Hasil untuk "Chemical industries"

Agnieszka Brandt-Talbot, Alexander J. O’Malley

Agnieszka Brandt-Talbot and Alexander J. O’Malley introduce the RSC Sustainability themed collection on Defossilising chemical industries.

Fatma S. Mahrous, Shimaa M. Khalifa, Fatma Sayed Abdel-Aal Farag et al.

Abstract The continuous increase in antibiotic resistance necessitates a global need to search for new sustainable antimicrobial agents, such as plant-delivered antimicrobial components. This study investigates the antimicrobial and antibiofilm properties of two tannins isolated from the flowers of Jatropha integerrima against multidrug-resistant Klebsiella pneumoniae. The two active tannins were isolated from the methanol-soluble portion of 70% aqueous methanol flower extract, by consecutive column chromatography. Their antimicrobial activity against the resistant K. pneumoniae isolate (BKP-122) was assessed through agar well diffusion and minimum inhibitory concentration (MIC) assays. Their antibiofilm activity was evaluated by using the microtiter plate method and real-time PCR to reveal their effect on the biofilm-associated genes. Their structures were identified as 2 hydrolysable ellagitannins, namely 1-O-galloyl-3,6-(R)-hexahydroxydiphenoyl-D-B1,4-glucopyranose (Jatrophenin-1) and 1-O-galloyl-3,6-(R)-valoneoyl-D-B1,4-glucopyranose (Jatrophenin-2), together with vicenin-2, acacetin 7-O-β-D-glucopyranoside, (E)-p-coumaric acid, and sucrose, based on the chromatographic characters, 1H-, and 13C NMR analyses. They were found to have potent antimicrobial activity and antibiofilm activity against the resistant K. pneumoniae isolate (BKP-122). Real-time PCR analysis indicated that treatment with tannins resulted in the downregulation of critical biofilm-related genes, including luxS, mrkA, pgaA, wzm, and wbbM. Additionally, the two compounds showed high docking binding scores against Topoisomerase IV, KPLpxH, and β-lactamase enzymes, and stable complexes, as evidenced by binding energy values ranging from -8.2 to -10 kcal/mol. These findings underscore the effectiveness of J. integerrima tannins as a viable therapeutic strategy to combat antibiotic resistance and biofilm-related infections, highlighting their role in modulating bacterial gene expression and biofilm development.

Lastarida Sinaga, Albert Eddy Husin, Eka Juni Arif et al.

Blockchain technologies have recently garnered substantial attention in research and industry sectors due to their potential advantages across various industries. Blockchain provides an effective solution to address challenges by offering distributed, secure, and permissioned transactional ledgers. This paper introduces an innovative conceptual framework that integrates blockchain technology with building information modeling, specifically designed for digital transactions and smart contracts in the retrofitting of green buildings within the chemical industry. The core objectives include enhancing cost efficiency, fortifying cybersecurity measures, improving information management and sharing, simplifying payment transactions, and promoting sustainability in this specific context. The research, conducted at a chemical facility in Cilegon, Banten, Indonesia, utilizes Structural Equation Modeling-Partial Least Squares (SEM-PLS) to analyze questionnaire data and identify influential factors. Results indicate that incorporating Blockchain-BIM leads to cost savings of 4.42%, 4.45%, and 4.40% for low-level, medium-level, and high-level retrofitting categories, respectively, highlighting the significant role of Blockchain-BIM in enhancing cost efficiency throughout the retrofitting process.

Paloma Toraño, Jordi Gombau, Iratxe Mejías et al.

Malolactic fermentation (MLF) in wine is driven by the lactic acid bacterium <i>Oenococcus oeni</i> in most cases. Although this bacterium is resistant to wine stress conditions, it often faces difficulties completing MLF. Previous studies indicate that yeast mannoproteins may improve <i>O. oeni</i> growth and survival in wine. However, very little is known about this topic. This study evaluated the effect of the addition of mannoprotein extracts to culture media on <i>O. oeni</i> growth and its survival to stress conditions and MLF performance. Three commercial mannoprotein extracts were characterized in terms of polysaccharide and protein richness and were used for <i>O. oeni</i> culture media supplementation. The addition of mannoprotein extracts improved the survival of the two evaluated <i>O. oeni</i> strains, PSU-1 and VP41, after acid shock (pH 3.2) in comparison to that of the control. The transcriptional response of four genes involved in mannose metabolism was different depending on the strain, indicating the complexity of sugar metabolism in <i>O. oeni</i>. PSU-1 cells grown with two of the mannoprotein extracts performed faster MLF compared with the control condition, indicating that mannoprotein addition may improve the performance of <i>O. oeni</i> starter cultures, although this effect depends on the strain.

Mojtaba Vafaee Baghban, Maryam Omidvar, Rahele Zhiani et al.

Polyethersulfone membrane modification by placing hydrophilic nanoparticles in the membrane matrix can improve antifouling ability. In this study, the Fe3O4 nanoparticles were modified by immobilizing SiO2, KCC-1, GMSI, and Carnosine. After surface modification, the nanoparticles were brought into polyether sulfone-based nanofiltration membranes to improve the membrane permeability, separation efficiency, and antifouling ability. The effect of nanoparticles on membrane structure and its performance was investigated using Field Emission Scanning Electron Microscopy (FE-SEM), Atomic Force Microscopy (AFM), water contact angle, mean pore size and porosity measurements, pure water flux, and wastewater treatment, as well as antifouling ability. Based on the results, increasing the concentration of nanoparticles from 0 to 0.1 wt% developed the membranes to a more porous structure in the sub-layer, higher thickness, increased pure water flux, higher hydrophilicity, and fouling resistance. Consequently, the membrane with 0.1 wt% of nanoparticles endorsed a decreasing contact angle from 76 ±1 to 60.3±0.2, increasing pure water flux from 50.96 L/m2h to 93.42 L/m2h at a pressure of 9 bar, and a relatively high flux recovery ratio of 95.5%. Thus, a considerable performance of the prepared membrane was established in treating the oily wastewater contaminants.

Peng Lin, Ali Basem, As'ad Alizadeh et al.

The initial temperature has a considerable effect on aluminum polycrystals' physical stability and mechanical performance, with the possibility to optimize their mechanical properties for practical applications. Thus, using a molecular dynamics technique, the effect of temperature on the mechanical properties of aluminum polycrystals is studied. Stress-strain curves, ultimate strength, and Young's modulus were all measured at temperatures of 300, 350, 400, and 450 K. The findings from MD simulations show that the initial temperature significantly affects the physical stability and mechanical performance of designed aluminum polycrystals. The aluminum polycrystal experiences a numerical increase in ultimate strength and Young's modulus from 6640 to 74.072 to 7.055 and 79.226 GPa, respectively, when subjected to the optimal initial conditions of 350 K. With further increasing temperature to 450 K, ultimate strength and Young's modulus decrease to 6.461 and 74.413 GPa, respectively. The observed decrease in ultimate strength and Young's modulus of the aluminum polycrystal as the temperature increased from the optimal condition of 350 K–450 K can be attributed to the weakening of interatomic attraction forces at higher temperatures. This reduction in interatomic bonding strength resulted in decreased material stiffness and resistance to deformation, leading to lower ultimate strength and Young's modulus values. This study's novelty lies in its comprehensive assessment of the initial temperature's effects on the mechanical performance of aluminum polycrystals, providing valuable insights for practical applications and advancing beyond previous efforts in the literature.

Filiz Akti

3D porous network structured cobalt and nickel bead catalysts were easily greenly fabricated in the presence of chitosan for the catalytic reduction of 4-nitrophenol to 4-aminophenol. Physicochemical properties and morphology were determined using XRD, nitrogen adsorption/desorption, FT-IR, and SEM /EDS analyses. While the XRD pattern and FT-IR spectra showed the presence of chitosan, peaks related to cobalt and nickel species were not observed. Nitrogen adsorption/desorption isotherms exhibited a behavior indicating of micro-mesoporous structure. The surface area (41.24 m2/g), total pore volume (0.035 cm3/g), and pore diameter (3.59 nm) values of Ni@chitosan catalyst were acquired higher than that of Co@chitosan catalyst. EDS mapping showed that cobalt and nickel were homogeneously distributed in the chitosan structure. Co@chitosan exhibited higher catalytic activity. Reaction rate constant values were found as 0.498 and 0.074 min-1 for Co@chitosan and Ni@chitosan, respectively. The catalytic activity of the catalysts was competitive and guided for 4-nitrophenol reduction applications.

David Spichiger

PRIMCO provides technical assistance to the chemical, petrochemical and oil & gas industries. As an outsourced technical support department, our team of expert engineers develops pragmatic and tailored solutions for plant operators (production, process, laboratory, maintenance & inspection teams) to troubleshoot, to optimize process performances and to improve asset integrity and reliability, while reducing operating costs.

Yi Qin, Tao Xiong, Jian-feng Zhu et al.

Abstract Thermoelectric (TE) performance of polycrystalline stannous selenide (SnSe) has been remarkably promoted by the strategies of energy band, defect engineering, etc. However, due to the intrinsic insufficiencies of phonon scattering and carrier concentration, it is hard to simultaneously realize the regulations of electrical and thermal transport properties by one simple approach. Herein, we develop Cu and Ce co-doping strategy that can not only greatly reduce lattice thermal conductivity but also improve the electrical transport properties. In this strategy, the incorporated Cu and Ce atoms could induce high-density SnSe2 nanoprecipitation arrays on the surface of SnSe microplate, and produce dopant atom point defects and dislocations in its interior, which form multi-scale phonon scattering synergy, thereby presenting an ultralow thermal conductivity of 0.275 W·m-1·K-1 at 786 K. Meanwhile, density functional theory (DFT) calculations, carrier concentration, and mobility testing reveal that more extra hole carriers and lower conducting carrier scattering generate after Cu and Ce co-doping, thereby improving the electrical conductivity. The co-doped Sn0.98Cu0.01Ce0.01Se bulk exhibits an excellent ZT value up to ~1.2 at 786 K and a high average ZT value of 0.67 from 300 to 786 K. This work provides a simple and convenient strategy of enhancing the TE performance of polycrystalline SnSe.

William Gustavo Sganzerla, Josiel Martins Costa, Miriam Tena-Villares et al.

Industrial beer production generates brewer’s spent grains (BSG) as a primary solid waste. The disposal of industrial waste can cause negative environmental side effects, including greenhouse gas emissions. This study evaluated the dry anaerobic digestion (AD) of BSG for bioenergy recovery as a solution toward a more sustainable brewery. The laboratory-scale agitated tank batch reactor (6.8 L) was started up with BSG (25%), mesophilic inoculum (45%), and water (30%). The experimental results showed 82.12% solids biodegradation, 57.38% soluble chemical oxygen demand removal, and an accumulated methane yield of 10.53 L CH₄ kg⁻¹ TVS. The methane production efficiency was evaluated by the modified Gompertz, Cone, and first-order kinetic models. The Cone model fitted methane evolution better than the modified Gompertz and first-order kinetic models. The biogas produced from the dry AD of BSG could generate electricity (0.133 MWh ton⁻¹) and heat (598.45 MJ ton⁻¹), mitigating 0.0099 and 0.0335 tCO_2eq ton⁻¹ BSG, respectively, for electricity and heat. The implementation of dry AD could supply 7.38% of the electricity and 6.86% of the heat required for beer production. Finally, in a biorefinery concept, dry AD can be an alternative route for solid waste management and bioenergy recovery, contributing to reduce the environmental impact of breweries.

Ma Hongqiang, Jia Jiwei, Luo Xinmei et al.

In order to ensure the safe operation of heat exchangers in the Liquefied Natural Gas (LNG), the stress analysis model of aluminum Plate-Fin Structure (PFS) is established based on the thermal-elastic-plasticity theory. The residual stress distribution of PFS and its influence on the structural strength is analyzed by the thermal-structural coupling method. The results indicate that the residual stress distribution of PFS is very complex, and the residual stress reaches the peak at the Brazed Joint (BJ). Due to the equivalent stress at BJ near the fin is higher than that at BJ near the plate, cracks are more easily produced at BJ near the fin. Therefore, the existence of residual stress has a negative impact on PFS, which may increase the possibility of strength failure at BJ under the typical operating conditions (normal operation, cut-down and heat-up) of the heat exchanger. In addition, the residual stress gradually decreases with the brazing cooling rate decrease. The residual stress within the PFS will be effectively reduced by properly reducing the brazing cooling rate, which can slow down the strength failure of the PFS. The above research results will provide an important basis for the design and safe operation of the aluminum plate-fin heat exchanger.

Kirgina Maria, Bogdanov Ilya, Altynov Andrey et al.

One of the most widely used way to improve low-temperature properties of diesel fuels is the use of additives. However, a variety of additives and the effect of susceptibility make it difficult to select additive for a particular composition of diesel fuel and operating conditions. The laws of interaction between functional groups of additives and hydrocarbons of the diesel fraction have not been investigated yet. The article discusses the influence of fractional, group and structural-group composition of straight-run diesel fuels on the effectiveness of cold flow improvers. The effect of additives concentration on the effectiveness of their action is considered. It was shown that when selecting a cold flow improver for diesel fuel and determining its optimal concentration, it is necessary to take into account the optimal content of various groups of hydrocarbons in diesel fuel, at which a cold flow improver is most effective.

Qiangliang Li, E. Dunn, E. Grandmaison et al.

Chitosan, a polycationic polymer and waste product from the sea food processing industry, is an abundant natural resource that has, as yet, not been fully utilized. Advantages of this polymer include availability, low cost, high biocompatibility, biodegradability and ease of chemical modification. In this paper, the physicochemical properties of chitosan, as well as its numerous applications, are reviewed with particular emphasis on its use in water treat ment, pharmaceutics, agriculture and membrane formation.

Hamid Zentou, Nurul Shafiqah Rosli, Cham Hue Wen et al.

In the last few decades, finding alternatives to fossil fuels has become a hot issue across all international frontiers. The Intergovernmental Panel on Climate Change (IPCC) has shed light on the feasibility of using biofuels to meet the growing energy demand as well as to reduce CO2 emissions which are a major cause of global warming, especially in the transportation sector. The production and use of biofuels in developing countries have further advantages, including social and economic benefits. On the other hand, the biofuel industry in some developing countries is facing critical challenges related to food security, land availability, production cost, etc. In this regard, several studies have recently been conducted to address these issues, and this paper comprehensively reviews these cases with respect to the successes, failures, and challenges faced by developing countries, such as Brazil, Africa and India, in expanding their biofuel production. It is clear that all the efforts devoted to promoting the biofuel sector are still insufficient to come over the challenges associated with biofuel production despite the achievements realized in some experiences as Brazil. However, the Brazilian experience cannot be spread over other countries. Implementation of policies with regard to the specifications of each country that integrate with the other sector without intersection is highly recommended. Moreover, further efforts are needed from scientists to reduce biofuel production costs, which may promote the biofuel market as an alternative to fossil fuel.

Maria Silva, Anderson Medeiros, Darne Almeida et al.

Surface biofouling of materials immersed in the marine environment is a problem that particularly affects maritime industries and equipment. The biological community present in these environments develops on the immersed surfaces of different structures, causing economic damages to the local facilities. Antifouling coatings based on synthetic chemicals, while being the primary strategy used to combat fouling in the marine industry, are detrimental to other ecosystem beings in addition to target organisms (biofouling). To avoid or reduce this biofouling, a non-biocidal strategy is the application of coatings based on natural surfactants, making them more hydrophobic, imposing it difficult to fix biofouling. In this context, the aim of the present study was to formulate a non-biocidal antifouling coating containing natural surfactants, obtained by fermentation process and/or by chemical modification of residual soybean oil, evaluating its antifouling effect on local marine biofouling. To this end, a natural resin-based matrix containing the natural surfactants was prepared, which was applied to metal panels and after curing the coating, these were followed for immersion tests at the Port of Recife-PE, Brazil for 25 days. After this period, the panels were photographed and analysed for the macrofouling biota present. There was a reduction in biofouling around 30% compared to untreated panel. After immersion tests at the Port of Recife-PE and analysis of the covered area, the panel coated by the matrix + laurate and matrix + hydroxylated acid exhibited the best antifouling activity during the period tested. The results of the embedded area, through the ImageJ software, demonstrated the promising effect of the antifouling coating in the field, evaluated in the treatments in relation to the negative control, evidencing the great biotechnological potential of natural surfactants in the treatment of the biofouling.

D. Delledonne, F. Rivetti, U. Romano

Marcelo Dal Bó, Francesc Medina

Resumen: Este trabajo estudia la aplicación del proceso de templado químico en porcelánicos hechos en España. El proceso de templado químico es largamente aplicado a vidrios y tiene por finalidad principal incrementar la resistencia mecánica de estos materiales. Para lograr este objetivo, fueron seleccionados 3 porcelánicos hechos en España de diferentes suministradores. Las piezas industriales fueron cortadas en probetas pequeñas con dimensiones de 70 × 17 × 9 mm de longitud, anchura y espesor, respectivamente. A continuación estas fueron sometidas a un tratamiento químico de intercambio iónico, también conocido por templado químico. El tipo de porcelánico, la temperatura y el tiempo del tratamiento químico fueron variados según un diseño factorial. Los resultados mostraron un incremento del ∼55% en la resistencia a la rotura de uno de los materiales porcelánicos. Además, el estudio estadístico desarrollado mostró que el tipo de porcelánico y la temperatura del tratamiento químico fueron las variables que influyeron en la resistencia mecánica a flexión de los porcelánicos. Abstract: This work studies the application of chemical tempering process in porcelain tiles made in Spain. The chemical tempering process is largely applied to glass and its main purpose is to increase the mechanical strength of these materials. To achieve this objective, three porcelain tiles made in Spain from different suppliers were selected. The industrial pieces were cut into small specimens with dimensions of 70 × 17 × 9 mm, length, width and thickness, respectively. These were then subjected to a chemical ion exchange treatment, also known as chemical tempering. The type of porcelain tile, the temperature and the time of the chemical treatment were varied according to a factorial design. The results showed a ∼55% increase in the breaking strength of one of the porcelain materials. In addition, the statistical study developed showed that the type of porcelain and the temperature of the chemical treatment were the variables that influenced the mechanical resistance to flexion of porcelain. Palabras clave: Gres porcelánico, Resistencia mecánica, Tensión de rotura, Intercambio iónico, Templado químico, Keywords: Porcelain tiles, Mechanical strength, Breaking strain, Ion exchange, Chemical tempering

Sayed Morteza Mozaffari, Mohammad Hosain Beheshty

Epoxy resins are widely used in composites, aerospace, construction, electronic, adhesive and coatings industries due to their high physical and mechanical, thermal resistance, electrical and chemical properties. For curing epoxy resins, a chemical material, called curing agent or hardener, must be used. Curing agents have strong effect on the processing conditions and final properties of the cured resins. In general, epoxy curing agents can be classified in two groups of normal (room or high temperature) and latent curing agents. Normal curing agents increase the resin viscosity at room temperature due to crosslinking or curing reactions and the resin is gelled and finally cured. The rate of viscosity increment would be different and depends on the kind of curing agent. On the other hand, latent curing agents cannot react with epoxy resin at room temperature and do not increase the resin viscosity. Therefore, they are being used for preparing one-part epoxy resins. Latent curing agents are not active at room temperature, but they will react with epoxy resin by the application of an external force like heat or light. Thermally-latent curing agents are well-known and they are widely used. They include substances with active hydrogen, and are catalyzed and protected by chemical groups and microcapsules. Selection of a latent curing system for an application is an important issue which affects the processing conditions and final properties of the cured resins. In this paper, the latest achievements in this area are reviewed.

Erzuah Samuel, Fjelde Ingebret, Omekeh Aruoture Voke

Wettability is an indispensable parameter in multiphase flow due to its profound effect in fluid phase distribution and flow properties in the oil reservoirs. One approach of unravelling the enigma associated with wettability characterization is to investigate oil adhesion onto reservoir rock surface during crude oil accumulation. This was accomplished using Quartz Crystal Microbalance with Dissipation (QCM-D) device. The QCM-D is a microbalance device that hinges on the changes in the frequency of a resonating crystal due to changes in the mass on sensor surface, precipitation, adsorption and desorption. However, this technique was confronted with numerous challenges during its early try-out. The objective of this study is to enumerate these challenges and how they were resolved. The piston-cell, valves, flow-lines and most of the experimental set-up were made from stainless steel. Hence, the high temperature coupled with high salinity brine resulted in the formation and deposition of corroded materials on the sensor. Due to the high sensitivity of the QCM-D technique, these corrosion deposits were detected via the high attenuation of the frequency signal as time elapsed during Formation Water (FW) injection. The second challenge was related to the dissolution of the thin sensor coatings (sensor etching) depicted by the relatively high increase in frequency signal with negligible changes in Dissipation (D). The third challenge was related to the trapping of fluids such as Stock Tank Oil (STO) inside the flow-cell. Finally, salt precipitation resulting from temperature variation during the initial experimental set-up was also observed. To resolve the corrosion challenge, all the stainless-steel components in the experimental set-up were replaced with titanium and non-metallic component such as peek materials. The sensor etching was also averted by injecting the brine through a packed column filled with similar mineral as the coatings on the sensor to attain equilibrium prior to injecting it onto the sensor. Geochemical simulation of the sensor etching was also confirmed using the geochemical simulator PHREEQ-C. Furthermore, the trapping of fluids inside the flow-cell was overcome by rotating the flow-cell to optimize the fluid displacement via capitalizing on their density contrast. Finally, the salt precipitation was avoided by conducting the experiment in a constant temperature experimental set-up. The QCM-D technique can be employed to estimate wettability by evaluating the tendency of the various minerals to adhere oil. The beauty of the QCM-D technique is that the surface interactions can be monitored on a real-time.