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Neem oil contains large amounts of azadirachtin, which have excellent antibacterial, antifungal, insecticidal, and pesticidal properties that can protect plants from various agricultural diseases. However, neem oil is hydrophobic and sensitive to environmental conditions, its direct application is limited by dilution, spraying, adhesion, and easy oxidation by components containing unsaturated bonds. Nanochitosan is a carrier system for the limitation of neem oil and is a biopesticide, antibacterial, and antifungal-enhancing agent. In this study, a novel fabrication of neem oil-encapsulated nanochitosan by ultrasound-assisted ionic gelation using sodium tripolyphosphate as a crosslinker. The effects of chitosan-neem oil mass ratios (1:0, 1:0.1, 1:0.25, 1:0.5, 1:0.75, 1:1 g/g) and ultrasonic times (5, 10, 15, 20, 25 min) on the particle size, encapsulation efficiency (EE), and loading capacity (LC) of neem oil loaded nanochitosan (CS/NO NPs) are comprehensively investigated. The CS/NO NPs have a diameter of 132.6–196.3 nm, zeta potential of 8.4–26.1 mV, EE and LC of 87.59–96.10%, and 21.90–24.03%, respectively. Ultrasonic treatment for 20 min is found to be the optimal time for the most stable nanoparticles. Field emission scanning electron microscope images demonstrated that nanochitosan had a spherical shape, whereas CS/NO NPs formed agglomerates with larger particle sizes. X-ray powder diffraction analysis revealed two distinct peaks at 2θ= 13° and 20°, characterized by the highly amorphous structure of CS/NO NPs. Therefore, the combination of neem oil and nanochitosan is a promising biopesticide with bioavailability, nontoxicity, and eco-friendliness for sustainable agriculture.

The increasing demand for energy storage solutions in recent years has driven the development of materials that are both environmentally friendly and long-lasting for battery manufacturing. As an alternative to conventional materials suffering from limited theoretical capacities, low energy densities, and a scarcity of active sites, carbon-based materials derived from wasted feedstocks such as rice straw could be regarded as a prospective precursor for the fabrication of anodes in lithium-ion batteries. Existing research concentrates on carbon materials with superior electrical conductivity and expansive specific surface areas, like graphene or carbon nanotubes. However, their intricate preparation methods, high costs, and nonrenewable nature significantly constrain their industrial-scale production and extensive use. For the first time, in this study, micro-fibrillated cellulose, which was extracted from agricultural waste, acted as the precursor for the synthesis of carbon aerogels through a facile route without any modification. The resulting carbon-based material exhibited an impressive initial specific charge capacity of 348.6 mAh g−1and maintained a stable performance with nearly 257.5 mAh g−1after over 100 cycles. These achievements not only represent a substantial advancement in the efficient utilization of agricultural waste to address environmental concerns but also introduce a valuable resource for advancing energy storage technology.

The conversion of cellulose-rich biomass into valuable materials for wastewater treatment has garnered attention in recent years. Particularly, the synthesis of aerogel materials with hydrophobic properties for oil adsorption applications has been of special interest due to the complexity and chemical usage in current processes. This study, therefore, aims to fabricate carbon cellulose chitosan aerogel material with the hydrophobicity inherent in using carbon fibers from the carbonization of cellulose fibers at high temperatures. Additionally, investigations were conducted into the impact of chitosan content in aerogel and the solid content in the gel on the adsorption capacity of carbon aerogel. The FTIR analysis and XRD profile validated the existence of disordered graphite exhibiting inherent hydrophobic characteristics. Meanwhile, the adsorption study indicates that the non-modified hydrophobic material with methyltrimethoxysilane (MTMS) possessed a superior oil adsorption capacity compared to the modified sample. Specifically, the adsorption capacity of the non-modified carbon aerogel sample for diesel was 54 g/g, while this figure was only 39 g/g for the MTMS-modified sample. Moreover, the material also demonstrated great adsorption capacity for solvents such as dichloromethane or DMF, with an adsorption capacity of approximately 48 g/g. Therefore, the research not only proposes a method to utilize pineapple leaves, an agricultural waste product, for the synthesis of valuable materials but also suggests a simplified approach for synthesizing hydrophobic materials for oil recovery and wastewater treatment processes in general.

Abstract: Rice straw is an abundant agricultural waste, especially in Asian countries, of which a large amount is still open burnt. This leads to the emission of greenhouse gases (CH4, N2O, etc.) causing huge environmental impacts and is a waste of a cellulose, lignin, and silica source, which are highly valuable compounds. In this work, nanocellulose (CNC) was produced from rice straw using chemical method, together with waste stream utilization. The acid waste from the hydrolysis and the black liquor from cellulose isolation were used to recover a hybrid material of lignin and silica (LS), which was then applied to remove methylene blue from water. CNC was prepared using acid hydrolysis presented as rod-like particles with a crystallinity of 85% and a diameter of 20–30 nm in width and 200–400 nm in length, which was of high quality and suitable for further applications. The LS hybrid performed well in adsorbing methylene blue in aqueous solution, with the trapping capacity of 68 mg/g. Subsequently, a pilot-scale integrated process to produce CNC and LS hybrid was proposed to reduce the chemical and water usage in treating waste stream and move towards the “zero-waste” concept and circular economy principle. The process is a possible solution for facile and feasible large-scale transformation of rice straw into value-added products. Graphical abstract:

The influences of -NH2and -Cl groups on the copper corrosion inhibition in 0.5 M H2SO4solution by benzotriazole were studied using experimental methods and density functional theory calculations. Mass loss tests, potentiodynamic polarization, and surface morphology analyses revealed notable differences: while unmodified benzotriazole showed an inhibition efficiency of 76.6%, the -Cl derivative increased this to 87.6%, whereas the -NH2derivative dropped it to 61.0% at the concentration of 5 × 10−4 M. Density functional theory calculations indicated these differences are not due to electronic properties or inhibitor-copper interaction energies but rather to the inhibitor’s influence on the oxygen reduction reaction, especially O2and H2O adsorption. The -NH2group formed strong hydrogen bonds with O2and H2O, reducing oxygen reduction inhibition, while the -Cl group repelled O2, resulting in enhanced inhibition. Free energy analysis of the oxygen reduction reaction supported these findings. These new insights into benzotriazole derivatives’ copper corrosion inhibition mechanisms offer valuable guidance for developing next-generation corrosion inhibitors.

Natural halloysite nanotubes (HNTs) have attracted great interest as smart nanocontainers of corrosion inhibitors. The adsorption behavior of corrosion inhibitors on HNTs will affect their loading capacity, a crucial property of smart nanocontainers. This work modified the surface of HNTs by preadsorbing metal cations (M2+: Fe2+, Zn2+, or Cu2+) to improve the adsorption of benzotriazole (BTA) on HNTs. The results based on the thermal gravimetric analysis showed that the loading capacities of BTA in Fe2+-, Zn2+-, and Cu2+-adsorbed HNTs were 8.25, 8.39, and 9.74 wt %, respectively, which are significantly higher than those in pristine HNTs of 4.57 wt %. Furthermore, density functional theory calculations exhibited that the adsorption energies of BTA on the M2+-adsorbed surfaces increased compared to that on the clean surface. Notably, the increasing trend of adsorption energies is in good agreement with that of measured loading capacities. Moreover, the presence of metal cations significantly enhances the charge transfer between BTA and the surface. The density of states analysis indicated that the adsorbed metal cations shifted the valence bands of the surface close to the Fermi level, thereby enhancing the coupling between the occupied bands of HNTs and the unoccupied orbitals of BTA.

Computational prediction of corrosion rates is still a challenging issue in the field of metal corrosion. In this study, we proposed a computational model to predict the corrosion rates of copper in the presence of adsorption-type corrosion inhibitors using density functional theory calculations, microkinetic simulation, and machine learning. The model-calculated corrosion current and potential of clean copper are close to values obtained in available experiments. The copper corrosion rates in the presence of inhibitors were further predicted using the adsorption free energy of adsorbed inhibitors and the inhibitor concentration in solution to describe the effects of inhibitors. The proposed model was applied to predict corrosion inhibition efficiency by combining it with a machine learning model. The combining model exhibited that it was more interpretative and accurate than a machine-learning-only model in predicting corrosion inhibition efficiencies of organic compounds on copper.