Current Research in Green and Sustainable Chemistry最新文献

The magnetic structure of NiFe₂O₄ particles has been obtained by using a sol-gel auto combustion technique with limejuice as a surface-active agent as well as a fuel agent. The above process is classified as sustainable chemistry, which is a procedure that is both environmentally friendly and less expensive than other methods. Some of the physical and chemical techniques used to diagnose nanomaterials include energy-dispersive X-ray spectroscopy, XRD, FTIR, TEM, FESEM, and Brunauer-Emmett-Teller. The phase purity and particle size of 24.27 ​nm were revealed by XRD patterns. Pb⁺², as well as Cd⁺² absorption characteristics, have been investigated in relation to adsorbent concentration, pH, temperature, and contact time. When the pH ranges from three to nine, the best time to contact is 60 ​min for Pb⁺² and 90 ​min for Cd⁺². When compared to the Langmuir adsorption model, the adsorption studies revealed a strong relationship with a Freundlich adsorption isotherm. The thermophysical properties have been described, showing an endothermic reaction for ΔH, a spontaneous process for ΔG, as well as a positive value for ΔS, which was characterized by an increase in process disorder.

Hybrid polymer composites reinforced with synthetic and natural fibers are gaining more interest in current composite technology in an effort to promote sustainability without sacrificing the performance of synthetic fiber reinforced polymer composites. The goal of this study is to see how the fiber stacking sequence of carbon and ramie fiber, as well as the orientation of ramie fiber, affects the quasi-static indentation behaviour of carbon/ramie fiber reinforced epoxy hybrid composites. The hybrid composite specimens were made using a hand layup approach followed by a hot pressing process. The quasi-static indentation properties of carbon/ramie fiber reinforcements in epoxy matrix were investigated using a hemispherical indenter at varying indenter displacement rates of 10, 20, and 30 ​mm/min for the stated stacking sequence and orientation. The indentation resistance qualities of carbon/ramie fiber reinforced epoxy hybrid composites were evaluated in terms of indentation force, hybrid composite specimen energy absorption capability, and hybrid composite specimen damage caused by hemispherical indenter penetration. The results reveal that a carbon/ramie fiber reinforced epoxy hybrid composite with 5 ramie fiber layers has better energy absorption capabilities, absorbing 114.926 ​J at a 20 ​mm/min indentation rate. Similarly, the indentation force in hybrid composites increases as the number of carbon/ramie fiber layers increases. These results indicate that carbon/ramie fiber reinforced epoxy hybrid composites have a great potential towards low velocity impact applications.

The present study deals with the disposal of MW in an eco-friendly manner to the environment and the production of valuable products from cheap waste. From the MW sample, fifteen bacterial isolates (B1–B15) have been isolated. The screening for the biological hydrolysis of MW by cellulases producing bacteria and total reducing sugar production (TRS) was studied. Bacterial isolates B1, B2, B3, B6, B7, and B10 were selected for their ability to hydrolyse MW and TRS production. The highest (TRS) were at 8528.1, 7636.1, 7189.8, 7152.9, 6564.1, and 6539.4 ​μg/mL produced by bacterial isolates B10, B2, B7, B6, B1 and B3 respectively. Carboxy methyl cellulase (CMCase), filter paperase (FPase), and avicelase production were studied. Bacterial isolate (B10) has the highest levels of CMCase (1576.5 U/mL), FPase (1421.4 U/mL), and Avicellase (2080.3 U/mL). Each selected bacterial isolate was tested for the production of biosurfactants. The highest drop displacement test and emulsification power, at 30 ​mm and 97%, respectively, were obtained from the biosurfactant. The isolate (B10) was identified as Bacillus subtilis DSM15029 by 16S rRNA. The effect of chemical and bio-surfactants on MW hydrolysis and cellulolytic enzyme production was carried out. The highest TRS, 9076.1 and 8367.6 ​μg/mL was observed using biosurfactant and Tween-80, respectively. The highest CMCase, FPase, and Avicellase activities (1643.5, 1590.73, and 2113.69 U/mL) were recorded with a biosurfactant. The batch fermentation of MW hydrolysate was performed with a biosurfactant. The highest bioethanol production (60.27 ​mL/L) was recorded after 72 ​h using GC analysis.

After the consumption of the edible part, the citrus fruits are thrown into landfills generating serious pollution and disposal problems. Therefore, the use of citrus fruits for engineering applications has a dual purpose: to generate wealth from waste as an efficient reduction of solid waste. The main objective was to obtain silica-based materials from the precursor (TEOS), replacing acetic acid in acid hydrolysis with different parts of a lemon: peel, juice and peel ethanol extract.

The solids obtained were characterized with different techniques such as TEM, SEM, FT-IR, potentiometric titration and XRD. TEM and SEM images were compared with the synthesized pure silica to contrast the morphology of the acidic hydrolysis with lemon. It can be concluded, in general terms, that the proposed objectives have been achieved, since materials were synthesized through a simple and fast method of obtaining, which allowed their inclusion in oxidic matrices. Until now, few attempts have been made to highlight the renewability of reagents used in the synthesis or to incorporate bio-based catalytic processes in larger scales. However, this research contributes to areas of environmentally friendly materials and synthesis, due to the synthesized solids could be used as a support in eco-catalysts.

Since antiquity, bronzes have been one of the main cultural heritage metallic artifacts. Currently, they continue to have many applications in various industrial fields. Nevertheless, bronzes are subject to the corrosion process in aggressive environments containing chlorides. To overcome this destructive phenomenon, various conventional protection inhibitors have been developed. Unfortunately, these prevention inhibitors have serious drawbacks are expensive and harmful to human health and the environment. Plant extracts are one of the alternatives that can be used as an ecological, cost-effective and efficient alternative. In this context, Aloe saponaria tannin (AST) extract has been tested as green corrosion inhibitor for bronze B66 in 3% NaCl. The experimental study was conducted by gravimetric and electrochemical measurements, supplemented by surface analysis scanning electron microscopy (SEM) coupled to energy dispersive X-ray spectroscopy (EDX). Which allowed us to highlight the protective effect of our inhibitor. In addition, to investigate the adsorption action of AST compounds over the bronze surface, the theoretical simulations based on the MD (molecular dynamics) and DFT (density functional theory) were done. The electrochemical measurements confirmed the results obtained from the gravimetric measurements and noted that the effect of our inhibitors alters the mechanism of the electrochemical process at the metal/solution interface. The experimental results obtained allowed to note that the AST compounds act as a cathodic type inhibitor. Then, the maximal inhibition efficiency reaches 90% at 150 ​ppm of AST extract. Moreover, the results of theoretical modeling studies supported the adsorption of AST molecules on the target metal substrate.

An effective and greener method for the synthesis of 2-(phenyl)-4H-chromen-4-ones has been developed by reacting 2-hydroxychalcones and tert-butyl hydroperoxide (TBHP) in the presence of a base via ultrasonic irradiation. Ultrasonic irradiation is used to replace conventional energy sources in synthesis. In terms of energy conservation and waste reduction, ultrasonic irradiations are increasingly being used as eco-friendly, green, and clean solutions in organic processes. Antifungal activity of all the synthesized compounds was evaluated against three fungi strains. Compound 4d showed the highest activity against A. fumigatus, R. stolonifer and M. mucedo with the values of 20 ​± ​0.47 ​mm, 19 ​± ​0.46 ​mm and 22 ​± ​0.49 ​mm respectively. Compound 4d also showed highest moldock score and formed H-bond with active amino acids. Compounds bearing lipophilic electron withdrawing groups showed more potent activity compared to compounds having electron donating groups.

Plastic usage is increasing the number of pollutants in the environment. Plastic particles and other plastic-based pollutants are found in our environment and food chain, posing a threat to human health. From this perspective, the biodegradable plastics material focuses on creating a more sustainable and greener world with a smaller environmental imprint. This assessment should consider the entire life cycle assessment of the objectives and priorities for producing a wide range of biodegradable plastics. Biodegradable plastics can also have properties similar to traditional plastics while also delivering additional benefits due to their minimised impact on the environment in terms of carbon dioxide, as long as appropriate waste management includes such as composting, are contained. The demand for cost-effective, eco-friendly materials increases to reduce waste management and pollution issues. This study seeks to comprehensively understand biodegradable plastics production and applications research, product prospects, sustainability, sourcing and ecological imprint. Academic and industry interest in biodegradable plastics for sustainability has exploded in recent years. Researchers used the triple bottom line to analyse the sustainability of biodegradable plastics (economic profit, social responsibility, and environmental protection). The research also discusses the variables that influence the adoption of biodegradable plastics and a sustainable framework for improving biodegradable plastics' long-term viability. This study provides a thorough yet simple theoretical design of biodegradable plastics. The research findings and future research endeavours provide a new avenue for further research and contribution to the area.

Developing an efficient technique for the treatment of laboratory wastewater is a challenge. In response, kaolinite clay (CLY) was functionalized with tetraethylammonium bromide to produce tetraethylammonium modified kaolinite clay (CLY@AM). Both CLY and CLY@AM were characterized with X-ray diffraction (XRD), Fourier transformed infrared spectroscopy (FTIR), energy-dispersive X-ray spectroscopy (EDS) and scanning electron microscopy (SEM). CLY and CLY@AM were evaluated for their ability to remove phenolphthalein (PH) and methyl orange (MO) from laboratory wastewater. Peaks from FTIR and XRD suggests the formation of CLY@AM, while SEM micrograph revealed the surfaces of CLY and CLY@AM to be irregularly shaped while CLY@AM has some patches. The adsorption capacities exhibited by CLY@AM towards PH (43.00 ​mg ​g⁻¹) and MO (40.00 ​mg ​g⁻¹) were found more promising compared to CLY, which showed 20.00 and 22.00 ​mg ​g⁻¹ towards MO and PH, respectively. The ΔH^o value for the sorption of PH was found to be −71.7523 ​kJ ​mol⁻¹, while the value was −46.1826 ​kJ ​mol⁻¹ for MO. The ΔH^o values are negative in nature which suggests the process to be exothermic. The removal of MO and PH from the solution may be described by Langmuir isotherm with a regeneration capacity above 80% even at the 14th regeneration cycle. Applying CLY@AM towards the purification of raw laboratory wastewater contaminated with PH and MO further proves the effectiveness of CLAY@AM as a potentially efficient material for the purification of laboratory wastewater systems contaminated with PH and MO.

There is increased enthusiasm towards the use of natural hair fibers for plastic reinforcement due to their toughness and light weight. In this research, low density polyethylene (LDPE) was reinforced using 0.25 ​M NaOH treated cow tail, human and sheep hair fibers at 2, 4, 6 and 8% concentration respectively prior to injection moulding. The average densities, diameters and lengths of hair fibres were assessed The results obtained from the analysis of reinforced LDPE composites indicated that cow tail hair gave the highest average density and diameter. Sheep hair had the highest length after grinding. The study also analyzed the ultimate tensile strength and modulus, flexural strength and modulus, elongation, impact and hardness test on the polymer and their composites as well as the morphology and statistical analysis of the composite. This study indicated that human hair LDPE composites achieved highest flexural strength, flexural modulus, ultimate tensile strength and tensile modulus at 8% fibre loading whereas elongation at break and hardness were at 4% fibre loading while impact strength was at 2%. The cow tail hair LDPE composite gave the best impact strength at 8% fibre loading and sheep hair at 6%. The SEM results showed no serious manufacturing defects on the composites. The analysis of variance indicated that only the means of the composites’ flexural properties were statistically significant. This study shows that short animal hair fibres could be effectively used to reinforced LDPE, and therefore suggest an alternative waste management strategy of these natural fibres that are currently viewed as environmental nuisance in the study area.