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Biomass-based aerogels are of interest due to their abundant precursors, ease of functionalization, eco-friendliness, low cost, and effectiveness in dye-contaminated water treatment. Coconut pith (CP) known as a by-product after coconut processing is a sponge-like and lightweight material discarded in large volumes. For the first time, carbon micro-particles resulting from two-step treatment and pyrolysis of CP have been successfully incorporated with chitosan to produce aerogel composites by high-speed homogenization and freeze-drying. After pretreatment, holocellulose content and crystallinity index of the recovered CP pulp are respectively 75.4 and 58.6 % along with a solid recovery rate of 27.5 %. Characteristic properties of the aerogel composites are featured by their density as low as 15.23–28.17 mg/cm3, remarkably high porosity of 98.17–99.05 %, and Young's modulus of 1.64–12.23 kPa. Synergistic effects of the porous network, electrostatic interactions between both amine groups in chitosan and carbon surface with methyl orange (MO) cause the as-fabricated aerogel composites to achieve an extremely high adsorption capacity of 454.13 mg/g and removal efficiency of 92.32 % at initial MO concentration of 500 mg/L. Therefore, the CP-derived carbon/chitosan aerogel composites synthesized from a feasible procedure exhibit their great potential in enhancing the value of coconut waste and dealing with dye-contaminated water pollution by simple and economical adsorption. [ABSTRACT FROM AUTHOR]

In this study, novel cobalt-doped carbon aerogels (Co-CA) are synthesized from jackfruit core via sequential steps of hydrothermal, impregnation, and pyrolysis. The aerogels show a uniform distribution of cobalt particles on the aerogel surface without any bunching regions. The large surface area of 160 m²/g and pore diameter of 10.5 nm are determined for the Co-CA by the Brunauer-Emmett-Teller equation and Barrett-Joyner-Halenda model. The as-fabricated Co-CA exhibit an excellent methylene blue (MB) degradation efficiency via a heterogeneous Fenton-like reaction in the presence of H2O2 and carbonate ions. While chloride (Cl-) and sulfate (SO42-) ions show insignificant changes in the MB degradation efficiency, the presence of carbonate (CO32-) and phosphate (PO43-) ons causes a great impact on the MB removal efficiency with the highest value of up to 90% when CO32- concentration is considerably low at 1 mM. Compared with the condition of only H2O2 in the environment, the addition of CO32- extensively increases the rate of MB degradation by recording the time of reaching the equilibrium state in only 15 min. The dye treatment efficiency is improved over the control condition (no inorganic anions) only when the CO32- concentration is low. At the anion concentrations of 10 mM or more, the MB degradation by Co-CA is hindered since the treatment efficiency is reduced. This study successfully develops functional Co-CA owning remarkable MB removal efficiency, indicating their great potential in dye-polluted wastewater management. [ABSTRACT FROM AUTHOR]

Chitosan - the second most abundant polysaccharide on Earth has been known as a kind of non-toxic, environmentally friendly, biodegradable, antibacterial, and antifungal material. Compared with bulk chitosanbased materials, nanochitosan has superior properties in terms of permeability, solubility, and bioactivity. Nanochitosan is used as a carrier encapsulating various components via complexes with NH2 and OH groups of chitosan molecules to protect, stabilize, and deliver targeted bioactive compounds. For the first time, chitosanzinc ion nanoparticles (CSZ NPs) have been successfully synthesized by ultrasound-assisted ionic gelation to produce much smaller particles with enhanced antibacterial and antifungal activities. The fabricated CSZ NPs have a diameter from 119.3 to 212.6 nm, polydispersity index ranging from 0.2 to 0.3, and zeta potential from 16.4 to 22.4 mV. The average size of the as-fabricated CSZ NPs is two times smaller than zinc ions loaded nanochitosan without ultrasonic treatment. The spherical shape of the nanochitosan particles is confirmed, along with a wide range of elemental distributions, including C (29.74 %), O (42.14 %), Na (15.80 %), and Zn (1.11 %). The antimicrobial activities of CSZ NPs are evaluated by using the agar well diffusion method with gramnegative bacteria (E. coli, P. aeruginosa), gram-positive (E. feacalis, S. aureus, S. aureus methicillin-resistant (MRSA)), and fungi (C. albicans, A. niger). The minimum inhibitory concentration of CSZ NPs is 14 µg/mL for bacteria and more than 58 µg/mL for fungi. CSZ NPs have potential antimicrobial applications in the food industry and agriculture. [ABSTRACT FROM AUTHOR]

Recently, oil spills have been received numerous concerns all over the world because of its harmful influences for ecosystem and human being. Various techniques are introduced to manage this kind of pollution, including physical adsorption by porous materials. Carbon aerogel is one of those promising materials because of its great potential in extremely fast oil adsorption without any emission of toxic compounds. Cigarette waste is one of the most littered things around the world that can be endanger for the environment. For the first time, carbon aerogels have been successfully fabricated via a simple pyrolysis of eco-friendly cellulose acetate-based aerogels from cigarette butts waste from the tobacco factory. The prepared ultralight carbon aerogels exhibit significantly low density (36.34-50.50 mg/cm³) and high porosity (98.39-97.76 %). The aerogel has highly porous structure with irregular shaped pore in range of 10 to 100 µm. Carbon aerogels express good hydrophobicity with water contact angles more than 120°. The oil adsorption capacity of carbon aerogels is up to 14-21 times their own weight within 40 s, which is significantly higher than original cellulose-based aerogels (11-14 times their own weight). The oil adsorption of carbon aerogel follows pseudo-second order kinetics which adsorbs quickly in few seconds and reaches equilibrium in less than 60 min. In conclusion, the carbon aerogels from cigarette butt-derived cellulose acetate exhibit a great potential in the field of oil spills treatment. [ABSTRACT FROM AUTHOR]

Each year, the global annual production of coconut fibre (CF) is around 350×10³ t, while they are utilized for fine art, fertilization, and animal feed. However, there have not seen many engineering applications to utilize these materials. The coir with high cellulose content of over 40 % has potential for high-value engineering applications like fabricating cellulose-based aerogels. Recently, the cellulose aerogel from CF was formed using a sol-gel method in an NaOH/Urea solution, with an anticipated completion time of 7 d due to the time required for gelation and solvent exchange, which might take up to 4 d. This demonstrates that the present approach is subject to several time limitations. To improve this, for the first time, a novel fabrication of aerogels from the CF with chemical pre-treatment in advance has been successfully developed by using polyvinyl alcohol (PVA) and xanthan gum (XTG) as biodegradable binders. The treated CFs are dispersed homogeneously into a PVA/XTG solution, followed by freeze-drying to remove water, leaving behind a highly porous called CF aerogel. The influences of CF content on CF aerogels' physical and mechanical characteristics, as well as oil adsorption and thermal conductivity, have all been thoroughly investigated. For oil removal, the fabricated CF aerogels are surface-modified with methyltrimethoxysilane (MTMS) to enhance their hydrophobicity. This method required 2 times less time and used fewer chemicals while retaining the same oil adsorption capabilities of up to 20 g/g as previous CF aerogel and demonstrating additional good insulation of 0.040 W/(m·K). Thus, this study provides a new novel approach to synthesize an oil-absorbing and insulating CF aerogel. [ABSTRACT FROM AUTHOR]

Over twenty million tons of pineapples have been produced annually worldwide, but their waste is mostly discarded or burnt after harvesting. In this work, the high-value added aerogels from the pineapple leaf waste are developed for the first time by using polyvinyl alcohol (PVA) cross-linkers and a cost-effective freeze drying process. The pineapple fibre (PF) aerogels have highly porous structures with the porosities of 96.98–98.85%, ultra-low densities of 0.013–0.033 g/cm3, and hydrophobicity with water contact angles of approximately 140°, after a surface modification with methyltrimethoxysilane (MTMS). The effects of PF concentrations (0.5–2.0 wt.%) on oil and organic solvent adsorption are investigated comprehensively. Experimental results indicate that the hydrophobic PF aerogels can adsorb motor oil up to 37.9 g/g, approximately two times greater than commercial polypropylene and polyurethane sorbents. The pseudo-second order model can provide a good fit for the oild adsorption kinetics of the developed aerogels. [ABSTRACT FROM AUTHOR]

Recent studies have developed varied delivery systems incorporating natural compounds to improve the limitations of plant extracts for clinical use while enabling their controlled release at treatment sites. For the first time, ethanolic limeberry extract (Triphasia trifolia) has been successfully encapsulated in thermo-sensitive chitosan hydrogels by a facile in situ loading. The extract-incorporated chitosan hydrogels have a pH value of nearly 7.00, gelation temperatures in the range of 37-38 °C, and exhibit an open-cell porous structure, thus allowing them to absorb and retain 756 % of their mass in water. The in vitro extract release from the hydrogels is driven by both temperature and pH, resulting in more than 70 % of the initial extract being released within the first 24 h. Although the release half-life of hydrogels at pH 7.4 is longer, their release capacity is higher than that at pH 6.5. Upon a 2 °C increase in temperature, the time to release 50 % initial extract is sharply reduced by 20-40 %. The release kinetics from the hydrogels mathematically demonstrated that diffusion is a prominent driving force over chitosan relaxation. Consequently, the developed hydrogels encapsulating the limeberry extract show their heat and pH sensitivity in controlled release for treating chronic wounds., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 Elsevier Ltd. All rights reserved.)

The global trend of increasing energy demand along the large volume of wastewater generated annually from the paper pulping and cellulose production industries are considered as serious dilemma that may need to be solved within these current decades. Within this discipline, lignin, silica or lignin-silica hybrids attained from biomass material have been considered as prospective candidates for the synthesis of advanced materials. In this study, the roles and linking mechanism between lignin and silica in plants were studied and evaluated. The effects of the extraction method on the quality of the obtained material were summarized to show that depending on the biomass feedstocks, different retrieval processes should be considered. The combination of alkaline treatment and acidic pH adjustment is proposed as an effective method to recover lignin-silica with high applicability for various types of raw materials. From considerations of the advanced applications of lignin and silica materials in environmental remediation, electronic devices and rubber fillers future valorizations hold potential in conductive materials and electrochemistry. Along with further studies, this research could not only contribute to the development of zero-waste manufacturing processes but also propose a solution for the fully exploiting of by-products from agricultural production., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have influenced the work reported in this paper., (Copyright © 2023 Elsevier B.V. All rights reserved.)

Chitosan hydrogel is a smart and highly applicable drug delivery carrier because of its nature, biocompatibility, biodegradability, and ability to encapsulate, carry and release the drug to the desired target flexibly depending on the conditions of the patient. Not only developing delivery systems but natural compounds are also increasingly being studied in supporting the treatment of diseases. However, the physicochemical and pharmacokinetic issues of the phytochemicals are remaining. This review summarizes the remarkable properties of chitosan hydrogel; approaches to loading natural extracts on the hydrogels to overcome the susceptibility of the phytochemicals to degradation; and their applications in biomedical fields. The drug loading efficiency, release profile, in vitro and in vivo results of the chitosan hydrogels carrying natural compounds are discussed to point out the remaining challenges of combining the extracts with chitosan hydrogels and controlling the release of the carried substances., (Copyright © 2022 Elsevier Ltd. All rights reserved.)

A promising and economic material for various applications, such as thermal insulation in construction building and oil clean-up in marine ecosystems, is successfully developed from the by-product of the sugarcane industry. Biodegradable sugarcane bagasse aerogels are produced using polyvinyl alcohol (PVA) binder, followed by a freeze-drying method. This environmental-friendly recycled aerogel has an ultra-low density ([0.016-0.112] g/cm 3 ), a high porosity ([91.9-98.9]%), and a very low thermal conductivity ([0.031-0.042] W/mK). Its superhydrophobicity properties and its maximum oil absorption capacity (up to 25 g/g) are measured after coating aerogel samples with methyltrimethoxysilane (MTMS). The biodegradable aerogel has a Young's modulus of 88 K Pa and can be bent without breaking, demonstrating its high flexibility., (Copyright © 2019 Elsevier Ltd. All rights reserved.)