Sustainable Chemistry for the Environment最新文献

Cerium oxide (CeO₂) was produced using the reflux process and then deposited on reduced graphene oxide (rGO). The CeO₂/rGO was confirmed by X-ray diffraction, Fourier transform infrared, UV–visible, scanning electron microscopy, and XPS techniques. When malachite green (MG) photodegradation was investigated, first-order kinetics revealed that MG could degraded up to 84 % in 120 min. The nanocomposite's anti-oxidative characteristics were examined against 2,2-diphenyl-1picrylhydrazyl (DPPH) radicals, and the IC₅₀ value of 356.763 mg/µL was evaluated, suggesting a 94 % efficiency rate. Tartaric acid and grape juice's electrochemical characteristics and sensing capacities were assessed using differential pulse voltammetry (DPV) and cyclic voltammetry (CV). Measurements show that grape juice and tartaric acid had detection limits of 13.2 μM and 32 μM, respectively.

The reliable characterisation of the physicochemical properties of micro-sized plastic particles requires quality reference materials for establishing, calibrating, and validating methods. Heterogeneity in particle size, shape and surface chemistry are important factors for reference materials for them to mimic environmental microplastics. This paper introduces a method for preparing model polystyrene micro and nano plastic reference materials using a solvent dissolution-precipitation approach. Polystyrene microplastic particles with mean particle sizes of 0.35, 15.7, 30.0 and 52.3 micron were produced using solvent precipitation under different synthesis conditions with the particle present in a well dispersed and partially dispersed system. The particle size can be controlled by reducing the initial polystyrene-cyclohexane concentration and adjusting the volume of methanol. At a fixed polystyrene-cyclohexane ratio, particles within the specified size range were consistently produced. Chemical analysis using pyrolysis-gas chromatography-mass spectrometry revealed that synthesized microplastics maintain their chemical properties, aligning with the original composition of virgin polystyrene pellets. A similar conclusion was drawn after examining the surface chemistry of the virgin and synthesised microplastic particles using ATR-FTIR analysis. The polystyrene particles produced in this way may be of use as reference materials and might be of interest for toxicological studies.

Controlled release formulations (CRFs) of the organophosphorus pesticides diazinon and dichlorvos were prepared from a novel cow dung ash (CDA) matrix and the more conventional starch (STA) matrix. Fourier transform infrared (FTIR) spectroscopy, scanning electron microscopy (SEM) and X-ray diffraction (XRD) were used to characterize the CRFs. FTIR and XRD spectral data provide evidence for pesticide-matrix interactions fundamental to observed matrix surface binding and pesticide release behaviour in water and soil environments. Properties evaluation of the CRFs reveal similar magnitudes of loading capacity and encapsulation efficiency of CDA- and STA-based CRFs of both pesticides, while the order CDA > STA prevails in matrix porosity and swelling ability. Technical grade (TG) and the CRF-encapsulated pesticides exhibit “burst” release profiles in water; pesticide quantities released at similar lengths of time follow the order TG >> STA-CRF > CDA-CRF, thus revealing the capacity of the CRFs to constrain the active ingredients from free mobility, with CDA-CRF being the more slightly efficacious. The Korsmeyer-Peppas equation reasonably models pesticide release from both CRFs into water, giving n values consistent with both water diffusion into the matrix and matrix relaxation as kinetically important in both matrices. Soil column experiments demonstrate the potential of the CFRs to mitigate ground water pollution. Overall, the results show that CDA- and STA-based CRFs of both pesticides have roughly the same potency for pesticide controlled release and ground water pollution mitigation. Deployment of these CFRs can contribute to the drive for agro-environmental sustainability, while the use of CDA, a waste material, as a matrix in controlled pesticide delivery would resonate with sustainable bioresource utilization.

Contamination of water bodies due to pharmaceutical pollutants including antibiotics is growing day by day due to enhanced consumption of these molecules. Biochar is a competent material for wastewater treatment due to ease of preparation as well as high adsorption capability towards desired pollutants. Cassia fistula biochar (CFB) was prepared by torrefaction process in an inert atmosphere. Owing to a large surface area of 672.3 m²/g, the purpose of this work is to carry out adsorption studies of three antibiotics, namely, ciprofloxacin (CFX), levofloxacin (LVX) and diclofenac sodium (DFC) in aqueous phase as well as for the sequestration of carbon dioxide in gaseous phase. The batch adsorption studies were carried and effects of various operational conditions were studied. The maximum adsorption capacities for CFX, LVX, and DFC were found to be 607.86 mg/g, 68.27 mg/g and 160.51 mg/g respectively under the optimum pH 6.0 for all the three adsorbates, contact time of 60 minutes for CFX, LVX and 20 minutes for DFC at room temperature condition of 298 K. Various operational parameters were optimized using Response Surface Methodology (RSM). Isotherm and kinetics studies for the adsorption of all three drugs followed Langmuir model (R² >0.99) and pseudo-second order kinetics (R² >0.95). Thermodynamic studies show the adsorption of all three drugs were enthalpy driven spontaneous processes. Fixed bed studies were performed showing the applicability of CFB for larger sample volumes. DFT calculations showed strong attractive interaction of CFB with all the three drug molecules. The same material has been applied for capture of carbon dioxide at different temperatures. The CO₂ capture studies showed maximum adsorption capacity of 64.78 cc/g at 273 K owing to activation of CFB with high CO₂ selectivity of 14.29 with respect to nitrogen. Hence, a multipurpose adsorbent has been thoroughly studied with environmental sustainability factor of 0.03.

Water contamination is a global concern as a result of growing industrialization and urbanization. Dye waste produced by numerous industries pollutes the water, so dye-based wastewater is a major alarm for animals, human health, and the environment. The elimination of these dye contaminants from water supplies is currently critical and significant due to the dyes' toxicity on humans, livestock, and plants. To remove/degrade dyes, various methods have been investigated, including extraction, absorption, membrane separation, coagulation, adsorption, biological treatment, and advanced oxidation process (AOPs). Graphitic carbon nitride (g-C₃N₄), a captivating formed polymer, has been transformed as an intriguing issue in AOP science because of its metal-free advantages and its high sensitivity to light. Accordingly, when AOPs are joined with g-C₃N₄, superb dye degradation has occurred. This paper overviewed the g-C₃N₄-based AOPs are discussed for dye removal. The synergist effectiveness and mechanisms behind catalytic activity of g-C₃N₄-based catalysts are broadly discussed. In the meantime, the impacts of pH, water temperature, dissolved oxygen, initial dye concentration, catalyst dosage, and scavengers on the reaction carried out by g-C₃N₄-based catalysts are illustrated.

In this study, nanostructured hydroxyapatite (HAp) was successfully extracted from the bones of Priacanthus macracanthus (Red Big Eye), a species commonly processed in the fish industry, generating significant waste. The extraction process utilized an alkaline hydrolysis method optimized with 2 M sodium hydroxide at 250 °C for 5 h, producing high-purity HAp. Fourier transform infrared spectroscopy (FT-IR) confirmed the presence of characteristic phosphate peaks at 1044 cm⁻¹ and 963 cm⁻¹, and hydroxyl peaks at 632 cm⁻¹. Powder X-ray diffraction (XRD) analysis showed prominent peaks at 2θ values of 25.9°, 32.2°, 39.8°, and 46.7°, corresponding to the crystalline planes of HAp. Field-emission scanning electron microscopy (FESEM) revealed spherical HAp particles with sizes ranging from 50 to 80 nm. Biocompatibility was assessed using human osteoblast-like MG-63 cells, showing a proliferation rate of 92 % compared to the control. Cytotoxicity tests indicated no significant adverse effects, supporting the potential use of this HAp in biomedical applications. Importantly, this method offers a sustainable solution for managing fish bone waste, contributing to pollution control by reducing environmental burdens associated with discarded bone wastes. Future research will focus on in vivo biocompatibility studies and exploring applications in pollution mitigation and tissue engineering. This study highlights the dual benefits of utilizing biowaste for valuable HAp production and addressing environmental pollution challenges, making it a promising approach for sustainable material synthesis and environmental management. The cost-effective and environmentally friendly process further underscores the feasibility of scaling up this method for industrial applications, providing a greener alternative to conventional HAp synthesis.

Extractions of cashew nut shell liquid (CNSL) have always widely been carried out with non-environmentally friendly solvents. Hence, greener solvents are desired as alternative to currently used solvents. Herein, batch extractions of Nigerian CNSL with greener solvents: ethyl acetate and cyclohexane mixture in different ratios were investigated in hot and cold system and results compared with conventional solvent (petroleum ether). Compositional studies of the extracted CNSL and its isolated components were done with Fourier-Transformed Infrared (FTIR), Nuclear Magnetic Resonance (NMR) spectroscopy and Ultra High-Performance Liquid Chromatography-Mass Spectrometry (UHPLC-MS). Cost effectiveness analysis for the extraction solvents and methods was also investigated. It was revealed that ethyl acetate and ethyl acetate-cyclohexane mixture at cold and hot conditions recorded higher CNSL yields than previous reports even at a lower liquid-to-solid ratio. Chemical composition and component quantity extracted did not significantly change under hot or cold system. The present composition of the Nigerian CNSL contains unusually higher amount of anarcardic acid (79 %) and cardanol (14 %) than ever reported. Additionally, degree of unsaturation in the alkyl chain of the CNSL is in the order triene>monoene>diene in the anarcardic acid and cardanol components of the liquid. Cost effectiveness analysis at a kilogramme scale revealed that the order of greenness of extraction route based on solvent type, energy requirement and condition of extraction is ethyl acetate-solvent cold system> ethyl acetate-hot system> ethyl acetate-cyclohexane-system> cyclohexane system > pet. ether system.

Several studies have explored nitrogen recovery from waste streams, focusing on technologies and approaches like electrochemical processes and membrane separation. However, these approaches need to become economically feasible and reliable. The feasibility of recovery processes is strongly influenced by the concentration of nitrogen, which is an important technical challenge in nitrogen recovery. Biological approaches, such as the cultivation of microalgae as well as constructed wetlands, are in focus for addressing nitrogen concentration steps. These approaches allow the conversion of nitrogen compounds into proteins for various applications. The aim of this study was not to review treatment processes to avoid negative environmental consequences but to highlight technologies that allow the concentration, recovery, and circulation of nitrogen compounds.

Lignin extracted from black liquor in chemical pulp mills can potentially replace fossil carbon feedstocks in fuels and materials, thereby increasing the economic and environmental added values of woody biomass. However, since lignin extraction reduces the electricity generation of the mill, the added value depends on the characteristics of the electricity market in which the mill operates. In this study, a model mill is exposed to two different electricity price profiles: the low and steady prices of south-central Sweden in Year 2019; and the high and volatile prices of the same region in Year 2022. For the model mill, investments in lignin extraction designed to increase pulp production are economically viable and have low levels of sensitivity to electricity price levels and price volatility. The viability of lignin extraction without increased pulp production depends on the relationship between the electricity and lignin prices. With stable electricity prices, or steady mill operation, a rule-of-thumb holds that for lignin extraction to be viable, the lignin price (€/t) must be 1.8-times the average electricity price (€/MWh) plus 40 €/t for the supply of chemicals. With volatile electricity prices and flexible operation of the recovery boiler, the mill can shift the loss in electricity sales to low-price hours, thereby saving 15–70 % of the operational costs of lignin extraction, as compared to steady operation. This effect can be further enhanced by increasing the capacity of the lignin extraction process or extending the size of the black liquor storage tank. The proposed flexibility measures allow the market-integrated pulp mill to export lignin to replace fossil carbon supplies in other sectors, while supporting the electricity system during hours with high demand and low supply.

In this study, BiOCl-Fe₂O₃ nanocomposite was synthesized by mixing 1:1 ratio of pre-prepared BiOCl and Fe₂O₃ in 100 mL of H₂O using Cocos nucifera (coconut milk) as a green fuel through the microwave irradiation method. X-ray diffraction analysis (XRD), Scanning electron microscopy (SEM) with, Fourier transform infrared spectroscopy (FTIR), UV–vis spectroscopy(UV–vis), and photoluminescence (PL) spectroscopy analysis were used to determine the structure, morphology, and optical features of synthesised nanocomposites. The characterized composites were used to dye degradation and electrochemical activity. Synthesized BiOCl-Fe₂O₃were degraded methylene blue (MB) 96.2 % in 105 min irradiation of visible light. The BiOCl-Fe₂O₃exhibits significant catalytic activity towards dopamine(DA) under optimal conditions. Cyclic Voltammetry(CV) and Linear sweep voltammetry (LSV) with different concentrations of DA was studied. These results indicate that this BiOCl-Fe₂O₃ is an effective approach for the precise and reliable identification of DA signals in biological samples.