Sustainable Chemistry

The contribution of the cathode to system-level efficiency in electrochemical oxidation (EO) is rarely isolated from anodic selectivity limitations, even though its influence on cell voltage, hydrogen evolution kinetics, and energy consumption is well recognized. This study presents a multicriteria methodology that deconvolutes cathode performance from these anodic constraints. A stable lead dioxide anode was paired with three cathodes, carbon felt (CF), stainless steel (SS), and titanium dioxide (TiO₂), for Rhodamine B degradation. The methodology combines conventional electrochemical diagnostics, a ten-parameter multicriteria assessment spanning activity, efficiency, and economics, and a sensitivity analysis prioritizing operational metrics. Application revealed that cathode material governs system-level performance through trade-offs between degradation rate and energy consumption: SS minimized cathodic voltage contribution, while CF maximized degradation rate, with sensitivity analysis confirming CF as the optimal practical choice. However, all systems were constrained by a universal limitation: Faradaic efficiencies remained below 0.3% at an applied current of 30 mA, with anode potential well above the oxygen evolution reaction (OER) threshold and more than 99.7% of charge diverted to unwanted water oxidation. Thus, cathode selection modulates cost and yield but cannot resolve the underlying anodic OER limitation. This methodology offers a transferable diagnostic protocol, indicating that future efforts should prioritize integrated system design over single-electrode optimization to overcome EO selectivity limitations. Full article

Wine pomace is the residue of pressed grapes from wine production. This research focuses on expanding the use of winery by-products by evaluating the bioactivity and safety of Portugieser wine pomace. Moreover, the study discussed that the valorisation of winery by-products can support circular economy principles and improve resource efficiency in agro-industrial management systems. Here, the phenolic profile and bioactivity of Portugieser wine pomace extract (WPE) were investigated. The (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl-2H-tetrazolium bromide) (MTT) assay was carried out on malignant human neuroblastoma (SH-SY5Y) and normal human fibroblast cells (MRC-5). The MIC assay and growth dynamics were evaluated in probiotic and pathogenic Escherichia coli strains. WPE antioxidant activity and in vivo toxicity in Artemia salina were evaluated. Predominant WPE compounds included trans-cinnamic acid, gallic acid, catechin, and naringenin. Moderate cytotoxicity to SH-SY5Y cells has been detected (up to 41.7%). The growth capacity of probiotic E. coli has been enhanced. WPE showed notable antioxidant activity and good safety, as indicated by the Artemia survival rate (LD₅₀: 2.27 mg/mL, 24 h). The results justify further rigorous testing of WPE to unambiguously confirm its potential as a functional ingredient and its application in the development of value-added products. Moreover, the study highlights the need for organisational strategies to foster the sustainable valorisation of by-products, such as wine pomace. Full article

The ordered copper-based intermetallic compound Cu_0.83Si_0.17 is capable of enhancing the catalytic efficiency of the in-demand green process of the electrochemical reaction of ammonia synthesis from nitrite in comparison with a pure copper metal catalyst, which is well known and studied. The Faradaic efficiency reaches 99% with its maximum at a potential of −0.525 V (RHE), and even at low potentials (−0.1 V) it does not fall below 90%, with an NH₃ yield rate of 132.3 µmol h⁻¹ cm⁻². In addition, the catalyst demonstrated high selectivity and stability. Full article

Plastic waste presents a persistent environmental burden, yet its constituent polymers represent structurally valuable chemical feedstocks. Mechanical recycling remains limited due to polymer degradation, additive contamination, and material downcycling, underscoring the need for alternative strategies. Chemical upcycling offers pathways to convert post-consumer plastics into higher-value monomers, functional chemicals, and bioactive or pharmaceutical precursors by exploiting inherent structural motifs such as aromatic rings, ester linkages, and heteroatom-containing backbones. Approaches such as catalytic depolymerization, molecular functionalization, microbial and enzymatic transformation, and scaffold repurposing enable the recovery of polymer-derived building blocks with improved functional value. Case studies illustrating the conversion of discarded plastics into advanced materials and biologically relevant small molecules demonstrate the potential of these approaches to stimulate innovation and expand sustainable chemical practices. Collectively, such developments align with green chemistry principles, support emerging circular chemical economies, and contribute to global sustainability priorities reflected in the United Nations Sustainable Development Goals. This review aims to outline the guiding principles of chemical upcycling and highlight the challenges in chemical design, encouraging the modern chemistry community to tap into the hidden potential of waste plastics. Full article

Libidibia coriaria (Cascalote), an underutilized leguminous species native to the tropical Americas, is a promising source of bioactive phenolic compounds with pharmaceutical and nutraceutical potential. This study compared microwave-assisted extraction (MAE), ultrasound-assisted extraction (UAE), and their hybrid combination (UMAE) for the recovery of hydrolyzable and condensed phenolics from cascalote pods and evaluated the antioxidant capacity of the resulting extracts. UMAE achieved the highest total phenolic content (223.49 mg GAE/g dry matter), while antioxidant capacity varied by assay: MAE showed the highest DPPH radical scavenging activity and FRAP reducing power, whereas UAE exhibited the highest ABTS radical-scavenging activity. Nevertheless, UMAE showed the lowest IC₅₀ values for DPPH and ABTS (228.91 and 155.65 mg/L, respectively), indicating greater concentration-dependent radical-scavenging efficiency. Qualitative HPLC–MS tentatively identified gallotannins, ellagitannins, and hydroxybenzoic acid derivatives. UAE yielded the broadest phenolic profile, whereas MAE and UMAE shared several major tannin-related compounds. FTIR analysis supported the presence of characteristic functional groups associated with gallotannins and ellagitannins. Overall, under the evaluated conditions, UMAE was the most effective extraction method for improving phenolic recovery. These findings highlight the potential of this hybrid extraction approach for the valorization of L. coriaria pods as a source of high-value bioactive phenolic compounds. Full article

Cellulose nanofibers (CNFs) are typically supplied as a 3 wt.% suspension and this leads to higher costs because of the economics associated with shipping a product that is 97% water. Filter pressing is the common approach to reduce shipping cost as water removal leads to approximately 20 wt.% CNF suspensions. In this manuscript, we describe a method to achieve an approximately 35 wt.% CNF suspension by contact dewatering with a dissolvable particle. In this work, contact dewatering was performed using slightly anionic precipitated calcium carbonate (PCC), anionic ground calcium carbonate (GCC), and cationic GCC. After dewatering, calcium carbonate is removed from the CNF suspension by washing with acidic water, and thus a pure CNF suspension is regenerated. Fiber size analysis and scanning electron microscopy imaging showed that the regenerated CNF suspensions had the same properties as the original supplied suspensions. Full article

Electrochemical conversion of carbon dioxide (CO₂) to ethanol offers a potential route for integrating carbon utilization with low-carbon electricity; however, its environmental performance is governed by the complete process system rather than by catalytic selectivity alone. This study presents a detailed attributional cradle-to-gate life cycle assessment of anion-exchange-membrane (AEM) and bipolar-membrane (BPM) electrolyzer systems using a functional unit of 1 kg of ethanol at the plant gate. The foreground inventory combines stoichiometric balances, peer-reviewed electrochemical evidence, process-energy estimates, and transparent engineering assumptions, while background processes are represented using ecoinvent 3.7.1. Climate-change impacts are evaluated with the IPCC 2021 100-year global warming potential method. The modeled AEM and BPM systems require 23.32 and 27.92 kWh of electricity per kilogram of ethanol, respectively. Wind-powered operation yields the lowest reported impacts, at 0.318 kg CO₂-eq kg⁻¹ ethanol for AEM and 0.442 kg CO₂-eq kg⁻¹ for BPM. Photovoltaic scenarios yield 1.812 and 2.231 kg CO₂-eq kg⁻¹, whereas the Austrian-grid scenarios yield 1.349 and 4.686 kg CO₂-eq kg⁻¹, respectively. Electricity supply is the dominant environmental driver, while separation heat, carbon utilization, component lifetime, and oxygen co-product treatment remain important secondary parameters. The BPM Austrian-grid result is disproportionately high relative to the 19.7% increase in modeled electricity demand and therefore requires exchange-level verification before it can be interpreted as a physical membrane effect. Overall, environmentally credible CO₂-to-ethanol deployment requires low-carbon electricity, reduced cell voltage, efficient carbon management, concentrated product streams, durable components, and transparent co-product accounting. Full article

The isoxazole-5-one ring system is a central structure in many synthetic bioactive molecules, showing a wide range of biological activities, including antibacterial, antitumor, anticorrosion, antifungal, antituberculosis, and antioxidant. They are also applied as agrochemicals with potential fungicidal effects. Given various applications, these pharmaceutically and biologically significant heterocyclic compounds have attracted the attention of chemistry researchers. This study aimed to investigate the application of glycerol as a reaction medium for the three-component synthesis of arylidenisoxazol-5(4H)-one derivatives. The results of the optimized investigations revealed that 3.0 mL of glycerol is the best reaction medium. Evaluation of the effect of reaction temperature showed that the best temperature for this strategy is 60 °C. In the present environmentally friendly study, the desired heterocyclic compounds were quickly synthesized via a one-pot three-component reaction of two keto-esters with hydroxylamine hydrochloride and a number of aryl/heteroaryl aldehydes. This synthetic approach has significant merits, such as cost-effectiveness of the reaction medium, rapid green synthesis, operational simplicity, easy workup, avoiding chromatographic purification, sustainability, acceptable yields, and relatively inexpensive as well as commercially available starting materials. Full article

Black seed (Nigella sativa L., Ranunculaceae) possesses antimicrobial activity due to its bioactive compound, thymoquinone. This study aimed to extract thymoquinone from black seed using an alternative natural deep eutectic solvent (NADES) through an optimization approach. A NADES based on malic acid and choline chloride was employed in this work. The Box–Behnken design was used to investigate the effects of the molar ratio of malic acid to choline chloride, water addition, and ultrasonication time. These variables were varied as follows: the malic acid to choline chloride molar ratio ranged from 2:1 to 4:1, the mass ratio of water to NADES from 0.5:2 to 1.5:2, and the ultrasonication time from 60 to 120 min. The results showed that the malic acid to choline chloride molar ratio, the quadratic term of the malic acid to choline chloride molar ratio, and the quadratic term of ultrasonication time significantly affected thymoquinone extraction. The optimal condition, which yielded the highest thymoquinone concentration, was determined to be a malic acid to choline chloride molar ratio of 4:1, a mass ratio of water to NADES of 1:2, and an ultrasonication time of 60 min. Under these conditions, the thymoquinone concentration was 70.57 ± 5.78 µg/mL, closely aligning with the predicted value. The thymoquinone-rich extract obtained using NADES exhibited antimicrobial activity against Staphylococcus aureus, Staphylococcus epidermidis, and Candida albicans. In conclusion, NADES serves as an effective alternative solvent for extracting thymoquinone from black seed. Full article

Deep eutectic solvents (DESs) have undergone a remarkable transformation over the past two decades, evolving from a laboratory curiosity into one of the most actively investigated solvent platforms in green chemistry. Yet, despite this rapid expansion, and although the field is well served by numerous topical reviews, it still lacks a corpus-wide, cross-disciplinary synthesis capable of guiding strategic research priorities, identifying critical knowledge gaps, and informing policy and industrial investment decisions. The present work addresses this need through a thorough analysis of global DES research from 2003 to 2025, based on a deduplicated corpus of 17,757 publications retrieved from the Web of Science Core Collection and Scopus following PRISMA-adapted screening guidelines. The analysis maps temporal publication dynamics, geographic and institutional contributions, thematic evolution, journal landscape, component usage patterns, international collaboration networks, market projections, and alignment with the United Nations Sustainable Development Goals. The results document an exponential growth trajectory—from a single publication in 2004 to 3954 in 2025 (CAGR > 30%)—and reveal a clear thematic transition from early electrochemistry-dominated research toward extraction, pharmaceutical, and environmental applications, with machine-learning-assisted design and hydrophobic DES formulations emerging as the most dynamic current frontiers. China leads global output with 6819 publications (38.4%), while the United States and Malaysia achieve the highest citation-per-publication ratios among the leading nations (≈46.7 and ≈38.9, respectively, versus ≈27.6 for China), and Spain pairs a comparatively modest output with a high h-index, indicating that impact is large relative to volume. Type III DESs and NADESs collectively account for approximately 69% of the literature, with choline chloride present in 72% of reported formulations. The global DES market, valued at approximately USD 166 million in 2024, is projected to reach USD 370 million by 2030. Despite this progress, critical translational barriers persist: fewer than 0.3% of publications include techno-economic or life cycle assessment analysis, standardized characterization protocols remain absent, and toxicological datasets are systematically incomplete. This panoramic analysis is intended to serve as an evidence-based reference for researchers prioritizing future directions, for funding agencies assessing the maturity and needs of the field, and for industrial stakeholders evaluating the readiness of DES technologies for scale-up. Full article

This work reports the design and validation of a reusable platinum (Pt) electrode platform (ST-E) for green electrochemical analysis. The device integrates Pt working and counter electrodes with an external Ag/AgCl reference and is engineered for repeated regeneration and refunctionalization. Surface renewal by alumina polishing followed by electrochemical activation in 0.5 M H₂SO₄ restores a clean, reproducible Pt surface, as confirmed by diffusion-controlled, reversible ferricyanide voltammetry over 5–150 mV s⁻¹ with near-Nernstian peak separation and i_pa/ipc ≈ 1. Platform versatility is demonstrated in two applications. First, ST-E is functionalized with PFOA-selective molecularly imprinted nanoparticles on an APTES layer, enabling trace determination of perfluorooctanoic acid (1–5 pg mL⁻¹), with a detection limit of 0.50 pg mL⁻¹ and sensitivity of 3.16 μA (pg mL⁻¹)⁻¹. Responses correlate with an equivalently modified commercial screen-printed electrode (r = 0.990, p < 0.005), with Bland–Altman analysis confirming concordance. Second, after regeneration, electropolymerization of o-phenylenediamine yields an insulating poly(o-phenylenediamine) film that attenuates redox currents and increases ΔE_p, illustrating compatibility with diverse surface chemistries. Green metrics (AGREE, AGREEprep ≈ 0.80; BAGI = 75.0) highlight reduced waste and solvent use versus single-use transducers and compatibility with portable potentiostats, supporting circular electrochemical sensing. Full article

This study investigates the synthesis of La_0.6Ca_0.4FeO₃ (LCF) perovskite via a ball milling method for application in reverse water–gas shift chemical looping (RWGS-CL) for CO₂-to-CO conversion. Unlike conventional wet-chemical routes such as the Pechini method, the ball milling approach offers a solvent-free, scalable synthesis using low-cost metal oxide precursors (e.g., La₂O₃, CaO, Fe₂O₃). Structural analysis by XRD confirmed the successful formation of single-phase cubic perovskite, with no secondary phases when using oxide precursors. Crystallite size increased with calcination temperature, from 118.9 Å (no calcination) to 404.3 Å (1050 °C). BET analysis revealed a decrease in surface area from 2.5 m²/g (no calcination) to 0.51 m²/g (1050 °C), consistent with sintering at higher temperatures. TPR-H₂ and TPO-CO₂ studies revealed that non-calcined LCF possesses slightly enhanced redox properties, with oxygen vacancy formation and CO₂ reoxidation activity both at 500 °C. RWGS-CL experiments demonstrate that all LCF samples exhibit stable CO production (910–970 µmol/g_LCF) over multiple cycles at 500 °C, with comparable performance across calcination conditions. A cost and sensitivity analysis reveals that the ball milling method had lower synthesis costs by approximately 92% at the laboratory-scale and 88% at the industrial-scale compared to the Pechini method, highlighting its strong potential for large-scale perovskite production. Full article

The replacement of n-hexane in vegetable oil extraction remains a significant challenge due to environmental and health concerns. This study integrates thermodynamic modeling and kinetic analysis to evaluate green solvents for soybean oil extraction. Solvent–triglyceride interactions were predicted using Conductor-like Screening Model for Real Solvents (COSMO-RS), employing σ-surfaces, σ-profiles, σ-potentials, activity coefficients at infinite dilution (γ∞), and relative solubility descriptors ($x_{RS}$ and $w_{RS}$). Representative triglycerides were modeled using DFT-optimized structures. Based on these predictions and sustainability criteria, cyclopentyl methyl ether (CPME), 2-methyltetrahydrofuran (2-MeTHF), tert-butyl methyl ether (TBME), and ethyl acetate were experimentally evaluated against n-hexane using accelerated solvent extraction (ASE) at 100 °C. CPME and 2-MeTHF achieved the highest extraction yields, exceeding n-hexane, while TBME showed comparable performance and ethyl acetate underperformed. Kinetic analysis using the hot-ball diffusion model revealed a two-stage mechanism: an initial solvation-controlled stage followed by a diffusion-controlled regime. COSMO-RS predictions correlated strongly with early-stage extraction behavior, whereas diffusion coefficients highlighted the influence of mass transfer properties at later stages. The proposed COSMO-RS, experimental extraction, and kinetic modeling framework, validated here for soybean oil, offers a transferable and resource-efficient platform for designing sustainable solvent-based extraction processes across diverse oilseed and natural product matrices. Full article

Sample preparation is frequently a time-consuming process and can be a major bottleneck in many analytical techniques that involve some form of modification to a sample so that it can be analyzed without interference or to increase its sensitivity. As part of the movement towards “green analytical chemistry”, the reduction in organic solvent usage and toxicity via alternative solvents compared to those traditionally used in analytical chemistry has gained increasing interest. Although ionic liquids were thought to have limitations, deep eutectic solvents (DESs) are being looked at as alternatives to traditional organic solvents in analytical chemistry because of their ability to produce a “tunable” set of physico-chemical properties that enable the selective and efficient extraction of a wide variety of analytes from a very diverse array of matrices. Although deep eutectic solvents have attracted increasing attention in analytical extraction applications, a systematic comparison of their performance across various extraction techniques is still lacking. This review fills this gap by offering a comprehensive and integrated evaluation of DES-based extraction approaches, emphasizing the interdependence between solvent characteristics, extraction efficiency, selectivity, and sustainability. The insights presented herein are intended to support the rational selection of appropriate DES-based extraction strategies for diverse analytical purposes. Moreover, these findings are expected to contribute to the advancement of greener, more efficient sample preparation methodologies within the field of green analytical chemistry. In this review article, we describe several analytical chemistry techniques that utilize DESs, such as dispersive liquid–liquid microextraction, solid-phase extraction, ultrasound-assisted extraction, etc., and explain the basic principles and mechanisms behind each technique. Additionally, comparative evaluations are provided to identify the relative advantages and disadvantages of the techniques mentioned above in terms of extraction efficiency and selectivity, and speculation regarding future trends and challenges in DES-based extraction systems will also be included. By integrating recent advances and comparative performance assessments, this review serves as a reference for researchers and industry practitioners, fostering innovation and promoting the wider adoption of sustainable extraction technologies. Full article

Sustainable binders are becoming decisive enabling materials for fiber-based packaging and cellulosic nonwovens because they govern strength, coating integrity, barrier performance, printability, wet durability, and end-of-life behavior. However, replacing fossil-derived latexes, fluorinated finishes, or persistent wet-strength systems with renewable alternatives is not a simple material substitution problem. This perspective argues that sustainable binders must be evaluated through an industrial lens that integrates performance, scalability, cost, process compatibility, food-contact safety, and recyclability. The discussion examines current binder limitations, emerging bio-based alternatives including starch, cellulose derivatives, nanocellulose, proteins, lignin, tannins, chitosan, hemicelluloses, and reactive green crosslinking systems, and the specific opportunity to move from bulk binder replacement toward engineered cellulose–cellulose junctions. Enzyme-assisted activation of cellulose surfaces, especially routes that generate controlled carboxyl and aldehyde functionality, is highlighted as a promising platform for low-energy bonding of recyclable all-cellulose webs when paired with rigorous spectroscopy, mechanical testing, and multiscale modeling. The central conclusion is that the next generation of sustainable binders will be selected not by renewable content alone, but by their ability to deliver reliable performance within high-throughput manufacturing and credible recovery pathways. Full article

Ruthenium possesses outstanding properties and is widely utilized in many fields. However, its natural scarcity makes the recovery of ruthenium from waste liquids particularly important. A dendrimer-grafted chitosan adsorbent is synthesized through Michael addition and amidation reactions on chitosan, which is then used to adsorb Ru(III) from aqueous solutions. Compared with unmodified chitosan, this adsorbent has abundant binding sites and can rapidly and efficiently adsorb Ru(III) through electrostatic attraction and complexation. Characterization techniques, including FT-IR, XPS, and SEM, confirmed successful modification. Adsorption experiments show that this adsorbent exhibits an adsorption efficiency of up to 97.79% for Ru(III) and saturated adsorption capacity of 162 mg/g. The results of competitive adsorption experiments demonstrate that the adsorbent has good selectivity for Ru(III), retaining 71.22% of adsorption efficiency after five cycles. This work offers a new possibility for the environmentally friendly and efficient recovery of Ru(III) from wastewater. Full article

The contamination of aquatic environments by cadmium and other toxic heavy metals represents a major environmental concern requiring efficient and operationally sustainable remediation strategies. In this work, iron oxide materials were synthesized through a microwave-assisted hydrothermal method and evaluated for Cd(II) removal from aqueous systems. Different precursor compositions and organic additives were initially screened in order to identify the most suitable adsorbent formulation. The selected Fe-Tart material was characterized by FTIR, SEM-EDS, and XRD analyses, revealing hydroxylated and poorly crystalline iron oxide structures with heterogeneous surface organization. Batch adsorption experiments were performed under controlled conditions to investigate the influence of pH and equilibrium adsorption behavior, while adsorption data were analyzed using Langmuir and Freundlich isotherm models. Cd(II) uptake showed strong pH dependence, with adsorption progressively increasing from acidic to near-neutral conditions and reaching approximately 80% removal at pH 7–8. The Langmuir model provided the best fitting results (R² = 0.988), suggesting preferential occupation of energetically comparable surface sites with a maximum adsorption capacity of 6.51 mg g⁻¹. The adsorption behavior was interpreted within a pH-dependent surface complexation framework involving hydroxylated iron oxide surfaces. Although the adsorption capacity remained lower than that reported for some highly engineered adsorbents, the results indicate that microwave-assisted synthesis may provide a relatively simple and rapid route for preparing iron oxide-based materials potentially applicable to water remediation systems. Full article

Electrochemical CO₂ reduction to ethanol is a promising route for circular carbon fuel and chemical production, but practical implementation remains limited by coupled membrane, catalyst, transport, and system integration constraints. This Communication reassesses anion-exchange membranes (AEMs) and bipolar membranes (BPMs) for CO₂-to-ethanol electroreduction by integrating recent 2024–2026 advances with foundational membrane and CO₂RR literature. The central argument is that membrane selection is not a passive separation choice; instead, it actively controls local pH, charge carriers, CO₂ availability, carbonate formation, water activity, proton/cation delivery, product crossover, and downstream techno-economic assessment (TEA) and life-cycle assessment (LCA) burdens. AEM operation can create alkaline cathodic microenvironments that favor C–C coupling, but bicarbonate/carbonate formation imposes carbon-loss, salt-management, and CO₂-recovery penalties. BPM operation can improve pH separation and carbon management through water dissociation and bicarbonate acidification, but its viability depends on water-dissociation efficiency, co-ion exclusion, junction stability, hydration management, and voltage control. Recent ethanol-selective catalyst studies further show that copper oxidation state, grain boundaries, subsurface dopants, ionomers, interfacial wettability, and dynamic operation interact strongly with membrane-imposed microenvironments. This Communication proposes a membrane-centered decision framework linking AEM/BPM selection with ethanol selectivity, single-pass carbon utilization, energy efficiency, durability, TEA/LCA boundaries, and future reactor design. Full article

In recent years, there has been growing awareness of the potential harmful effects that analytical methods can have on human health and the environment. Green analytical chemistry (GAC) integrates sustainability into chemical analysis by emphasizing a reduction in waste, energy consumption, and hazardous reagents while maintaining analytical performance. This review summarizes the most recent developments in atomic spectrometry techniques used for analyzing trace metals in various types of samples. Key advances include green metrics, sampling methods, direct analysis, and instrument miniaturization. Since direct sample analysis via spectrometric methods is rarely feasible, recent developments in sample pretreatment, which align with the 12 principles of GAC, are also discussed. Passive sampling can serve as a valuable approach for conducting analyses with reduced sample pretreatment steps and overall costs, thereby addressing these concerns. Current green assessment metrics and their application in atomic spectrometry are also reviewed. This article aims to provide researchers with detailed information to improve the determination of trace metals in accordance with GAC principles. Full article