Depolymerization of Rice Straw Lignin into Value-Added Chemicals in Sub-Supercritical Ethanol.

Depolymerization of lignin is an important step to obtain a lignin monomer for the synthesis of functional chemicals. In the context of more lignin produced from biomass and pulp industry, converting real lignin with low purity is still required more studies. In this study, the influence of solvent composition and reaction parameters such as binary solvents ratio, time, and temperature, the solvent-to-lignin ratio on the depolymerization of rice straw lignin was investigated carefully. Essential lignin-degraded products including liquid product (LP), char (solid), and gas were obtained, and their yields were directly influenced by reaction conditions. Results show that the maximum lignin conversion rate of 92% and LP yield of 66% was under the condition of 275°C, 30 min, 75 : 1 (mL solvent/1 g lignin), and ethanol 50%. Gas chromatography-mass spectroscopy (GC-MS) analysis was used for the analysis of the depolymerization products and identified 11 compounds which are mainly phenolic compounds such as 2-ethylphenol, 3-ethylphenol, phenol, methyl 2,4,6-trimethylbenzoate. The structure changes of LP and char in various conditions were analyzed using Fourier-transform infrared (FTIR).

A data-driven QSPR model for screening organic corrosion inhibitors for carbon steel using machine learning techniques.

Machine learning (ML) techniques have shown great potential for screening corrosion inhibitors. In this study, a data-driven quantitative structure-property relationship (QSPR) model using the gradient boosting decision tree (GB) algorithm combined with the permutation feature importance (PFI) technique was developed to predict the corrosion inhibition efficiency (IE) of organic compounds on carbon steel. The results showed that the PFI method effectively selected the molecular descriptors most relevant to the IE. Using these important molecular descriptors, an IE predictive model was trained on a dataset encompassing various categories of organic corrosion inhibitors for carbon steel, achieving RMSE, MAE, and R2 of 6.40%, 4.80%, and 0.72, respectively. The integration of GB with PFI within the ML workflow demonstrated significantly enhanced IE predictive capability compared to previously reported ML models. Subsequent assessments involved the application of the trained model to drug-based corrosion inhibitors. The model demonstrates robust predictive capability when validated on available and our own experimental results. Furthermore, the model has been employed to predict IE for more than 1500 drug compounds, suggesting five novel drug compounds with the highest predicted IE on carbon steel. The developed ML workflow and associated model will be useful in accelerating the development of next-generation corrosion inhibitors for carbon steel.

Recovery of aluminum from plastic packages containing aluminum by gasification.

The standing pouch, a packaging material made of multiple layers of plastic and metal, presents a significant challenge for full recycling. Gasification shows promise as a method to recover aluminum from this type of waste and convert it into energy. This study aims to evaluate the efficiency of gasification in treating aluminum-containing plastic packages, and recovering aluminum while identifying the optimal combinations of temperature and equivalence ratio (ER) to achieve the best outcomes. The study achieved a conversion rate of 43.06 wt% to 69.42 wt% of the original waste mass into syngas, with aluminum recovery rates ranging from 35.2 % to 65.3 %. Temperature and ER alterations affected the product distribution, aluminum recovery rate, and aluminum partitioning in the products. The results indicated that the combination of 700 °C, ER = 0.4 would provide the largest amount of syngas about 69.42 %, which is the main product of the gasification process, and therefore, this combination is the most optimal for syngas-yielding purposes. Under the reclaiming aluminum is more prioritized, the combination of 800 °C, ER = 0.6 would be the most optimal condition, the majority of Al in fuel was found in char and fly ash were 67.5 % and 4.81 %, respectively. The study focused on the partitioning of aluminum during the gasification process, which was observed to mainly exist in the form of Al2O3(s), with gaseous species including AlCl3(g), AlH(g), and Al2O(g) due to their medium volatility. As the ER increased, the amount of O2 also increased, leading to more Al2O3(s) formation. In conclusion, this research provides a foundation for further exploration of gasification as a means of energy conversion and metal recovery.

Innovative ultrasonic emulsification of cinnamon essential oil pickering emulsion stabilized by rice straw-derived cellulose nanocrystals.

For the first time, ultrasonic emulsification was studied for cinnamon essential oil (CEO) Pickering emulsion, stabilized by cellulose nanocrystal (CNC) from rice straw. Sonication proved to be an effective method for emulsifying CEO, creating small emulsion droplets around 700 nm in size, with an even dispersion characterized through a low polydispersity index. The biomass-derived CNC exhibits high encapsulation efficiency (> 95 %) with varying CEO concentration (5-25 vol%), creating droplets with negative surface charge with limited aggregation of emulsions. Optimization through the Box Behnken design using response surface methodology provides a model for the interaction and effects of variables towards the formulation. Optimal condition was concluded to be at 11.47 vol% CEO, 0.84 wt/vol% CNC and at 6 sonication cycles. The optimized Pickering emulsions retain the antimicrobial properties of CEO, with a large inhibition zone and low MIC value of around 0.048 vol% CEO. DPPH inhibition assay indicates that the emulsification process enhances the antioxidation properties of cinnamon essential oil, expressed through a lower IC50 of 0.90 vol% CEO, in comparison to pure essential oil at 1.33 vol% CEO. Overall, this research proposes a novel approach towards using nanocellulose as carriers for essential oil with potential in a large variety of applications.

Silk fibroin/chitosan/montmorillonite sponge dressing: Enhancing hemostasis, antimicrobial activity, and angiogenesis for advanced wound healing applications.

Open wounds present a significant challenge in healthcare, requiring careful management to prevent infection and promote wound healing. Advanced wound dressings are critical need to enhance their hemostatic capabilities, antimicrobial properties, and ability to support angiogenesis and sustained moisture for optimal healing. This study introduces a flexible hemostatic dressing designed for open wounds, integrating chitosan (CS) for hemostasis and biocompatibility, silk fibroin (SF) for mechanical strength, and montmorillonite (MMT) for enhanced drug transport. The CSSF@MMT dressings showed promising mechanical strength and swift hemostasis. The CIP-loaded CSSF@MMT demonstrated sustained release for up to one week, exhibiting antibacterial properties against both Gram-positive and Gram-negative bacteria. In vitro cell migration assay demonstrated that erythropoietin-loaded CSSF@MMT dressings promoted the proliferation and migration of endothelial cells. Similarly, the chick embryo chorioallantoic membrane study indicated the same dressings exhibited a significant increase in vascular regeneration. This research suggests that the CSSF@MMT sponge dressing, incorporated with CIP and erythropoietin, holds promise in effectively halting bleeding, creating a protective environment, diminishing inflammation, and fostering wound tissue regeneration. This potential makes it a significant advancement in open wound care, potentially lowering the need for limb amputation and decreasing wound care burden worldwide.

Encapsulation of Triphasia trifolia extracts by pH and thermal dual-sensitive chitosan hydrogels for controlled release.

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.

A review of the extraction methods and advanced applications of lignin-silica hybrids derived from natural sources.

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.

Recent developments in chitosan hydrogels carrying natural bioactive compounds.

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.

Development of a paddy-based biorefinery approach toward improvement of biomass utilization for more bioproducts.

Improvement of biomass utilization productivity following cascading strategy is a priority for the biorefinery-based circular bioeconomy. In recent years, the field of energy research has seen an increasing interest in bio-products from paddy-based biorefinery, but the utilization of the entire value of paddy biomass to guide the commercial viability of its products has not been got feasible outcomes. Here we propose a potential pathway for a conceptual paddy biorefinery framework by addressing wastes for producing more products. The feasibility of the integrated biorefinery was demonstrated by the conversion of wastes into value-added products such as nano-silica and lignin. In particular, this is the first time that silica recovered from bioethanol system was continued to be reused to produce ZSM-5 and Ni/ZSM-5 as catalysts of rice straw lignin depolymerization achieving high conversion of lignin up to 95% and fair yield of phenolic products up to 41%. Material flow of an integrated biorefinery model was reported to give a future outlook for making most of the processing routes of rice residues. We also established a life cycle that follows the circular bioeconomy concept and discussed the relationship between each of potential bioproducts and their market opportunities.

Recent Progresses in Eco-Friendly Fabrication and Applications of Sustainable Aerogels from Various Waste Materials.

Tons of waste from residential, commercial and manufacturing activities are generated due to the growing population, urbanization and economic development, prompting the need for sustainable measures. Numerous ways of converting waste to aerogels, a novel class of ultra-light and ultra-porous materials, have been researched to tackle the issues of waste. This review provides an overview of the status of aerogels made from agricultural waste, municipal solid, and industrial waste focusing on the fabrication, properties, and applications of such aerogels. The review first introduced common methods to synthesize the aerogels from waste, including dispersion and drying techniques. Following that, numerous works related to aerogels from waste are summarized and compared, mainly focusing on the sustainability aspect of the processes involved and their contributions for environmental applications such as thermal insulation and oil absorption. Next, advantages, and disadvantages of the current approaches are analyzed. Finally, some prospective waste aerogels and its applications are proposed.

The novel method to reduce the silica content in lignin recovered from black liquor originating from rice straw.

Difficulties in the production of lignin from rice straw because of high silica content in the recovered lignin reduce its recovery yield and applications as bio-fuel and aromatic chemicals. Therefore, the objective of this study is to develop a novel method to reduce the silica content in lignin from rice straw more effectively and selectively. The method is established by monitoring the precipitation behavior as well as the chemical structure of precipitate by single-stage acidification at different pH values of black liquor collected from the alkaline treatment of rice straw. The result illustrates the significant influence of pH on the physical and chemical properties of the precipitate and the supernatant. The simple two-step acidification of the black liquor at pilot-scale by sulfuric acid 20w/v% is applied to recover lignin at pH 9 and pH 3 and gives a percentage of silica removal as high as 94.38%. Following the developed process, the high-quality lignin could be produced from abundant rice straw at the industrial-scale.

Cellulose-based aerogels from sugarcane bagasse for oil spill-cleaning and heat insulation applications.

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/cm3), 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.