This work describes the production of nanocellulose by removing lignin from biomass by the peroxide method in the presence of an H2SO4 catalyst and the study of its physicochemical properties. The structure of cellulose and modified nanocellulose was studied using Raman spectroscopy, IR (infrared) spectroscopy, X-ray diffraction, and SEM (scanning electron microscopy). The resulting increase in the crystallinity of NFC (nanofibrous cellulose) was confirmed by X-ray diffraction analysis. This indicates that cellulose was associated with the removal of amorphous parts. As a result of X-ray diffraction, overlap on NFC radiographs occurred even in the area of intense lines. In the sample obtained by IR spectroscopy, the presence of groups (3413.12 cm⁻¹; 2918.34 cm⁻¹; 1373.30 cm⁻¹; 617.52 cm⁻¹) corresponding to the nature of NFC was detected. Strong absorption at 1429.8 cm−1 in the spectrum of CMC (carboxylmethylcellulose) revealed –COOH groups, indicating successful carboxylation of cellulose. The morphological surface, average particle size and structure of the samples were studied. As a result of a comparative analysis of morphological structures, an ordered filamentous structure of nanofibrous cellulose characteristic of fibers and a porous structure of CMC with a modified surface and uneven fibers were revealed. The developed method for producing modified cellulose from biomass does not require multi-stage processing compared to traditional methods and is safe for the environment. It has been shown that it is possible to obtain high-quality cellulose in one stage without the use of reagents containing sulfur and chlorine, high pressure and high water consumption.

Contamination of water bodies by emulsified gasoline hydrocarbons, particularly BTEX compounds (benzene, toluene, ethylbenzene, and xylenes), represents a critical environmental challenge due to their toxicity and resistance to conventional treatment methods. In this study, carbonized biosorbents derived from rice husk (CRH) and walnut shell (CWS) were developed for efficient removal of emulsified gasoline from water. The materials were prepared via carbonization under CO₂ atmosphere (300–800 °C), enabling simultaneous carbonization and activation. Structural and surface properties were characterized using Brunauer–Emmett–Teller (BET) analysis, scanning electron microscopy (SEM), Fourier-transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), and X-ray fluorescence spectroscopy (XRF). The results demonstrated a strong dependence of adsorption performance on carbonization temperature, with maximum removal efficiencies of 90.2% (CRH-600) and 96.5% (CWS-700). The superior performance of CWS-700 was associated with its highly developed hierarchical pore structure (up to 670 m² g⁻¹), increased carbon content, and enhanced hydrophobicity. Kinetic studies revealed pseudo-second-order behavior, with equilibrium achieved within 25–30 min at near-neutral pH. Gas chromatographic analysis confirmed the complete removal of BTEX and light hydrocarbons (C1–C9) using CWS-700, highlighting its high selectivity toward aromatic compounds. The adsorption mechanism was attributed to the synergistic effect of micropore filling, hydrophobic interactions, and π-π interactions with aromatic hydrocarbons. The obtained results demonstrate that biomass-derived carbon materials, particularly walnut shell-based sorbents, are promising low-cost candidates for the treatment of complex water systems contaminated with emulsified petroleum hydrocarbons.

This paper discusses the process of obtaining microcrystalline cellulose by removing lignin from biomass and studying its properties. Rice husks, which are agricultural waste, were used as biomass. The effect of the ratio of biomass to peroxyacetic acid on the yield of microcrystalline cellulose was determined. The yield of microcrystalline cellulose from rice husks at a ratio of 1/14 was 70%. Additionally, gel films based on rice MCC and sodium alginate were prepared, and their hydrolytic degradation properties were studied. In an acidic medium (pH 4.08), the gel film showed a 66% mass loss within 7 days, indicating pH sensitivity and biodegradability. The morphological surface, average particle size, and structure of the samples were studied. The surface morphology of the samples was examined using a scanning electron microscope, and it was found that the average particle size was 7–10 µm. X-ray diffraction (XRD) analysis confirmed the amorphous–crystalline nature of the material. Fourier-transform infrared spectroscopy (FTIR) confirmed the presence of hydroxyl, carbonyl, and ether functional groups. Thermogravimetric analysis (TGA) demonstrated the thermal stability of the gel films. The developed method for producing microcrystalline cellulose from biomass requires fewer processing stages compared to traditional methods and is environmentally safe. It was shown that high-quality microcrystalline cellulose can be obtained in one stage without the use of reagents containing sulfur and chlorine, high pressure, or large amounts of water. The interest in microcrystalline cellulose is due to its unique properties, such as lightness, non-toxicity, biocompatibility, and biodegradability. Currently, it is in high demand in the production of aerogels, gels, biocomposites, biodegradable materials, and films.