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This context presents the study of ultrasonic-assisted extraction (UAE) to obtain phenolic and flavonoid compounds from watermelon rind powder (WRP). The antioxidant activity of the extracts was investigated using DPPH and ABTS+ assays. One-factor experiments were conducted to examine the effect of each factor (solid-to-liquid ratio (SLR), acetone concentration (AC), temperature, and time) on the UAE of WRP. Box-Behnken Design (BDD) model was employed to optimize the UAE conditions based on total phenolic contents (TPC), total flavonoid content (TFC), and their antioxidant activities. The optimal conditions were 1:30.50 SLR, 70.71% AC, 29.78 °C, and 10.65 min extraction time. There were no significant differences between predicted and experimental results (less than 6.0%), recommending a feasible and innovative process of deploying UAE to extract phenolics and flavonoids effectively from watermelon rind.

In this study, the gasification of rice husk in a downdraft process is simulated by Aspen Plus software to predict an appropriate operation condition for designing small-scale equipment. Gibbs models of the reactions occurring in the process are applied for the simulation while tuning the equivalence ratio (ER) to forecast the syngas’ compositions. Based on the analysis, ER value of 0.096 is selected to generate a syngas mixture consisting of CO (43.26 mol%), CH4 (0.09 mol%), and H2 (33.87 mol%), corresponding to the optimal calorific value of 8.92 MJ/kg and efficiency of 86.98 %. A real experiment is performed with the small-scale gasifier to evaluate the results obtained from the simulation. The pilot results show that not only the input air flow rate but other confounding factors also affect the combustion efficiency at some degree, which is compatible with the simulation model. The total energy value acquired from the conversion of 5.0 kg of dry rice husk was 86.82 MJ, while the energy value of the syngas obtained was 44.42 MJ syngas.

Recently, bio-based materials that are both environmental-friendly and highly functional were synthesized from various waste and biomass. Rice straw, a by-product of paddy production, is abundant lignocellulosic biomass with high cellulose content. The utilization of this natural resource for high functional material often meets with difficulties due to a large amount of lignin and silica present in the material matrix. While rice straw has been employed for biofuel production on pilot scale, its use for cellulose recovery has only been performed in laboratory-scale equipment. Here we show a simple process to effectively recover cellulose from rice straw on a pilot scale, after which the extracted cellulose was used for the preparation of aerogel. The alkali pretreatment removed the majority of lignin and silica, yielding semi-product with cellulose content of 73 %, then the bleaching step with hydrogen peroxide further eliminated colored impurities to increase the cellulose content to 90 %. The obtained cellulose was then employed to fabricate cellulose aerogel with low density, high surface area, and porous structure, which showed a good performance in the separation of oil and water, with the maximum capacity reaching 21.7 g/g. The process is a promising solution for converting rice straw into a more valuable product for water treatment on a larger scale.

Nanocellulose is one of the most valuable biomass-derived materials, possesses outstanding properties, and is widely used in numerous applications for biomedical fields, packaging, and environmental waste treatment. Rice straw is an abundant by-product from the rice industry and among cellulose-rich feedstocks. The pristine structural network of this raw material is complicated composing cellulose, hemicellulose, and lignin. Therefore, the pretreatment step is necessary to facilitate further stages in the biomass conversion process. The effect of such methods on the characteristics of nanocellulose products from rice straw has not been widely investigated in comparison with other types of biomass. This review summarized the common methods for rice straw pretreatment and the effects of distinct methods on the obtained nanocellulose. Alkaline pretreatment is considered as one of the most effective method for the extraction of cellulose from lignocellulosic complex. Based on a comprehensive summary, this review also shows that cellulose nanocrystals (CNCs) which is usually isolated by acid hydrolysis, has a high crystallinity index due to the removal of amorphous region. Cellulose nanofibrils (CNFs) is obtained by employing mechanical methods to reduce the particle size of cellulose fibers.

Aerogels from cellulose and its derivatives, especially cellulosic wastes, have been known as an excellent heat insulation material in steam generation, buildings, intelligent food packaging, fire-retardant clothing, and thermal protective equipment because of their lightweight properties, high stability, and extremely low thermal conductivities. Towards the scope of maximizing the bio-based resources utilization in day-to-day life, pineapple leaves (PLs) are converted into microfibrillated cellulose (MFC) fibers. PLs are first pretreated step by step with NaOH and NaOH/H2O2 solution to enrich cellulose content. This was followed by acid hydrolysis (H2SO4 40 wt%) and high-speed homogenization for MFC production. The obtained cellulose microfibers are further exploited to produce cost-effective, eco-friendly, and high-value engineering aerogels cross-linked by a common polyamide amine-epichlorohydrin (PAE) for the first time. The developed procedure is feasibly applied to mass production at a pilot-scale because of its simplicity, cost-effectiveness, and environmental friendliness. The resulting aerogels exhibit ultra-low density (below 30.0 g/cm3) and high porosity (above 98.0 %) along with high elasticity. Morphology analysis reveals that most of the pores within the aerogels are macroporous, and the diameter of fibers is around 2-3 µm. The heat conductivity of as-fabricated aerogels is in the range of 0.035-0.043 W/m?K, which is comparable to some heat insulation products such as glass wool (0.031-0.043 W/m?K), cellular glass (0.038-0.043 W/m?K), and mineral wool (0.034-0.045 W/m?K). The effects of cellulose and PAE contents on the morphology, physical, mechanical, and thermal behaviors of the synthesized aerogels are also investigated. The MFC aerogels from pineapple leaves are considered novel and promising candidates for bio-based heat insulation applications.

This research presented a method to synthesize magnetic nanocrystalline cellulose-based nanocomposites using in-situ co-precipitation technique to produce ferromagnetic oxide particles (Fe3O4) that were grafted on the surface of cellulose nanocrystals (CNCs). The synthesized material was used to remove lead ions from aqueous solutions. Different physicochemical analyst techniques such as XRD, FTIR, SEM, and TEM were used to characterize the structure of the material upon the different ratios of cellulose nanocrystals/ Fe3O4. The XRD analysis showed that CNC/Fe3O4 nanocomposite has characteristic diffraction peaks corresponding to Fe3O4 and cellulose nanocrystals. The FTIR spectrum indicated the specific functional groups of Fe3O4 and CNC in the nanocomposite materials. The size of nanoparticles produced in this work were less than 15 nm with Fe3O4 and roughly 25 nm with CNC via image SEM and TEM. According to these studies, with the same Pb2+ concentration in water of 200 ppm, the best condition for homogenous materials was the 1:1 ratio (cellulose nanocrystals: Fe3O4) and the absorption capacity at time balance (qe) was 0.1132 mg/g. The lead adsorption of material was evaluated by the ICP-OES measurement method. The equilibrium data fitted the Freundlich isotherm model better than the Langmuir isotherm model. The new adsorbent can help removing 60 % of Pb2+ from the solution and can be magnetically separated from the continuous phase.

An imidazolium-based zwitterionic compound bearing two ether groups at the C-1 and C-2 positions and one sulfonate group at the C-3 position of the imidazolium ring was successfully synthesized. The compound was characterized using nuclear magnetic resonance spectroscopy and elemental analysis. The product (2.5 wt%) was added to a commercial electrolyte for lithium-ion batteries containing 1 M LiPF6 in ethylene carbonate, dimethyl carbonate, and ethyl methyl carbonate (1:1:1 by volume). The resulting electrolyte had a slightly higher ionic conductivity in the range 10–70 °C than the model electrolyte, implying that the additive had a beneficial impact, possibly due to the C-2 rather than the C-1 ether group. Cyclic voltammetry analysis indicated that the electrochemical stability of the electrolyte did not change. The effect of the electrolyte additive on the cell’s 1C cycling performance was also examined: it was found that a stable discharge capacity was maintained for up to 100 cycles. Fourier transform infrared spectra of complexes formed by the synthesized product and LiPF6 at different ratios showed that the Li+ ions interacted with all the functional groups.

This study investigates the combination of acidic and alkaline for pretreatment to enhance the efficiency of cellulose enrichment for a lignocellulosic material, herein, rubber sawdust. Treating the material with acid followed by alkaline treatment resulted in higher efficiency, leading to an increased hydrolysability of the material in Simultaneous Saccharification and Fermentation (SSF) Processes. The pretreatment of rubber sawdust with an H2SO4 1.0 wt% solution for 5.5 h, followed by NaOH 2.75 wt% solution for 24 h, gave the best response to a factorial experimental design. Under these conditions, the efficiency was 69.25 %with a cellulose crystallinity index of 50.31 %. The SSF conversion of different pretreated materials to bioethanol also confirmed that increasing the amorphous cellulose content led to higher efficiencies.

Deoiled coconut cake powder (DCCP) was hydrolyzed to reduce the ratio of insoluble/soluble dietary fiber (RIS) by partially converting insoluble dietary fiber to soluble using Celluclast 1.5 L, a commercial cellulase preparation in citrate buffer medium. Firstly, the influence of citrate buffer amount, enzyme concentration, pH, and retention time on the enzymatic hydrolysis efficiency was investigated. Then, response surface methodology (RSM) was employed to optimize the process in which the insoluble and soluble dietary fiber contents were the responses. The results revealed that 10.3 g buffer/g of materials, 3.7 U/g of the materials, and 60 min of retention time were the optimal conditions for the enzymatic hydrolysis to obtain the insoluble and soluble contents of 68.21%db and 8.18%db, respectively. Finally, DCCP or hydrolyzed DCCP (HDCCP) was partially substituted for wheat flour at different replacement ratios in a cookie recipe at 0, 10, 20, 30, and 40%. The cookies with a 10% replacement ratio of hydrolyzed deoiled coconut cake powders had a lower RIS by more than two folds those of DCCP and had the same sensorial score as the control sample. This study proposed that Celluclast 1.5 L effectively reduced RIS by partially converting insoluble to soluble dietary fiber, improving the soluble dietary fiber content in fiber-enriched cookies.

Red Ganoderma lucidum (G. lucidum) is a popular medicinal herb commonly used in Vietnamese traditional remedies due to its potential value for health. In this study, polysaccharides were extracted from G. lucidum using ultrasound-assisted enzymatic extraction method. The response surface methodology and Box–Behnken design were employed to investigate the effects of pH, extraction temperature, extraction time, and ultrasonic power on the content of polysaccharides. Based on ultraviolet-visible spectroscopy analysis, the highest content of polysaccharides in the extract was 32.08 mg/g under optimum experimental parameters including enzyme concentration of 3%, pH of 5.5, extraction temperature of 45°C, extraction time of 30 min, and ultrasonic power of 480 W. The Fourier-transform infrared spectroscopy was also used to identify the functional groups in the extracts. The molecular weights of polysaccharides were determined by gel permeation chromatography. The obtained extract was then evaluated for anticancer activities by using (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) assay, showing the anticancer activities with the half-maximal inhibitory concentration value of more than 512 μg/mL. This result suggested that UAEE could be considered as an appropriate and effective extraction method for bioactive crude polysaccharides from G. lucidum.

Vietnamese Callisia fragrans (C. fragrans) has been considered as a valuable traditional plant with various medicinal properties. In this study, polyphenols were extracted from Vietnamese C. fragrans leaves by supercritical carbon dioxide (SC-CO2) extraction method using ethanol as a cosolvent. The investigation of four factors influencing the total polyphenol content (TPC) and antioxidant activity of the extracts obtained from each single-factor experiment was conducted including ethanol concentration, CO2 flow rate, extraction temperature, and pressure. Besides, the extraction efficiency of the SC-CO2 method under the best extraction conditions, namely ethanol concentration of 14%, CO2 flow rate of 20 g/min, extraction temperature of 45°C, and pressure of 200 bar was compared to that of the Soxhlet extraction (SE) method in terms of the TPC and antioxidant activity of the extracts. The results showed that using SC-CO2 method, the TPC and the half-maximal inhibitory concentration value obtained were of 87.42 ± 1.33 mg/g and 243.83 ± 5.30 μM TE/g, respectively, with much less time and solvent amount required while that obtained using SE method were of 85.34 ± 4.27 mg/g and 236.33 ± 7.66 μM TE/g, respectively. This indicated that SC-CO2 would be suitable for the industrial production of polyphenols with high antioxidant activity of the extracts obtained due to the restrictions of using the SE method and advantages of applying SC-CO2 method. Therefore, SC-CO2 method could be regarded as a potentially upcoming extraction technique which might be employed to replace the conventional SE method.

The optimal solutions to treat dyeing and textile wastewater to contribute to the global goal of ''Net Zero'' emissions have attracted attention worldwide. The anaerobic digestion process has some advantages, including its low sludge production, effective removal of color, high COD reduction, and the recovery of CH₄ gas, which helps to mitigate greenhouse gas emissions. This study applied a batch-scale anaerobic digestion system at mesophilic conditions (∼35 °C) and thermophilic conditions (∼55 °C) to treat dyeing and textile wastewater containing a mixture of reactive dyes, including Reactive Yellow 145 (RY145), Reactive Red 198 (RR198), and Reactive Black 5 (RB5). The results indicated that the methane gas production from the thermophilic anaerobic digestion process was 1.41 times higher than that from the mesophilic process. Additionally, the specific methanogenic activity of the thermophilic process also outperforms the mesophilic one, with a specific organic load of 0.284 kgCOD/kgVSS.d for sludge in the thermophilic process compared to 0.195 kgCOD/kgVSS.d for the mesophilic process. The removal of color in the thermophilic process was 6.7% higher than that of mesophilic one. In addition, the first-order kinetic rate constant (k) for thermophilic anaerobic digestion (0.32 1/d) was 1.46 times higher than the mesophilic process (0.22 1/d). Further, an interesting observation is that color removal from real dyeing and textile wastewater was better than that from synthetic wastewater, with rates of 6.92 1/d and 0.32 1/d, respectively.

In this study, silver‐titanium dioxide/graphene aerogel (Ag−TiO2/GA−ATG) was synthesized via chemical reduction using ethylene diamine (EDA). The effects of reductant doses on the formation of the three‐dimensional structure and the photocatalytic degradation efficiency of ATG were evaluated with five different volumes (20, 30, 40, 50, and 60 μL), corresponding to the ATG1, ATG2, ATG3, and ATG4, respectively. The results showed that 40 μL of EDA was the suitable condition for the formation of ATG three‐dimensional structure. Characterizations revealed that ATG3 was successfully synthesized with distinctive peaks of Ag and TiO2 in the X‐ray diffraction patterns whilst scanning electron microscope and high resolution transmission electron microscope images showed a porous structure, silver nanoparticles and TiO2 with an average size of 10–25 nm were uniformly distributed on the graphene surface. Furthermore, ATG3 possessed the highest photocatalytic capability to deteriorate methyl orange with an efficiency of up to 99.53 % with a catalyst dose of 0.3 mg/mL, superior compared to those of TiO2 and TiO2/GA. The radicals scavenging experiments elucidated ⋅O2 ${{{\rm { O}}}_{{\rm { 2}}}^{{\rm { \char60 M-\char62 }}}}$ to majorly contribute to the photodegradation process. Moreover, ATG3 showed high recyclability, which retains 80 % of yield even after 10 cycles. Those findings proved that ATG has high potential in the environmental remediation field. [ABSTRACT FROM AUTHOR]

This research presented a method to synthesize magnetic nanocrystalline cellulose-based nanocomposites using in-situ co-precipitation technique to produce ferromagnetic oxide particles (Fe3O4) that were grafted on the surface of cellulose nanocrystals (CNCs). The synthesized material was used to remove lead ions from aqueous solutions. Different physicochemical analyst techniques such as XRD, FTIR, SEM, and TEM were used to characterize the structure of the material upon the different ratios of cellulose nanocrystals/Fe3O4. The XRD analysis showed that CNC/Fe3O4 nanocomposite has characteristic diffraction peaks corresponding to Fe3O4 and cellulose nanocrystals. The FTIR spectrum indicated the specific functional groups of Fe3O4 and CNC in the nanocomposite materials. The size of nanoparticles produced in this work were less than 15 nm with Fe3O4 and roughly 25 nm with CNC via image SEM and TEM. According to these studies, with the same Pb2+ concentration in water of 200 ppm, the best condition for homogenous materials was the 1:1 ratio (cellulose nanocrystals: Fe3O4) and the absorption capacity at time balance (qe) was 0.1132 mg/g. The lead adsorption of material was evaluated by the ICP-OES measurement method. The equilibrium data fitted the Freundlich isotherm model better than the Langmuir isotherm model. The new adsorbent can help removing 60 % of Pb2+ from the solution and can be magnetically separated from the continuous phase. [ABSTRACT FROM AUTHOR]

In this study, rice husk ash-silica/graphene oxide (RHA-SiO2/GO) nanocomposites were synthesized by the in situ method using (3-aminopropyl) triethoxysilane as a coupling agent. The obtained products were used to remove lead ions (Pb2+) from aqueous solution. Effects of SiO2:GO mass ratio, contact time, pH and initial Pb2+ concentration on the adsorption capacity were studied. It was found that the suitable ratio of SiO2:GO for Pb2+ adsorption is 100:2. The suitable RHA-SiO2/GO was characterized by Fourier-transform infrared spectroscopy, X-ray diffraction, transmission electron microscopy, Brunauer–Emmett–Teller specific surface area and thermal gravimetric analysis. Accordingly, RHA-SiO2/GO nanocomposite could be used as promising adsorbent for the removal of Pb2+ from water. [ABSTRACT FROM AUTHOR]

In this study, the conditions of ginsenoside Rb1 extraction from Panax notoginseng (Burk.) F.H. Chen (P. notoginseng) roots by enzyme-assisted method were investigated by using the central composite design (CCD). This design was applied to survey the effects of pH, temperature, and time on Rb1 content. The concentration of Rb1 was determined based on high-performance liquid chromatography (HPLC). The investigation of anticancer activities of P. notoginseng extract on breast carcinoma (MCF-7) cell lines and human lung carcinoma (Lu) showed that the extract had remarkable cytotoxic activity against these cancer cell lines. [ABSTRACT FROM AUTHOR]

As an abundant biomass of surface water, water hyacinth was used as an input material to produce bioethanol in this study. Steam explosion and alkaline pre-treatment were applied on the material before simultaneous saccharification and fermentation (SSF) process was carried out. Experimental data suggested the optimal enzyme dosage be 1.0 wt% of the dry mass of the biomass, and the mass of the material be up to 8.0 wt% of the whole mixture in a one-step loading procedure to obtain the climax efficiency after 78 h. The process does not need additional nitrogen nutrition, such as corn steep liquor (CSL), as those in other common lignocellulosic bioethanol processes, because water hyacinth itself contains much protein in its chemical composition. Protein content analysis showed that it was 17.2 wt% (on dry basis), similar to what reported in some published studies. The SSF efficiency was positively 72.8 % at the optimal conditions resulted out from the experiments. Such a convenient conversion of water hyacinth to bioethanol is not only meaningful in term of biofuel production but also in term of environmental treatment. [ABSTRACT FROM AUTHOR]