Hasil untuk "Chemical technology"

Lingxin Chen, Shoufang Xu, Jinhua Li

B. Tiwari

H. Strathmann

G. Centi, S. Perathoner

Zhu-wei Du, Hao-ran Li, T. Gu

W. Johnson

M. Darmostuk, S. Rimpelová, H. Gbelcová et al.

R. Muñoz, Leslie Meier, I. Díaz et al.

The lack of tax incentives for biomethane use requires the optimization of both biogas production and upgrading in order to allow the full exploitation of this renewable energy source. The large number of biomethane contaminants present in biogas (CO2, H2S, H2O, N2, O2, methyl siloxanes, halocarbons) has resulted in complex sequences of upgrading processes based on conventional physical/chemical technologies capable of providing CH4 purities of 88–98 % and H2S, halocarbons and methyl siloxane removals >99 %. Unfortunately, the high consumption of energy and chemicals limits nowadays the environmental and economic sustainability of conventional biogas upgrading technologies. In this context, biotechnologies can offer a low cost and environmentally friendly alternative to physical/chemical biogas upgrading. Thus, biotechnologies such as H2-based chemoautrophic CO2 bioconversion to CH4, microalgae-based CO2 fixation, enzymatic CO2 dissolution, fermentative CO2 reduction and digestion with in situ CO2 desorption have consistently shown CO2 removals of 80–100 % and CH4 purities of 88–100 %, while allowing the conversion of CO2 into valuable bio-products and even a simultaneous H2S removal. Likewise, H2S removals >99 % are typically reported in aerobic and anoxic biotrickling filters, algal-bacterial photobioreactors and digesters under microaerophilic conditions. Even, methyl siloxanes and halocarbons are potentially subject to aerobic and anaerobic biodegradation. However, despite these promising results, most biotechnologies still require further optimization and scale-up in order to compete with their physical/chemical counterparts. This review critically presents and discusses the state of the art of biogas upgrading technologies with special emphasis on biotechnologies for CO2, H2S, siloxane and halocarbon removal.

M. Movsisyan, E. Delbeke, Jan Berton et al.

Yanhao Liu, Wan Zhao, Yingming Zhao et al.

Abstract Bottom-up construction of artificial cells helps elucidate the working mechanism of cells. Signal transduction from extracellular to intracellular artificial cells is essential for autonomous artificial cells. It remains highly challenging to reconstitute G protein-coupled receptor (GPCR) signaling pathways to regulate downstream metabolism in artificial cells. Here, we reconstitute β2-adrenergic receptor, Gs subunit α and adenylate cyclase V into artificial cell membranes to enable signal transduction from extracellular isoproterenol (ISO) to intracellular cAMP (visualization via Epac1-cAMP probes). cAMP production is ISO dose-dependent, with a maximum amplification fold of 22.45 ± 2.14. By encapsulating the glycogenolytic pathway, cAMP activates protein kinase A, triggering phosphorylation of phosphorylase kinase and glycogen phosphorylase to convert glycogen to glucose-1-phosphate (G-1-P). G-1-P is further converted to 6-phosphogluconolactone accompanying with NADPH. ISO stimulation induces G-1-P and NADPH generation, achieving progressive signal amplification. The successful reconstitution of GPCR-mediated signaling pathway in artificial cells paves the way for developing autonomous artificial cells.

Osama M. Ibrahim, Baqer S. Habib, Abdullah A. Alazemi et al.

This study investigates the development of high-surface-area boehmite (γ-AlO(OH)) and activated alumina (γ-Al2O3) coatings on FeCrAl sintered fibers. The coatings were synthesized using colloidal aluminum oxide hydroxide (AlO(OH)) nanoparticles to increase the fibers' active surface area and enhance their performance as filtering media and catalyst substrates. Detailed methodologies for sample preparation, coating deposition, and material characterization are presented. The specific surface areas of the powders and coated fibers were determined using the Brunauer–Emmett–Teller (BET) method. In powder form, boehmite and activated alumina exhibited surface areas of 263 m2/g and 176 m2/g, respectively, after heat treatments at 300 °C and 500 °C for 2 h. Following deposition onto FeCrAl fibers, the coatings achieved surface areas of 134 m2/g for boehmite and 145 m2/g for activated alumina. Although the coated layers exhibited reduced surface areas compared to their powder forms, they significantly improved the surface characteristics of the FeCrAl substrates. This work introduces a novel coating approach, involving a thin layer of boehmite and activated alumina, on FeCrAl sintered fibers, achieving substantial surface area enhancement through controlled thermal processing. Comprehensive structural and surface characterization (TGA, XRD, XRF, BET, SEM, and EDS) established strong correlations among phase composition, morphology, and coating adhesion, revealing superior bonding for activated alumina. These innovations highlight the potential of the developed coatings to advance next-generation FeCrAl-based materials for applications in adsorption, filtration, and catalysis.

Saheed O. Sanni, Ajibola A. Bayode, Hendrik G. Brink et al.

Over the years, the abuse of antibiotics has increased, leading to their presence in the environment. Therefore, a sustainable method for detecting these substances is crucial. Researchers have explored biomass-based carbon dots (CDs) to detect various contaminants, due to their low cost, environmental friendliness, and support of a circular economy. In our study, we reported the synthesis of CDs using pinecones (PCs) and pinebark (PB) through a sustainable microwave method. We characterized the PCCDs and PBCDs using X-ray diffraction, Raman spectroscopy, Transmission Electron Microscope, and Fourier transform infrared, Ultraviolet-visible, and photoluminescence (PL) spectroscopy. The PCCDs and PBCDs were tested for the detection of amoxicillin (AMX) and tetracycline (TC). The results indicated that the sizes of the PCCDs and PBCDs were 19.2 nm and 18.39 nm, respectively, and confirmed the presence of the 002 plane of the graphitic carbon structure. They exhibited excitation wavelength dependence, good stability, and quantum yields ranging from 6% to 11%. PCCDs and PBCDs demonstrated “turn-off” detection for TC and AMX. The limits of detection (LOD) for TC across a broader concentration range were found to be 0.062 µM for PCCDs and 0.2237 µM for PBCDs. For AMX detection, PBCDs presented an LOD of 0.49 µM.

K. S. Ojha, Timothy J. Mason, C. O’Donnell et al.

Fermentation processes involve the participation of enzymes and organic catalysts, generated by range of microorganisms to produce chemical transformations. Ultrasound can be used in such processes to either monitor the progress of fermentation or to influence its progress. High frequency ultrasound (>2MHz) has been extensively reported as a tool for the measurement of the changes in chemical composition during fermentation providing real time information on reaction progress. Low frequency ultrasound (20-50kHz) can influence the course of fermentation by improving mass transfer and cell permeability leading to improved process efficiency and production rates. It can also be used to eliminate micro-organisms which might otherwise hinder the process. This review summarises key applications of high and low frequency ultrasound in food fermentation applications.

Zonglin Pan, Chengwen Song, Lin Li et al.

Abstract Organic contaminants in wastewater have become one of the most serious environmental problems due to their toxicity, persistence and being bio-refractory. Many efforts have been made to develop effective technologies for wastewater treatment over the past few decades. In this review, membrane technologies coupled with electrochemical advanced oxidation processes (EAOPs) for wastewater treatment are presented, where membrane materials used in such systems are categorized based on their electrical conductivities. Various EAOPs, including electro-chemical anodic oxidation, electro-catalysis, photoelectro-catalysis, and electro-Fenton integrated with membrane technologies for effective wastewater treatment, are discussed. The coupling systems using the membrane as an electrode are particularly examined. This review also elaborates the existing challenges with membrane technologies coupled with EAOPs for wastewater treatment, and their prospects are provided as well.

B. Meghzili, F.A. Benyahia, K. Szkolnicka et al.

Background: Buttermilk, a significant by-product of the dairy industry, is acknowledged as a beneficial food due to its content of water-soluble vitamins, polar lipids, and milk fat globule membranes. This research is focused on investigating the potential of buttermilk as a substitute in the production of a novel soft cheese type ‘‘camembert’’. Methods: A total of 12 cheese samples of camembert cheese, both with and without buttermilk, were prepared and subjected to a series of physico-chemical analyses in October 2023 to measure protein, fat, total solids, pH, and production yield. Texture Profile Analysis was applied to evaluate textural characteristics, and the microstructure was examined using Scanning Electron Microscopy. A hedonic scale was employed in sensory evaluation to measure taste intensity. Results: The sample containing 90% cow's milk and 10% buttermilk exhibited the most significant (p≤0.05) physico-chemical characteristics as production yield of 45.33%±0.710, protein content of 28.9%±0.58, fat content of 24.88%±0.026, total solids of 54.62±0.23, and a pH of 6.42±0.58. Sensory evaluations demonstrated that camembert samples containing buttermilk were distinguished by high sensory quality and satisfactory taste profiles. In addition, a dense and tightly fused protein matrix was observed in the microstructure of the buttermilk fortified cheese. The results also emphasized that the acidic nature of buttermilk significantly affected the production yield, total solids content, and textural characteristics, evidenced by a hardness of 3.36 N and fracturability of 1.75 N. Conclusion: The results validate the use of buttermilk as an effective alternative in the production of a new type of soft cheese, manifesting improved sensory, structural, and physico-chemical characteristics. This investigation supports the innovative utilization of buttermilk in cheese production, potentially offering a valuable avenue for dairy industry by-products. DOI: 10.18502/jfqhc.11.2.15647

Li Wei, Lei Zhao, Xun Zhu et al.

In this study, polylactic acid/graphene oxide/Dopamine (PLA/GO/DA) porous nanofiber membrane was prepared by electrospinning. L _16 (4 ^3 ) orthogonal experiment was designed to investigate the effects of reaction temperature, reaction time, and DA concentration on the adsorption performance of DA oxidized and self-polymerized on the fiber. Based on the characterization of scanning electron microscopy and the determination of the adsorption performance of the fiber membrane to methylene blue (MB) dye, data visualization analysis, variance analysis, and F-test were conducted to determine the optimal process parameters: reaction temperature of 45 °C, reaction time of 30 h, and DA concentration of 2 mg ml ^−1 . PLA/GO/PDA(Polydopamine) nanofiber was prepared and characterized under the optimal process parameters. The results showed that the average diameter of the PDA-loaded nanofiber increased from 737 nm to 996 nm, and a layer of PDA with a thickness of about 129 nm was loaded on the outer surface of the fiber, making the contact angle of the fiber membrane with 0° and becoming a hydrophilic material. In adsorption performance testing of MB, the PLA/GO/PDA nanofiber membrane prepared based on the PLA/GO/DA fiber membrane with an adsorption rate of 98.81 % in 24 h was superior to the PLA/GO/PDA nanofiber membrane prepared based on the PLA/GO fiber membrane.

Huiyang Hu, Prabhakar Busa, Yue Zhao et al.

Externally triggered drug delivery systems empower patients or healthcare providers to utilize external stimuli to initiate drug release from implanted systems. This approach holds significant potential for clinical disease management, offering appealing features like enhanced patient adherence through the elimination of needles and medication reminders. Additionally, it facilitates personalized medicine by granting patients control over the timing, dosage, and duration of drug release. Moreover, it enables precise drug delivery to targeted locations where external stimuli are applied. Advances in materials science, nanotechnology, chemistry, and biology have been pivotal in driving the development of these systems. This review presents an overview of the progress in research on drug release systems responsive to external stimuli, such as light, ultrasound, magnetic fields, and temperature. It discusses the construction strategies of externally triggered drug delivery systems, the mechanisms governing triggered drug release, and their applications in disease management.

S. Foit, I. Vinke, L. D. de Haart et al.

I. Banat, Q. Carboué, G. Saucedo-Castañeda et al.

Surfactants are multipurpose products found in most sectors of contemporary industry. Their large-scale manufacturing has been mainly carried out using traditional chemical processes. Some of the chemical species involved in their production are considered hazardous and some industrial processes employing them categorised as "having potential negative impact on the environment". Biological surfactants have therefore been generally accepted worldwide as suitable sustainable greener alternatives. Biosurfactants exhibit the same functionalities of synthetic analogues while having the ability to synergize with other molecules improving performances; this strengthens the possibility of reaching different markets via innovative formulations. Recently, their use was suggested to help combat Covid-19. In this review, an analysis of recent bibliography is presented with descriptions, statistics, classifications, applications, advantages, and challenges; evincing the reasons why biosurfactants can be considered as the chemical specialities of the future. Finally, the uses of the solid-state fermentation as a production technology for biosurfactants is presented.

Mohd Izrul Izwan RAMLI, Siti Farahnabilah MUHD AMLI, Norainiza SAUD et al.

Hot Air Solder Leveling (HASL) is one of the most commonly used surface finishes in the industry. HASL is also one of the least expensive types of PCB surface finishes available. This study aims to examine the influence on the solder joint microstructure of dipping time and solder temperature. During soldering process, the temperature that used were 300°C and 400°C. The dipping time was split into three batches which is 20s, 60s, and 100s. The Sn-0.7Cu0.05Ni solder alloy was used in this analysis to shape the solder coating microstructure. In this analysis, an Optical Microscope (OM) was used to determine the microstructure of the shape of the solder coating microstructure. As dipping time and dipping speed increased, the interfacial IMC thickness was found to increase, grown up and getting thicker. This outcome results can be used as the basis in order to improve the solder joint properties.