The crystallinity of cellulose substrates is a key factor in their processability, as well as an indication of their susceptibility to undergo sensitive reactions (such as enzymatic saccharification) with high yields. FT-IR and X-ray diffraction spectroscopy are useful, reliable, and easy-to-reach solid-state characterization methods for assessing the crystallinity of different cellulose substrates including wood and wood-based materials. Due to their specific methodology, they can be used to analyze not only starting materials and their final products but also intermediates. Data obtained by these methods substantiated the structural changes in cellulose substrates, as well as the alterations that occurred in their supramolecular architectures. The conversion of crystalline cellulose I into amorphous cellulose II during enzymatic saccharification, with or without pre-treatment (solubilization in ILs), was evidenced beyond any reasonable doubt by FT-IR and XRD experimental results. Enzyme hydrolysis rates of the ILs-treated cellulose substrates can be significantly increased, as evidenced by reducing sugar yields. Crystallinity index values for cellulose of different origins (initial, pre-treated with ILs, and hydrolyzed with enzyme, as well as cellulose submitted to one-pot procedure with ILs and enzyme) can be determined using FTIR and X-ray diffraction data and discussed for comparison purposes. The same solid-state characterization methods can be also successfully employed for investigation of surface changes, expressed as cellulose crystallinity, in wood samples before and after impregnation with natural-based products, as well as under biodegradation conditions in soil burial tests.

Geotextiles, a group of high-performance materials, have grown during the last decades into needful auxiliaries when it comes to infrastructure, soil, construction, agriculture and environmental applications. Although geotextiles made of synthetic fibers (geosynthetics) are considered a modern achievement, the basic concept dates back to ancient times when textiles consisting of locally available natural fibers were employed to increase the stability of roads and soils. In recent decades, considering the growing interest in environmental protection and sustainable development based on using renewable resources and the recovery and recycling of waste of various origins, the use of natural fibers-based geotextiles is a viable alternative, despite their limited-life service owing to their biodegradability. In addition to this feature, their low cost, good mechanical properties and large-scale accessibility recommend them for geo-engineering applications, environmental sensitive applications in geotechnical engineering, such as land improvements and soil erosion control. This paper focuses on geotextiles as a versatile tool in environmental applications given their high theoretic and practical relevance as substantiated by recent literature reports. Natural and synthetic geotextiles are presented herein, as well as their features that recommend them for geo-engineering. Insights on the main types of applications of geotextiles are also included, along with a wide variety of materials employed to perform specific functions.

Textiles with antimicrobial functionality have been intensively and extensively investigated in the recent decades, mostly because they are present in everyday life in various applications: medicine and healthcare, sportswear, clothing and footwear, furniture and upholstery, air and water purification systems, food packaging etc. Their ability to kill or limit the growth of the microbial population in a certain context defines their activity against bacteria, fungi, and viruses, and even against the initial formation of the biofilm prior to microorganisms’ proliferation. Various classes of antimicrobials have been employed for these highly specialized textiles, namely, organic synthetic reagents and polymers, metals and metal oxides (micro- and nanoparticles), and natural and naturally derived compounds, and their activity and range of applications are critically assessed. At the same time, different modern processing techniques are reviewed in relation to their applications. This paper focuses on some advances and challenges in the field of antimicrobial textiles given their practical importance as it appears from the most recent reports in the literature.

Raw cellulose, or even agro-industrial waste, have been extensively used for environmental applications, namely industrial water decontamination, due to their effectiveness, availability, and low production cost. This was a response to the increasing societal demand for fresh water, which made the purification of wastewater one of the major research issue for both academic and industrial R&D communities. Cellulose has undergone various derivatization reactions in order to change the cellulose surface charge density, a prerequisite condition to delaminate fibers down to nanometric fibrils through a low-energy process, and to obtain products with various structures and properties able to undergo further processing. Selective oxidation of cellulose, one of the most important methods of chemical modification, turned out to be a multitask platform to obtain new high-performance, versatile, cellulose-based materials, with many other applications aside from the environmental ones: in biomedical engineering and healthcare, energy storage, barrier and sensing applications, food packaging, etc. Various methods of selective oxidation have been studied, but among these, (2,2,6,6-tetramethylpiperidin-1-yl)oxyl) (TEMPO)-mediated and periodate oxidation reactions have attracted more interest due to their enhanced regioselectivity, high yield and degree of substitution, mild conditions, and the possibility to further process the selectively oxidized cellulose into new materials with more complex formulations. This study systematically presents the main methods commonly used for the selective oxidation of cellulose and provides a survey of the most recent reports on the environmental applications of oxidized cellulose, such as the removal of heavy metals, dyes, and other organic pollutants from the wastewater.

Global resources have to be used in responsible ways to ensure the world’s future need for advanced materials. Ecologically friendly functional materials based on biopolymers can be successfully obtained from renewable resources, and the most prominent example is cellulose, the well-known most abundant polysaccharide which is usually isolated from highly available biomass (wood and wooden waste, annual plants, cotton, etc.). Many other polysaccharides originating from various natural resources (plants, insects, algae, bacteria) proved to be valuable and versatile starting biopolymers for a wide array of materials with tunable properties, able to respond to different societal demands. Polysaccharides properties vary depending on various factors (origin, harvesting, storage and transportation, strategy of further modification), but they can be processed into materials with high added value, as in the case of gels. Modern approaches have been employed to prepare (e.g., the use of ionic liquids as “green solvents”) and characterize (NMR and FTIR spectroscopy, X ray diffraction spectrometry, DSC, electronic and atomic force microscopy, optical rotation, circular dichroism, rheological investigations, computer modelling and optimization) polysaccharide gels. In the present paper, some of the most widely used polysaccharide gels will be briefly reviewed with emphasis on their structural peculiarities under various conditions.

Wood surface modification is a comprehensive concept which, in time, turned out to be as successful as challenging when it comes to improve the resistance of wood during its life cycle in both indoor and outdoor applications. The initial approaches have aimed at simple methods with immediate results. Nowadays, the paradigm has slightly changed due to the scientific and technical advances, and some methods has become intermediate stages in more complex processes, after being used, for long time, as stand-alone procedures. The esterification was employed as a convenient method for wood surface modification due to the high amount of free hydroxyl groups available at the surface of wood and other lignocellulosic materials. Therefore, different esterification approaches were tested: activated condensation with carboxylic acids (monocarboxylic, as well as dicarboxylic acids, fatty acids, etc.) in the presence of condensation activating agents (such as trifluoroacetic anhydride); reaction with β-halogen-substituted carboxylic acids; esterification using carboxylic acids derivatives (acyl chlorides, anhydrides) or even multifunctional carboxylic acids (i.e., tricine). Thus, wood with improved dimensional stability and weathering resilience, higher fire resistance, enhanced hydrophobic character, and mechanical durability was obtained. This paper offers an overview of some of the most recent advances reported in the field, presented in a systematic manner, using the type of reaction as classification criterion. The main improvements will be outlined in a critical assessment in order to provide an useful tool for a wise choice in future applications.