Applied Chemical Engineering

Abstract One of the primary constraints on the use of activated persulfate (PS), a precursor of the sulfate radical (SR), is a lack of understanding of its reaction pathways in the subsurface. SRs can degrade the target dye Bromothymol Blue (BTB) depending on several parameters, including the initial concentrations of PS and BTB, time, water salts cations (Na + and K + ), ionic strength, catalytic ions (), and temperature. Experiments and numerical simulations using the established kinetic model yielded second-order rate constants for the reaction of BTB with the dominant SR at pH 3 of (1.1 ± 0.55) × 10 8 , ((1.5 ± 0.77) × 10 8 , (1.9 ± 0.95) × 10 8 and (2.2 ± 1.1) × 10 8 M -1 s -1 at 40, 50, 60, and 70°C, respectively. These rate constants were used to calculate the kinetic activation parameters ( E a , ∆H ≠ , ∆S ≠ , ∆G ≠ ) according to the Arrhenius and Eyring equations. The results obtained are as follows: 19.8 kJ mol -1 , 16.36 kJ mol -1 , - 0.038 kJ mol -1 K -1 , and 27.78 kJ mol -1 . Finally, a possible mechanism for the discoloration of BTB by SR is proposed, in which the destruction of aromatic ring structures occurs alongside the discoloration of BTB.

Abstract Dairy farming has become a key business to fulfill the daily milk needs in populated countries like India. Conversely, pathogenic and spoilage microorganisms in raw milk are killed by applying different heat treatments to increase shelf life, preserve quality, and ensure safety. Among the heat treatment processes used at the dairy plant, pasteurization consumes a significant amount of heat, which increases the energy demand in the dairy sector. Since milk pasteurization occurs between 65°C and 150°C, multiple solar thermal collector alternatives are available for various kinds of pasteurization processes. Employing solar thermal collectors for milk pasteurization allows the dairy sector to use free solar energy. Solar energy in milk heat treatments minimizes fuel and power consumption, reducing carbon emissions and promoting sustainability. However, solar milk pasteurization in dairy sector is limited by the large area requirement, high initial cost, and weather dependency. There have been attempts to use different types of solar thermal collectors to pasteurize the milk in an effort to replace conventional energy usage with solar energy. The parameters of milk heat treatment, primarily pasteurization, have been discussed concerning energy usage. The benefits and limitations of various solar collectors for milk pasteurization and other heating applications in the dairy sector have been addressed. Multiple studies on integrating various solar thermal collectors with different pasteurization systems have been reviewed, summarized, and concluded.

Abstract The integration of sustainable polymers in fused deposition modeling (FDM) 3D printing offers a promising pathway toward reducing the environmental impact of additive manufacturing. However, the energy-intensive nature of FDM processes presents a significant challenge to the overall sustainability of this technology. In this study, we explore the use of bio-based and recycled polymers in FDM printing and develop optimization strategies to reduce energy consumption without compromising material and print performance. Our results demonstrate that by systematically optimizing key printing parameters such as extrusion temperature, print speed, and layer height it is possible to achieve up to 20% energy savings. Additionally, we find that novel material formulations and advanced thermal management techniques enhance the mechanical properties of printed objects by up to 15%, all while minimizing energy use. This research not only advances the field of sustainable 3D printing but also provides a framework for the development of next-generation materials and processes that align with the principles of a circular economy.

Abstract The transition to sustainable polymers is crucial for reducing the environmental footprint of additive manufacturing, particularly in fused deposition modeling (FDM). This study investigates surface metamorphosis techniques—methods to modify polymer surfaces at micro and nanoscale levels to enhance performance and minimize environmental impact. We explore plasma treatment, chemical etching, and laser texturing on biodegradable and recycled polymers, assessing their effects on surface properties, such as adhesion, roughness, and chemical resistance. Our results demonstrate significant enhancements in mechanical properties. For example, PLA’s tensile strength increased from 55.3 MPa (untreated) to 63.8 MPa (plasma treated), and its elongation improved from 4.2% to 5.1%. PHA showed a similar trend, with tensile strength rising from 45.1 MPa to 52.6 MPa, and elongation increasing from 5.6% to 6.4%. rPET and rPP also exhibited improvements, indicating the effectiveness of these surface treatments. Employing a multi-criteria decision-making approach, we assess and prioritize these techniques based on their mechanical enhancements and sustainability profiles. While this study presents hypothetical results, it establishes a comprehensive framework for optimizing surface metamorphosis processes, guiding future experimental research. Our findings suggest that tailored surface modifications can significantly improve the performance and environmental sustainability of polymers in FDM, offering pathways for integrating eco-friendly materials into advanced manufacturing. This work contributes to the development of green manufacturing technologies by highlighting surface metamorphosis as a key strategy for achieving high-performance and sustainable materials.

Abstract The study of aluminium corrosion in contact with biogas before and after purification on different types of carbon aims to understand the impact of impurities present in biogas, in particular hydrogen sulphide (H₂S), on aluminium degradation. The study highlights the importance of biogas purification in minimising aluminium corrosion. Depending on the level of purification and the types of carbon used for filtering, it is possible to improve the durability of infrastructures in contact with biogas. This has direct implications for the maintenance and operating costs of facilities using biogas as an energy source. Hydrogen sulfide (H₂S) is a colorless, flammable and highly toxic gas characterized by an unpleasant odor. It is often present in industrial and natural environments, particularly in biogas. This gas is involved in the degradation of metals used in anaerobic digestion equipment, in the petrochemical industry, etc. The aim of this work is to study the performance of biochar and activated carbon prepared from corn cobs in removing H 2 S from biogas, and to evaluate the reduction of the corrosive effect of filtered biogas on metallic aluminum. The impregnation and carbonization method was used to prepare activated carbon from corn cobs, and the gravimetric method to study the corrosion rate of metal in biogas. The results indicate that the activated carbon prepared is microporous, has a good specific surface and a better adsorption capacity. Furthermore, the prepared activated carbon samples also showed good H 2 S removal efficiency in the biogas. The aluminum-induced protective power values in filtered biogas for biochar and activated carbon are 58 % and 82.22 % respectively. We plan to increase the contact time and experiment with other metals and carbons.  

Abstract Several parameters, including temperature, water activity and water content, play a crucial role in maintaining food quality over time. Temperature control during the preservation process is essential to inhibit the growth of unwanted microorganisms while avoiding the degradation of nutrient and aromatic compounds. Proper storage conditions help to prolong the life of food. The main objective of this study is to optimize the preservation process of dates to maintain their quality, including organoleptic quality and nutritional characteristics, by examining the influence of temperature, water activity on water content. The research aims to determine how these parameters influence the quality of dates. In this perspective, an uncoded unit regression equation of water content, temperature and water activity was developed. The model is more meaningful and has a better predictive capacity for new observations. Water activity is the main characteristic influenced, followed by temperature. Specifically, increasing water activity increases water content, while increasing temperature reduces water content.

Abstract A nanocomposites of aluminum dioxide was employed as a fuel additive in a compression engine test. Nanoparticle stability in diesel was measured by their impact on the fuel's flash point, density, and viscosity. When compared to other forms of fuel, conventional biodiesel has superior qualities. Al 2 O 3 was also put through its paces in terms performance of engine and pollution testing. The thermal efficiency of the engine's brakes may be improved by adding nanoparticles in to the jatropha biodiesel. Using Al 2 O 3 nanoparticles has been shown to reduce brake-specific fuel consumption by 23%. In addition, this solution can cut hydrocarbon emissions by 19%.

Abstract This article presents a comprehensive review of advanced techniques for integrating nanomaterials into fused deposition modeling (FDM) processes, addressing prevalent challenges such as limited surface quality and wear resistance in traditional FDM-printed parts. The integration of nanomaterials offers potential solutions to these issues by enhancing surface properties. This review explores key methodologies, including direct nanoparticle mixing with polymer filaments, in-situ polymerization, and surface coating techniques, and demonstrates their impact on improving surface roughness and wear resistance. Specifically, nanomaterial-enhanced composites achieve up to a 30% reduction in surface roughness and a 40% improvement in wear resistance compared to conventional materials. To optimize manufacturing processes, we apply the Taguchi method to identify critical process parameters such as extrusion temperature, print speed, layer thickness, and nanoparticle concentration that influence surface properties. Our simulations and analysis of variance (ANOVA) indicate that optimal settings can enhance surface quality by 25% and improve wear resistance by 35%. The proposed methodologies and theoretical framework lay the groundwork for experimental validation, which will involve testing the optimized parameters and assessing their practical impact. This research advances the field of additive manufacturing by providing novel insights into nanomaterial integration, paving the way for improved FDM technology with applications spanning aerospace, biomedical engineering, and beyond. The findings contribute significantly to overcoming existing limitations and enhancing the performance of FDM-printed parts.

Abstract The existential war between pathogens and humans has heavily intensified during the last few decades. The former war side has been strengthened by developing various mechanisms of resistance to the currently-in-use antimicrobial drugs. To overcome the consequences of this development, it becomes an urgent global request to explore new potent, wider-ranging, and biosafe prospects as antimicrobial medications. In response to this request, this work was designed to include three parts. In the first one, coumarin-based compounds were created using a toxic material named 2-methyl-3,5-dinitrophenol as a starting block. The Pechmann condensation reaction was conducted to convert this building block to the precursor, P-MDNP , which was esterified with various phenols to create MDNPU1–MDNPU10 . The antimicrobial function was evaluated in the second study part using a broth microdilution approach and three standards, including ciprofloxacin, metronidazole, and nystatin. The studied pathogens were four-infectious bacterial aerobes, four-infectious bacterial anaerobes, and two-infectious fungi. Given the third study part, the biosafety of the synthesized compounds was quantified on the three healthy cellular species, two non-infectious aerobic bacteriomers, and human blood processed in the lab. The synthesized compounds showed strong, wide-ranging, and biosafe antimicrobial properties versus the pathogens examined, according to the outcomes. Moreover, the study showed that some of these compounds demonstrated anti-anaerobic bacterial activity that is superior to metronidazole. Furthermore, the study found a connection between the number and distribution of chlorides in the off-side aromatic rings, antimicrobial activity, and biosafety. Finally, it is determined that the health-damaging effects of the toxicant under study can be mitigated by grafting it into coumarin frameworks. These are potent, ascribed to MDNPU9 , and have great levels of biosafety and wider-ranging antimicrobial efficacy. Furthermore, this approach offered the chance to turn the health-detrimental effects of the nitrophenols into potential benefits. Coumarin-4-acetic acid and MDNPU9 can be employed as a synthetic fragment and a bioactive scaffold, respectively, to accomplish this.

Abstract An experimental investigation was conducted on novel design of triple basin solar still with different modification in the climatic conditions of India. The triple basin solar still was modified with attachments of evacuated tubes (ETCs), heat pipes (HP), corrugated surfaces and energy storage materials called modified triple basin solar still (MTBSS). To get the more water in distillate output and higher water temperature solar still was designed with three basin area. From experimental results it was found that the total distillate output obtained by MTBSS during day and night was 16.46 l/m 2 and 7.40 l/m 2 , respectively. The performance of MTBSS was also check by 4E (Energy, Exergy, Exergo-Economic, Exergo-Environmental) analysis for economical and environmental point of view. The generation of exergy for evaporation (Exe,bw-ig) and convection (Exc,bw-ig)  for MTBSS (Modified triple basin solar still) were 24.03 & 1.30 (joule) respectively. The values of energy efficiency (ƞ energy ) and exergy efficiency (ƞ exergy ) obtained for MTBSS were 31.89% & 3.04% respectively. An economic point of view, the CPL of water remains higher in MTBSS. The NPBT for MTBSS was 2.5 months. For environmental assessment, the CO 2 mitigation for MTBSS was 0.48 t/year, based on the exergy approach. The additions of ETCs, H.P, corrugated surface, and ESMs with MTBSS are effective from an exergo-economic and carbon credit point of view.

Abstract In this article, an experimental endeavour has been reported to enhance the performance of single slope solar still by placing jute-covered hemispherical plastic cups in the water. The logic behind the augmentation is that the jute causes capillary action, due to which a thin film of water forms on the surface of the jute. The plastic cups will act as heat insulation, which will try to block the heat from going to the basin water, hence resulting in heat localization and quick evaporation of thin water film. It has been observed that this adaptation has increased overall distillate output of the single slope solar still by 36.2%. The modified still performs best till 14:00 h due to high solar insolation. In the afternoon hours, the reduction of solar radiation adversely impacts its performance in comparison to the conventional single slope solar still. The overall cost of the distillate due to the augmentation of the jute-covered hemispherical plastic cups has been reduced by 24.34% in comparison to the conventional solar still.

Abstract Large volumes of contaminated water should not be dumped without being cleaned beforehand. The water contained a significant number of biological contaminants. The pollution of color usually causes harm for living organisms. The photocatalytic removal of methylene blue (MB) and crystal violet (CV) from aqueous solutions is explored. TiO2 concentration as a catalyst in both dark and light scenarios, pH value and the concentration of contaminants are the optimization factors. The results demonstrated that the photocatalysis method was quite effective in eliminating these contaminants. Following treatment in a basic solution with a pH of 9, the typical clearance durations for CV and MB are 30 and 60 minutes, respectively. The influence of different photocatalyst concentration. (o.5-1.5mg/l) on dissociation rate, Effect of pH on breakdown speed(3-9) and  the initial concentration of the pollutant  (10 -5 -10 - 4 M) For studied CV and MB. The best concentrations for each case are 1 mg/l of TiO 2  in dark and light applied and 5*10 -5  M of the pollutant. According to the findings of the kinetics study conducted on the dyes CV and MB, the observed quantities at steady-state step (qe) values are quite similar to the experimental TiO 2  adsorption capacity. Based on the outcomes of the Langmuir and Freundlich studies, TiO 2  is a suitable option for removing the dye pollution since it is a good adsorbent with a high capacity for sorption. The results show that the equilibrium data fitted to the Freundlich model with R 2  =0.981  and 0.919 for studied CV and MB within the concentration range studied.

Abstract The issue of recycling and reusing waste from the wood processing industry has garnered significant attention from researchers, as effective solutions could yield economic benefits while mitigating environmental impacts. This article focuses on the development of artificial wood using unsaturated polyester resin combined with waste materials from carpentry workshops, specifically investigating its water absorption properties. Research findings indicate that the water absorption coefficient of the samples increased with longer immersion times, higher organic filler content, and larger particle diameters. The calculated density reveals a broad spectrum of solid industrial boards that can be produced from these compositions, suggesting that consistent forming conditions enhance economic viability. Notably, optimal results were achieved with samples made from mixed wood powder without prior sorting, which contributes to reduced production costs, aligning with the study's objectives. Furthermore, the investigation highlighted that the water absorption coefficient escalates with increased soaking time, organic filler content, and particle size, indicating that in humid environments, it is advisable to limit both filler content and particle size to maintain performance. Overall, the studies confirm the feasibility of utilizing wood powder as a filler, with varying particle diameters imparting distinct characteristics to the final product. These findings underscore the potential for innovative approaches to wood waste management in the industry.