Urea Release Research Articles

Network Analysis Reveals the Combination of Controlled-Release and Regular Urea Enhances Microbial Interactions and Improves Maize Yields.

Increased complexity of microbial networks can contribute to increased biodiversity and multifunctionality and thus crop productivity. However, it is not clear which combination ratio of regular and controlled-release urea will increase the soil microbial community complexity and improve maize yield in the North China Plain. To address this knowledge gap, a 2-year field experiment was conducted to explore the effects of the combination of regular (U) and controlled release (S) urea ratios [no fertilizer control (CT), regular urea alone (U), controlled-release urea alone (S), controlled-release urea mixed with regular urea 3:7 (SU3), controlled-release urea mixed with regular urea 5:5 (SU5), and controlled-release urea mixed with regular urea 7:3 (SU7)] on XianYu 688 yield and its rhizosphere and bulk soil microbial community composition and network complexity at different fertility stages. The combination of controlled-release and regular urea increased the N agronomic efficiency, N partial factors productivity, maize yield, and grain number per spike, with the maximum maize yield (9,186 kg ha–1) being achieved when the ratio of controlled-release urea to regular urea was 3:7 (SU3, p < 0.05). Maize yield increased by 13% in the SU3 treatment compared to the CT treatment. Rhizosphere soil microbial diversity remained stable at the silking stage of maize while increased at the physiological maturity stage of maize, with the increasing controlled-release to regular N fertilizer ratios (from 3:7 to 7:3, p < 0.05). This result suggests that a combination of regular and controlled-release N fertilizer can still substantially increase soil microbial diversity in the later stages of maize growth. The combination of controlled-release and regular urea is more effective in improving microbial network total links and average degree, and N agronomic efficiency (R2 = 0.79, p < 0.01), N partial factor productivity (R2 = 0.79, p < 0.01), spikes per unit area (R2 = 0.54, p < 0.05), and maize yield (R2 = 0.42, p < 0.05) increased with the microbial network complexity. This result indicates that the higher microbial network complexity is strongly associated with the higher N agronomic efficiency and N partial factors productivity and maize yield. In conclusion, the ratio of controlled-release to regular urea at SU3 not only increases the yield of maize and N agronomic efficiency but also enhances microbial diversity and network complexity in the North China Plain.

Hydrogel Composite Based On Arrowroot Starch-G-Poly (Acrylamide-Co-Acrylic Acid)/Zeolite as Matrix of Controlled Release Urea Fertilizer

Agricultural yields can be increased through fertilization. Conventional fertilization by spreading fertilizer on agricultural land is very ineffective. As much as 40-70% of the nitrogen from urea given through conventional fertilization will be leaching. This problem can be overcome by implementing a new fertilization system, namely by applying controlled fertilizer release technology or Control Release Fertilizer (CRF). The CRF system is made by loading or mixing urea fertilizer at the time of synthesis of a composite based on Arrowroot Starch-g-poly (acrylamide-co-acrylic acid)/zeolite. Fertilizer will come off gradually during fertilizing the land. Synthesis of starch-based hydrogel composite Arrowroot Starch-g-poly (acrylamide-co-acrylic acid)/zeolite loaded or mixed with urea fertilizer, has been successfully carried out. The composite's structure characterized by IR spectroscopy and its ability as CRF has also been tested through swelling and urea release tests in distilled water, phosphate buffer pH 5, pH 7 and pH 9. The results show that the swelling capacity and urea release in distilled water &gt; Buffer pH 7 &gt; pH 9 &gt; pH 5. The welling degree in distilled water, Buffer pH 5, pH 7 and pH 9 is 39.078; 18,719; 36,296 and 33,510 g.g-1 respectively and the release of urea is 2,129; 1,829; 2,110; and 2,091 mg.mL-1 respectively and they showed significant differences.

Incorporation of Urea Fertilizer and Activated Carbon in Carboxymethyl Cellulose-Based Bioplastics

The high mobility of urea as a nitrogen nutrient in the soil leads to inefficient absorption by plants. Hence efforts to design a slow-release fertilizer (SRF) are significant. This paper reports the incorporation of urea fertilizer with carbon or zeolite in a bioplastic made of carboxymethyl cellulose as the matrix. The bioplastics were made by mixing the zeolite or activated carbon suspensions into a sodium carboxymethyl cellulose (Na-CMC) gel. Glycerol was then added as a plasticizer. Six variations of bioplastics were prepared, namely CMC-urea 0.5 and 1.0, CMC-urea-zeolite, CMC-urea-zeolite-glycerol, CMC-urea-activated carbon, and CMC-urea-activated carbon-glycerol. The weight ratio of CMC and urea fertilizer was kept constant at 2:1 since the resulted bioplastics showed higher texture transparency and homogeneity than those of bioplastics with a weight ratio of CMC to urea 1:1. The addition of zeolite increased the tensile strength of the bioplastics by about two times. While, the glycerol addition improved the elongation at break. The release of urea from the bioplastics was slower for bioplastics with zeolite than with activated carbon. The composite bioplastics may serve as a slow-release urea for agriculture.

Designing a novel type of multifunctional soil conditioner based on 4-arm star-shaped polymer modified mesoporous MCM-41

A novel type of multifunctional soil conditioner was designed based on 4-arm star-shaped polymer modified mesoporous MCM-41 and was used as a carrier for urea and scavenger for noxious chemicals. The 4-arm star-shaped polymer was linked to the MCM-41 through a silane coupling agent. FTIR, NMR, XRD, BET, SEM, and TEM were adopted to analyze the structure characteristics of the samples, verifying that mesoporous MCM-41 and the 4-arm star-shaped polymer were successfully prepared. The experimental results demonstrated that the urea release effect of modified MCM-41 was significantly improved by nearly 50% compared to raw MCM-41. The loading efficiency (LE) and encapsulation efficiency (EE) were increased by nearly 39% and 42%, respectively, with the crop growth effectively promoted by 20–25%. The 4-arm star-shaped polymer modified mesoporous MCM-41 also possessed preferable adsorption properties for the methylene blue. Furthermore, the modified MCM-41 presented no biological toxicity and good biocompatibility because of the special structure. Consequently, the multifunctional soil conditioner provides potential application value for the improvement of the soil environment and the promotion of crop growth in agricultural applications.

Eco-friendly and biodegradable sodium alginate/quaternized chitosan hydrogel for controlled release of urea and its antimicrobial activity

Hydrogels could be employed in agriculture for efficient management of water and controlled-release urea (CRU). This study aimed to synthesize a superabsorbent hydrogel for CRU by cross-linking sodium alginate (Alg) and N-(2-hydroxy-3-trimethyl ammonium) propyl chitosan chloride (HTACC). The hydrogel structure was characterized by various techniques, and the urea loading and releasing behaviors of the synthetic hydrogels were investigated. The results revealed that the maximum urea loading ranged between 107 and 200%, and that the urea loading kinetics fitted with Langmuir model followed by the Freundlich model. The urea release behavior reached equilibrium after 30 days and urea releasing kinetics fitted with the zero-order and Higuchi models. The synthesized hydrogels exerted significant antimicrobial activities and molecular docking showed their binding affinity toward glucosamine-6-phosphate synthase, β-lactamase II, TraR binding site and nucleoside diphosphate kinase. In conclusion, these Alg/HTACC hydrogels showed swelling, urea release, and antimicrobial properties suitable to meet the plant requirements and produce economic and environmental benefits.

Phenotypical, functional and transcriptomic comparison of two modified methods of hepatocyte differentiation from human induced pluripotent stem cells.

Directed differentiation of human induced pluripotent stem cells (iPSCs) into hepatocytes could provide an unlimited source of liver cells, and therefore holds great promise for regenerative medicine, disease modeling, drug screening and toxicology studies. Various methods have been established during the past decade to differentiate human iPSCs into hepatocyte-like cells (HLCs) using growth factors and/or small molecules. However, direct comparison of the differentiation efficiency and the quality of the final HLCs between different methods has rarely been reported. In the current study, two hepatocyte differentiation methods were devised, termed Method 1 and 2, through modifying existing well-known hepatocyte differentiation strategies, and the resultant cells were compared phenotypically and functionally at different stages of hepatocyte differentiation. Compared to Method 1, higher differentiation efficiency and reproducibility were observed in Method 2, which generated highly homogeneous functional HLCs at the end of the differentiation process. The cells exhibited morphology closely resembling primary human hepatocytes and expressed high levels of hepatic protein markers. More importantly, these HLCs demonstrated several essential characteristics of mature hepatocytes, including major serum protein (albumin, fibronectin and α-1 antitrypsin) secretion, urea release, glycogen storage and inducible cytochrome P450 activity. Further transcriptomic comparison of the HLCs derived from the two methods identified 1,481 differentially expressed genes (DEGs); 290 Gene Ontology terms in the biological process category were enriched by these genes, which were further categorized into 34 functional classes. Pathway analysis of the DEGs identified several signaling pathways closely involved in hepatocyte differentiation of pluripotent stem cells, including ‘signaling pathways regulating pluripotency of stem cells’, ‘Wnt signaling pathway’, ‘TGF-beta signaling pathway’ and ‘PI3K-Akt signaling pathway’. These results may provide a molecular basis for the differences observed between the two differentiation methods and suggest ways to further improve hepatocyte differentiation in order to obtain more mature HLCs for biomedical applications.

Preparation of biodegradable sodium alginate/carboxymethylchitosan hydrogels for the slow-release of urea fertilizer and their antimicrobial activity

Nonpolluting and biodegradable hydrogels for the slow-release of urea fertilizer that also exhibit antimicrobial activity against some pathogenic bacteria and fungi in soil were developed. The sodium alginate/O-carboxymethyl chitosan hydrogels (Alg/O-CMCh) were prepared by blending the components in the presence of calcium chloride as a crosslinker. Some variables that affected the controlled loading and release of urea were investigated, including the polymer blend ratios of the components in the hydrogels and the concentration of the crosslinker. The prepared hydrogels were examined via Fourier-transform infrared spectroscopy, X-ray diffraction, and scanning electron microscopy, and their antimicrobial activity was also analyzed. The data show that the release of urea reached equilibrium after 26 days, with a cumulative percentage of approximately 75%–91%. The kinetics of urea release were fitted to zero-order, Higuchi, and Korsmeyer-Peppas models. Overall, the prepared hydrogels exhibit better antimicrobial activity than O-CMCh alone.

Hidrogel Superabsorben Berbasis Natrium Alginat-Bentonit sebagai Pelapis Pupuk Lepas Lambat

The application of slow-release fertilizer in agriculture is currently very necessary because of its performance that can control the release of fertilizer. However, the case of excessive use of urea on agricultural land has the potential to cause water pollution because the process of nitrification produces nitrite ions that are toxic and eutrophication of water and prevent harmful N2O gas emissions. This research has been done making urea slow-release fertilizer in the form of superabsorbent hydrogel with crosslink method and bentonite coating technique by sodium alginate. The hydrogels formed characterized its structure and morphology with FTIR and SEM-EDS, as well as swelling tests to see its ability to store water. Furthermore, to test the performance of hydrogel as a slow-release fertilizer is carried out urea release test at various pH and times. The results showed that urea fertilizer has filled the structure and surface of hydrogel with a swelling ratio of 2.894,30% (BAC1) and 3.428,52% (BAC2). The addition of CaCl2 crosslinking agent provides increased gelation power, swelling, and adsorption capacity against urea in addition to the urea release process is not affected by pH.

Design and degradation of permanently porous vitamin C and zinc-based metal-organic framework

Bioapplication is an emerging field of metal-organic frameworks (MOF) utilization, but biocompatible MOFs with permanent porosity are still a rarity in the field. In addition, biocompatibility of MOF constituents is often overlooked when designing bioMOF systems, intended for drug delivery. Herein, we present the a Zn(II) bioMOF based on vitamin C as an independent ligand (bioNICS-1) forming a three-dimensional chiral framework with permanent microporosity. Comprehensive study of structure stability in biorelavant media in static and dynamic conditions demonstrates relatively high structure resistivity, retaining a high degree of its parent specific surface area. Robustness of the 3D framework enables a slow degradation process, resulting in controllable release of bioactive components, as confirmed by kinetic studies. BioNICS-1 can thus be considered as a suitable candidate for the design of a small drug molecule delivery system, which was demonstrated by successful loading and release of urea—a model drug for topical application—within and from the MOF pores.

Porous Silica Biofiber: A Reusable, Sustainable Fertilizer Reservoir.

Nitrogen fertilizers, namely urea, are prone to leaching that causes inefficiency in crop production and environmental pollution; hence porous particles were explored for slow release. Nevertheless, discrete particles add cost; therefore, jute cellulose has been tested as twine to tether silica together for reusability. On the other hand, silica serves as an exoskeleton to give pore memory property to cellulose, which otherwise is susceptible to loss of porosity during irrigation. The composite shows ∼70% more absorption capacity in the fifth cycle than the fiber without silica coating. The urea release kinetics shows only <1/3 and 3/4 of urea release from the jute-silica composite compared to naked porous silica and cellulose, respectively. The slow and sustained release of fertilizer from the composite results in a continuous increase in the chlorophyll content in rice crops.

Evaluation of the utility of the Beta Human Liver Emulation System (BHLES) for CFSAN's regulatory toxicology program

Microphysiological systems (MPS), such as organ-on-a-chip platforms, are an emerging alternative model that may be useful for predicting human physiology and/or toxicity. Due to the interest in these platforms, the Center for Food Safety and Applied Nutrition partnered with Emulate to evaluate the utility of the Beta Human Liver Emulation System (BHLES) for its regulatory science program. Using known hepatotoxic compounds (usnic acid, benzbromarone, tamoxifen, and acetaminophen) and compounds that have no reported human cases of liver toxicity (dimethyl sulfoxide, theophylline, and aminohippurate) the platform's performance was evaluated. Chemical toxicity was assessed by albumin secretion, urea and LDH release, nuclei number, mitochondrial membrane potential, and apoptosis. System/platform performance was evaluated in terms of sensitivity and specificity, power, and variability and repeatability. Chemical interactions with the Chip material were also assessed. Preliminary findings suggested that for the model test compounds selected, the BHLES accurately predicted toxicity, demonstrated high sensitivity and specificity, high power, and low variability. However, some compounds interacted with the Chip material indicating variable exposure levels that should be accounted for when planning experimentation. The details of the evaluation are presented herein.

Coating of urea granules with epoxidised vegetable oil cured by triethylenetetramine for control release: A green approach

The manuscript represents epoxidation of linseed oil to be coated on urea granules for their control release. Linseed oil was epoxidized in the presence of acetic acid and hydrogen peroxide. Structural transformation of unsaturated oil to epoxy group was confirmed by FTIR and end group analysis. Thereafter, the epoxidized linseed oil (ELO) was coated on the surface of urea granules and crosslinked subsequently using triethylenetetramine (TETA) a renewable substrate. Coated urea as an essential release component was first characterized for coating using optical microscope and SEM images. The control release behaviour of the prepared coated urea fertilizer was studied using dissolution and release urea from the crosslinked structure. The results demonstrated fast dissolution of pristine urea that is responsible for unwanted losses, toxicity, and harmfulness to environment, while coated with ELO and crosslinked with TETA required more time as necessary for slow and control release. The results demonstrated epoxidized oil as a green solution to coat urea granules for its control release.

A rodent thyroid-liver chip to capture thyroid toxicity on organ function level.

Endocrine disruption by environmental chemicals continues to be a concern for human safety. The rat, a widely used model organism in toxicology, is very sensitive to chemical-induced thyroid perturbation, e.g., histopathological alterations in thyroid tissue. Species differences in the susceptibility to thyroid perturbation lead to uncertainty in human safety risk assessments. Hazard identification and characterization of chemically induced thyroid perturbation would therefore benefit from in vitro models addressing different mechanisms of action in a single functional assay, ideally across species. We here introduce a rat thyroid-liver chip that enables simultaneous identification of direct and indirect (liver-mediated) thyroid perturbation on organ-level functions in vitro. A second manuscript describes our work toward a human thyroid-liver chip (Kühnlenz et al., 2022). The presented microfluidic model consisting of primary rat thyroid follicles and liver 3D spheroids maintains a tissue-specific phenotype for up to 21 days. More precisely, the thyroid model exhibits a follicular architecture expressing basolateral and apical markers and secretes T4. Likewise, liver spheroids retain hepatocellular characteristics, e.g., a stable release of albumin and urea, the presence of bile canalicular networks, and the formation of T4-glucuronide. Experiments with reference chemicals demonstrated proficiency to detect direct and indirect mechanisms of thyroid perturbation through decreased thyroid hormone secretion and increased gT4 formation, respectively. Prospectively this rat thyroid-liver chip model, together with its human counterpart, may support a species-specific quantitative in vitro to in vivo extrapolation to improve a data-driven and evidence-based human safety risk assessment with significant contributions to the 3R principles.

Selective chlorination of iminosydnones for fast release of amide, sulfonamide and urea-containing drugs.

Herein, we describe a methodology for iminosydnone chlorination and we demonstrate the high beneficial effect of this modification on the reactivity of these mesoionic dipoles in strain-promoted cycloaddition reactions. Exploiting their reaction with cyclooctynes, we used these new iminosydnones for bioorthogonal release of amide, urea and sulfonamide containing drugs. Notably, drugs containing a terminal amide function were released for the first time with good kinetic constants.

CONTROLLED RELEASE OF UREA USING MESOPOROUS SILICA

Mesoporous silica has many applications due to its porous and morphological characteristics. This study used mesoporous silica as a carrier of fertilizer for controlled release. Mesoporous silica was synthesized by using cetyltrimethylammonium bromide (CTAB) as a template. Urea was taken as a model fertilizer to study the control release behaviour of mesoporous silica. For loading of urea on silica simple immersion technique was used. The high concentration of urea was taken for loading. In vitro release studies of urea loaded on porous silica in water indicate a fast release of urea within 12 hours, attributed to urea adsorbed on the external surface of porous silica. Then slow and sustained release for the next 4 days, ascribed to urea entrapped in the pores of silica. The release profile of urea loaded in silica synthesized without CTAB was also observed. The release profile of urea loaded on silica gel shows the full urea release within two days. The release profile of Neem-coated urea, commercially used in India as fertilizer, was also studied, in which maximum urea was released within one day. The great potential of developing a fertilizer carrier system based on mesoporous silica was revealed. The nanostructured delivery system for fertilizer could minimize losses of nutrients and consequently reduce the amount applied.

Synthesis and Characterization of Slow-Release Fertilizer Hydrogel Based on Hydroxy Propyl Methyl Cellulose, Polyvinyl Alcohol, Glycerol and Blended Paper.

In this study, biodegradable slow-release fertilizer (SRF) hydrogels were synthesized from hydroxyl propyl methyl cellulose (HPMC), polyvinyl alcohol (PVA), glycerol and urea (SRF1) and HPMC, PVA, glycerol, urea and blended paper (SRF2). The fertilizer hydrogels were characterized by SEM, XRD and FTIR. The swelling capacity of the hydrogels in both distilled and tap water as well as their water retention capacity in sandy soil were evaluated. The hydrogels had good swelling capacity with maximum swelling ratio of 17.2 g/g and 15.6 g/g for SRF1 and SRF2 in distilled, and 14.4 g/g and 15.2 g/g in tap water, respectively. The water retention capacity of the hydrogels in sandy soil exhibited higher water retention when compared with soil without the (SRFs). The soil with the hydrogels was found to have higher water retention than the soil without the hydrogels. The slow-release profile of the hydrogels was also evaluated. The result suggested that the prepared fertilizer hydrogels has a good controlled release capacity. The blended paper component in SRF2 was observed to aid effective release of urea, with about 87.01% release in soil at 44 days compared to the pure urea which was about 97% release within 4 days. The addition of blended paper as a second layer matrix was found to help improve the release properties of the fertilizer. The swelling kinetic of the hydrogel followed Schott’s second order model. The release kinetics of urea in water was best described by Kormeye Peppas, suggesting urea release to be by diffusion via the pores and channels of the SRF, which can be controlled by changing the swelling of the SRF. However, the release mechanism in soil is best described by first order kinetic model, suggesting that the release rate in soil is depended on concentration and probably on diffusion rate via the pores and channels of the SRF.

Physiological and Molecular Investigation of Urea Uptake Dynamics in Cucumis sativus L. Plants Fertilized With Urea-Doped Amorphous Calcium Phosphate Nanoparticles.

At present, the quest for innovative and sustainable fertilization approaches aiming to improve agricultural productivity represents one of the major challenges for research. In this context, nanoparticle-based fertilizers can indeed offer an interesting alternative with respect to traditional bulk fertilizers. Several pieces of evidence have already addressed the effectiveness of amorphous calcium phosphate-based nanoparticles as carriers for macronutrients, such as nitrogen (N), demonstrating increase in crop productivity and improvement in quality. Nevertheless, despite N being a fundamental nutrient for crop growth and productivity, very little research has been carried out to understand the physiological and molecular mechanisms underpinning N-based fertilizers supplied to plants via nanocarriers. For these reasons, this study aimed to investigate the responses of Cucumis sativus L. to amorphous calcium phosphate nanoparticles doped with urea (U-ACP). Urea uptake dynamics at root level have been investigated by monitoring both the urea acquisition rates and the modulation of urea transporter CsDUR3, whereas growth parameters, the accumulation of N in both root and shoots, and the general ionomic profile of both tissues have been determined to assess the potentiality of U-ACP as innovative fertilizers. The slow release of urea from nanoparticles and/or their chemical composition contributed to the upregulation of the urea uptake system for a longer period (up to 24 h after treatment) as compared to plants treated with bulk urea. This prolonged activation was mirrored by a higher accumulation of N in nanoparticle-treated plants (approximately threefold increase in the shoot of NP-treated plants compared to controls), even when the concentration of urea conveyed through nanoparticles was halved. In addition, besides impacting N nutrition, U-ACP also enhanced Ca and P concentration in cucumber tissues, thus having possible effects on plant growth and yield, and on the nutritional value of agricultural products.

Controlled Release Modeling of Urea from Chitosan Microspheres: Effect of Stirring Speed and Volume Ratio of Continuous to Dispersed Phase

The purpose of this study was to determine the release kinetics and diffusion coefficient of chitosan microspheres containing urea based on changes in the stirring speed and the volume ratio of the continuous to dispersed phase (CP/DP). Chitosan microspheres filled with urea were prepared using the emulsion cross-linking method. The initial stage of this method has formed an emulsion then slowly dripped with glutaraldehyde saturated toluene as a crosslinker. Urea-loaded chitosan microspheres were washed and dried and then tested for release in an aqueous medium. The calculated cumulative release was used to determine the release kinetics and diffusion coefficient of chitosan microspheres. The appropriate release kinetics model was Simple Power Law with the Burst Effect because it produces an R2 value of 0.99. The mechanism of urea release from chitosan microspheres is Case II the transport mechanism represents pure relaxation behavior. Determination of the diffusion coefficient values from 1,180 x 10-14 up to 1,433 x 10-14 cm2/sec.

Uji Pupuk Slow Release Urea Dirakit dari Berbagai Bahan Polimer terhadap Pertumbuhan dan Hasil Bawang Merah Tiron pada Tanah Sawah Purwosari

This research aims to determine 1) the effect of four formulas on slow release urea on the growth and yield of shallot plant at Purwosari village and 2) formula of slow release urea that have the best growth and yield of shallot plant at Purwosari village. The research was conducted in November 2019 untill Maret 2020 The research was conducted at the ex-paddy fields of Purwosari village, Baturraden District, Banyumas Regency and Research Laboratory, Jenderal Soedirman University. Research in the form of non-factorial field experiments using RAKL with five treatments repeated five times. The formula of each treatment includes: F0 = NPK (Urea, SP-36, and KCl), F1 = 70% urea + 6% chitosan + 24% humic acid, F2 = 70% urea + 10% Azolla microphylla + 10% gondorukem + 10% humic acid , F3 = 60% urea + 10% Azolla microphylla + 10% montmorillonite + 10% gondorukem + 10% humic acid, and F4 = 56% urea + 3% humic acid + 24% zeolite + 11% tapioca flour + 6% gondorukem. The observed variable including growth and yield components of shallot. The variable of growth including the height of plant, the number of leaves, the weight of fresh plant of clump-1, the weight of fresh plant of effective plot, the weight of dry plant of clump-1, the weight of dry plant of effective plot, and the number of clump-1 bulbs. The yield components of shallot is a bulbs. Result of the research showed that the best formula for plant growth and yield of shallot plant is F2. The growth and yield of shallot produced by F4 is always lower than in the control treatment (F0). Farmers can fertilize less and optimize nitrogen uptake by plants with application of slow release of urea.

Study on the Cd (II) adsorption of biochar based carbon fertilizer

In this study, the biochar-based infiltration urea fertilizer (BIUF) was prepared by the infiltration technology. The urea slow-release performance and Cd (II) adsorption ability of BIUF were investigated. Compared with urea, the slow release rate of BIUF was obvious decreased during urea release process. Moreover, the equilibrium adsorption capacity of the BIUF reached 14.24 mg/g, which was 1.73 times of that of biochar. The Cd (Ⅱ) adsorption fits the pseudo-second order model better, which indicated that the chemical adsorption dominated. The O-containing and N-containing functional groups had a great contribution to Cd (II) adsorption. The NH4+ increased the occurrence rate of ion exchange reaction. The present study indicated that the BIUF had the potential of Cd (II) adsorption and urea slow release.