Review Articles

Lignin, a prospective bioresource from plants, has been undervalued for several dozen years because of the unpredictable structures and their changeability during extraction. Recently, lignin has become a star for certain researchers who are aiming to develop sunscreen products offering production against UV radiation. The preparation of lignin into sunscreens as a natural alternative to chemical products may offer new perspectives. This review discusses how lignin isolation methods and the resulting structural characteristics affect UV absorption, thereby determining the potential of lignin as a UV-absorbing and blocking agent in sunscreen formulations. The application of lignin in cosmetics may present great benefit to humans and their skin care needs.

Lignocellulosic biomass is an abundant renewable energy resource whose total energy content far exceeds current global demand. Its polysaccharides, cellulose, and hemicelluloses are primary targets for valorization; however, the recalcitrant structure of plant cell walls necessitates effective pretreatment. Among physical, physicochemical, chemical, and biological methods, advanced oxidation processes (AOPs) have emerged as an efficient and environmentally compatible chemical strategy. This review systematically evaluates nine major AOPs for lignocellulosic biomass pretreatment: Fenton and Fenton-like processes, alkaline H₂O₂, peracetic acid, persulfate, ozone, photocatalysis, electrochemical oxidation, wet air oxidation, and cavitation-assisted methods. For each, reaction mechanisms, advantages and limitations, recent advances, economic considerations, and scale-up challenges are discussed. Persulfate-based systems, wet air oxidation, and hybrid strategies (e.g., photo-Fenton, alkaline H₂O₂–cavitation, electrochemical–ozone–H₂O₂) are identified as particularly promising. Future research should prioritize novel catalyst development, reactor optimization, multi-mechanism integration, and rigorous techno-economic and life-cycle assessments. Coupling AOPs with renewable energy sources will be critical to improving energy efficiency and enabling cost-effective large-scale application.

Establishing an economically efficient supply chain for biomass feedstock is a critical prerequisite for achieving large-scale bioenergy development under China’s “dual carbon” strategy. Focusing on agro-forestry residue feedstocks, this paper systematically reviews the technologies and models for the key stages of their collection, storage, and transportation (CST) system. The inherent physicochemical characteristics of biomass, such as low bulk density and high moisture content, constitute a fundamental physical bottleneck that constrains its economic viability. To this end, pretreatment technologies, with densification at their core, are widely recognized as a critical technological stage for enhancing logistics efficiency and achieving value addition. In contrast to the technological optimization of individual stages, systemic integration strategies—such as establishing a hybrid “decentralized-centralized” supply chain model and employing multi-modal transport—represent a more effective pathway to achieving whole-chain cost reduction and efficiency enhancement. Through a systematic integration of research in this field, this paper emphasizes that the key to resolving CST bottlenecks lies in adopting a whole-chain perspective that involves the deep coupling of essential pretreatment technologies with innovative supply chain organizational models.

The paper industry has achieved relatively high levels of recovery and reuse of cellulosic fibers by the recycling of paper. The industry’s record of recovering material from used paper products far exceeds that of, for instance, the plastics industry. However, in the course of that success there are challenges. This paper provides a tutorial review of problems related to the stickies content of recovered used paper material. The review considers what stickies are composed of, how they can affect papermaking and its products, and how papermakers can minimize their adverse effects. Stickies tend to be problematic in mills without deinking systems. Though some stickies can be removed by screening, much of the material is expected to deform and thereby pass through industrial screens. Larger stickies (macrostickies) can be removed using hydrocyclones, whereas smaller ones (microstickies) are often removed using flotation. Other approaches to dealing with stickies include using detackifiers, which essentially means covering the stickies with a polymer or a mineral product. Production teams can optimize conditions to retain the stickies, ideally as small particles, onto cellulosic fibers. Because the processes are complex, and the composition of recovered stock tends to change over time, continuing efforts will be required. Effective control of stickies can be expected to require effective collaboration among people at the mill, chemical supplier companies, and machinery specialists.

This review examines the biomethane value chain from feedstock selection and feedstock-specific pretreatment to digester operation, gas upgrading, utilization pathways, and life-cycle constraints. Rather than evaluating biomethane by methane purity alone, it emphasizes the combined effects of feedstock quality, pretreatment intensity, process stability, upgrading energy demand, methane slip, digestate management, and end-use infrastructure. Key anaerobic digestion variables, including temperature, pH, volatile fatty acids, carbon-to-nitrogen ratio, organic loading rate, hydraulic retention time, and inhibitor control, are linked to process robustness. Major upgrading technologies, including water scrubbing, chemical absorption, pressure swing adsorption, membrane separation, and cryogenic separation, are compared in terms of methane purity, methane loss, energy demand, cost tendency and deployment fit. Biomethane shows the strongest mitigation potential when wastes are locally sourced, methane losses are controlled and digestate is safely recycled.

Corrugated board, traditionally used in packaging, is increasingly explored as a structural material for lightweight engineering applications, including furniture, panels, and temporary building components. This transition requires moving beyond empirical design rules toward performance-driven and optimization-based methodologies. This paper presents a critical review of optimization techniques applied to the structural design of corrugated board, with emphasis on the mechanical and numerical foundations required for physically reliable optimization. The reviewed studies were selected from major scientific databases using keywords related to corrugated board, structural optimization, finite element modeling, homogenization, surrogate modeling, machine learning, hygro-mechanical behavior, failure mechanisms, and experimental validation. Unlike earlier reviews focused mainly on industrial optimization practices and algorithms, this review highlights model fidelity, validation hierarchy, moisture sensitivity, local failure, interface damage, and the maturity of data-driven workflows. Analytical models, finite element approaches, homogenization frameworks, reduced-order models, and surrogate-assisted strategies are discussed in terms of their applicability to iterative optimization. Key design variables, including flute geometry, layer configuration, material anisotropy, and environmental conditions, are related to stiffness, strength, stability, ECT, BCT, and material efficiency. The main gaps include limited validation, simplified moisture-dependent and failure descriptions, weak interface-damage modeling, and the early development of digital-twin concepts for corrugated board design.