Search Results (67)

Japanese sake, a traditional alcoholic beverage, contains several organic acids that may contribute to its sour taste. To identify these, a precolumn derivatization reagent, benzyl 5-(2-aminoethyl)-3-methyl-4-oxoimidazolidine-1-carboxylate (CIM-C₂-NH₂), developed for labeling carboxyl groups, was synthesized and applied to liquid chromatography–tandem mass spectrometry (LC-MS/MS) analysis of organic acids in six commercial sake samples. The majority primarily contained lactic acid (LA), and dicarboxylic acids, such as succinic acid (SA), malic acid (MA), and citramalic acid (CMA). The organic acid concentrations and compositions in the sake differed among brands. Notably, both l- and d-forms of LA were detected in all samples, while only d-CMA was present. To estimate the total acidic content, neutralization titration with sodium hydroxide was performed. In four of the six samples, titration results closely matched LC-MS/MS data, suggesting that l-LA, d-LA, SA, MA, and d-CMA were the primary contributors for the sour taste in these sakes. The discrepancy between titration and LC-MS/MS data for the other samples was attributed to the presence of other organic acids, which will be investigated in future studies. Full article

The construction industry faces a growing challenge in managing waste materials, making the development of sustainable alternatives critical. This study investigates the preparation of geopolymers using construction and demolition waste materials, such as cement, brick, and glass waste. Specifically, crushed glass was used to produce sodium silicate, a key source of silicate ions and alkali necessary in geopolymerization processes. The performance of this in-house activator was compared to that of the commercial counterpart. Seven geopolymer formulations were prepared and characterized using SEM-EDX, ATR-FTIR, and XRD techniques. Chemical resistance against harsh environments was assessed through a 7-day immersion in water, hydrochloric acid (pH ~ 1), and sodium hydroxide (pH ~ 13) solutions. The samples were then dried and weighed to determine mass loss, revealing the promising resistance of specific formulations. Similarly, Portland cement specimens of the same dimensions as the geopolymer ones were prepared, tested, and compared to the geopolymers. Our study emphasizes the potential of transforming waste materials into high-performance, resistant geopolymers for construction materials. By optimizing waste-derived geopolymers, we may achieve significant environmental benefits through waste recycling and contribute to advancing sustainable construction technology. Full article

Brine purification is an important process unit in chlor-alkali industrial plants for the production of sodium hydroxide, chlorine, and hydrogen. The membrane cell process requires ultrapure brine, which is obtained through mechanical filtration, chemical precipitation and fine polishing, and ion exchange using polymer resins. Temperature variations can lead to the degradation of the exchange properties of these resins, primarily causing a decrease in their exchange capacity, which negatively impacts the efficiency of the brine purification. After multiple ion exchange regeneration cycles, significant quantities of spent resins may be generated. These must be managed in accordance with resource efficiency and hazardous waste management to ensure the sustainability of the industrial process. In this paper, a comparative study is conducted to characterize the long-term stability of a new commercial chelating resin used in the industrial electrolysis process. The spectroscopic methods of physicochemical characterization included: scanning electron microscopy with energy dispersive X-ray spectroscopy (SEM-EDX) and attenuated total reflectance–Fourier transform infrared spectroscopy (ATR-FTIR). The thermal behavior of the polymer resins was evaluated using the following thermogravimetric methods: thermogravimetry (TG), derivative thermogravimetry (DTG), and differential thermal analysis (DTA), while the moisture behavior was studied using dynamic vapor sorption (DVS) analysis. To assess the energy potential, the polymer resins were analyzed to determine their calorific value and overall energy content. Full article

Sugarcane bagasse (SCB), an organic waste generated during sugar and ethanol production, is a potential biomass source with a high cellulose content. In this study, cellulose was extracted from SCB using a hydrothermal method with various types of solvents, following which the extracted materials were used for food container production. An alkali solvent—sodium hydroxide (NaOH)—and organic acids—citric acid and formic acid—were included as extractive solvents at two different concentrations (0.25 M and 2.0 M). Hydrothermal extraction with the alkali solvent demonstrated higher cellulose extraction abilities (67.7–74.0%) than those with the acids (52.5–57.3%). Using a low alkali concentration in the hydrothermal extraction (H-NaOH_low) demonstrated a cellulose extraction ability near that when using a high alkali concentration in the conventional boiling method (B-NaOH_high): 67.7% and 70.5%, respectively. Moreover, cellulose extracted with H-NaOH_low had better mechanical properties than that from B-NaOH_high, likely due to fewer defective fibers in the former. A high alkali concentration led to vigorous reactions that damaged the cellulose fibers. Thus, hydrothermal extraction has the benefit of using fewer chemicals, leading to a lower environmental impact. In addition, H-NaOH_low fibers were employed for food container production, and it was found that the obtained product has excellent properties, comparable to those of commercial containers. Full article

This study investigates the fire resistance capabilities of newly developed loose-fill thermal insulation materials crafted from annual plants such as wheat straw, corn stalk, and water reed. Three processing methodologies were employed: mechanical crushing (raw, size ≤ 20 mm), chemi-mechanical pulping (CMP) using 4% sodium hydroxide, and steam explosion (SE). An admixture of boric acid (8%) and tetraborate (7%) was added to all treated materials to enhance fire retardancy. The fire reaction characteristics of the insulation materials were assessed using a cone calorimeter measuring the key parameters like time to ignition, total heat release, heat release rate, and total smoke production. The findings indicate that nearly all tested insulation samples, apart from the raw and SE water reed, demonstrated fire resistance comparable to commercial cellulose insulation, surpassing the fire performance of various synthetic foams and composite materials. Furthermore, the single-flame source fire tests indicated that the developed insulation materials achieved a fire classification E, except for the SE water reed sample. Thus, the fire performance results approve the suitability of developed plant-based insulation materials for competing materials in building constructions. Full article

A consistent life cycle assessment (LCA) methodology was employed to show how the type of alkali (NaOH or Na₂CO₃) used for extracting water glass from rice husks, as well as the type of acid (HCl, H₂SO₄, or HNO₃) used for precipitating water glass to nanosilica, affects the environmental emissions of rice husk-derived nanosilica (RH nanosilica). Six nanosilica production scenarios were explicitly compared to determine the most environmentally friendly route. The LCA results show that under the same circumstances, the majority of the environmental emissions of sodium hydroxide (NaOH) are significantly better than those of sodium carbonate (Na₂CO₃), except for the MAETP and ODP indicators. Similarly, except for the MAETP indicator, the environmental emissions of hydrochloric acid (HCl) are generally superior to those of sulfuric acid (H₂SO₄) and nitric acid (HNO₃). NaOH and HCl were selected as preferable for the extraction of silica from rice husks and the precipitation of water glass, respectively. In addition, the preferred route underwent further in-depth optimization with the aim of achieving optimal environmental emissions for RH nanosilica. The effects of electricity, diesel, fertilizers, and pesticides on the life cycle emission factors of RH nanosilica were examined. The results demonstrate that replacing traditional coal power with cleaner alternatives, such as wind, hydropower, solar power (both photovoltaic and thermal), and biogas electricity, can result in a substantial decrease in the life cycle emission factors of nanosilica, with reductions varying between 20% and 60%. An effective method to reduce emissions associated with diesel, fertilizers, and pesticides is to adopt effective measures to decrease their consumption. These findings provide valuable theoretical foundations and insights for the industrial application of RH nanosilica. These results have great significance for guiding and promoting the industrialization process of nanosilica derived from rice husks and accelerating its commercialization. Full article

Glycerohydrogels based on silicon glycerolate, chitosan (CS) and polyvinyl alcohol (PVA) are widely studied for use in biomedical applications. In line with the general trend of replacing synthetic polymers with natural ones in such compositions, it would be of interest to replace PVA with the polysaccharide glucomannan (GM), as well as to introduce functional additives to impart the desired properties, including gelation time, to the final hydrogel. In this work, a comprehensive study of the preparation conditions and properties of glycerohydrogels based on silicon tetraglycerolate, chitosan hydrochloride (CS·HCl) and GM was carried out. Viscometry was used to assess the conformational state of CS·HCl and GM macromolecules, and their associates in solution before gelation. Gelation was studied using the vessel inversion method. The mucoadhesive and the dermoadhesive properties of the glycerohydrogels obtained were assessed using the tearing off method from the model substrates simulating mucous and dermal tissues. The conformational state of the individual polymers and their mixed associates in solution before gelation was estimated; the intrinsic viscosity and the hydrodynamic radius of the macromolecular coils were calculated. The influence of various factors (addition of ε-aminocaproic and hydrochloric acids, sodium chloride, hydroxide and tetraborate to vary the acidity and ionic strength of the medium, as well as temperature) and the molecular weight of chitosan on the gelation time was studied. The gelation time achieved was less than 2 min, which is promising in practical terms, i.e., for creating liquid plasters. Our best samples are not inferior to the commercial preparation “Metrogyl Denta”^® in terms of tearing force during mucoadhesion and dermoadhesion at short gelation times. Thus, the glycerohydrogels synthesized by us and based on silicon tetraglycerolate, CS·HCl and GM could find usage in new biopharmaceutical and biomedical applications. Full article

Bioplastics are emerging as a promising solution to reduce pollution caused by petroleum-based plastics. Among them, polyhydroxyalkanoates (PHAs) stand out as viable biotechnological alternatives, though their commercialization is limited by expensive downstream processes. Traditional PHA extraction methods often involve toxic solvents and high energy consumption, underscoring the need for more sustainable approaches. This study evaluated physical and chemical methods to extract PHAs from Pseudomonas putida U, a bacterium known to produce poly-3-hydroxyoctanoate P(3HO). Lyophilized cells underwent six extraction methods, including the use of the following: boiling, sonication, sodium hypochlorite (NaClO), sodium dodecyl sulfate (SDS), sodium hydroxide (NaOH), and chloroform. Physical methods such as boiling and sonication achieved yields of 70% and 60%, respectively, but P(3HO) recovery remained low (30–40%). NaClO extraction provided higher yields (80%) but resulted in significant impurities (70%). NaOH methods offered moderate yields (50–80%), with P(3HO) purities between 50% and 70%, depending on the conditions. Spectroscopic and analytical techniques (FTIR, TGA, NMR, GPC) identified 0.05 M NaOH at 60 °C as the optimal extraction condition, delivering high P(3HO) purity while minimizing environmental impact. This positions NaOH as a sustainable alternative to traditional halogenated solvents, paving the way for more eco-friendly PHA production processes. Full article

This study investigates a novel method of utilizing Direct Air Capture (DAC) technology for fertilizer production. Unlike traditional Direct Air Carbon Capture and Utilization (DACCU) technologies, Direct Air Carbon Capture for Fertilizers (FDAC) has the potential to produce fertilizers directly. This study aims to assess the feasibility of FDAC-based fertilizer production by examining the current state of traditional DAC technologies, evaluating the CO₂ fixation potential of FDAC, and analyzing the decarbonization effect of producing fertilizers using FDAC. Our evaluation results indicate that CO₂ emissions from producing 1 ton of conventional chemical fertilizer, FDAC fertilizer (current status), FDAC fertilizer with ingredient adjustment (sodium hydroxide), and FDAC fertilizer with ingredient adjustment (magnesium hydroxide) are 1.69, 1.12, 1.04, and 1.06 tons of CO₂, respectively. The FDAC fertilizer (current status) emits 0.57 tons of CO₂ per ton less than commercial fertilizers. FDAC fertilizers also have the potential to reduce CO₂ emissions further when the fertilizer composition is adjusted, offering a promising solution for lowering the environmental impact of fertilizer production. Significant CO₂ reduction can be expected by replacing conventional low-intensity chemical fertilizers with FDAC-produced fertilizers. Full article

In this research, we developed a novel slow-release biofertilizer by utilizing an environmentally friendly method to synthesize ZnO-NPs using sodium hydroxide, zinc acetate salt, and Lepidium sativum seed extract. The commercial fertilizer urea 46% was encapsulated in the nano-ZnO/alginate beads. The structural and morphological characteristics of the nanocomposites were confirmed using X-ray diffraction (XRD) and scanning electron microscopy, which confirmed the successful creation of nanocomposite alginate beads. The results indicated that the ZnO/alginate/urea beads exhibited a steady and continuous release of urea for up to one hour and extended nutrient availability over time. This research demonstrates the potential of ZnO-NP/alginate composites as a promising platform for developing slow-release biofertilizers, combining the beneficial properties of ZnO nanoparticles with the controlled-release capabilities of alginate matrices. This research highlights the potential of ZnO-NP/alginate composites as a sustainable and efficient solution for agricultural applications, providing a controlled release of nutrients that could minimize their environmental impact and enhance crop productivity. Full article

The compound p-Nitrophenol (p-NP) is widely recognized as a highly toxic nitro-aromatic substance that urgently requires emission control. Reducing p-NP to p-aminophenol (p-AP) not only decreases its toxicity and mineralization properties in nature but also provides a key raw material for the chemical and pharmaceutical industries. The study used coal fly ash (CFA) as a catalyst carrier for synthesizing the p-NP reduction catalyst. Using CFA as an alternative option not only reduces costs but also achieves the objective of treating waste with waste compared to utilizing commercial solid materials for synthesizing catalysts. By employing hydrochloric acid and sodium hydroxide pretreatment methods, the physicochemical properties of CFA are significantly improved, enhancing the dispersion of palladium (Pd) nanoparticles. The structural features of the prepared samples were characterized using various surface analysis techniques, and both intermittent and continuous modes were experimentally tested for the model catalytic reaction involving the sodium borohydride (NaBH₄)-mediated reduction of p-NP. The results demonstrate that CFA has potential in wastewater treatment. Full article

Hydrogen represents an environmentally friendly and renewable energy source that could substitute fossil fuels and diminish greenhouse gas emissions. However, conventional methods of producing hydrogen are frequently expensive, energy-intensive, or detrimental to the environment. This study proposes an innovative and eco-friendly approach for hydrogen production using activated carbon derived from fennel flower waste, an inexpensive agricultural by-product abundant in Qatar. The researchers prepared the activated carbon by carbonizing and chemically activating it with potassium hydroxide, and characterized its properties through various techniques, including scanning electron microscopy, Fourier-transform infrared spectroscopy, and Brunauer–Emmett–Teller analysis. They subsequently evaluated the activated carbon’s catalytic performance in a hydrogen production system utilizing sodium borohydride and water as reactants, comparing the results with those obtained from commercial catalysts such as nickel and platinum. The findings revealed that the activated carbon derived from fennel flower waste exhibited a high hydrogen yield of 99.8%, which was comparable to or even surpassed that of the commercial catalysts. Furthermore, the activated carbon demonstrated good stability and reusability over multiple cycles. This study shows that fennel flower waste can be transformed into a valuable catalyst for hydrogen production, offering a sustainable and environmentally conscious solution for energy generation. Full article

A lack of strategies for the utilization of harvest residues (HRs) has led to serious environmental problems due to an accumulation of these residues or their burning in the field. In this study, wheat and corn HRs were used as feedstock for the production of microcrystalline cellulose (MCC) by treatment with 2–8% sodium hydroxide, 10% hydrogen peroxide and further hydrolysis with 1–2 M hydrochloric acid. The changes in the FT-IR spectra and PXRD diffractograms after chemical treatment confirmed the removal of most of the lignin, hemicellulose and amorphous fraction of cellulose. A higher degree of crystallinity was observed for MCC obtained from corn HRs, which was attributed to a more efficient removal of lignin and hemicellulose by a higher sodium hydroxide concentration, which facilitates the dissolution of amorphous cellulose during acid hydrolysis. MCC obtained from HRs exhibited lower bulk density and poorer flow properties but similar or better tableting properties compared to commercial MCC (Ceolus^TM PH101). The lower ejection and detachment stress suggests that MCC isolated from HRs requires less lubricant compared to commercial MCC. This study showed that MCC isolated from wheat and corn HRs exhibits comparable tableting behaviour like commercial sample, further supporting this type of agricultural waste utilization. Full article

Produced waters are often treated in open lagoons where hydrogen sulfide (H₂S) can off gas, posing a risk to human health and the environment. The aim of this study was to optimize a treatment process using hydrogen peroxide (H₂O₂) to oxidize H₂S while minimizing off gassing. Samples of produced water from West Texas and laboratory-prepared waters utilizing sodium sulfide (Na₂S) or biogenic polysulfides were oxidized with H₂O₂ alone or in combination with copper or iron catalysts, sodium hydroxide (NaOH), or a commercial sulfide oxidizer, HydroPower Green™. Sulfur speciation was measured using Hach test kits for sulfide/sulfate/sulfite and Dräger tubes for headspace H₂S. HydroPower Green™ (HPG) helped to reduce H₂S in the headspace of water samples; some of this was pH related as NaOH also worked, but not as well as HPG. The dose of peroxide necessary to oxidize sulfides to sulfate is a function of the oxidation-reduction potential (Eh) of the water and total sulfide concentration as well as pH; approximately a 1–4:1 ratio of peroxide to sulfide concentration was needed to oxidize sulfidic waters of pH 7–10 with half-lives under 30 min. Both copper and iron catalysts reduce H₂O₂ demand and the half-life of H₂S. Peracetic acid (PAA) and copper (II) sulfate pentahydrate (CuSO₄, 5H₂O) were explored as biocides for controlling sulfate-reducing bacteria (SRBs) that produce H₂S. An AquaSnap (Hygenia) test kit was employed to monitor relative microbial activity in a wetland porewater containing H₂S. Microbial regrowth occurred after a few days using the highest dose of PAA; these results showed that PAA was being used by bacteria as a carbon source even after the initial substantial reduction in the microbial activity. CuSO₄, 5H₂O at a dose of 1 ppm prevented microbial regrowth. The recommended treatment process from this research is determined by jar testing with H₂O₂, a base for pH control, a biocide, and possibly a metal catalyst or other co-oxidants in order to achieve oxidation of sulfides without H₂S release or the precipitation of metal carbonates or oxides. Full article

Particulate aluminum salts have long occupied a central place worldwide as inexpensive immunostimulatory adjuvants that enable induction of protective immunity for vaccines. Despite their huge benefits and safety, the particulate structures of aluminum salts require transportation and storage at temperatures between 2 °C and 8 °C, and they all have exquisite sensitivity to damage caused by freezing. Here, we propose to solve the critical freezing vulnerability of particulate aluminum salt adjuvants by introducing soluble aluminum salts as adjuvants. The solubility properties of fresh and frozen aluminum chloride and aluminum triacetate, each buffered optimally with sodium acetate, were demonstrated with visual observations and with UV–vis scattering analyses. Two proteins, A244 gp120 and CRM₁₉₇, adjuvanted either with soluble aluminum chloride or soluble aluminum triacetate, each buffered by sodium acetate at pH 6.5–7.4, elicited murine immune responses that were equivalent to those obtained with Alhydrogel^®, a commercial particulate aluminum hydroxide adjuvant. The discovery of the adjuvanticity of soluble aluminum salts might require the creation of a new adjuvant mechanism for aluminum salts in general. However, soluble aluminum salts might provide a practical substitute for particulate aluminum salts as vaccine adjuvants, thereby avoiding the risk of inactivation of vaccines due to accidental freezing of aluminum salt particles. Full article