Study on Release Properties of Slow Release Urea Coated by Industrial Lignin

This study aimed to investigate the release properties of slow release ure- a coated by industrial lignin and the influences of temperature, pH and post-ripening period on the release of nutrients in coated urea. According to the experimental results, the release of nutrients in coated fertilizers showed an S-shaped curve; on the 28th d, the nutrient release rate reached 73.77%; the differential solubility was 1.83%, and the theoretical release period was 50.25 d. The release of nutrients was significantly influenced by temperature. As the incubation temperature rose from 25 to 40 ℃, preliminary solubility increased from 8.03% to 16.24%; differential solubility increased from 1.83% to 1.88%; theoretical release period was reduced from 51.25 d to 45.55 d. The release of nutrients was promoted by H＋ and OH-. After they were placed at room temperature within 30 d, coated fertilizers exhibited the optimal release properties.

A Comparative Study of Nitrogen Loss after Application of Biochar Coated Urea and Common Urea in Vegetable Soil at Chaihe Catchment of Dianchi Lake

[Objective] This study aimed to provide the basis for scientific and rea- sonable application of nitrogen fertilizer and control Of agricultural non-point source pollution in vegetable-growing area at Chaihe catchment of Dianchi Lake. [Method] A pot experiment was carried out to compare the loss of nitrogen via ammonia volatilization and nitrogen leaching after application of biochar coated urea （BCU） and common urea （Urea） with different nitrogen rates （0 mg N/kg soil, 400 mg N/kg soil, 320 mg N/kg soil and 280 mg N/kg soil）. [Result] The results indicated that the amount of nitrogen loss was proportional to nitrogen applied rate. Leaching nitrogen was higher than ammonia volatilization. Compare with Urea treatments, ammonia volatilization and nitrogen leaching losses were significantly lower in BCU treatments at the same nitrogen application rate. At the nitrogen application rate of 320 and 280 mg N/kg soil, nitrogen loss, ammonia volatilization and leaching nitrogen was 43.5%-45.5%, 3.7%-21.7% and 49.8%-52.1% lower in BCU treatments than in Ure- a treatments, respectively. [Conclusion] The application of BCU could minimize nitro- gen loss by reducing nitrate leaching loss. It can be concluded that the low nitrogen application rate combined with BCU have a practical influence on controlling the risk of nitrogen pollution in Dianchi Lake.

Study on the Nitrogen Release Law of Bamboo Charcoal-coated Urea and Its Biological Utilization Effects

[Objective] The study about the nitrogen releasing law of bamboo-charcoal coated urea and the biologic utilization effect was to find the coated urea with high efficiency,low price and simple production technology.[Method]Two kinds of bamboo-charcoal coated urea(BCCU)with different coating thickness were made by using bamboo-charcoal and macromolecule polymer as coating material.The experiments of soil eluviate,ammonia volatilization in corn field and potted plant of corn were conducted to study the nitrogen releasing law and the biologic utilization effect of self-made BCCU.[Result]The BCCU showed some slow-release capability and their accumulated nitrogen releasing rates in 29 d were 9.93%-16.27% lower than that of normal urea.Compared with the normal urea,the volatilization rate of ammonia in BCCU reduced to 16.66%-31.8%,the biomass of corn and nitrogen utilization rate increased by 12.8%-24.1% and 10.5%-16.99%,respectively.[Conclusion]Bamboo-charcoal in coated urea not only had some slow-release capability,but also had some adsorbability,which would reduce the eluviation and volatilization of nitrogen and protect environment from N pollution.

Nitrogen Cycling and Losses Under Rice-Wheat Rotations with Coated Urea and Urea in the Taihu Lake Region

A lysimeter experiment with undisturbed soil profiles was carried out to study nitrogen cycling and losses in a paddy soll with applications of coated urea and urea under a rice-wheat rotation system in the Taihu Lake region from 2001 to 2003. Treatments for rice and wheat included urea at conventional, 300 （rice） and 250 （wheat） kg N ha^-1, and reduced levels, 150 （rice） and 125 （wheat） kg N ha^-1, coated urea at two levels, 100 （rice） and 75 （wheat） kg N ha^-1, and 150 （rice） and 125 （wheat） kg N ha^-1, and a control with no nitrogen arranged in a completely randomized design. The results under two rice-wheat rotations showed that N losses through both NH3 volatilization and runoff in the coated urea treatments were much lower than those in the urea treatments. In the urea treatments N runoff losses were significantly （P 〈 0.001） positively correlated （r = 0.851） with applied N. N concentration in surface water increased rapidly to maximum two days after urea application and then decreased quickly. However, if there was no heavy rain within five days of fertilizer application, the likelihood of N loss by runoff was not high. As the treatments showed little difference in N loss via percolation, nitrate N in the groundwater of the paddy fields was not directly related to N leaching. The total yield of the two rice-wheat rotations in the treatment of coated urea at 50% conventional level was higher than that in the treatment of urea at the conventional level. Thus, coated urea was more favorable to rice production and environmental protection than urea.

Synthesis and Performance of Polyurethane Coated Urea as Slow/controlled Release Fertilizer

Polyurethane coated urea slow/controlled release fertilizer was prepared based on urea granules, isocyanate, polyols and paraffin. Isocyanate reacted with polyols to synthesize the polyurethane skin layer on urea granules surface. Paraffin serves as a lubricant during syntheses of polyurethane skin layers. The structure and nutrient release characteristics of the polyurethane skin layers were investigated by FTIR, SEM and TG. Urea nitrogen slow-release behavior of the polyurethane coated urea was tested. The experimental results indicated that compact and dense polyurethane skin layers with a thickness of 10-15 lam were formed on urea surface, the urea nitrogen slow-release time can reach 40-50 days. Paraffin proves to play a key role in inhibiting water to penetrate into urea, but excessive addition would decrease the polyurethane crosslinking density.

The Production of Organic-Inorganic Compound Film-Coated Urea and the Characteristics of Its Nutrient Release

The effect of different concentrations of natural macromolecular compound on the characteristics of nutrient release in the membrane materials of organic-inorganic compound film-coated urea was discussed, and the optimal concentrations for better nutrient release was proposed. The characteristics of nutrient release of film-coated urea were evaluated by soil column leaching experiment. Organic-inorganic compound film-coated urea showed good characteristics of nutrient release, which could be well simulated by Logistic curve. The two parameters in this curve, a and r, can be used to present nutrient release of film-coated urea, and followed the order of B 〉 C 〉 A and C 〈 B 〈 A, respectively, indicating that the release was stronger with the increasing concentration of natural macromolecular compound in the membrane, which implied better controllability of nutrient release. The concentration of 5% of natural macromolecular compound showed better characteristic of nutrient release and can be utilized as a membrane material combined with inorganic mineral powders to develop film-coated slow-release fertilizer.

Release Kinetics of Urea from Polymer Coated Urea and Its Relationship with Coating Penetrability

Four kinds of polymer coated urea(PCU)were put in distilled water at 30℃ to determine the variation of coating penetrability and give a precise description of the urea release kinetics. The urea release from PCU could be divided into four stages: lag stage, swell stage, steady stage and decay stage. The release rate coefficient K, a measure of coating penetrability, was linearly increased at swell stage, but almost not variable at steady stage. At decay stage, the relation of X to time t could be described by the equation K= mtn-1where m and n are the coefficients). When n>1, the coating penetrability was gradually increased, and the urea release from PCU was accelerated; when n=1, the coating penetrability was steady, and the urea release from PCU obeyed the first-order kinetics; and when n<1.the coating penetrability was gradually decreased, and the urea release from PCU was delayed, resulting in a significant 'tailing effect'.

Kinetic of Adsorption of Urea Nitrogen onto Chitosan Coated Dialdehyde Cellulose under Catalysis of Immobilized Urease

The adsorption of urea nitrogen onto chitosan coated dialdehyde cellulose (CDAC) under catalysis of immobilized urease in gelatin membrane (IE) was studied in batch system. The pseudo first-order and second-order kinetic models were used to describe the kinetic data, and the rate constants were evaluated. The experimental data fitted well to the second-order kinetic model.

Study on Membrane Microstructures and Characteristics of Infrared Spectra and Nitrogen Release of Solid-Liquid Reaction Coated Urea

The membrane microstructures and the mechanism of two coated ureas formed through solid- liquid reaction were observed by scanning electron microscope and infrared spectra, the relation of the structural characteristics with the nitrogen release feature was also discussed by combining with nitrogen dissolution in water. The results showed that the membranes were made of solid particles tightly connected to each other and were piled up layer by layer through liquid glue. Porosity and aperture of membrane were determined by compactness of piled layers and the particles in a single layer and also related to the characteristics of coating materials. Research of the infrared spectra of membrane, made of a solid powder and a liquid glue, proved that O-H on the solid surface was bonded with the double bond of the liquid glue, thus forming membrane and keeping it stable. It was found that the two coated ureas showed obvious differences in nitrogen releasing due to their membrane structures, the porosity and aperture of membrane were the critical factors for nitrogen releasing.

Reducing Nitrogen Loss in Subsurface Tile Drainage Water with Managed Drainage and Polymer-Coated Urea in a River Bottom Soil

Poorly-drained, river bottom soils can be high corn (Zea mays L.) yielding environments, but saturated soil conditions often reduce corn yields. Wabash soils located in river bottoms in Northeast Missouri have not been traditionally tile drained due to high clay content which requires narrow tile drain spacings. Increased land prices in the region have increased interest in tile draining poorly-drained bottom land soils to increase corn yields which could have a deleterious effect on water quality. The objectives of the three-year study were to determine whether use of managed subsurface drainage (MD) in combination with a controlled release N fertilizer could reduce the annual amount of NO3--N loss through tile drainage water compared to free subsurface drainage (FD) with a non-coated urea application. Annual NO3--N loss through tile drainage water with FD ranged from 28.3 to 90.1 kg·N·ha-1. Nitrogen fertilizer source did not affect NO3--N loss through tile drainage water, which was likely due to limited corn uptake over the three-year study due to adverse weather conditions. Averaged over three years, MD reduced tile water drained 52% and NO3--N loss 29% compared to FD. Reduction in NO3--N loss through tile drainage water with MD compared to FD was due to reduced tile flow during the non-cropping period. Annual flow-weighted mean concentration of NO3--N in the tile water was 5.8 mg·N·L-1 with FD and 8.1 mg·N·L-1 with MD. Tile draining river bottom soils at this location for continuous corn production may not pose a health risk over the evaluated duration.

Mineral Coated Fertilizer Effect on Nitrogen-Use Efficiency and Yield of Wheat

A field experiment with winter wheat （Triticum aestivurn L.） was conducted on a silt loam calcaric endorusti-ustic Cambosols derived from the Yellow River alluvial deposits in Henan, China, from 2001 to 2002 to evaluate N recovery and agronomic performance of different mineral coated fertilizers （MiCFs） compared to normal urea used in wheat cropping systems under field conditions. Five treatments, including CK （check, no N fertilizer）, urea and three different MiCFs at an equivalent N application rate were established in a randomized complete block design. N release from MiCFs in soil was more synchronous with the N requirement of wheat throughout the growth stages than that from urea, with grain yield of the MiCF treatments significantly higher （P 〈 0.05） than that of the treatment urea. Correspondingly, the N recovery rate was greater for all MiCFs compared to urea, increasing from 32.8% up to 50.1%. Due to its high recovery and low cost, use of the mineral coated N fertilizers was recommended instead of the polymer coated N fertilizers.

控释掺混肥对小麦–玉米轮作体系产量、氮肥利用效率及氨挥发的影响

【目的】针对华北平原冬小麦-夏玉米轮作体系氮肥施用量大、氮肥利用率低、氮素损失严重等问题,探讨不同配比的控释掺混肥减氮和一次性施肥对周年作物产量、氨挥发损失和施肥经济效益的影响,确立麦玉轮作体系轻简高效和环境友好的施肥技术。【方法】于2022—2023年,在山东省德州市现代农业科技园区开展田间试验。冬小麦和夏玉米均设不施氮对照(CK)、农户习惯施氮(FFP)、优化施氮(OPT)、CRBF1(包膜尿素与普通尿素在冬小麦和夏玉米上的掺混比例分别为5∶5和3∶7)和CRBF2(包膜尿素与普通尿素在冬小麦和夏玉米上的掺混比例分别为7∶3和5∶5),共5个处理。基施和追施肥后,监测了氨挥发量、强度和损失率。分析了作物干物质积累和产量、氮素吸收量和氮肥利用效率,并计算了施肥经济效益。【结果】与FFP处理相比,CRBF1和CRBF2处理的夏玉米、冬小麦和周年产量差异不显著;CRBF1和CRBF2处理夏玉米氮肥偏生产力提高了8.87~9.86 kg/kg,CRBF2处理玉米氮肥回收率提高了48.4%(P<0.05);CRBF1和CRBF2处理冬小麦季氮肥回收率、氮肥农学利用率和氮肥偏生产力分别提高了30.3%~37.2%、5.22~5.77 kg/kg和6.52~7.06 kg/kg(P<0.05)。与FFP和OPT处理相比,CRBF1和CRBF2处理的肥料+施肥人工投入减少381~960元/hm^(2),周年净收入增加1208~2654元/hm^(2)。CRBF1和CRBF2处理的周年氨挥发损失量、损失强度和损失率较FFP处理分别降低了69.7%~71.9%、72.0%~74.5%和90.0%~94.1%(P<0.05)。【结论】包膜尿素与普通尿素在冬小麦、夏玉米季按照5∶5、3∶7,或者按照7∶3、5∶5的比例掺混一次性基施,均可在减少氮肥用量和施肥劳力投入的条件下,确保周年作物产量稳定,提高生产效益,并显著降低氨挥发损失,是华北平原冬小麦-夏玉米轮作系统高产高效、轻简施肥的有效氮肥施用技术。

生物炭包膜尿素的制备及其固氮潜力的研究

为了探究生物炭包膜尿素的缓释性能及对土壤固氮的影响,以300、500和700℃下制备的杨木生物炭为包膜材料制备了3种生物炭包膜尿素,采用间歇土柱淋溶试验对氮素的释放特征进行分析。结果表明,杨木生物炭对铵态氮和硝态氮具有较好的吸附性能,低温下制备的生物炭对铵态氮吸附效果更好;与尿素相比,施用生物炭包膜尿素土壤的总氮淋溶量减少了9.73%~14.67%,铵态氮淋溶量减少了25.28%~30.36%,硝态氮淋溶量减少了10.34%~18.38%;在同等施氮水平下,生物炭包膜尿素相较于尿素可以显著增加土壤铵态氮和硝态氮的含量。其中,土壤中铵态氮含量增加了66.4%~200.1%,土壤硝态氮的含量增加了477.9%~537.6%。因此,生物炭用作肥料的包膜材料具有广阔的应用前景。

低甲醛脲醛树脂基钢结构防火涂料的制备

本试验制备了一种低甲醛脲醛树脂基膨胀型钢结构防火涂料,探究了脲醛树脂加入量对防火涂料性能的影响,并分析其耐火机理。结果表明,在甲醛与尿素低摩尔比(0.8∶1)时,加入0.1%过氧化氢,制备低甲醛脲醛树脂,甲醛含量符合GB 18582-2020规定;加入脲醛树脂对膨胀型钢结构防火涂料的基本性能无影响,对涂层发泡性能和耐火性能影响显著,当脲醛树脂加入量在6%~10%时,涂层发泡厚度在3 cm以上,钢板背面温度在300℃以下,最低为271.9℃;脲醛树脂发生热解,分子链断裂产生大量阻燃气体,形成致密碳层,起到气源、碳源的作用。

长链烷基脲类消泡剂的合成及性能研究

开发无硅型消泡剂是未来消泡剂领域的发展方向之一。本工作将十八烷基异氰酸酯分别与油胺、1,6-己二胺和三(2-氨基乙基)胺反应合成了三种长链烷基脲,并以烷基脲为消泡活性物、矿物油为载体、Span-Tween为乳化剂制备了三种脲类消泡剂。用核磁共振氢谱(1H NMR)和红外光谱(FT-IR)对产物进行结构表征。通过显微观察手段研究了疏水粒子在油基消泡剂中的消泡过程和机理,并通过单因素实验探究了各组成及用量对消泡剂性能的影响。结果表明:当选用低黏度白油,脲消泡活性物占消泡剂质量分数为4%,Span-Tween复合乳化剂亲水亲油平衡(HLB)值为8、用量占消泡剂质量分数为5%时,制得的脲类消泡剂在涂料应用中有着比同类市售产品更优异的消泡性能。

缓释包膜尿素配施对土壤性质和夏玉米生长的影响

缓释肥料根据作物需肥特征可达到养分释放与作物吸收同步的目的.缓释包膜尿素与普通尿素混施既可以降低肥料成本,又能够满足作物生长需求,实现氮肥的合理运筹.研究通过在黄淮海平原豫北地区连续两年(2017—2018年)开展不同施氮剂量下包膜尿素与普通尿素配施试验,于收获季收集0-20 cm表层土壤和植物样品,进行土壤基本理化性质和植株生长指标测定.试验共设置2个施氮水平(L,低氮施用量;H,高氮施用量)和3个配施比例(CU1,包膜尿素∶普通尿素=40∶60;CU2,包膜尿素∶普通尿素=49∶51;CU3,包膜尿素∶普通尿素=57∶43),并设置常规高施氮量全普通尿素处理对照(CK),共计7个处理.研究结果表明,土壤含全氮、速效磷和有效钾量分别较对照增加37.1%~142.0%、16.5%~33.6%和22.0%~73.1%,含有机质量提高7.0%~42.5%,碳氮比降低33.7%~48.8%.各配施处理连续两年夏玉米的株高、基径、千粒质量和产量较对照增加21.4%~31.2%、10.4%~18.7%、6.18%~11.2%和15.2%~32.7%.综合考虑作物产量和土壤肥力等指标,建议采用低氮水平下高包膜尿素配施比例NPK混合方案(包膜缓释尿素148.2 kg/hm^(2),普通尿素111.8 kg/hm^(2),过磷酸钙833 kg/hm^(2)和硫酸钾180.0 kg/hm^(2))既能满足夏玉米高产对养分的需求,又能保证土地持续的生产力.

不同包被缓释尿素的瘤胃缓释效果的评价

[目的]本文旨在通过体外批次发酵、瘤胃灌注和持续动态人工瘤胃模拟系统等不同方法评价包被缓释尿素的瘤胃缓释效果。[方法]体外发酵试验:选取1种普通尿素和4种商业包被缓释尿素,体外培养24 h,采集不同时间点(0、1、3、6、9、12、24 h)发酵液测定氨氮浓度,将筛选出缓释效果最好的缓释尿素用于进一步的研究。瘤胃灌注试验:12只体重(平均27.6 kg)相近的安装有瘤胃瘘管的育肥公湖羊,随机平均分为2组,分别向瘤胃中灌注剂量为日干物质采食量0.5%的普通尿素或日采食量0.55%的缓释尿素(等氮当量),灌注后不同时间点(0、1、3、6、9、12和24 h)采集瘤胃液,测定pH值和氨氮浓度。人工瘤胃试验:在基础日粮中分别添加3.5%的豆粕(普通日粮组)、0.5%的普通尿素(普通尿素组)和0.55%的缓释尿素(缓释尿素组),使用玉米补充普通尿素和缓释尿素组能量的缺乏;试验重复3次,每次持续7 d(4 d适应期和3 d采样期),采样期每天早上投料前后不同时间点采集发酵液和溢流液,测定发酵参数和微生物蛋白浓度。[结果]体外发酵试验:在发酵开始的9、12 h,缓释尿素A组的氨氮浓度显著低于普通尿素组和其余3个缓释尿素处理组(P<0.05)。体内瘤胃灌注试验:在灌注尿素后1 h,缓释尿素组瘤胃pH值和氨氮浓度显著低于普通尿素组(P<0.05),在灌注尿素后6 h,缓释尿素组的pH值显著高于普通尿素组(P<0.05)。人工瘤胃模拟试验:相比于其他2组,日粮添加缓释尿素显著提高了发酵液中丙酸和微生物蛋白的浓度(P<0.05);相比于普通日粮组,日粮添加缓释尿素显著降低了发酵液pH值(P<0.05)。[结论]不同包被缓释尿素的瘤胃缓释效果存在差异,体外发酵筛选出的缓释尿素A在动物瘤胃灌注条件下同样表现出较好的缓释效果。在人工瘤胃发酵试验中添加缓释尿素A能够改善瘤胃发酵,促进微生物蛋白的合成,但对生长性能和瘤胃菌群的影响仍需动物饲养试验做进一步的验证。

Material characterization and inter/intra-particle validation for DEM simulation of urea coating process

Particle coating is a common operation in the controlled-release fertilizer (CRF) industry,where a coating layer is appliedto the urea cores.A discrete element method (DEM) computer simulation was applied to model the coating process for the urea granules using measured model parameters.The accuracy of DEM input parameters for the coating material properties and the physical and mechanical characterizations of urea granules are crucial to the study of particle coating processes.Thus,to enhance the simulation accuracy,information on the material properties (urea granules) is required.In this study,the elasticity parameters,shear modulus ,coefficient of restitution (CoR),and coefficient of rolling and static friction (CoRF) and (CoSF) of urea granules are estimated experimentally in addition to the physical characteristics.The sensitivity of the angle of repose of the urea bed was investigated at different coefficients of friction.According to the obtained experimental value of the angle of repose,values of 0.2 and 0.3 for CoRF and CoSF,respectively,were adjusted to obtain consistent urea granules’ motion for simulation and the experiment.Moreover,the spray droplet sizes and velocity distributions were estimated using the video-imaging process technique.Based on this experimental characterization,elasticity parameters and spray properties were integrated into DEM simulation software as input data to perform numerical analysis of the coating process to compare simulation and experimental results,which show uniformity at three different pan speeds with a maximum deviation of 0.033 at 5 rpm.Also,consistency between DEM and experiment results was achieved in terms of average coating thickness (μm) of the selected samples and average intra-particle thickness variation ( CoV intra ).These results revealed that the coating film thickness is proportional to the rotation speed for the experiment and simulation.To enhance the inter-particle coating uniformity,the effects of the most significant parameters such as pan speed,filling ratio,particle size,spray rate,and spray angle,were examined.A low spray rate,filling ratio,and high pan speed improved the coating uniformity.The particle size and spray angle show considerable influence on the coating uniformity,where larger particle sizes and spray angles tend to reduce the inter-particle coating uniformity.

抑制剂和包膜尿素对河套灌区土壤养分含量和向日葵产量的影响

本研究通过田间小区试验,探讨了不同种类的氮素抑制剂和包膜尿素对河套灌区向日葵产量及土壤肥力的影响。试验设6个处理:不施肥(Control)、常规施氮(NPK)、常规施氮+脲酶抑制剂HQ+硝化抑制剂DCD(HDN)、常规施氮+脲酶抑制剂NBPT+硝化抑制剂DCD(NDN)、50%包膜尿素+50%普通尿素(PCU1)和70%包膜尿素+30%普通尿素(PCU2)。结果表明:与NPK处理相比,抑制剂联用显著增加土壤有机碳、全氮、速效磷、速效钾和无机氮含量,增幅分别为2.4%~5.0%、11.6%~12.1%、36.7%~50.0%、12.4%~13.2%和24.0%~56.6%。相反,包膜尿素处理则对土壤有机碳、全氮、速效磷、速效钾和无机氮含量无显著影响。抑制剂联用显著增加土壤可溶性有机碳含量7.3%~10.2%,施用包膜尿素对土壤可溶性有机碳无显著影响。抑制剂联用和PCU1处理显著增加向日葵地上部分生物量,以HDN处理最高,增幅达到16.8%,而PCU2处理则无显著影响。与NPK处理相比,PCU1、HDN和NDN处理显著增加了向日葵产量和氮肥利用率,以HDN处理最高。相反,PCU2处理对向日葵产量无显著影响,并降低了氮肥利用率。综上所述,常规施氮与双效氮素抑制剂配合施用是提高河套灌区土壤养分保蓄能力和向日葵产量的重要措施。

PREPARATION OF UREA NITROGEN ADSORBENT OF COMPLEX TYPE AND ADSORPTION CAPACITY OF UREA NITROGEN ONTO THE ADSORBENT

The urea nitrogen adsorbent of complex type, which consists of chitosan coated dialdehyde cellulose （CDAC） and immobilized urease in gelatin membrane （IE）, was prepared. The cellulose, the dialdehyde cellulose （DAC） and the CDAC were characterized by scanning electronic microscope. The results indicate that the cellulose C2-C3 bond was broken under the oxidation of periodate and it was oxidated to DAC. The DAC was coated with chitosan and the CDAC was obtained. The adsorption of urea nitrogen onto the adsorbent in Na2HPO4-NaH2PO4 buffer solution was studied in batch system. The effects of the experiment parameters, including degree of oxidation of CDAC, initial urea nitrogen concentration, pH and temperature, on the adsorption capacity of urea nitrogen onto the adsorbent at CDAC/IE weight ratio 10：1 were investigated. The results indicate that these parameters affected significantly the adsorption capacity. The adsorption capacity of urea nitrogen onto the adsorbent was 36.7 mg/g at the degree of oxidation of CDAC 88%, initial urea nitrogen concentration 600 mg/L, pH 7.4 and temperature 37℃.