Synthesis and characterization of aluminosilicate and zinc silicate from sugarcane bagasse fly ash for adsorption of aflatoxin B1.

Sugarcane bagasse fly ash, a residual product resulting from the incineration of biomass to generate power and steam, is rich in SiO2. Sodium silicate is a fundamental material for synthesizing highly porous silica-based adsorbents to serve circular practices. Aflatoxin B1 (AFB1), a significant contaminant in animal feeds, necessitates the integration of adsorbents, crucial for reducing aflatoxin concentrations during the digestive process of animals. This research aimed to synthesize aluminosilicate and zinc silicate derived from sodium silicate based on sugarcane bagasse fly ash, each characterized by a varied molar ratio of aluminum (Al) to silicon (Si) and zinc (Zn) to silicon (Si), respectively. The primary focus of this study was to evaluate their respective capacities for adsorbing AFB1. It was revealed that aluminosilicate exhibited notably superior AFB1 adsorption capabilities compared to zinc silicate and silica. Furthermore, the adsorption efficacy increased with higher molar ratios of Al:Si for aluminosilicate and Zn:Si for zinc silicate. The N2 confirmed AFB1 adsorption within the pores of the adsorbent. In particular, the aluminosilicate variant with a molar ratio of 0.08 (Al:Si) showcased the most substantial AFB1 adsorption capacity, registering at 88.25% after an in vitro intestinal phase. The adsorption ability is directly correlated with the presence of surface acidic sites and negatively charged surfaces. Notably, the kinetics of the adsorption process were best elucidated through the application of the pseudo-second-order model, effectively describing the behavior of both aluminosilicate and zinc silicate in adsorbing AFB1.

Synthesis and Characterization of Environmentally Friendly ß-Cyclodextrin Cross-Linked Cellulose/Poly(vinyl alcohol) Hydrogels for Adsorption of Malathion.

The widespread use of malathion enhances agricultural plant productivity by eliminating pests, weeds, and diseases, but it may lead to serious environmental pollution and potential health risks for humans and animals. To mitigate these issues, environmentally friendly hydrogel adsorbents for malathion were synthesized using biodegradable polymers, specifically cellulose, ß-cyclodextrin (ß-CD), poly(vinyl alcohol) (PVA), and biobased epichlorohydrin as a cross-linker. This study investigated the effects of the cellulose-to-PVA ratio and epichlorohydrin (ECH) content on the properties and malathion adsorption capabilities of ß-CD/cellulose/PVA hydrogels. It was found that the gel content of the hydrogels increased with a higher cellulose-to PVA and ECH ratio, whereas the swelling ratio decreased, indicating a denser structure that impedes water permeation. In addition, various parameters affecting the malathion adsorption capacity of the hydrogel, namely, contact time, pH, hydrogel dosage, initial concentration of malathion, and temperature, were studied. The hydrogel prepared with a ß-CD/cellulose/PVA ratio of 20:40:40 and 9 mL of ECH exhibited the highest malathion adsorption rate and capacity, which indicated an equilibrium adsorption capacity of 656.41 mg g-1 at an initial malathion concentration of 1000 mg L-1. Fourier transform infrared spectroscopy (FTIR), ζ-potential, and X-ray photoelectron spectroscopy (XPS) and NMR spectroscopy confirmed malathion adsorption within the hydrogel. The adsorption process followed intraparticle diffusion kinetics and corresponded to Freundlich isotherms, indicating multilayer adsorption on heterogeneous substrates within the adsorbent, facilitated by diffusion.

Production of PLA/cellulose derived from pineapple leaves as bio-degradable mulch film.

Mulch films were fabricated from polylactic acid (PLA) with cellulose nanocrystals (PNC) extracted from pineapple leaves. The PNC was modified by incorporating 4 wt% triethoxyvinylsilane (TEVS), designated as 4PNC, to enhance its interaction with PLA. The films incorporated varying concentrations of PNC (1, 2, 4, and 8 wt%). The results indicated that higher PNC concentrations increased the water vapor permeability (WVP) and biodegradability of the composite films, while reducing light transmission. Films containing 4PNC, particularly at 4 wt% (PLA/4PNC-4), exhibited an 11.18 % increase in elongation at break compared to neat PLA films. Moreover, these films showed reduced light transmission, correlating with decreased weed growth, reduced WVP, and enhanced barrier properties, indicative of improved soil moisture retention. Additionally, PLA films with 4PNC demonstrated greater thermal degradation stability than those with unmodified PNC, suggesting enhanced heat resistance. However, there was no significant difference in aerobic biodegradation between the PLA films with PNC and those with 4PNC. This study confirms that TEVS-modified cellulose significantly enhances the properties of bio-composite films, making them more suitable for mulch film applications.

Effect of the Structure of Highly Porous Silica Extracted from Sugarcane Bagasse Fly Ash on Aflatoxin B1 Adsorption.

Sugarcane bagasse fly ash is industrial waste produced by incinerating biomass to generate power and steam. The fly ash contains SiO2 and Al2O3, which can be used to prepare aluminosilicate. This latter material exhibits high potential as an adsorbent in various applications, including the livestock industry where issues related to contamination of aflatoxins in animal feeds need to be addressed; addition of adsorbents can help decrease the concentration of aflatoxins during feed digestion. In this study, the effect of the structure of silica prepared from sugarcane bagasse fly ash on physicochemical properties and aflatoxin B1 (AFB1) adsorption capability compared with that of bentonite was investigated. BPS-5, Xerogel-5, MCM-41, and SBA-15 mesoporous silica supports were synthesized using sodium silicate hydrate (Na2SiO3) from sugarcane bagasse fly ash as a silica source. BPS-5, Xerogel-5, MCM-41, and SBA-15 exhibited amorphous structures, while sodium silicate possessed a crystalline structure. BPS-5 possessed larger pore size, pore volume, and pore size distribution with a bimodal mesoporous structure, while Xerogel-5 exhibited lower pore size and pore size distribution with a unimodal mesoporous structure. BPS-5 with a negatively charged surface exhibited the highest AFB1 adsorption capability compared with other porous silica. However, the AFB1 adsorption capability of bentonite was superior to those of all porous silica. Sufficient pore diameter with high total pore volume as well as high intensity of acid sites and negative charge on the surface of the adsorbent is required to increase AFB1 adsorption in the in vitro gastrointestinal tract of animals.

Pineapple-Leaf-Derived, Copper-PAN-Modified Regenerated Cellulose Sheet Used as a Hydrogen Sulfide Indicator.

Regenerated cellulose (RC) produced from waste pineapple leaves was used to develop a colorimetric sensor as a Cu-PAN sheet (RCS). Microcrystalline cellulose derived from dried pineapple leaves was combined with Cu-PAN, dissolved in NaOH and urea, and made into an RC sheet using Na2SO4 as a coagulant. The RCS was used as an H2S indicator at various H2S concentrations (0-50 ppm) and temperatures (5-25 °C). The RCS color changed from purple to New York pink when exposed to H2S. A colorimeter method was used to develop prediction curves with values of R2 > 0.95 for H2S concentrations at 5-25 °C. The physicochemical properties of fresh and spent RCS were characterized using various techniques (Fourier transform infrared spectroscopy, X-ray diffraction, scanning electron microscopy/energy-dispersive X-ray spectroscopy, and thermogravimetric analysis). In addition, when stored at 5 and 25 °C for 90 days, the RCS had outstanding stability. The developed RCS could be applied to food packaging as an intelligent indicator of meat spoilage.

Spray drying of non-chemically prepared nanofibrillated cellulose: Improving water redispersibility of the dried product.

Despite increasing interest in using nanofibrillated cellulose (NFC) as food thickener and emulsifier, poor water redispersibility of dried NFC, which is form suitable for practical utilization, significantly limits such applications. Studies are lacking on preparation of dried NFC with superior redispersibility. The present study therefore proposed and examined strategies to improve water redispersibility of spray dried NFC via the use of selected co-carriers, i.e., gum Arabic with/without xanthan gum, carboxymethyl cellulose or pectin. Synergistic interactions between NFC and co-carriers, as confirmed by X-ray diffraction (XRD) patterns and Fourier transform infrared (FTIR) spectra, helped prevent NFC agglomeration during spray drying. All reconstituted spray-dried NFC/co-carriers suspensions exhibited shear-thinning and gel-like behaviors, thus supporting the use of such suspensions as thickener and emulsifier. Spray-dried NFC with 80% gum Arabic and 20% xanthan gum (SD-NFC/GA20XG) resulted in suspension with highest viscosity; the suspension also performed best at recovering viscous characteristics of NFC. Water thickened by SD-NFC/GA20XG had strongest shear-thinning behavior, indicating that SD-NFC/GA20XG suspension resulted in smoothest mouth feel and easiest swallowing. Such observations were supported by XRD patterns of SD-NFC/GA20XG, which suggested that its relative crystallinity was the lowest. Its FTIR spectra also showed the highest intensity of -OH bending and carbonyl bands, which are directly related to water adsorption capability of NFC. Use of reconstituted SD-NFC/GA20XG as emulsifier also resulted in highest stability for oil-in-water (O/W) Pickering emulsion during storage for up to 30 days.

Textural properties and muscle activities during mastication of normal and ultrasonically softened sticky rice aimed for consumers with swallowing disorder: A pilot study.

Ultrasonication was used to develop softer sticky rice for elder adults. Textural properties of original sticky rice (oSR) and ultrasonically modified sticky rice (mSR) were determined. In addition, jaw muscle activities during mastication of both oSR and mSR were investigated. Twenty-seven healthy elderly subjects, age 68.9 ± 7.6 years, were asked to masticate both types of sticky rice in random sequence for three times with a 5-min rest between each test. Activities of bilateral masseter and suprahyoid muscles were recorded. Root mean square (RMS) and mastication duration were analyzed. After mastication trials, subjects were asked to rate preference and softness of the samples. mSR exhibited significantly lower hardness than oSR, while cohesiveness and adhesiveness values of the two samples were not significantly different. Interestingly, all the muscle activities were not significantly different between masticating oSR and mSR, whereas the number of chewing cycles while chewing the mSR was larger. However, 92% of the subjects preferred mSR and felt that it was softer. mSR may therefore be regarded as having potential for elder people who have difficulty masticating hard solid foods based on its lower hardness and higher level of preference compared to oSR.

Modification of pineapple leaf fibers with aminosilanes as adsorbents for H2S removal.

Pineapple leaves were used as a natural fiber source to prepare various modified microcrystalline cellulose (MCC) samples as sorbents for H2S sorption. Pineapple leaf fibers were first extracted from pineapple leaves, followed by hydrolyzing to produce MCC before various modifications using primary amine (3-aminopropyltrimethoxysilane, APS), secondary amine (N-methyl-3-aminopropyltrimethoxysilane, MAPS), or tertiary amine (N,N-dimethyl-3-aminopropyltrimethoxysilane, DAPS). The characterization results proved that all the aminosilane groups were successfully grafted onto the MCC. In addition, the thermal stability and the porosity of the modified sorbents were enhanced relative to those of unmodified MCC. The H2S sorption studies of MCC modified with APS, MAPS, and DAPS at 0, 3, or 5%w/w showed that MCC-MAPS had better H2S sorption performance than MCC-APS and MCC-DAPS, respectively, when comparing the H2S sorption performance at the same loading level. The optimum H2S sorption performance of each aminosilane group was achieved from MCC-APS at 5%, MCC-MAPS at 3%, and MCC-DAPS at 5%. An additional study of H2S sorption of these three sorbents in the presence of CO2 showed that MCC-DAPS at 5% was the best sorbent for selective H2S removal. Our results indicated that MCC modified with the aminosilane groups, especially MAPS, were promising materials for H2S sorption, with potential application in gas separation.

Synthesis of Value-Added Chemicals via Oxidative Coupling of Methanes over Na2WO4-TiO2-MnO x /SiO2 Catalysts with Alkali or Alkali Earth Oxide Additives.

Na2WO4-TiO2-MnO x /SiO2 (SM) catalysts with alkali (Li, K, Rb, Cs) or alkali earth (Mg, Ca, Sr, Ba) oxide additives, which were prepared using incipient wetness impregnation, were investigated for oxidative coupling of methane (OCM) to value-added hydrocarbons (C2+). A screening test that was performed on the catalysts revealed that SM with Sr (SM-Sr) had the highest yield of C2+. X-ray photoelectron spectroscopy analyses indicated that the catalysts with a relatively low binding energy of W 4f7/2 facilitated a high CH4 conversion. A combination of crystalline MnTiO3, Mn2O3, α-cristobalite, Na2WO4, and TiO2 phases was identified as an essential component for a remarkable improvement in the activity of the catalysts in the OCM reaction. In attempts to optimize the C2+ yield, 0.25 wt % Sr onto SM-Sr achieved the highest C2+ yield at 22.9% with a 62.5% C2+ selectivity and a 36.6% CH4 conversion. A stability test of the optimal catalyst showed that after 24 h of testing, its activity decreased by 18.7%.

Removal of Heavy Metal Ions Using Modified Celluloses Prepared from Pineapple Leaf Fiber.

Since large amounts of pineapple leaves are abandoned after harvest in agricultural areas, the possibility of developing value-added products from them is of interest. In this work, cellulose fiber was extracted from pineapple leaves and modified with ethylenediaminetetraacetic acid (EDTA) and carboxymethyl (CM) groups to produce Cell-EDTA and Cell-CM, respectively, which were then used as heavy metal ion adsorbents. A solution of either lead ion (Pb2+) or cadmium ion (Cd2+) was used as wastewater for the purpose of studying adsorption efficiencies. The adsorption efficiencies of Cell-EDTA and Cell-CM were significantly higher than those of the unmodified cellulose in the pH range 1-7. Maximum adsorptions toward Pb2+ and Cd2+ were, for Cell-EDTA, 41.2 and 33.2 mg g-1, respectively, and, for Cell-CM, 63.4 and 23.0 mg g-1, respectively. The adsorption behaviors of Cell-CM for Pb2+ and Cd2+ fitted well with a pseudo-first-order model, but those of Cell-EDTA for Pb2+ and Cd2+ fitted well with a pseudo-second-order model. All of the adsorption behaviors could be described using the Langmuir adsorption isotherm. Desorption studies of Pb2+ and Cd2+ on both adsorbents using 1 M HCl suggested that regenerability of Cell-EDTA was, for both adsorbates, better than that of Cell-CM. Moreover, adsorption measurements in a mixture of Pb2+ and Cd2+ at various ratios showed that for both adsorbents the adsorption of Pb2+ was higher than that of Cd2+, while the adsorption selectivity for Pb2+ of Cell-CM was greater than that of Cell-EDTA. This study showed that the modified cellulosic adsorbents made from pineapple leaves were able to efficiently adsorb metal ions.

Synthesis of Dimethyl Ether via CO2 Hydrogenation: Effect of the Drying Technique of Alumina on Properties and Performance of Alumina-Supported Copper Catalysts.

Thermal treatment during catalyst preparation is one of the important factors affecting the characteristics and performance of a catalyst. To improve the catalytic performance of an alumina-supported copper catalyst prepared by an impregnation method for dimethyl ether (DME) synthesis from CO2, the effects of the use of hot air and infrared drying as well as calcination at 600 and 900 °C to prepare alumina supports were investigated. Infrared drying could shorten the required drying time by 75% when compared with hot air drying. Infrared drying could also help maintain the pore size and pore volume of the supports, leading to their larger surface areas. Different drying techniques were additionally noted to result in different sizes and shapes of the pores as well as to different copper distributions and intensities of acid sites of the catalyst. An increase in the calcination temperature resulted in a decrease in the surface area of the supports because of particle aggregation. The drying technique exhibited a more significant effect than calcination temperature on the space-time yield of DME. A catalyst utilizing the support prepared by infrared drying and then calcined at 600 °C exhibited the highest yield of DME (40.9 gDME kgcat -1 h-1) at a reaction temperature of 300 °C. Stability of the optimal catalyst, when monitored over a 24 h period, was noted to be excellent.

Influence of the Calcination Technique of Silica on the Properties and Performance of Ni/SiO2 Catalysts for Synthesis of Hydrogen via Methane Cracking Reaction.

Deactivation of catalysts due to rapid blocking of active surfaces and pores is a major problem for methane cracking. The removal of the template using different calcination methods contributes to the different characteristics of catalyst support. Therefore, silica supports were prepared with the sol-gel method, where sodium silicate and chitosan are a silica source and a template, respectively. Calcination using a microwave muffle furnace (MWF) was preferred over the conventional electric muffle furnace at the heating rates of 2 and 17 °C/min (CEF2 and CEF17, respectively) in order to remove the chitosan template. A nickel nitrate precursor was loaded onto the obtained silica supports by the incipient wetness impregnation method. The properties of the silica support and the Ni/SiO2 catalysts were characterized by means of N2-sorption, X-ray diffraction, scanning electron microscopy-energy-dispersive X-ray, field emission transmission electron microscopy, and H2 temperature-programmed reduction. The catalytic activity was evaluated using a fixed-bed reactor at 550 °C with a CH4/N2 ratio of 1:4 in the feed. The amount and the allotropes of carbon deposited on the spent catalysts were investigated using thermogravimetric/differential thermal analysis. The results showed that the SiO2-MWF support had a higher surface area and a larger pore volume of a mesoporous structure with larger interparticle channels than that of the SiO2-CEF supports. This leads to the higher dispersion of Ni metal particles over and inside the interparticle channels of the SiO2-MWF support. This provided a higher metal-support interaction, resulting in lower rates of methane conversion and carbon deposition on the catalyst surface than those of Ni/SiO2-CEF catalysts. However, it displayed a lower bed pressure. It was found that the carbon fibers deposited on all the catalysts were multiwalled carbon nanotubes (MWCNTs). Additionally, the base-growth mechanism of MWCNTs was only exhibited by the Ni/SiO2-MWF catalyst.

Production of Glycerol Carbonate from Glycerol over Templated-Sodium-Aluminate Catalysts Prepared Using a Spray-Drying Method.

Glycerol carbonate (GLC) was synthesized from glycerol and dimethyl carbonate (DMC) over sodium aluminate (NaAlO2) catalysts. The catalysts were prepared using a spray-drying method and compared with those prepared using the conventional hot-air drying method. Polyvinylpyrrolidone and glycerol were used as a catalyst template to increase the surface area and porosity of the catalysts. Additionally, different operating conditions were investigated such as the catalyst concentration, glycerol-to-DMC ratio, reaction temperature, reaction time, and catalyst reusability. The NaAlO2 catalyst prepared using the spray-drying method with 30 wt % glycerol as the template yielded the maximum GLC (85%) with 100% GLC selectivity.

Texture Modification Technologies and Their Opportunities for the Production of Dysphagia Foods: A Review.

Dysphagia or swallowing difficulty is a common morbidity experienced by those who have suffered a stroke or those undergone such treatments as head and neck surgeries. Dysphagic patients require special foods that are easier to swallow. Various technologies, including high-pressure processing, high-hydrodynamic pressure processing, pulsed electric field treatment, plasma processing, ultrasound-assisted processing, and irradiation have been applied to modify food texture to make it more suitable for such patients. This review surveys the applications of these technologies for food texture modification of products made of meat, rice, starch, and carbohydrates, as well as fruits and vegetables. The review also attempts to categorize, via the use of such key characteristics as hardness and viscosity, texture-modified foods into various dysphagia diet levels. Current and future trends of dysphagia food production, including the use of three-dimensional food printing to reduce the design and fabrication time, to enhance the sensory characteristics, as well as to create visually attractive foods, are also mentioned.

Evaluation of bioactive compounds and bioactivities of soybean dried by different methods and conditions.

Soybean has attracted significant research and commercial interests due to its many health-promoting bioactive compounds, especially isoflavones (ß-glucosides, malonyl-ß-glucosides, acetyl-ß-glucosides and aglycones). Isoflavones possess antioxidant activity and α-glucosidase inhibitory activity, which has proved effective in the treatment of type 2 diabetes mellitus. Prior to its use, however, soybean needs to be dried to extend its storage life and to prepare the material for subsequent food or pharmaceutical processing. The present study investigated the effects of drying methods and conditions on the drying characteristics, isoflavones, antioxidant activity and α -glucosidase inhibitory activity of dried soybean. Hot-air fluidized bed drying (HAFBD), superheated-steam fluidized bed drying (SSFBD) and gas-fired infrared combined with hot air vibrating drying (GFIR-HAVD) were carried out at various drying temperatures (50, 70, 130 and150°C). The results showed that higher drying temperatures led to higher drying rates and higher levels of ß-glucosides and antioxidant activity, but to lower levels of malonyl-ß-glucosides, acetyl-ß-glucosides and total isoflavones. At the same drying temperature GFIR-HAVD resulted in the highest drying rates and the highest levels of ß-glucosides, aglycones and total isoflavones, antioxidant activity as well as α-glucosidase inhibitory activity of dried soybean. A drying temperature of 130°C gave the highest levels of aglycones and α-glucosidase inhibitory activity in all cases. The relationships between all the studied parameters were monitored and simple correlations between them were determined.