Sustainable Process Research Articles

Optimization of Polyelectrolyte Coacervate Membranes via Aqueous Phase Separation.

Polymeric membranes fabricated via the nonsolvent-induced phase separation process rely heavily on toxic aprotic organic solvents, like N-methyl-pyrrolidine (NMP) and dimethylformamide. We suggest that the "saloplastic" nature of polyelectrolyte complexes (PECs) makes them an excellent candidate for fabricating next-generation water purification membranes that use a more sustainable aqueous phase separation process. In this study, we investigate how the properties of PECs and their interactions with salt can form pore-containing membranes from the strong polyelectrolytes poly(sodium 4-styrenesulfonate) (PSS) and poly(diallyldimethylammonium chloride) (PDADMAC) in the presence of potassium bromide (KBr). How the single-phase polymer-rich (coacervate) dope solution and coagulation bath impacted the formation, morphology, and pure water permeance (PWP) of the membranes was systematically evaluated by using scanning electron microscopy and dead-end filtration tests. The impact of a salt annealing post-treatment process was also tested; these treated PEC membranes exhibited a PWP of 6.2 L m-2 h-1 bar-1 and a dye removal of 91.7% and 80.5% for methyl orange and methylene blue, respectively, which are on par with commercial poly(ether sulfone) nanofiltration membranes. For the first time, we have demonstrated the ability of the PEC membranes to repel Escherichia coli bacteria under static conditions. Our fundamental study of polyelectrolyte membrane pore-forming mechanisms and separation performance could help drive the future development of sustainable materials for membrane-based separations.

Mechanisms of Phase Evolution in the Cu-Sb-S System Controlled by the Incorporation of Cu in Sb2S3 Thin Films.

Ongoing research in metal chalcogenide semiconductors aims to develop alternative materials for optoelectronic devices. However, due to cost and environmental considerations, there is an increasing emphasis on utilizing green materials. This shift toward sustainable materials and processing is expected to become essential in materials research. In this work, we report the microstructural evolution of thin films of the Cu-Sb-S (CAS) system. The films were obtained by annealing amorphous Sb2S3 precursor films previously immersed in a copper solution with variable residence time. Our main findings demonstrate that varying the residence time in immersion together with the annealing and crystallization of the precursor films leads to a controlled incorporation/distribution of Cu into the films, which promotes the formation of films with phases spanning from a mixture between Sb2S3 and CuSbS2 to a pure Cu12Sb4S13 phase, which represents a significant variation in optoelectronic properties. The phase transition mechanisms were investigated using first-principles calculations and correlated with the structural, morphological, and optoelectronic characterization. Results indicate that vacancies serve as nucleation sites for copper incorporation. Subsequently, interstitial sites are occupied during the phase transformation from Sb2S3 to CuSbS2, whereas the transition from CuSbS2 to Cu12Sb4S13 proceeds via a substitutional mechanism. This study contributes to understanding the fundamental phenomena underlying our proposed methodology. These results could promote the development of CAS-based semiconductors with predetermined properties by manipulating simple process parameters, such as the residence time in a copper solution.

Effects of salt concentration, temperature, and blanching time on insect protein extraction yield: optimisation by response surface methodology

Abstract This study aimed to optimise the protein extraction yield from black soldier fly larvae by employing a blanching process to enhance protein solubility and mitigate oxidation. Through response surface methodology, we determined the optimal blanching conditions, with the temperature set at 85.152 °C, a duration of 12.411 s, and a sodium chloride concentration of 0.46 M. These parameters were selected to maximise protein solubility while minimising oxidation. The results of this study reveal significant improvements in protein functionality after blanching, particularly with respect to increased emulsification stability. Notably, no significant effect on foam formation was observed. These findings underscore the efficacy of blanching as a pre-processing step to enhance the quality of proteins extracted from black soldier fly larvae. Moreover, these optimised conditions have promising applications in various food and feed formulations, contributing to sustainable protein sourcing and processing methods. By addressing key challenges related to food security and environmental sustainability, this study provides valuable insights into the utilisation of insect proteins as an alternative protein source in the face of global challenges, such as climate change and dwindling natural resources.

Grape Pomace as a Source of Phenolics for the Inhibition of Starch Digestion Enzymes: A Comparative Study and Standardization of the Efficacy

The increase in the incidence of hyperglycemia and diabetes poses the challenge of finding cost-effective natural inhibitors of starch digestion enzymes. Among natural compounds, phenolics have been considered as promising candidates. The aims of this study were as follows: (a) to investigate the effectiveness of the inhibition of different winemaking byproducts towards intestinal brush border α-glucosidase and pancreatic α-amylase in vitro; (b) to calculate an efficacy index relative to the standard acarbose for the phenolic pool of winemaking byproducts, as well as for isolated phenolic compounds and for the phenolic pools of different plants studied in the literature, in order to rank winemaking byproducts with respect to the reference drug and other natural alternatives. Among winemaking byproducts, red grape skins showed the highest inhibitory activities towards both α-glucosidase and α-amylase, which were, on average, 4.9 and 2.6 µg acarbose equivalents/µg total phenolics (µg Ac eq/µg GAE), respectively. A correlation was observed between the total phenolic contents of red grape skins and their inhibitory effectiveness, which is useful for standardizing the efficacy of phenolic extracts obtained from different winemaking processes. In general, the inhibitory activity of the phenolic pool of grape skins was higher than those of isolated phenolic compounds, namely anthocyanins and monomeric and polymeric flavanols and flavonols, probably due to synergistic effects among compounds. Hence, bioactive phenolic fractions could be produced with the focus on functionality rather than purity, in line with the principles of sustainable processing. Based on the efficacy index developed to compare different phenolic compounds and phenolic-rich plants studied in the literature as starch digestion enzyme inhibitors, red grape skins proved to be cost-effective candidates.

The Strategic Integration of ESG Metrics in Performance Evaluation: Insights from Management Accounting Practices

The integration of Environmental, Social, and Governance (ESG) metrics into performance evaluation has become increasingly vital in achieving corporate sustainability and competitive advantage. This study investigates the impact of ESG metrics on organizational performance within the framework of strategic management accounting (SMA). Using a quantitative approach, secondary data were collected from ESG reports of 100 publicly listed companies across various industries. The analysis employs multiple linear regression to examine the relationships between ESG dimensions—Environmental, Social, and Governance—and financial performance indicators, including Return on Assets (ROA), Return on Equity (ROE), and Tobin’s Q. The results reveal a significant positive correlation between ESG scores and financial performance, with the Environmental dimension exhibiting the strongest influence (β = 0.45, p < 0.01), followed by Social (β = 0.30, p < 0.05) and Governance (β = 0.25, p < 0.05). Firms with high ESG scores (≥75) reported 15% higher ROA and 20% higher ROE than those with lower scores. These findings underscore the importance of integrating ESG into SMA practices to enhance transparency, stakeholder trust, and sustainable decision-making processes. This study contributes to the literature by providing a comprehensive evaluation framework that aligns ESG metrics with corporate objectives. Practical recommendations include adopting global ESG standards, improving transparency in ESG reporting, and prioritizing strategic initiatives in sustainability. Future research could explore the long-term effects of ESG integration on non-financial outcomes, such as brand reputation and employee satisfaction.

Synergistic Integration of a Ru(bda)‐Based Catalyst in a Covalent Organic Framework for Enhanced Photocatalytic Water Oxidation

AbstractTo address the urgent need for sustainable energy processes, there is a growing demand for multifunctional materials that mimic natural photosynthetic enzyme functions, specifically light‐harvesting, efficient photoinduced charge separation, and integration of molecularly defined catalysts, synergistically interacting within these structures. Herein, the successful synthesis of an innovative Covalent Organic Framework (COF‐TFPT‐IsoQ) constructed from optically active triazine (TFPT) and isoquinoline units (IsoQ) as building blocks is reported. Post‐synthetic incorporation of a Ru(bda)‐based water oxidation catalyst (WOC) is achieved through the IsoQ moieties acting as coordinating sites. Leveraging the synthetic flexibility of the designed COF architecture featuring binding sites on its pore walls, various Ru@COF‐TFPT‐IsoQ systems at different Ru:COF ratios are synthesized and tested in the photoinduced (λ > 400 nm) oxygen evolution reaction (OER) under sacrificial conditions. All synthesized Ru@COF‐TFPT‐IsoQ systems demonstrate efficiency in the photocatalytic OER, with the highest turnover number (TON) of 9.1 observed for the system where the Ru‐based WOC is incorporated every fourth COF‐TFPT‐IsoQ unit cell. This work provides valuable insights into the structural integration and catalytic behavior of Ru‐based complexes within COF architectures, highlighting the potential of Ru@COF‐TFPT‐IsoQ as a robust, efficient, and synthetically flexible multifunctional material for light‐induced water oxidation catalysis.

Innovating sustainable fashion design: an exploration of the sustainability of a hybrid method through the C2CAD framework

ABSTRACT Sustainability in the fashion industry is evolving, with a trend towards integrating digital technology with traditional crafts, as more eyes are on artisanal values than manufacturing benefits. Meanwhile, a hybrid design and making method merges human skills with digital tools for sustainable creation, as investigated in the design innovations of the opera costume in this study. The study applies the C2CAD framework to guide design, develop an optimised design model, and validate the sustainable impact of each design step. The design model focuses on small-scale customised pieces by the designer and highlights the stages of hybrid design and making, resulting in a sustainable design process that displays a non-linear recursive route. The research reveals the interaction between the making techniques and necessitates a balance between aesthetics and sustainability. The findings provide a valuable insight into the application of the sustainable fashion design model and making method in the design process.

The electrochemical ion membrane system (EIMs) enhanced light reactions of photosynthesis with intermittent electrical stimulation.

Despite the widespread application of electrochemical systems in bioproduction, their detailed effects on photosynthetic organisms remain to be explored. In this study, a three-chamber electrochemical ion membrane system (EIMs) was optimized for minimizing carbon resource interference in the cathode chamber, thereby elucidating the role of EIMs in the light reactions of photosynthesis. By applying intermittent electrical stimulation, the photosynthetic activity of microalgae was enhanced, manifesting as the promoted accumulation of intracellular ATP and NADPH, while allowing the collection of hydrogen and oxygen as by-products. These findings suggest that EIMs not only facilitate photosynthesis by enhancing both light and dark reactions but also provide new avenues for improving the efficiency of photosynthetic production and advancing sustainable biotechnological processes.

Recent trends and advancements in the utilization of green composites and polymeric nanocarriers for enhancing food quality and sustainable processing

Abstract Consumers now have access to synthetic natural organic nanofoods with tailored properties. These nanofoods use organic or inorganic nanostructured ingredients to enhance bioavailability, making them more effective than traditional supplements. Common materials include metals like iron, silver, titanium dioxide, magnesium, calcium, selenium, and silicates. Modifying the surface of these nanoparticles can provide unique benefits such as improved preservation, mechanical strength, moisture control, and flavor enhancement. Nanocarriers, such as polymeric, lipid, and dendrimer-based carriers, are used in food production. Common polymers include polyglycolic acid, poly (lactic acid), chitosan, and sodium alginate. Lipid carriers have a hydrophobic outer layer and a hydrophilic core, while dendrimer carriers are made from materials like polyethylene glycol and polyamidoamine. These nanocarriers can encapsulate up to 99% of active ingredients, ensuring precise delivery and stability. The nanocarriers in commercial foods are emulsions, inorganic coatings, and fiber coatings. For instance, cucumbers coated with nano emulsions show up to 99% antimicrobial effectiveness. Inorganic coatings, such as potassium sorbate, calcium caseinate, and titanium dioxide, significantly extend the shelf life of packaged foods. Lipid and protein-encapsulated nanosystems offer complete gas barrier protection. This review highlights the exclusive use of nanoparticles in food processing and packaging to enhance quality, safety, and shelf life.

Merger of Single-Atom Catalysis and Photothermal Catalysis for Future Chemical Production.

Photothermal catalysis is an emerging field with significant potential for sustainable chemical production processes. The merger of single-atom catalysts (SACs) and photothermal catalysis has garnered widespread attention for its ability to achieve precise bond activation and superior catalytic performance. This review provides a comprehensive overview of the recent progress of SACs in photothermal catalysis, focusing on their underlying mechanisms and applications. The dynamic structural evolution of SACs during photothermal processes is highlighted, and the current advancements and future perspectives in the design, screening, and scaling up of SACs for photothermal processes are discussed. This review aims to provide insights into their continued development in this rapidly evolving field.

Integrated Experimental and Mathematical Modeling to Guide Microbial Biocatalysis: Pseudomonas putida Conversion of L-Phenylalanine to trans-Cinnamic Acid.

trans-Cinnamic acid (tCA) can be produced by the deamination of L-phenylalanine using phenylalanine ammonia-lyase (PAL). In bioprocesses, optimizing production processes to improve key performance metrics such as titer, rate, and yield has proved challenging. This study investigates tCA production in Pseudomonas putida KT2440 using a whole-cell biocatalyst expressing four different PAL genes. Among these, RmXAL showed the highest titer and rate. Biocatalysis at pH 8.5 and 37°C were identified as the best conditions, giving a tCA concentration of 2.65 g L-1 and a production rate of 0.44 g L-1 h-1. To improve the metrics further, a decoupled bioprocess with various biocatalyst concentrations in the second stage was examined. With a whole-cell biocatalyst concentration of 30 gDCW L-1, optimal process parameters were achieved, giving a titer of 29.88 g L-1, rate of 5.99 g L-1 h-1, yield on glucose of 0.27 g tCA g glucose-1, and yield on L-phe of 0.75 g tCA g L-phe-1. This study is the first report of a model that enables performance metrics to evaluate a suitable process for tCA production and provides valuable insights into tCA production using a decoupled bioprocess. This would appear applicable to larger-scale production, paving the way for an efficient and sustainable industrial process.

Advanced Control Strategies for Cleaner Energy Conversion in Biomass Gasification

The escalating climate crisis necessitates urgent and decisive action to mitigate greenhouse gas emissions. Gasification stands out as a highly adaptable process for energy conversion, capable of handling a wide range of feedstocks, from coal to biomass. The process plays a significant role in improving sustainability by converting these feedstocks into synthesic gas (syngas), which can be used as a cleaner energy source or as a building block for producing various chemicals. The utilization of syngas obtained through gasification not only reduces the reliance on fossil fuels but also helps in reducing greenhouse gases (GHGs), thereby contributing to a more sustainable energy landscape. To maintain optimal operational conditions and ensure the quality and safety of the product, an effective control system is crucial in the gasification process. This paper presents a comparative analysis of three control strategies applied to a numerical model of rice husk gasification: classical control, fuzzy logic control, and dynamic matrix control. The analysis is based on a comprehensive model that includes the equations necessary to capture the dynamic behavior of the gasification process across its various stages. The goal is to identify the most effective control strategy, and the performance of each control strategy is evaluated based on the integral of the absolute value of the error (IAE). The results indicatethat fuzzy logic control consistently outperforms classical control techniques, demonstrating superior disturbance rejection, enhanced stability, and overall improved control accuracy. These findings highlight the importance of selecting an appropriate advanced control strategy to optimize sustainable gasification processes.

Optimization of sustainable polymer composites for surface metamorphosis in FDM processes

The demand for the development of sustainable manufacturing processes is enhanced by the necessity to optimize polymer composites, particularly in the context of fused deposition modeling (FDM). This research aims to enhance sustainable polymer composites to improve the surface metamorphosis during FDM processes. Various eco-friendly polymer matrices were integrated with novel composite reinforcements to evaluate their impact on surface quality, structural integrity, and the performance of FDM-printed components. Key surface features, including roughness (Ra), texture, and function, were quantified through both experimental and computational methods. The optimized composites led to a significant reduction in surface roughness, with Ra values improving by up to 45% compared to standard filaments. In addition, tensile strength was increased by 30% and flexural strength by 20% relative to unmodified polymer composites. Optimization strategies, guided by green chemistry principles and materials science, successfully enhanced surface finishes and functional properties, aligning with sustainability goals. The results demonstrate that optimized sustainable polymer composites can significantly improve the quality and performance of FDM prints, supporting more efficient and environmentally friendly manufacturing practices. This study contributes to advancing materials and processes in line with sustainability principles and surface engineering.

Scaling up Trickle Bed Reactor for Gas Fermentation Technology: The Effect of Temperature and Reactor Characteristics on Mass Transfer

The increasing demand for efficient and sustainable industrial processes has accelerated research into green alternatives. Gas fermentation in a trickle bed reactor is a promising technology; however, optimal scaling up is still challenging. A mass transfer model is crucial for identifying bottlenecks and suggesting design improvements to optimize the scale-up of TBR for gas fermentation. This study explores the effects of temperature, reactor dimensions, and packing material size on the volumetric mass transfer coefficient (kLa) in a commercial-scale trickle bed reactor (TBR). Using dynamic mass transfer modeling, the research results highlight that thermophilic conditions (60 °C) significantly enhance kLa and mass transfer rates for H2, CO, and CO2, despite reduced gas solubility at higher temperatures. Additionally, packing material of smaller particles improves kLa by increasing the surface for gas–liquid interaction, while reactor dimensions, particularly volume and diameter, are shown to critically influence kLa. This study provides valuable insights into optimizing TBR design and scale-up, emphasizing the importance of thermophilic conditions, proper packing material selection, and reactor geometry for efficient gas–liquid mass transfer in syngas (a mixture of H2, CO, and CO2) biological conversion. Overall, the findings offer practical guidelines for enhancing the performance of industrial-scale TBR systems.

Time-Dependent Analysis of Catalytic Biomass Pyrolysis in a Continuous Drop Tube Reactor: Evaluating HZSM-5 Stability and Product Evolution

This study investigates a continuous deoxygenation of bio-oil vapor in a catalytic fixed-bed reactor coupled to a continuous drop tube reactor (DTR) for biomass pyrolysis. Beech wood pyrolysis was initially examined without catalysts at various temperatures (500–600 °C). The products were characterised using GC-MS, Karl Fischer titration, GC-FID/TCD, and thermogravimetric analysis. The highest bio-oil yield (58.8 wt.%) was achieved at 500 °C with a 500 mL/min N2 flow rate. Subsequently, ex situ catalytic pyrolysis was performed using an HZSM-5 catalyst in a fixed-bed reactor at a DTR outlet, operating at 425 °C, 450 °C, and 500 °C. The HZSM-5 catalyst exhibited declining deoxygenation efficiency over time, which was evidenced by decreasing conversion rates of chemical families. Principal component analysis was employed to interpret the complex dataset, facilitating a visualisation of the relationships between the experimental conditions and product compositions. This study highlights the challenges of continuous operation as experimental durations were limited to 120 min due to clogging issues. This research contributes to understanding continuous biomass pyrolysis coupled with catalytic deoxygenation, providing insights into the reactor configuration, process parameters, and catalyst performance crucial for developing efficient and sustainable biofuel production processes.

Kinetic Modelling of Ralstonia eutropha H16 Growth on Different Substrates

Due to environmental pollution and the depletion of fossil fuels, there is growing interest in the development and use of biofuels as environmentally friendly alternatives. One of the most promising biofuels is biohydrogen, hydrogen produced through sustainable processes using microorganisms such as bacteria and algae. One of the most interesting bacteria for hydrogen production is Ralstonia eutropha H16, known for its ability to produce oxygen-tolerant hydrogenases. These enzymes play a crucial role in biohydrogen metabolism and production. The aim of this work was to determine the optimal conditions (reactor type and synthetic medium composition) for the cultivation of R. eutropha H16. The culture media contained different concentrations of fructose and glycerol (mono- or double-substrate cultivation) and the experiments were carried out in a batch reactor. The initial experiments were carried out with 4 g/L fructose or glycerol in the culture medium at pH 7, T = 30 °C, and 120 rpm. The mathematical model, consisting of the growth kinetics (described by the Monod’s model) and the corresponding mass balances, was proposed. The developed model was validated using two independent experiments with different initial substrate concentrations: 2 g/L glycerol and fructose in one medium and 4 g/L fructose and 1 g/L glycerol in the second. In order to propose the optimal cultivation procedure for future research, the mathematical model simulations were performed for different reactor types (batch, fed-batch, and continuous stirred tank reactors) and different initial substrate concentrations. The most successful experiment was the one with 4 g/L glycerol, where γX = 0.485 ± 0.001 g/L of biomass was achieved. Further calculations showed that the most biomass would be produced at higher glycerol concentrations (at γG = 6.358 g/L, γX = 1.311 g/L should be achieved after 200 h of cultivation) and when using a fed-batch reactor (γX = 0.944 g/L after 200 h of cultivation).

Sustainability in the Desert: ESG Governance Practices in Saudi Arabia's Oil Industry

Sustainability has become an important issue for companies and countries, especially in the energy sector. As one of the world's largest oil exporters, Saudi Arabia's oil industry's practices are essential. By taking Saudi Aramco (Aramco) as an example, this article explores sustainable development practices in the desert of Saudi Arabia, focusing on its strategies and results in environmental protection, social responsibility, and corporate governance. As the world's leading energy company, Aramco dominates the oil industry and has actively taken steps to address the growing challenges in environmental protection, supporting the diversity and equality of its employees and the development of local community development, and still be able to have sound financial results to pay back to its shareholders. In this article, the case of Aramco is used to explore in depth the best environmental, social, and governance (ESG) practices of energy companies, research of Aramco's ESG strategies, threats of balancing economic growth with environmental protection in resource-rich but environmentally vulnerable regions, and the difficulties of promoting labor equality would be conducted, and how the best practices can impact and inspire the sustainable development processes on a global scale would be discussed.

Immobilized Eosin Y on Modified Silica Nanoparticles and their Applications in Organic Synthesis

AbstractThe development of novel photocatalytic systems is crucial for advancing sustainable chemical processes in organic synthesis. In this study, we report the preparation, characterization, and application of a heterogeneous photocatalyst based on Eosin Y (EY) covalently immobilized on silica nanoparticles (SNPs). The SNPs‐EY photocatalyst was thoroughly characterized using various techniques, including SEM, TEM, X‐ray diffraction, UV‐vis diffuse reflectance spectroscopy, solid‐state fluorescence spectroscopy, XPS, FT‐IR, TGA, and DLS. These analyses confirmed the successful immobilization of EY on SNPs and demonstrated the uniformity and favourable photophysical properties of the resulting hybrid material. The photocatalytic performance of SNPs‐EY was evaluated in a series of model reactions, including aza‐Henry reaction (cross‐dehydrogenative coupling), reduction of nitrocompounds, and photooxidation of dimethylanthracene. The reaction results demonstrated that SNPs‐EY is an effective and recyclable photocatalyst, offering yields comparable to or higher than those of homogeneous systems, while providing the advantages of easy separation and reuse. This study highlights the potential of SNPs‐EY as a versatile photocatalyst for various organic transformations, promoting the advancement of green and sustainable chemistry.

Editorial: Microfluidic-based technologies for sustainable process intensification

Editorial: Microfluidic-based technologies for sustainable process intensification

A sustainable approach for concurrent recovery of metals from H2 reduced bauxite residue (“red mud”): Process optimization

Bauxite residue (BR), a polymetallic waste, offers significant potential for valuable metal recovery. This study introduces a low temperature H2 reduction-alkaline (NaOH) roasting, followed by water leaching - wet magnetic separation, aimed at efficient recovery of Fe, Na, and Al, alongside non-magnetic tailings (Ca, Ti, and Si). To minimize H2 consumption, 5 vol % H2 + 95 vol % N2 with 200 L/kg was sufficient. Utilizing response surface methodology (RSM), the optimal H2 reduction process conditions were determined as a temperature of 600 °C and a time of 120 min with 20 wt% NaOH. Under these conditions, the maximum recoveries achieved were 74.4 % Fe (grade = 63.6 %), 84.6 % Al, and 91.6 % Na, with RSM model predicted Fe, Al, and Na recovery values at optimum conditions closely matching experimental results (<5 % deviation). The proposed sustainable process minimizes waste and offers a possible solution for BR processing.