Jovale Vincent Tongco

The urgent need for bio-based functional materials has driven a shift away from fossil-fuel-sourced materials toward renewable lignocellulosic biomass (LCB). This comprehensive review explores the advancements in LCB carbonization between 2020 and 2026, marking a shift from traditional, low-yield combustion processes toward highly selective and sustainable thermochemical conversion pathways. The primary objective of this review is to evaluate the integration of green pretreatment strategies, conversion technologies, and efficient valorization of the aqueous effluents and by-products. The goal of green pretreatment is to overcome the inherent recalcitrance of LCB without the use of harsh chemicals and reaction conditions, specifically highlighting the effectiveness of deep eutectic solvents (DESs) and ionic liquids (ILs). The review also evaluates the emerging conversion technologies, including hydrothermal carbonization (HTC), microwave-assisted pyrolysis (MAP), and the synergistic co-pyrolysis of LCB with synthetic polymeric wastes. Another novel concept in preparing hard carbon and other related materials is the “lignin-first” biorefinery strategy, which facilitates the subsequent production of high-value aromatic monomers, platform chemicals, and biofuels. The engineered carbon materials are increasingly utilized well beyond their traditional use as solid fuels. The products have been proven to be excellent for use in high-performance energy conversion and storage, serving as renewable bio-based electrode materials for supercapacitors and carbon electrodes in next-generation batteries.

This study presents a sustainable strategy for improving the thermal properties of pine wood through the application of calcium carbonate nanopowder (CCNP) chelated with polycarboxylic acids (citric acid (CA) and tartaric acid (TA)) as coatings. The chelation reaction was confirmed by the detection of carbon dioxide (CO₂) gas. CCNP was characterized using microscopy and particle size analysis. The formation of crystalline calcium citrate and calcium tartrate was verified using FTIR and Raman spectroscopies, and XRD analysis. Wood treatment was conducted using different volumetric ratios of CA and TA. The CA-TA-treated (coated) wood blocks achieved the highest mass gain after treatment of around 89%, while the pure TA treatment exhibited enhanced leaching resistance, maintaining around 69% mass gain after leaching test. TGA conducted under oxidative (air) conditions showed that the coatings promoted char formation and produced inorganic residues from 6.4% to 7.8%, with the control resulting in negligible residual mass. Flame retardancy tests showed that the chelated coatings effectively delayed combustion and inhibited heat transfer, with the TA treatment showing improved flame retardancy performance by limiting the surface temperature to ~200 °C after 60 s of exposure, as compared to >550 °C for the control.

Lignocellulosic bio-based materials, such as wood, biocomposites, and natural fibers, exhibit desirable structural properties. This comprehensive review emphasizes the foundational and latest advancements in bioinspired improvement strategies, such as direct mineralization, biomineralization, lignocellulosic nanomaterials, protein-based treatments, and metal-chelating processes. Significant focus was placed on biomimetics, emulating natural protective mechanisms, with discussions on relevant topics including hierarchical mineral deposition, free-radical formation and quenching, and selective metal ion binding, and relating them to lignocellulosic bio-based material property improvements, particularly against fire and fungi. This review evaluates the effectiveness of different bioinspired processes: mineralized and biomineralized composites improve thermal stability, nanocellulose and lignin nanoparticles provide physical, thermal, and chemical barriers, proteins offer biochemical inhibition and mineral templating, and chelators interfere with fungal oxidative pathways while simultaneously improving fire retardancy through selective binding with metal ions. Synergistic approaches integrating various mechanisms could potentially lead to long-lasting and multifunctional protection. This review also highlights the research gaps, challenges, and potential for future applications.

The generation of over 150 million tons of hemp waste annually is as much of a sustainability challenge as it is an opportunity for the circular bioeconomy. This review provides a critical analysis of the recent trends in the use of industrial hemp waste as a precursor to producing sustainable bioproducts. The objective is to synthesize the current state of knowledge and to identify the various pathways for valorizing hemp waste beyond the traditional applications. The methodology involved the systematic assessment of the recent literature to identify the applications in textiles, biocomposites, packaging, and, most importantly, advanced areas such as hemp-based carbon materials for storing energy, biomedical materials, and smart biomaterials. Findings showed that hemp waste is a versatile material for creating high-value products, as it shows promise in carbon electrodes for supercapacitors as well as reinforcement for 3D-printed biocomposites. However, there are some limitations in terms of standardization and scalability. The review concludes that future progress depends on multidisciplinary research to optimize conversion and utilization processes, including the development of comprehensive life-cycle assessments and reliable supply chains.