heating treatment to decompose the urea and release alkaline components, promoting the confined transformation and immobilization of aluminum species in the open pores and pore openings of the perlite; subsequently washing, aging, and drying to obtain the perlite-based adsorbent material. The obtained material is a granular material with a particle size of 2–6 mm, containing an aluminum-based immobilization layer on its surface and within its open pores, and can be used for the treatment of phosphorus-containing water.

The invention relates to an iodine-based positive electrode material with cobalt species confined in nitrogen-doped porous carbon for an aqueous zinc-iodine battery as well as a preparation method and application of the iodine-based positive electrode material. The iodine-based positive electrode material comprises a nitrogen-doped porous carbon carrier, a cobalt species confined in a porous carbon skeleton and an iodine active substance loaded in a pore channel. Compared with the prior art, the method has the advantages that the freeze drying and inert atmosphere pyrolysis technologies are combined, in-situ nitrogen doping on the surface of the carbon material is carried out by using the ammonia gas generated by decomposition of introduced urea, and efficient confinement anchoring of cobalt species is realized by virtue of a hierarchical pore structure derived and constructed in the pyrolysis process. The obtained positive electrode material can improve the utilization rate and the structural stability of an iodine active substance, so that the rate capability and the cycling stability of an aqueous zinc-iodine battery are improved.

The invention discloses a preparation method of a MgAl-LDH / AlOOH catalyst, which comprises the following steps: taking urea, magnesium sulfate and aluminum nitrate nonahydrate as raw materials, taking ultrapure water as a solvent, and preparing the target product MgAl-LDH / AlOOH catalyst through a one-step hydrothermal method. The invention also discloses an application of the MgAl-LDH / AlOOH catalyst in catalytic treatment of antibiotic wastewater. The MgAl-LDH / AlOOH catalyst is prepared by adopting a one-step hydrothermal method, urea, magnesium sulfate and aluminum nitrate nonahydrate are selected as raw materials, hydroxyl generated by urea decomposition in the hydrothermal process is utilized, the MgAl-LDH / AlOOH catalyst with different surface Lewis acid sites is generated by adjusting the magnesium-aluminum ratio, activation of PMS and generation of active oxygen species are regulated and controlled, and the PMS-LDH / AlOOH catalyst with different surface Lewis acid sites is obtained. The efficient degradation and safe conversion of antibiotics are improved. In addition, magnesium and aluminum serve as raw materials and are cheap and easy to obtain, and the hydrothermal method is simple in preparation process and suitable for large-scale industrial production.

A urea treatment method in which hypobromite ions are generated by adding a chlorine-based oxidizer and a bromide salt to to-be-treated water containing urea so as to break down the urea in the to-be-treated water and obtain treated water, the method including: a) determining the free residual bromine concentration and the free residual chlorine concentration in the treated water; and b) controlling the added amount of the chlorine-based oxidizer and the bromide salt on the basis of the free residual bromine concentration and the free residual chlorine concentration. The device includes a bromide salt adding means, a chlorine-based oxidizer adding means, a urea decomposition tank, a residual chlorine meter, and a control device for controlling the added amount of the chlorine-based oxidizer by the chlorine-based oxidizer adding means on the basis of the method.

The invention discloses a preparation method of a boron nitride nanotube without a template and a catalyst, and belongs to the technical field of preparation of inorganic non-metal nano materials. The method comprises the following steps: dissolving boric acid and urea in deionized water to form a precursor solution; the solution is directionally frozen under the vertical one-way temperature gradient by controlling the low temperature of the bottom of the container and the room temperature of the top of the container, and a frozen body with a vertical columnar ice crystal structure is formed; performing freeze drying to obtain a precursor with axial ordered pore channels; and finally, pyrolyzing in an inert atmosphere to obtain the boron nitride nanotube. According to the preparation method, the precursor structure is precisely regulated and controlled through a directional freezing technology, and the tube is formed through directional release guidance of urea decomposition gas, so that the technical problem that a product in a template-free catalyst-free system is easy to be a nanosheet instead of a nanotube is solved. The method is simple in process and low in cost, and the product is uniform in morphology and pure.

To provide a Fagopyrum plant having changed properties of starch.SOLUTION: A Fagopyrum plant has defects in starch synthase (SSIIa) activity. Such a Fagopyrum plant gives buckwheat flour having a urea disintegratability that is 1.5 or more times higher than that of the wild-type and a gelatinization peak temperature that is 95% or less relative to that of the wild-type.SELECTED DRAWING: None

The invention discloses a soil improvement fertilizer based on Yangtze sandy soil and a preparation method and application thereof, and the preparation method comprises the following steps: spraying and inoculating a microbial agent of urea-decomposing bacteria on the surfaces of clay particles, mixing with calcium chloride powder, and then mixing with a sodium alginate solution on a wet granulator to obtain coated clay; mixing the coated clay with the cellulose gel, and drying by using a supercritical drying method to obtain the composite aerogel fertilizer. Mixing the composite aerogel fertilizer with barnyard manure particles to obtain a soil improvement fertilizer; according to the prepared soil improvement fertilizer, the sandy soil structure is improved by promoting formation of soil aggregates, the soil improvement fertilizer has slow release and water retention effects through sodium alginate and cellulose gel, the retention time of the soil improvement fertilizer after fertilization is prolonged, the fertilizer efficiency of the soil improvement fertilizer after fertilization is improved, and the soil improvement effect is improved through the cementation effect of cellulose aerogel on soil. The soil improvement fertilizer provided by the invention is easier to settle, and has good improvement on the deep structure of sandy soil.

The application provides a light diesel tight-coupling SDPF high-efficiency flow-guiding distributed mixing device, the gas inlet end of the mixing device is connected with the gas outlet end of a DOC component, the gas outlet end of the mixing device is connected with the gas inlet end of an SDPF component, the DOC component and the SDPF component are arranged in a V shape; a nozzle base is arranged at the upper end of the mixing device, the nozzle base is used for mounting a urea nozzle, the urea nozzle is communicated with the inside of the mixing device; a flow guide plate is arranged in the inside of the mixing device, a dispersion breaking plate component is connected with the flow guide plate, and a cyclone plate is arranged at the outlet end of the mixing device. The mixing device can realize urea flow guiding and dispersion in a narrow space, improve the urea decomposition efficiency, realize the double-effect mixing effect of urea and soot, improve the uniformity of urea and soot distribution on the end surface of the SDPF, and prevent the urea from being directly injected to the bottom of the SDPF and deposited in the bottom in a compact space.

The invention belongs to the technical field of high-salt organic wastewater treatment, and particularly relates to a copper-based layered metal catalyst rich in oxygen vacancies as well as a preparation method and application of the copper-based layered metal catalyst. In order to efficiently degrade refractory organic pollutants, copper nitrate, cobalt nitrate and ferric nitrate are used as metal sources, urea is used as a structure regulating agent, and the catalyst with a layered structure is prepared through a hydrothermal method. And oxygen vacancies are introduced into crystal lattices through reducing gas generated by urea decomposition, so that the electron transfer capability of the catalyst and the persulfate activation performance are remarkably improved. In a high-salt environment, singlet oxygen (1O2) is generated by activating persulfate in a non-free radical path so as to degrade organic pollutants which are difficult to degrade.

The invention discloses a FeNiOOH / S-coated N-MWCNT / CC composite electrode as well as a preparation method and application thereof, and belongs to the technical field of food safety detection. In order to solve the problems that an existing electrochemical sensor cannot detect urea in one step and is not suitable for an ethanol-containing sample, the invention provides a preparation method of a FeNiOOH / S (at) N-MWCNTs / CC composite electrode, and the preparation method comprises the following steps: repeatedly soaking activated carbon cloth in an N-MWCNTs aqueous dispersion liquid for ultrasonic treatment to obtain an N-MWCNTs / CC electrode, then synthesizing the FeNiS (at) N-MWCNTs / CC electrode by a hydrothermal method, and finally obtaining the FeNiOOH / S (at) N-MWCNTs / CC composite electrode. And finally, synthesizing the FeNiOOH / S (at) N-MWCNTs / CC composite electrode rich in Ni (III) through a chronopotentiometric method. Urea decomposition can be catalyzed in one step, the detection time is short, the detection limit is low, the sensitivity is high, and on-site rapid detection of urea in vinasse and fermented grains can be achieved.

This invention relates to a self-healing steel slag-based solid waste cementitious material based on microbial mineralization and its preparation method, belonging to the field of building materials technology. The material, by mass parts, comprises: 100-150 parts steel slag powder, 50-100 parts blast furnace slag powder, 8-23 parts alkaline activator, 10-20 parts porous steel slag carrier loaded with urea-decomposing bacteria, 200-300 parts aggregate, and 50-70 parts mixing water. The porous steel slag carrier has a porosity of 35%-50% and an average pore size of 10-50 μm, effectively isolating the highly alkaline environment inside the cementitious material from microbial damage. When cracks appear in the material, the invading water activates dormant microorganisms within the carrier, inducing the formation of calcium carbonate precipitate to automatically fill the cracks. This invention not only achieves the resource utilization of industrial solid waste such as steel slag but also possesses continuous self-healing capabilities, with a strength recovery rate of over 90% after 28 days, a significantly reduced chloride ion diffusion coefficient, and significantly improved durability.

A diesel exhaust fluid (DEF) for reducing nitrogen oxides in diesel exhaust streams while also reducing the deposition of urea and / or urea decomposition compounds in diesel exhaust systems of engines that use DEF and require selective catalytic reduction. The DEF has about 15 wt. % to about 40 wt % urea; substantially purified water; and a compound additive that generates water in the diesel exhaust streams at temperatures greater than 100° C., interferes with competing reactions that would otherwise prevent decomposition of urea or produce undesired decomposition deposit compounds including biuret, cyanuric acid, ammelide, ammeline, and melamine, or both generates water and interferes with the competing reactions. The compound additive is preferably a sugar, acetic acid, or ammonium acetate. Also disclosed are a related method of using the DEF in a diesel exhaust system and a system including the DEF as one component.