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Catalytic urea hydrolysis by composite metal oxide catalyst towards efficient urea-based SCR process:performance evaluation and mechanism investigation

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Frontiers of Environmental Science & Engineering 2023年第5期17卷 67-80页

作者： Yuchen Li Zhen Chen Xiangyu Zhang Kun Yang Lidong Wang Junhua Li MOE Key Laboratory of Resources and Environmental Systems Optimization Department of Environmental Science and EngineeringNorth China Electric Power UniversityBeijing 102206China State Key Joint Laboratory of Environment Simulation and Pollution Control School of EnvironmentTsinghua UniversityBeijing 100084China Xi’an Thermal Power Research Institute Co. Xi’an 710032China

As a promising option to provide gaseous NH_(3) for SCR system,catalytic urea hydrolysis has aroused great attention,and improving surface area and activity of catalysis are the crucial issues to be solved for efficient urea ***,a composite metal oxide(TiO_(2)@Al_(2)O_(3))catalyst was prepared by a simple hydrothermal method,with mesoporous alumina(γ-Al_(2)O_(3))as *** results verify the mesoporous structure and submicron cluster of TiO_(2)@Al_(2)O_(3),with exposed crystal faces of(101)and(400)for TiO_(2)andγ-Al_(2)O_(3),*** electronegativity difference of Ti4+and Al3+changes the charge distribution scheme around the interface,which provides abundant acid/base sites to boost the urea ***,for an optimal proportioning with nano TiO_(2)content at 10 wt.%,the hydrolysis efficiency can reach up to 35.2%at 100℃ in 2 h,increasing by~7.1%than that of the blank experiment.^(13)C NMR spectrum measurements provide the impossible intermediate species during urea *** calculations are performed to clarify the efficient H_(2)O decomposition at the interface of TiO_(2)@Al_(2)O_(3).The result offers a favorable technology for energy-efficiency urea hydrolysis.

关键词： SCR urea hydrolysis Catalytic Water dissociation Electronegativity

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urea hydrolysis and recovery of nitrogen and phosphorous as MAP from stale human urine

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Journal of Environmental Sciences 2008年第8期20卷 1018-1024页

作者： LEE Duujong Department of Chemical Engineering "National"Taiwan UniversityTaipeiTaiwan 10617China

Laboratory-scale tests for magnesium ammonium phosphate（MAP）precipitation following urea hydrolysis of human urine were conducted using orthogonal experiment *** effects of initial pH,temperature and the volumetric ratios of stale urine to fresh urine,on urea hydrolysis in urine were studied to determine the final hydrolysis time to recover most nitrogen from separated human urine by *** a volumetric ratio of stale to fresh urine>10% and at temperature≥20℃,urea hydrolysis could be completed in two *** pH inhibited urea hydrolysis *** final pH values were all around 9.0 following urine hydrolysis,while the suspension pH might act as an indicator to detect the start and extent of urea *** 95% of ammonium nitrogen and over 85% of phosphorus from hydrolyzed urine as MAP precipitate were obtained using MgCl;·6H;O and Na;HPO;·12H;O as precipitation agents at pH 8.5,molar ratio of Mg;:NH;-N:PO;-P at（1.2-1.3）:1:1,mixing speed of 120 r/min,and precipitation time and reaction time of 3 h and 15 min,*** precipitate has a structure resembling pure MAP crystal.

关键词： urea hydrolysis human urine magnesium ammomum phosphate(MAP) ammonium-nitrogen(NH_4^+-N) phosphorus

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urea transport and hydrolysis in the rumen: A review

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Animal Nutrition 2021年第4期7卷 989-996页

作者： Samson Hailemariam Shengguo Zhao Yue He Jiaqi Wang State Key Laboratory of Animal Nutrition Institute of Animal SciencesChinese Academy of Agricultural SciencesBeijing100193China Dilla University College of Agriculture and Natural ResourceDilla P.O.Box 419Ethiopia

Inefficient dietary nitrogen(N)conversion to microbial proteins,and the subsequent use by ruminants,is a major research focus across different *** bacterial ammonia(NH3)produced due to degradation or hydrolyses of N containing compounds,such as urea,leads to an inefficiency in a host’s ability to utilize *** is a non-protein N containing compound used by ruminants as an ammonia source,obtained from feed and endogenous *** is hydrolyzed by ureases from rumen bacteria to produce NH_(3) which is used for microbial protein ***,lack of information exists regarding urea hydrolysis in ruminal bacteria,and how urea gets to hydrolysis ***,this review describes research on sites of urea hydrolysis,urea transport routes towards these sites,the role and structure of urea transporters in rumen epithelium and bacteria,the composition of ruminal ureolytic bacteria,mechanisms behind urea hydrolysis by bacterial ureases,and factors influencing urea *** review explores the current knowledge on the structure and physiological role of urea transport and ureolytic bacteria,for the regulation of urea hydrolysis and recycling in ***,underlying mechanisms of urea transportation in rumen bacteria and their physiological importance are currently unknown,and therefore future research should be directed to this subject.

关键词： urea transporter urea urea hydrolysis Ruminal bacteria

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β-Cyclodextrin-modified AuBi metallic aerogels enable efficient peroxidase mimicking for colorimetric sensing of urease-positive pathogenic bacteria

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Nano Research 2023年第7期16卷 9663-9671页

作者： Minghui Wang Peixian Wu Sha Yang Gui-long Wu Na Li Xiaofeng Tan Qinglai Yang Center for Molecular Imaging Probe Hunan Province Key Laboratory of Tumor Cellular and Molecular PathologyCancer Research InstituteHengyang Medical SchoolUniversity of South ChinaHengyang 421001China

The detection of pathogenic bacteria with improved accessibility,reduced analysis time,and increased sensitivity is of great importance for diagnosing the infected *** have attracted rising attention in the bioassay *** a model nanozyme needs the combined merit of sensible nanostructures and a large specific surface area to guarantee exceptional enzyme-mimic ***,aβ-cyclodextrin modified AuBi aerogel is prepared by a one-pot reduction *** introduction ofβ-cyclodextrin(featured with a hydrophobic cavity and hydrophilic surface)enhances the catalytic activity of AuBi aerogels by engendering host-guest complex and improving dispersity/*** on the specific urea hydrolysis,which could produce NH_(3)to raise pH by urease,the pH up-regulation would inhibit the peroxidase-mimicking performances ofβ-cyclodextrin/AuBi ***,the sensitive colorimetric detection platform for urease activity could be ***,the sensing platform can detect straightforwardly urease-positive Proteus mirabilis in urine circumstances with a wide detection range and a low limit of detection(LOD)of 4 colony-forming unit(CFU)·mL^(-1).The reproducibility,stability,and specificity of this approach are verified to be ***,as an inhibitor of urease activity,the fluoride ion could be detected by the constructed sensing platform sensitively and ***,this work provides a blueprint for designing an ideal nanozyme and paves a new roadway for detecting pathogenic bacteria.

关键词： metallic aerogels surface modification urea hydrolysis urease activity fluoride ion proteus mirabilis bacteria detection

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Reaction of Ferralsol to Acidifying Effect of Nitrogen Fertilisation

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Journal of Agricultural Chemistry and Environment 2021年第1期10卷 69-79页

作者： John Stephen Tenywa Jean Bosco Ngarukiyimana Alice Amoding Katushabe College of Agricultural and Environmental Sciences Makerere University Kampala Uganda

Background: The objective of this study was to determine the short-term effect of urea fertiliser application on soil reactions in a Ferralsol, with particular thrust on P sorption. Methods: Two experiments were conducted for this purpose: 1) a screenhouse pot experiment; and 2) a laboratory P sorption component. The pot (10 litre capacity plastic pots) experiment was conducted at the Makerere University Agricultural Research, Kabanyolo in Uganda, using a Ferralsol. The study comprised of four urea N (46% N) fertiliser treatments, namely, 0, 40, 80 and 120 kg N·ha-1, equivalent to 0, 200, 400 and 600 mg N per pot. A completely randomised design was adopted with three replicates. Urea rates were applied in 50% split doses, one at planting and the other at 19 days after seedling emergence (to simulate farmer practice). This was followed by watering to field capacity using distilled water. Soil samples were taken at three daily intervals until day fourteen;thereafter, soil sampling was at an interval of seven days. The second urea split dose was applied at 21 days followed by soil sampling at an interval of three days till day fourteen. Thereafter, soil was sampled at seven day intervals until the end of experiment. Soil samples were analysed for exchangeable H+, Al3+, NH4+and NO3- ions. The reaction trends of the concentrations of these ions and Bray 1 P were used to structure different response curves repres

关键词： urea hydrolysis Ammonification Phosphorus Sorption

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