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The current study focuses on finding an ecological method to dispose of black liquors (BLs), containing lignin macromolecules, which are produced as byproducts of rice straw-based paper production. In addition to maximizing their value as precursors in the preparation of novel formaldehyde scavengers to avoid the environmental risks associated with using urea formaldehyde in agro-wood composites. To optimize the route, various black liquors are prepared from pulping of rice straw by different pulping agents (alkali, neutral, acidic and kraft reagents) used as additions or precursors for carbon compounds. Elemental analysis, thermogravimetric analysis [TGA], Fourier transform infrared [FTIR] and scanning electron microscope (SEM), are the techniques used to characterize the BLs; while the gel time, bond strength, and differential scanning calorimetry (DSC) methodologies are applied to determine the impact of black liquor (BL) and black liquor‑carbon nanostructures (BL-CNSs) on performance of urea formaldehyde (UF) adhesive. The behavior of the investigated BL-CNSs as HCHO-scavengers is assessed from their affinity to capture the HCHO, and reduction of free-HCHO in UF-palm fibers agro-composites. BL-CNSs, as novel scavengers, exhibit promising properties where the bonding strength of BL-CNSs-UF adhesives increased to 19.7 MPa even though the UF was only 8.4 MPa. Moreover, the formaldehyde adsorption capacity ranges from 35.4 to 63.6 mg/g as well as lowering the gel time. It is interesting to note that the investigated scavengers not only reduced the free-HCHO of composites by about 40-91 %, but also enhancement in their mechanical and water resistance properties; where the modulus of rupture (MOR), internal bond (IB) and reduction in thickness swelling improved to about 50 % and 83.3 %, and 38.8 %, respectively. According to the American National Standards Institute (ANSI) standard these new scavengers, especially from BL of neutral pulping, permit the production of an eco-board (E1) with static bending exceeding the H-3 class., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier B.V. All rights reserved.)

Fast-swelling, porous cellulose hydrogels (PCHs) were generated via simple acid treatment of cellulose hydrogel prepared in NaOH/urea medium. Structural characteristics of the PCHs were investigated by scanning electron microscopy (SEM) and Fourier transform infrared spectroscopy (FTIR). Swelling behavior was assessed by measuring the swelling kinetics in deionized water. Mechanical properties were also examined. The results showed that acid treated PCHs had many more micropores, mesopores and macropores, and PCH-6% displayed a high specific surface area of 33.98 m 2 /g. However, cellulose hydrogel without acid treatment had a low specific surface area (2.499 m 2 /g). Mechanical property of hydrogel was found to be slightly deteriorated with the improvement of porous structure. The equilibrium swelling rate of PCHs had drastically improvement after acid treatment. This porous cellulose hydrogel skeleton presents a wide range of possibilities for the further development of fast swelling cellulose-based functional hydrogel., (Copyright © 2019 Elsevier Ltd. All rights reserved.)

A fast and convenient headspace gas chromatographic (HS-GC) approach was described for the estimation of urea in human urine. The HS-GC could detect the generated carbon dioxide derived from the urease-catalyzed hydrolysis of urea. It was found that the hydrolysis of urea catalyzed by urease was completed within 40 min at 35 °C. The results proved the great accuracy (relative errors ≤ 8.48%) and precision (RSD ≤ 2.66%) of the HS-GC approach. Moreover, the recoveries ranged from 97.9% to 101.5%. The new approach is rapid and automated, which provides a new way to routinely analyze urea in urine for the control of metabolic disease., (Copyright © 2019 Elsevier Inc. All rights reserved.)

This paper describes self-reinforced antibacterial and oil-resistant properties that were successfully prepared by surface selective dissolution of filter paper in a NaOH/Urea/ZnO (weight ratio of 8:12:0.25) aqueous solution. The effect of the processing time on the mechanical properties of this paper was evaluated at -12°C. The paper morphologies were characterized using Scanning Electron Microscopy (SEM), X-ray Diffraction (XRD), Fourier Transform Infrared Spectroscopy (FT-IR) and X-ray photoelectron spectroscopy (XPS). The oil-resistance and antibacterial properties of the produced paper were also investigated. Excellent mechanical properties were observed for an optimized handling time. The tensile and burst strengths of the modified paper were in excess of 100% of the original. Meanwhile, the treated paper was completely oil-resistant within 24 h and demonstrated good antibacterial properties when exposed to Staphylococcus aureus. The traces of residual zinc oxide were found to be safe for food.

The combination of nitrogen recovery and pharmaceutical removal processes for livestock urine treatment were investigated to suppress the discharge of pollutants and recover nitrogen as resources. We combined methylene urea synthesis from urea and adsorption and photocatalytic decomposition of sulfonamide antibiotic using rotating advanced oxidation contactor (RAOC) contained for obtaining both safe fertilizer and reclaimed water. The methylene urea synthesis could recover urea in synthetic urine, however, almost all sulfonamide antibiotic was also incorporated, which is unfavorable from a safety aspect if the methylene urea is to be used as fertilizer. Conversely, RAOC could remove sulfonamide antibiotic without consuming urea. It was also confirmed that the methylene urea could be synthesized from synthetic urine treated by RAOC. Thus, we concluded that RAOC should be inserted prior to the nitrogen recovery process for effective treatment of urine and safe use of methylene urea as fertilizer.