Conventional Process Research Articles

Development and Techno-Economic Evaluation of Crystallization Techniques for GABA Purification from Fermentation Broth.

γ-aminobutyric acid, a critical neurotransmitter, is experiencing an increasing demand in the medical and health fields. Conventional processes for γ-aminobutyric acid purification from fermentation broth encounter significant challenges, such as high ethanol usage, low yield, complex process flow, and environmental pollution. Therefore, a purification process based on crystallization techniques was developed to address the above issues. The process was implemented in two stages: desalination and γ-aminobutyric acid treatment. Na2SO4 was effectively removed through a cooling crystallization technique. γ-aminobutyric acid with a purity of 98.66% and a yield of 67.32% was further obtained through a designed "antisolvent-cooling" crystallization process in a 3.2 L system. Moreover, the new process reduced ethanol usage compared to conventional processes, streamlined the purification process flow, and was more environmentally sustainable. Furthermore, we established an industrial-scale model for γ-aminobutyric acid production. Techno-economic analysis indicates that an investment in a plant with an annual capacity of 74.16 tons of γ-aminobutyric acid is projected to achieve payback in 1.98 years. In conclusion, the crystallization-based purification process is poised for industrial-scale γ-aminobutyric acid production due to its high efficiency, economic viability, energy conservation, and environmental compatibility.

Fully analog iteration for solving matrix equations with in-memory computing.

Memristive in-memory computing has demonstrated potential for solving matrix equations in scientific computing. However, the inherent inaccuracies of analog mechanisms create challenges in achieving high-precision solutions while maintaining low-energy consumption. This study introduces a memristive matrix equation solver that considerably accelerates solutions by performing mathematical iterations directly within an analog domain. Our approach facilitates rapid approximate solutions with a scalable circuit topology and expedites the high-precision refinement process by substantially reducing the digital-to-analog conversion overhead. We experimentally validated this methodology using a heterogeneous computing system. We performed simulations of multiple scientific problems on these circuits, including solving the diffusion equation and modeling equilibration in silicon P-N junctions. Notably, our memristive solver, combined with digital refinement, achieved software-equivalent precision (with an error of 10-12). Compared to conventional digital processing units, this approach offered a 128-fold improvement in solution speed and a 160-fold reduction in energy consumption. This work establishes a foundation for future scientific computing using imprecise analog devices.

Comprehensive Mass Spectrometry Workflows to Systematically Elucidate Transformation Processes of Organic Micropollutants: A Case Study on the Photodegradation of Four Pharmaceuticals.

Organic micropollutants (OMPs) in the aquatic environment challenge conventional water treatment processes. Advanced oxidation processes, such as UV photolysis, serve as effective strategies to remove OMPs. However, these often yield unknown transformation products (TPs). High-resolution mass spectrometry (HRMS)-based non-target analysis (NTA) is commonly used to screen large numbers of chemicals but faces specific challenges such as low concentrations of compounds of interest, lack of reference standards, and the need for sophisticated data analysis workflows when used for TP identification. This article describes comprehensive workflows to study UV photolysis-related processes and the resulting TPs, by combining an automated photodegradation setup and HRMS and advanced NTA approaches. Four pharmaceuticals were successfully degraded in a case study, and 38 NTA features were effectively prioritized from complex sample matrices and identified as TPs through complementary approaches developed in this work. The identified TPs were structurally diverse and mostly novel. Semi-quantitation suggested that the TPs explained a relevant part of the parent removal. The developed workflows are a step toward systematic comprehensive analysis of transformation processes in water and beyond. The openly available data-processing tools and data enhance transformation data repositories and algorithms and support NTA studies in general.

Topological data analysis with digital microscope leather images for animal species classification

This study presents a method for classifying cow and horse leather using a small number of digital microscope images and topological data analysis. In this method, hair pore coordinates in the images are used as essential information for classification. First, the coordinates were semiautomatically extracted using conventional image processing methods and persistent homology (PH) computation. Binary images with white pixels corresponding to the coordinates were generated, and their PHs were computed using filtration based on the Manhattan distance. In addition to the pairwise distance between the two pores, zeroth- and first-order lifetimes were used as explanatory variables to construct the classifier. Among the three explanatory variables, the zeroth-order lifetime resulted in the highest classification accuracy (86%) for the test data. Furthermore, we constructed logistic regression (LR) and random forest (RF) models using the zeroth-order lifetime computed from all images and conducted model interpretation. In both LR and RF, information on a zeroth-order lifetime of less than 10 was used as an important explanatory variable. Additionally, the inverse analysis of birth–death pairs suggested that the zeroth-order lifetime contains topological information distinct from the conventional pairwise distance. Our proposed method is designed to be robust in data-limited situations because it only uses hair pore coordinates as explanatory variables and does not require other information, such as hair pore density or pore size. This study demonstrates that accurate classifiers can be obtained using topological features related to hair pore arrangement.Graphical

Facile Enhancement of Mechanical Interfacial Strength of Recycled Carbon Fiber Web-Reinforced Polypropylene Composites via a Single-Step Silane Modification Process.

In this study, a surface treatment process was introduced into the conventional dispersion process for preparing wet-laid nonwoven fabrics to improve their properties, using recycled carbon fibers (rCFs). The conventional binder solution was replaced with a solution containing different amounts of silane, and the changes in the fiber properties of the prepared nonwoven fabrics were examined after the addition of modified rCFs and polypropylene. FE-SEM analysis confirmed that a silane layer was formed on the rCF surface due to the formation of a siloxane network. FT-IR and XPS analyses further confirmed the presence of siloxane bonds and chemical modification of the rCF surface. When an optimal amount of silane content was used, the mechanical strength increased by 64% compared to untreated rCFs, owing to the improved molecular chain entanglement within the matrix. Our findings indicate that the simultaneous use of dispersion and a surface treatment can produce composites with excellent mechanical properties and improved processing and surface properties; thus, this method can be used to help upcycle rCFs, thereby expanding their applications.

Assessing closed-circuit reverse osmosis (CCRO) efficiency in removing contaminants of emerging concern (CECs) in a high-recovery water reclamation pilot study

ABSTRACT Contaminants of emerging concern (CECs) are increasingly recognized due to the proliferation of recycled water projects worldwide, particularly in California, aimed at addressing water scarcity and escalating demands. This research investigates the efficacy of closed-circuit reverse osmosis (CCRO) in treating tertiary effluent from municipal wastewater within a high-recovery framework, conducted as a pilot study at the San Jacinto Valley Regional Water Reclamation Facility. The primary aim of this pilot-scale investigation was to subject the CCRO process to elevated recovery rates and assess its capability in treating municipal wastewater. A selected list of the removal rates of CECs was examined and analyzed. Furthermore, the performance of membrane process at recovery rates ranging from 90 to 95% was evaluated. Results indicate that conventional municipal wastewater treatment effectively eliminates the majority of select CECs; however, certain contaminants may bypass conventional treatment processes. Our findings demonstrate that CECs such as select N-nitrosamines, hormones, and pharmaceuticals can be efficiently removed by the CCRO system at high recovery rates of 90–95%. Hydrophobic molecules like fluoxetine, tris(1,3-dichloro-2-propyl)phosphate, and tris(chloropropyl) phosphate exhibited high rejection rates by the rRO membrane, while some hydrophilic constituents such as N-nitrosodimethylamine and caffeine were not effectively rejected by the membrane process.

Seawater Membrane Distillation Coupled with Alkaline Water Electrolysis for Hydrogen Production: Parameter Influence and Techno-Economic Analysis.

The production of green hydrogen requires renewable electricity and a supply of sustainable water. Due to global water scarcity, using seawater to produce green hydrogen is particularly important in areas where freshwater resources are scarce. This study establishes a system model to simulate and optimize the integrated technology of seawater desalination by membrane distillation and hydrogen production by alkaline water electrolysis. Technical economics is also performed to evaluate the key factors affecting the economic benefits of the coupling system. The results show that an increase in electrolyzer power and energy efficiency will reduce the amount of pure water. An increase in the heat transfer efficiency of the membrane distillation can cause the breaking of water consumption and production equilibrium, requiring a higher electrolyzer power to consume the water produced by membrane distillation. The levelized costs of pure water and hydrogen are US$1.28 per tonne and $1.37/kg H2, respectively. The most important factors affecting the production costs of pure water and hydrogen are electrolyzer power and energy efficiency. When the price of hydrogen rises, the project's revenue increases significantly. The integrated system offers excellent energy efficiency compared to conventional desalination and hydrogen production processes, and advantages in terms of environmental protection and resource conservation.

Photo-Induced Bandgap Engineering of Metal Halide Perovskite Quantum Dots In Flow.

Over the past decade, lead halide perovskite (LHP) nanocrystals (NCs) have attracted significant attention due to their tunable optoelectronic properties for next-generation printed photonic and electronic devices. High-energy photons in the presence of haloalkanes provide a scalable and sustainable pathway for precise bandgap engineering of LHP NCs via photo-induced anion exchange reaction (PIAER) facilitated by in situ generated halide anions. However, the mechanisms driving photo-induced bandgap engineering in LHP NCs remain not fully understood. This study elucidates the underlying PIAER mechanisms of LHP NCs through an advanced microfluidic platform. Additionally, the first instance of a PIAER, transforming CsPbBr3 NCs into high-performing CsPbI3 NCs, with the assistance of a thiol-based additive is reported. Utilizing an intensified photo-flow microreactor accelerates the anion exchange rate 3.5-fold, reducing material consumption 100-fold compared to conventional batch processes. It is demonstrated that CsPbBr3 NCs act as photocatalysts, driving oxidative bond cleavage in dichloromethane and promoting the photodissociation of 1-iodopropane using high-energy photons. Furthermore, it is demonstrated that a thiol-based additive plays a dual role: surface passivation, which enhances the photoluminescence quantum yield, and facilitates the PIAER. These findings pave the way for the tailored design of perovskite-based optoelectronic materials.

Effects of Mg Content and Pulsed Magnetic Field Treatment on Microstructure and Properties of As-Cast Biodegradable Zn-3Cu Alloy

The microstructure, mechanical properties, corrosion behavior, cytocompatibility, and antibacterial properties of biodegradable Zn-3Cu-xMg (x = 0, 0.5, 1 wt.%) alloys with or without pulsed magnetic field treatment during casting were systematically investigated. Mg addition induced the formation of fine Mg2Zn11 precipitated along the matrix grain boundaries. With the increase in Mg content, the precipitation of the Mg2Zn11 phase increased, and the grain size became finer. Pulsed magnetic field treatment exacerbated the occurrence of this phenomenon. Under the combined action of the Mg2Zn11 phase and refined grain size, Zn3Cu0.5Mg alloy with pulsed magnetic field treatment had the best strength–ductility match (σUTS = 181.46 ± 1.06 MPa, δ = 3.95 ± 0.07%), moderate corrosion rate (icorr = 5.69 ± 3.96 μA/cm2), positive cytocompatibility, and antibacterial properties. This study indicated that Zn3Cu0.5Mg alloy with pulsed magnetic field treatment had the greater potential to further improve its properties through subsequent conventional metal-forming processing and severe plastic deformation techniques to meet clinical requirements, compared to existing as-cast Zn alloys.

Minimizing Carbon Capture Costs in Power Plants: A Novel Dimensional Analysis Framework for Techno‐Economic Evaluation of Oxyfuel Combustion, Pre‐combustion, and Post‐combustion Capture Systems

ABSTRACTThe imperative to mitigate anthropogenic CO2 emissions from power generation plants, which account for approximately 40% of global emissions, necessitates developing and deploying carbon capture, utilization, and storage (CCUS) technologies. This study undertakes a comprehensive techno‐economic evaluation of three primary CO2 capture technologies—pre‐combustion, post‐combustion, and oxy‐fuel combustion—integrated with natural gas power plants. Utilizing Aspen HYSYS design simulation and economic assessments, the technical and economic viability of each technology were investigated, considering key metrics such as levelized cost of energy (LCOE), carbon emission intensity (CEI), cost of carbon avoidance (COA), investment costs, production costs, net present value, and rate of return. A multi‐criteria evaluation framework incorporating dimensional analysis was employed to compare the technologies, and the results revealed post‐combustion capture as the most viable option with a cost factor (CF) value of 0.85, striking an optimal balance between efficiency, costs, and environmental impact. With minimized TIC and TPC, well below the conventional processes, this study produced a unique framework for reducing costs in CCS technology deployment. Conversely, oxy‐fuel combustion has huge drawbacks regarding low profitability as it was found to have the highest total investment cost (TIC) of $8,258,483.99 and annual production cost (APC) of $9,234,870. In contrast, a higher CEI of 0.05 tCO2/MWh and COA of $150.33/tCO2 make pre‐combustion less environmentally friendly than the three technologies. The findings of this study provide critical insights to inform decision‐making in CCUS development, supporting a low‐carbon energy transition. Future research directions should focus on evaluating feasible configurations and optimizing post‐combustion capture technology for commercial‐scale deployment.

¬¬¬An Investigation into Revolutionizing Auto Component Manufacturing: An IoT-Based Approach for Improved Productivity and Waste Elimination

The Auto Component Manufacturing industry is confronted with numerous challenges pertaining to productivity, waste reduction, and operational efficiency on the shop floor. Conventional manufacturing processes often prove to be time-consuming, resulting in substantial waste generation, leading to elevated production costs and heightened environmental concerns. In response to these issues, the adoption of an IoT-based approach presents a promising solution for enhancing manufacturing efficiency and sustainability. This research paper delves into the realm of IoT implementation within the Auto Component Manufacturing sector. The primary objective is to explore case studies, identify bottlenecks in existing processes, and examine the outcomes of these case studies. By focusing on real-world examples, we aim to shed light on the practical applications and benefits of integrating IoT technology into the manufacturing landscape. One novel aspect of this study is the holistic implementation of a Whole IoT enterprise that spans from suppliers to end customers within a company. This comprehensive approach has seamlessly connected various departments and led to a significant reduction in waste generation across the supply chain. Through the integration of IoT technology, companies gain access to real-time insights into their production processes and equipment. This invaluable data empowers them to make informed, data-driven decisions promptly, resulting in substantial cost savings and enhanced operational efficiency. The findings presented in this paper underscore the potential of IoT-based solutions to revolutionize traditional manufacturing practices in the Indian Auto Component Manufacturing industry. In conclusion, this research paper not only discusses case studies to uncover operational bottlenecks but also showcases the tangible outcomes of IoT implementation. By offering a comprehensive view of the scope of IoT integration and its transformative impact, this paper underscores the potential for achieving greater efficiency, cost savings, and sustainability within the Auto Component Manufacturing industry through IoT technology.

Development and characterization of Putranjiva roxburghii with addition of SiO2 and graphene nanoparticles for using it as a cutting fluid

Cutting fluids are used in the machining to lubricate and cool the tool-workpiece combination. Recent trend is to use vegetable oils as cutting fluid in place of synthetic oils to ensure sustainability. This work explores the lubrication ability of Putranjiva roxburghii vegetable oil by adding suitable proportions of silicon dioxide (SiO2) and graphene nanoparticles for achieving the goal of sustainable machining. Pure base oil was obtained from the seeds of the Putranjiva roxburghii tree by the conventional extraction process. Nanoparticles of SiO2 and graphene were mixed separately in different weight percentage, viz., 0.25%, 0.5%, 0.75%, and 1% to prepare the nanofluids. Nanofluids with equal proportions of SiO2 and graphene nanoparticles were also prepared. Characterization techniques were employed to properly examine the structure and composition of nanoparticles. Thermal, rheological, and wettability tests were conducted for prepared nanofluids. The properties of the nanofluids were superior to those of the base oil. It was noted that no single concentration of nanoparticles is the best for all properties. For example, the highest thermal conductivity was obtained for 0.75 wt.% of graphene-dispersed nanofluids. On the other hand, the wettability on inconel 718 was the highest for graphene plus SiO2 nanofluids at concentrations of 0.5 wt.%. Hence, the optimum composition of cutting fluids can be obtained by solving a multi-objective problem depending on the need of machining. The efficacy of the developed bio-based nanofluids was tested during the milling of Inconel 718 by evaluating surface roughness and temperatures. The results were compared against dry machining and base oil-wetted conditions to assess its performance. Putranjiva roxburghii based hybrid (SiO2 + graphene) oil performed better.

Selective Recovery of Metallic Zinc from Zinc Leaching Residue by Calcification Roasting and Acid Leaching.

It is essential to recycle zinc leaching residue (ZLR) generated by the conventional zinc hydrometallurgy process, as it is a hazardous and potentially valuable industrial waste. A combined calcification roasting-acid leaching process was developed to selectively separate and recover zinc from ZLR. This work investigates the effectiveness of using calcium oxide as an additive to transform zinc ferrite during the roasting process. The feasibility of the reaction was investigated based on thermodynamic calculations and compositional analysis. The transformation ratio of zinc ferrite reached 95.27% after roasting at 900 °C for 2 h with a Ca/Fe molar ratio of 3. During the calcification roasting process, the zinc ferrite was effectively converted into zinc oxide and calcium ferrite. The selective leaching of zinc was achieved at an L/S of 15, 25 g/L H2SO4, 60 °C, and 90 min. The extraction ratios of Zn and Fe were 86.26% and 0.06%, respectively. After the leachate was evaporated and purified, metallic zinc with a purity of 99.53% was obtained by constant current electrolysis for 60 min with a current efficiency of 86.7%. The proposed process provides a viable alternative method for recycling zinc resources from ZLR by an environmentally friendly method.

Creation of Dopant-Plasmon Synergism in Double Perovskites for Bias-free Photoelectrochemical Synthesis of Bromohydrins and Hydrogen Peroxide.

The integration of photoexcited charge carriers into the synthesis of valuable chemicals offers substantial sustainability benefits, particularly by replacing toxic and costly oxidants and reductants typically used in conventional processes. The efficiency of such transformations is fundamentally governed by the ability to optimize light absorption and charge carrier dynamics within photoelectrodes/photocatalysts. Herein, we present a Cu+/Cu2+-substituted double perovskite Cs2AgBiBr6 photoanode, embedded with plasmonic Ag nanoparticles, for bias-free photoelectrochemical production of bromohydrins and H2O2. Spectroscopic analyses, coupled with three-dimensional finite-difference time-domain simulations, demonstrate that the inclusion of Ag nanoparticles significantly enhances electromagnetic energy utilization and improves carrier separation efficiency. The synergistic effect of the Cu2+ and Ag nanoparticles results in a 7-fold increase in the yield of 2-bromo-1-phenylethanol, compared to pristine Cs2AgBiBr6, alongside an impressive H2O2 productivity of 25.8 μmol h-1 cm-2. Experimental and theoretical investigations reveal that the Cu2+ substitution strengthens Br- adsorption and oxidation, promoting the bromohydroxylation of alkenes via electrophilic addition in the bulk solution. These findings offer critical insights into the design of advanced metal halide perovskites for sustainable and solar-driven chemical transformations.

A Study on the Pyrolysis and Product Regulation Mechanism of Waste Polystyrene at Threshold Temperatures.

Pyrolysis technology, as a method for recycling waste polystyrenes (WPs), is widely regarded as an effective means to achieve the high value reutilization of WPs due to its environmental friendliness and the renewability of the resources used. However, in the conventional pyrolysis process for WPs, relatively high temperatures are often required to induce pyrolysis. This process not only consumes a significant amount of energy but also leads to complex and variable product compositions due to the high pyrolysis temperatures. Therefore, there is an urgent need to develop a high-value-added pyrolysis process that can lower the pyrolysis temperature of WPs and regulate its products, achieving the efficient conversion of WPs. This paper proposes a high-value "threshold temperature pyrolysis process" based on the relationships between pyrolysis temperature, threshold activation energy, and the conversion rate of WPs. The study found that under a heating rate of 10 K/min, when the conversion rate of WPs reaches 0.3, the maximum activation energy required for the entire pyrolysis process is approximately 223 kJ/mol, corresponding to a pyrolysis temperature of 673.15 K. Therefore, conducting isothermal pyrolysis at this temperature is expected to achieve the efficient conversion of WPs. The experimental results show that, compared to the conventional pyrolysis of WPs, the threshold temperature of the pyrolysis process not only lowers the pyrolysis temperature by 40 K but also regulates the distribution of pyrolysis products and the composition of pyrolysis oil, leading to a 7%wt increase in the yield of the pyrolysis oil, reaching 89.3%wt. Meanwhile, the relative content of low-molecular-weight aromatic hydrocarbons (Toluene, Styrene, and α-Methylstyrene) in the pyrolysis oil increases by 7.4%wt, which also suggests that the threshold temperature of the pyrolysis process promotes the shift in pyrolysis oil towards lighter fractions. These findings provide a solution for energy saving, emissions reductions, and the efficient conversion of WPs.

Enhanced micropollutant degradation over catalyst-free synergistic activation of periodate and persulfate under solar light.

Micropollutants are ubiquitous in water sources, posing threats to both human health and ecosystems. Conventional water and wastewater treatment processes are inefficient in micropollutant removal. In this study, the energy-effective and environmentally friendly solar light-driven periodate (PI) and peroxydisulfate (PDS) synergistic activation process (PI/PDS/solar light) is developed for efficient micropollutant decontamination. The PI/PDS/solar light process (0.5mM PI and 0.25mM PDS) achieves 100% degradation of 2ppm CBZ in 15min with a CBZ degradation rate constant of 0.31min-1, which is 6.6 and 13.2 times that of PI/solar light (0.046min-1, 0.5mM PI) and PDS/solar light (0.023min-1, 0.5mM PDS). Mechanistic studies reveal that the enhanced solar light utilization and charge transfer between PI and PDS lead to the synergistic activation of the dual oxidants in the PI/PDS/solar light process, thus promoting micropollutant degradation. Additionally, the scavenging tests demonstrate that •OH and SO4•- are the dominant radicals for CBZ degradation. Furthermore, the PI/PDS/solar light process exhibits excellent applicability in different types of water sources, where several water components (pH, natural organic matter, and anions) pose insignificant impacts on CBZ degradation. Nonetheless, the developed process still has a disadvantage in that the degradation intermediates of PPCPs may bring potential toxicity. The study offers valuable mechanistic insights into the novel synergistic PI and PDS coactivation process under solar light and highlights the practicability of the developed technique as an efficient strategy for micropollutant decontamination.

In Situ Grown Cs2Ag0.3Na0.7InCl6 Double Perovskites within a PVDF Matrix for High-Performance Flexible Piezoelectric Nanogenerators.

Incorporating perovskite nanocrystals (PNCs) into poly(vinylidene fluoride) (PVDF) is an effective method to improve the performance of PVDF-based piezoelectric nanogenerators (PENGs). The conventional techniques are typically performed via a two-step process, namely, the synthesis of PNCs and then introducing them into the PVDF matrix. Here, we report the exploration of flexible PENG with boosted performance by in situ growth of Zr-doped Cs2Ag0.3Na0.7InCl6 double perovskites (ZCDP) within the PVDF matrix (PENGin). The as-constructed PENGin delivers an open-circuit voltage of 44.4 V and a short-circuit current density of 10 μA cm-2, both of which are more than 2 times those of PENGs built by a conventional two-step process and ∼6 and ∼9 times the best ones of in situ grown Cs2InI6@PVDF-based PENGs ever reported, respectively. The enhanced performance could be ascribed to the optimized spontaneous polarization, thanks to the uniform dispersion of PNCs with a solid ZCDP/PVDF interface within the matrix, which collectively facilitates the electron migration and aggregation, thereby establishing a strong built-in electric field to amplify the dipole spontaneous polarizability. Additionally, the PENGin exhibits excellent performance with robust stability in pressure sensing, wearable energy harvesting, and DC power applications, representing its promise toward practical use.

Policy analysis in sport: a review of mainstream meso-level frameworks and developing more sustainable policy for grassroots sport.

This paper reviews some mainstream meso-level policy analysis frameworks widely applied in sport. There is, however, an absence of consensus for an established framework for analysing sport policy in general and, instead, techniques emanating from other fields of study have been relied upon. The resultant approach to sport policy analysis is inconsistent, multidimensional, and lacks unanimity, leading to calls for a sport-specific framework. This research outlines how meso-level frameworks have been applied in sport policy and issues linked to sustainability from a grassroots policy perspective. A narrative literature review provides an overview of prevalent approaches, namely Institutional Analysis, the Multiple Streams Framework, Policy Network Theory, and the Advocacy Coalition Framework. Aspects of applying these models to sport policy-including some key advantages and disadvantages-are outlined, especially the issue of conventional top-policy processes, the impact on policy implementers at grassroots level, and the potential for bottom-up policy influence. The article examines the four frameworks in the context of praxes in sport, noting the overall importance of a meso-level approach to sport policy analysis and that arriving at an holistic and inclusive accord has merit.

TiO2/SiO2/g-C3N4 flower-like spheres with g-C3N4 sheets for enhanced visible-light-driven photodegradation of industrial pollutants via an adsorption–photocatalysis synergy

Abstract Wastewaters containing toxic pollutants such as dye, pharmaceuticals and other chemicals have adverse effect on human and aquatic life. The pharmaceuticals cannot be efficiently removed by conventional wastewater treatment processes. The use of the proper photocatalyst for the removal of pharmaceuticals in aquatic systems is getting extensive attention. In this research, TiO2/SiO2/g-C3N4 nanostructured photocatalysts in the form of powder (NP) and thin film (TF) with different concentrations of graphite-carbon nitride (g-C3N4) sheets were prepared by simple hydrothermal and dip-coating methods, respectively. The morphology, composition, structure, and optical properties of the samples were systematically investigated using proper characterization technics. Based on the obtained results, it was indicated that modification of Titanium dioxide (TiO2) with Silicon dioxide (SiO2) effectively preserves the active anatase phase of TiO2, increases the specific surface area of the TiO2 sample and improves the ability of visible light absorption due to the formation of imperfection in the crystal structure. The results of photocatalytic experiments indicated that adding g-C3N4 enhances photodegradation of methylene blue (MB) and tetracycline (TC) due to increase in effective surface area, charge carrier separation, and increased light absorption in the visible region. Highest efficiency was achieved for the sample with 0.03 g of g-C3N4 in the precursor solution. TiO2/SiO2/g-C3N4 NP compared to its TF counterpart possesses higher visible photodegradation with an efficiency of ~96% for a solution of 20 mg/l MB with corresponding adsorption of 88% in darkness within 60 min. In addition, TF photocatalysts showed good reusability and feasible separation from the refined solution. Efficient removal of TC by a reactor with a design to be applicable for both synthesized TF and NP photocatalysts was achieved under visible light illumination. This work may propose an effective approach to remove antibiotics in wastewater.

Evolution and Latest Trends in Cooling and Lubrication Techniques for Sustainable Machining: A Systematic Review

This document presents a review on cooling and lubrication methods in machining. A systematic search of information related to these methods was carried out based on the PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) methodology. The importance of the sustainability of machining processes is highlighted, as they represent between 10 and 17% of the total manufacturing cost of the final part and have negative environmental and health impacts. Although dry machining completely eliminates the use of cutting fluids, in many cases it produces unsatisfactory results due to the increase in temperature inside the tool, which requires prior analysis to ensure its viability compared to conventional techniques. On the other hand, semi-dry machining, which significantly reduces the volume of cutting fluids, is a more competitive alternative, with results similar to those of conventional machining. Other sustainable cooling and lubrication methods are also being investigated, such as cryogenic and high-pressure cooling, which offer better machining results than conventional processes. However, they have a high initial cost and further research is needed to integrate them into industry. While the combination of these cooling and lubrication methods could lead to improved results, there is a notable lack of comprehensive studies on the subject.