Environmental Friendly Process Research Articles

Green-process preparation and characterizations of optically transparent, thermally stable and mechanically superior regenerated silk-hyaluronate composite films

High-performance regenerated silk-hyaluronate composite films prepared by an environment-friendly process were highly desirable for medical dressing base material. In this study, sericin was removed from silk by steam treatment without using any chemical reagent, and a low concentration solution of Na2CO3 was used as a green process to dissolve silk fibers. Then the obtained silk fibroin was physically blended with sodium hyaluronate to generate optically transparent, thermally stable and mechanically superior regenerated silk-hyaluronate films. The results of structural characterizations and property tests showed that the insoluble silk short fibers prepared by the dissolution of Na2CO3 were dominated by a β-sheet crystalline structure while the soluble silk fibroins by an amorphous structure. Moreover, both insoluble silk short fibers and soluble silk fibroins could form uniform composite films with a low coefficient of thermal expansion after being blended with sodium hyaluronate, which were named as insoluble silk film (ISH) and soluble silk film (SSH), respectively. The tensile strength of ISH could reach 138.8 MPa and SSH reached 153.9 MPa, which were 65.7 % and 30.5 % higher than that of the commercial control insoluble fibroin film (83.8 MPa) and commercial control soluble fibroin film (117.9 MPa), and 173.2 % and 203.0 % higher than that of pure hyaluronate film (50.8 MPa), respectively. Also, ISH and SSH had a modulus higher than 3 GPa. In this study, the low-concentration Na2CO3 method provides a simple and green technique for the preparation of high performance silk-hyaluronate composite materials.

Closed-loop cleaning treatment system — resource recovery of coal gangue

ABSTRACT Coal gangue (CG) is one of the main solid wastes emitted by coal mining. It causes severe damage to the environment. CG contains high levels of valuable elements (Al, Si) and has the potential for utilization and clean disposal. Here, an environment-friendly process for separating valuable components from CG was proposed: the closed-loop system of activation-leach-separation. The results show that the decarbonization rate was close to 100% under the optimum conditions of CG particle size of 0.075 mm to 0.15 mm and activated at 800°C for 120 min. Subsequently, it was transformed into a mixed-acid system with a hydrochloric acid (HCl) concentration of 4.5 mol/L, hydrofluoric acid (HF) volume fraction of 15%, and the liquid-solid ratio of 10:1, which achieved excellent separation efficiency. The residual rate of Al in the solution was only 0.7%, and the extraction rate of Si can reach 71.6%. Further, industrial-grade AlF3 products were also recovered. By adding saturated KCl solution and reacting at 33°C for 15 min, Si was further recovered in K2SiF6, and the yield was 85.83%. Particularly, the leaching solution maintained good extraction efficiency in the subsequent three cycles, the yield of K2SiF6 was 88.29%, confirming the feasibility of the closed-loop system. This treatment embodied the environmental-friendly properties of low acid consumption and low effluent discharge, providing a feasible method for clean treatment and resource utilization of CG.

Environmentally friendly solvent debinding technique of POM binder system for titanium injection molding

An environment-friendly solvent debinding process for polyoxymethylene (POM) for metal injection molding (MIM) is presented as an alternative to the traditional catalytic debinding method. This study investigated the influence of various acid solvents and debinding temperature. The optimal debinding parameters were 5 M nitric acid solution at 60 °C. Based on the calculation of effective diffusivity and activation energy, the solvent-debinding mechanism for POM is proposed. The removal of POM was controlled by three processes: dissolution, diffusion, and chemical reaction. The resulting final titanium parts have a high density of over 95% and an ultimate tensile strength of 406 MPa.

Degradation of antibiotic sulphamethoxazole by application of modified photo-Fenton processes: kinetics, degradation pathways and toxicity

ABSTRACT Degradation of antibiotic sulphamethoxazole (SMX) was studied by applying modified photo-Fenton reactions (MPF) with the novel choice of using sodium tripolyphosphate (STP) and sodium hexametaphosphate (SHP) complexing agents. STP and SHP have a strong ability as complexing agents because they can sequester and complex with different ions. Process optimisation was performed using Doehlert design at pH = 6. This study presented higher performance for MPF using STP and SHP complexing agents than conventional photo-Fenton and H2O2 + UV process. The best yields were associated with the formation of a smaller number of intermediates with high degradation efficiency and low oxidative stress, environment-friendly and promising processes.

Synthesis of biowaste-derived nanostructured material for the nanomolar detection of glucose: Biological sample analysis

Glucose electro-oxidation in an alkaline media was investigated using an electrode composed of carbon paste and sugarcane bagasse activated carbon (SBAC). The SBAC was prepared using an easy, affordable, and environmental friendly process. The porous activated carbon was produced using sugarcane bagasse through a pre-treatment process that involved carbonization at 650 °C and K2CO3. X-ray diffraction (XRD) was used to observe the formation of carbon crystallites during activation at higher temperatures. The Fourier-transform infrared (FTIR) spectrum shows functional groups that are present in the carbon material. The carbon sample's morphology was evaluated using scanning electron microscope (SEM). The surface roughness was studied using atomic force microscopy (AFM). Porous activated carbon derived from sugarcane bagasse was carefully mixed into electrode components such as graphite powder and mineral oil for glucose (GLS) detection. For precise GLS detection, the SBACs were employed as non-enzymatic electrochemical sensor probes in their as-prepared condition. According to the electrochemical experiments, the constructed sensor shows exceptional electrochemical performance towards glucose oxidation, including excellent selectivity, a low detection limit, good sensitivity, and a wide linear range. Investigation has been conducted on the oxidation of GLS in alkaline solutions with varying concentrations of halide ions such as iodide and chloride. The GLS oxidation peak current increased the performance of a SBAC modified electrode was compared to that of a bare carbon paste electrode (CPE). The role of sensitivity in minimizing halide poisoning is significant. The risk of poisoning is increased if iodide > chloride. As the modified electrode's voltage changes in a chloride solution containing glucose, the peak current gradually reduces. The redesigned electrode that is currently in use as a consequence not only promotes glucose oxidation but also shows strong resistance to electrode poisoning caused by halides. The sensitive and targeted SBAC/CPE has also improved its reliability while evaluating samples of human serum, urine, and breast milk.

Eco-Friendly Synthesis of Alstonia scholaris (L.) R. Br. Extract-Mediated Nanostructured Material: Removal of Organic Pollutants from Water Resources

In this modern era, pollution of water resources due to industrial waste effluents is an alarming problem as it can cause various health problems in aquatic animals as well as in humans. Among the industrial pollutants, organic dyes are one of the leading chemicals that cause severe damage to the aquatic environment. These harmful organic dyes are practically omnipresent in various types of industries such as textile, tannery, cosmetic, food industries, etc. Photodegradation of these organic dyes is regarded as a promising technology for industrial waste treatment as it is a cost-effective and environment-friendly process. In this study, a nanostructured material of iron has been synthesized using the Alstonia scholaris (L.) R. Br. extract in an easy and eco-friendly way. The potential of this synthesized nanostructured material to act as a photocatalyst, for the degradation of organic dyes, has been explored. Due to its small size and high dispersion, more than 72 % degradation has been achieved within 90 min. A comparative study of its photocatalytic efficiency in different degradation processes has also been performed.

Efficient and selective gold recovery using amine-laden polymeric fibers synthesized by a steric hindrance strategy

Various alkylamines are commonly used for efficient Au recovery; however, their high hydrophilicity can result in dissolution in water, hindering effective Au recovery and potentially causing environmental contamination. Currently, the forms in which alkylamines are immobilized on supports provide unsatisfactory Au recovery capabilities and exhibit low structural stability. This study proposes a pragmatic approach for synthesizing amine-laden polymeric fiber (ALPF) adsorbents with efficient Au recovery capabilities and superior structural stability. Polyacrylonitrile fibers (PANF) were employed as a supportive matrix to immobilize the alkylamine molecules chemically. The densely grafted amine groups on the ALPF adsorbed significant amounts of Au ions and reduced them to Au(0) crystals. This chelation–precipitation hybrid method achieved a Au recovery efficiency of nearly 100 % over a wide pH range of 1–4. In addition, it demonstrated an exceptional Au adsorption capacity of 1463 mg/g, surpassing the values reported for other adsorbents categorized by size and shape. Even in the presence of 14 different coexisting metal ions, the ALPF showed a Au recovery efficiency above 99.9 %. It also exhibited excellent reusability, maintaining a Au recovery rate of ∼91 % after 10 cycles. Furthermore, fibrous adsorbents alleviated the pressure drop in columns filled with adsorbents, thereby enabling energy-efficient and environment-friendly processes.

Improving Charge Storage of Biaxially-Oriented Polypropylene Under Extreme Electric Fields by Excimer Uv Irradiation.

Biaxially-oriented polypropylene (BOPP) is one of the most commonly used materials for film-based capacitors for power electronics and pulsed power systems. To address the pressing issue of performance-limiting loss under extreme electric-fields, here we demonstrate a one-step, high-throughput, and environment-friendly process based on very low-dose ultra-violet irradiation from KrCl (222nm) and Xe2 (172nm) excimer. The performance of commercial BOPP is boosted in terms of withstanding electric-field extremes (Weibull breakdown strength 694 to 811V μm-1 by 17% at 25°C and 428 to 651V μm-1 by 52% at 120°C), discharged energy density, and conduction losses. Importantly, the depth profile of space charge is precisely measured in-situ with a high resolution of 500nm by laser induced pressure pulse. Consequently, the space charge effect and electric-field distortion are reduced and related to the improved polymer films. It is demonstrated that energetic UV photons act as scissors for BOPP chains and dissociate oxygen molecules leading to the more thermally stable oxygen-containing structures, as deep traps to impede charge migration. This work provides a promising approach to produce polymers with customized microscopic characteristics that is compatible with the assembly lines of polymer-based capacitors. This article is protected by copyright. All rights reserved.

Efficacy Study of Eco-Friendly Bleaching Agent for Skeleton Preservation in Animal Skeleton

The currently used bleaching materials in skeletal preservation are hydrogen and carbamide peroxide materials with specific concentrations and techniques that impact environmental sustainability. This research describes a simple and eco-friendly technique for preserving skeletons. This research used a qualitative approach. Data were collected through observation and documentation. The collected data were analyzed descriptively. The results show that natural extracts, such as lemon combined with baking soda and commercial bleaching cloth agent, can bleach the skull and bone to preserve the skeleton. The commercial bleaching cloth agent is more capable of bleaching animal skulls and bones to preserve skeletons than natural extracts combined with baking soda do; however, the result is more brittle skeletons. Although specimens in lemon extract combined with baking soda solution more slowly clean and bleach skeleton than commercial bleaching solution, skeletal animals have bond strength and environment-friendly processes. This study recommends that an eco-friendly bleaching agent for skeletal preservation should be applied because it can cope with biological practices about osteology and other science subjects.

Synthesis of CuO/NaCuSO4 nanocomposite using an aqueous extract of Tribulus Terrestris and their structural, optical, morphology and dielectric studies

The development of an environment-friendly process for synthesizing nanoparticles in the field of bionanotechnology is growing day-by-day. Increasing drug resistance in microbes has compelled researchers to synthesize biologically active nanoparticles. In this study, we used Tribulus terrestris plant extract to synthesize CuO/NaCuSO4 nanocomposite. The synthesized samples were characterized through functional groups analysis of FTIR and morphological analysis of SEM. The X-ray diffraction (XRD) and ultra-visible light absorbance analysis (UV–vis) were used to find the nanocrystalline nature and bandgap energy of the biosynthesized copper oxide (CuO) nanoparticles, respectively. In the metal oxide region of Fourier transform infrared (FTIR) spectroscopy the copper oxide nanoparticles were confirmed at 523 cm−1 which showed the nature of plant extracts to control over the reduction and stabilizing of the nanoparticles. The Rietveld refinement analysis yielded unit cell compositions of 53.39% for CuO and 46.61% for NaCuSO4, respectively. The monoclinic structure of CuO was confirmed, and the crystalline size was calculated as 37 nm by XRD analysis. From UV–vis spectroscopy, the absorption peak was observed at 277 and 337 nm, revealing the presence of CuO nanoparticles. In fact, the cluster-like morphology patterns are captured by scanning electron microscopy (SEM) and particle sizes were observed around 102 nm. Finally, the dielectric properties of the synthesized copper oxide nanoparticles have been examined and reported in detail.

Biosynthesis of Gold Nanoparticles Using Aqueous Extract of Paramignya trimera Roots and Its Anticancer Activity

Developing environment-friendly processes for metal nanoparticle synthesis without using toxic chemical is very necessary to meet the demand for biological and medical applications. In this work, biosynthesis of gold nanoparticles (AuNPs) using aqueous extract of Paramignya trimera roots as the reducing and stability agents was carried out. The formation of gold nanoparticles was confirmed by the presence of an absorption peak at 550 nm using UV–Visible spectrophotometry. The size and morphology of gold nanoparticles was monitored by Field emission scanning electron microscopy (FE-SEM) and High resolution transmission electron microscopy (HR-TEM). Analysis of these particles showed the synthesized AuNPs were spherical in shape, with the particle size range of 10 nm–15 nm. The element gold and the crystalline nature of AuNPs were finalized using Energy dispersive X-ray (EDX) and X-ray diffraction (XRD) spectrometer, respectively. Fourier transform infrared (FTIR) spectroscopy revealed possible involvement of reductive groups on the surfaces of nanoparticles. The synthesized AuNPs are evaluated for its activity against MCF-7, HepG2, KB, LU-1 and MKN7 cancer cell lines with inhibition concentration 50% (IC50) of 2.01, 7.60, 3.89, 3.99 and 3.53 ppm respectively after 72 hours of treatment.

Honeyberry-derived carbon quantum dots ameliorate LPS-induced neuroinflammation and oxidative stress through Nrf2/HO-1 signalling in HMC3 cells

Carbon quantum dots (CQDs) were synthesized from blue honeysuckle (Lonicera caerulea) berry fruit extracts using a well-known, cost-effective, and environmental friendly hydrothermal process. The material was characterized using UV-vis spectroscopy, photoluminescence (PL), XPS, and TEM studies. The as-synthesized carbon dots exhibit excellent PL properties, with a quantum yield of ∼35.92%. CQDs vary in size from ∼2 nm to 9 nm. This study established the neuroprotective effects of CQDs against lipopolysaccharide (LPS)-induced human microglial cell model. LPS was found to induce cytotoxicity, reactive oxygen species, and pro-inflammatory cytokines interleukin (IL)-1β, IL-6, and tumour necrosis factor-α) and downregulated enzymatic antioxidants such as nuclear factor-erythroid factor 2-related factor 2 (Nrf2), superoxide dismutase, catalase, haem oxygenase (HO)-1, HO-2, and glutathione peroxidase, while CQDs treatment reversed LPS induced cytotoxicity, induced anti-inflammatory cytokines (IL-4, IL-10, and transforming growth factor β) and induce enzymatic antioxidants both at transcriptional and translational levels. The study suggested the potential role of CQDs prepared from Lonicera caerulea, as anti-inflammatory and antioxidative agents in neuroinflammatory and neurodegenerative diseases. In addition, CQDs could be exploited in various biomedical applications such as biosensing, drug delivery and tissue engineering.

METAVERSE CONTRIBUTION TOWARDS SDG 9- INTERFACE AND INTERACTION

The metaverse phenomenon -- gained a lot of focus during the COVID-19 outbreak. It can be related to meeting concerns about meeting Sustainable Development Goals assigned by the United Nations. Global warming changes the local and regional ecology and is one of the significant agendas and goals related to the SDGs. It can be linked to creating industry concerns to be innovative by applying ICT to bring in development and human well-being. In this context, the application of Metaverse technology can be highlighted. Even though there are several critics of Metaverse, an attempt has been made in this work to link the usage of Metaverse application to attaining SDG number 9 of industry infra of innovative and environment-friendly processes. The information for this work has been taken from the websites, mainly accessible from India. From an economic perspective, the benefits of employing this technique out ways the social critics and contribute towards sustainable practices in terms of opportunities for optimal utilization of human capabilities and efforts, saving man-hours. Finally, user discretion in applying and adopting the latest technology must be employed to mitigate the opposing side and promote the positive impacts of its sustainable application. This research paper explores the dynamic technology landscape, focusing on applying Metaverse technology for sustainable industrial infrastructure. It categorizes existing literature into technical and application-based segments. The study addresses fundamental questions regarding Metaverse applications, stakeholders, and associated concerns to enhance our understanding of its potential impact on future global development.

A rapid and environment-friendly process for dolomite pellets calcination with Joule-heating

Dolomite is an important industrial raw material for the production of metal magnesium. However, the calcination of dolomite is a typical pollution-intensive industry and is one of the major contributors to CO2 emissions in China. The requirements of energy conservation and environmental protection are driving the development of new calcination technologies. Herein, we developed a rapid and environment-friendly strategy for the calcination of dolomite used in subsequent magnesium production through carbothermal reduction, in which the pellets containing dolomite and carbon additive are calcined with in-situ Joule-heating in a vacuum. The effect of input volumetric specific power, heating time, vacuum conditions, carbon additive, and the size of the pellets on the decomposition process has been systematically studied. The dolomite in the pellets can be completely decomposed within tens of seconds. And the kinetic analysis shows that the activation energy of the decomposition of dolomite with the Joule-heating method is 108.4 kJ mol−1, which is much lower than the previous reports. Note that, the novel strategy shows a reduction of calcination time by 70 times, a reduction of energy consumption by 6.22% and a reduction of direct carbon emissions by 56.77% compared to the traditional methods. Combining the results of finite element simulations and density functional theory calculations, we revealed the mechanism of Joule-heating to enhance the decomposition of dolomite. The results show that the Joule-heating method can offer a distinct heating mechanism and deteriorate the structure stability of CaMg(CO3)2.

Surface-Immobilized ZnNx Sites as High-Performance Catalysts for Continuous Flow Knoevenagel Condensation in Water.

By immobilizing the metal complex on the substrate surface, our previous results have demonstrated that heterogeneous catalysts with well-dispersed active MNC (metal-nitrogen-carbon) sites can be prepared in a rational and efficient manner. In this study, we employed agarose aerogel (AA) as the substrate to illustrate a straightforward strategy for immobilizing ZnNx sites on the surface. Under relatively low temperatures, the amine group of the ligand condenses with the surface carbonyl group generated in situ, resulting in the surface immobilized Zn sites. This can be supported by the IR, PXRD, and XPS data. Comprehensive characterization methods, including synchrotron powder XRD and spherical aberration-corrected TEM, confirmed the absence of ZnNx site aggregation in the surface immobilization process, even with a high Zn content (up to 8 wt %). The immobilized ZnNx sites exhibited high catalytic performance in Knoevenagel condensation, and α,β-unsaturated compounds were obtained with high yield in both batch and continuous flow reactions. AA-ZnNx-200 showed the best catalytic activity, which was processed under 200 °C with a Zn content of 4.62 wt %. The immobilized ZnNx sites activated both the aldehyde and nitrile substrates, which were quantitatively converted into the corresponding α,β-unsaturated compounds, with water as the solvent at room temperature. In continuous flow reaction conditions, a conversion rate up to 99% can be achieved with malononitrile. This heterogeneous catalyst can be facilely produced with quantitative yield in a large scale from cheap starting material under mild conditions. No catalyst deactivation was observed after seven batch reaction cycles or 80 h of continuous flow reaction, indicating its high robustness under catalytic reaction conditions. This catalyst enables a separation-free, energy-saving, and environment-friendly production process, offering a practical way for the industrial production.

Macromolecular Size and Architecture of Humic Substances Used in the Dyes’ Adsorptive Removal from Water and Soil

Humic substances are naturally occurring materials composed of complex biogenic mixtures of substituted aromatic and aliphatic hydrocarbon core materials derived from the degradation and decomposition of dead plant and animal matter. They are ubiquitous in both terrestrial and aquatic systems constituting biotic pools and are characterized by unique properties; they are amphiphilic redox compounds with exceptional chelating features. Humic substances play a crucial role in both agriculture and the environment as carbon sequestrators, soil improvers, plant health promoters, as well as stabilizers of soil aggregates and regulators of organic/inorganic nutrients bioavailability. This review article attempts to summarize current knowledge about the molecular nature and characterization techniques employed for the study of humic substances worldwide as the chemistry of their components differs markedly and depends on natural processes, several abiotic and biotic factors, the origin of the organic matter, and their complexation with inorganic, e.g., metal-ion, compounds. This work is equally concerned with the association of humic substances with dyes, a notorious pollutant, responsible for various environmental issues generally arising from the discharge of untreated effluents into soils and water bodies. Azo dyes, in particular, negatively affect soil microbial communities, as well as plant germination and growth. The aim is to feature the potential contribution of humic substances as novel materials for environment-friendly and sustainable processes.

Controlling carbon dioxide-to-hydrogen ratio to improve hydrogen utilization and denitrification rates of hydrogenotrophic autotrophic denitrification through homoacetogenesis-heterotrophic denitrification pathway

Hydrogenotrophic denitrification, an environment-friendly process for organic-free influents, is limited due to poor hydrogen mass transfer efficiency and significant pH fluctuations. In this study, we manipulated the carbon dioxide-to-hydrogen ratio to improve hydrogenotrophic denitrification. When carbon dioxide-to-hydrogen ratio was 1:1 (carbon dioxide, 200 ml: hydrogen, 200 ml), the hydrogen utilization and denitrification rates were 2.4 times and 3.0 times that when carbon dioxide-to-hydrogen ratio was 0:1 (carbon dioxide, 0 ml: hydrogen, 200 ml), respectively. The pH fluctuation decreased from 3.1±0.3 to 0.2±0.1. Furthermore, the hydrogenotrophic denitrification, acetoclastic denitrification, homoacetogenic, and electron transfer activities of the sludge were improved. A high carbon dioxide-to-hydrogen ratio augmented the acid-producing and heterotrophic denitrifying microorganism populations. By maintaining a high carbon dioxide-to-hydrogen ratio, the dominant hydrogenotrophic autotrophic denitrification pathway was transformed into a homoacetogenesis-heterotrophic denitrification pathway, thereby achieving higher hydrogen utilization and denitrification rates.

A novel environmental friendly and sustainable process for textile dyeing with sulphur dyes for cleaner production

This investigation herein primarily focuses on developing a new textile dyeing process with sulphur dye class at room temperature using bacterial Lysate. Sulphur dyes are applied on cotton to produce dark shades at a lower cost, primarily providing excellent colour fastness, except against chlorinating agents. The insoluble sulphur dyes, like vat dyes, are first reduced and then applied as soluble leuco compounds that need to be kept under alkaline conditions, along with a reducing agent. The conventionally followed method of dying process involves the process of reduction of dyes using hazardous chemicals as reducing agent and alkali at higher temperature as well as subsequent dyeing at higher temperatures (60–80 °C) varying with the nature of dyes and processes. It eventually eliminates traditional heating arrangements and achieving easier control of the dyeing process at room temperature than at high temperatures. This investigation compares the newly designed processing route with the followed traditional process in the context of exhaust dyeing and rope dyeing methods with padding mangle. In addition, it involves in substituting the conventional reducing agent i. e. sodium sulphide partially with sodium hydrosulphite for sulphur dyeing. In nut-shell, this process comprises of reduction of dyes in the presence of an alkali agent, a reducing agent and a catalytic agent, wherein the reducing catalytic agent is a bacterial Lysate, establishing it to be environmentally viable, energy and cost effective, and sustainable dying process along with promising improvement quality in terms of dye uptake and comparable fastness properties.

Fungus reinforced sustainable gold nanoparticles: An efficient heterogeneous catalyst for reduction of nitro aliphatic, aromatic and heterocyclic scaffolds

Heterogeneous catalyst is essential for an efficient and environmental friendly process development in chemical industries. As a green chemistry prospective, recovery and reusability of catalyst is in great demand for industrial processes. Herein this report, a robust protocol with novel catalyst has been developed for the selective reduction of nitro functionality on aliphatic, aromatic and heterocyclic scaffolds using sodium borohydride in water. Aspergillus trinidadensis (VM ST01′ OL587588) supported gold nano heterogeneous catalyst (AtGNHC) has efficiently and selectively reduced the nitro group in the presence of different other functional groups like olefins, esters, amide, nitriles, carboxylic and halides (-F, -Cl, -Br). The amino products with industrial importance for the preparation of pharmaceuticals, polymers and agrochemicals are obtained in good isolated yields (up to >95 %) under mild conditions. AtGNHC is lyophilized to make it as a robust free flowing powder, which can be used as regular chemicals. As a requirement of sustainable chemistry, the catalyst reusability has been also investigated and it has shown almost same efficiency all the time (10 cycles are performed). A storage stability of lyophilized AtGNHC has been also performed and it has shown excellent catalytic activity even after one year of storage at normal conditions. AtGNHC has demonstrated its efficacy in scale-up process (tried up to 5gm batch) also with same reactivity. Results presented and discussed in this report are clearly showing the potency of AtGNHC as a choice for chemical industries with commercial value.

Optimizing conditions for the recovery of lignans from sesame cake using three green extraction methods: Microwave-, ultrasound- and accelerated-assisted solvent extraction

Lignans, a group of polyphenolic low molecular weight bioactive compounds with health benefits, are major constituents of sesame cake (SC), a by-product derived from sesame oil processing. The utilization of this by-product in the food or nutraceutical industries could explore its valorization route in compliance with sustainability and circular economy principles. This study aimed to investigate the impact of different environmental-friendly processing approaches such as ultrasound-assisted extraction (UAE), microwave-assisted extraction (MAE) and accelerated solvent extraction (ASE) for lignans extraction from SC using central composite design (CCD) with response surface methodology (RSM). Sesaminol triglucoside (SETRI) and sesaminol diglucoside (SEDI) were identified and quantified as the major lignan glucosides in SC. Ethanol/water mixture was selected as ‘green’ solvent for all extraction methods. The influence of ethanol concentration (X1), extraction time (X2), temperature (X3) and solid-to-solvent (SS) ratio or solid weight (X4) on extraction yield (EY), SETRI and SEDI contents for each technique was examined. The developed models exhibited a high degree of desirability (> 0.72) with determined optimal levels of extraction parameters as follows: X1 = 71%, X2 = 10 min, X3 = 50 °C, X4 = 1.50 g/20 mL for UAE; X1 = 80%, X2 = 5 min, X3 = 50 °C, X4 = 0.85 g/20 mL for MAE; X1 = 80%, X2 = 20 min, X3 = 65 °C, X4 = 2 g for ASE. Under these optimal conditions, the experimental values for EY, SETRI and SEDI contents in SC extracts were: 8.28%, 105.98 mg/g and 16.93 mg/g, respectively for UAE; 8.75%, 105.41 mg/g and 18.76 mg/g, respectively for MAE; 9.34%, 108.00 mg/g and 18.34 mg/g, respectively for ASE. The ANOVA analysis from the RSM were fitted with quadratic models yielding acceptable R2 (> 0.87), adjusted R2 (> 0.77), predicted R2 (> 0.74), and nonsignificant lack-of-fit (p > 0.05) values. Ethanol concentration and solid-to-solvent ratio were the most influencing factors affecting lignans extraction. Although ASE was found as the most suitable method for extracting lignans from SC, from an industrial viewpoint, UAE could be a more affordable technique due to advances in ultrasonic processing devices for large scale applications.