Nasser Zouli

An experimental investigation was conducted to evaluate the thermal conductivity (TC) and local heat-transfer coefficients (LHTCs) of nanofluids containing alumina (Al₂O₃), hematite (Fe₂O₃), and copper oxide (CuO) nanoparticles dispersed in deionized water. A newly developed non-invasive LHTC probe was integrated into the inner wall of the test section to enable direct quantification of interfacial heat-transfer performance. The measurements were conducted under laminar and turbulent flow conditons across Reynolds numbers ranging from 1000 to 10,000. The selected nanoparticles were chosen based on their high intrinsic thermal conductivity, cost effectiveness, and, in the case of Fe₂O₃, magnetic recoverability. The nanoparticles enhanced both TC and LHTCs through improved thermophysical propoerties and possible interfacial effects. Maximum TC enhancements of 19%, 21%, and 25% were achieved for Al₂O₃/distilled water (DW), Fe₂O₃/DW, and CuO/DW nanofluids, respectively, at 0.05 vol% and 55 °C, while the corresponding LHTC enhancements reached 44%, 50%, and 53%. Under turbulent flow, CuO/DW exhibited the highest heat-transfer performance, attributed to a 25% increase in TC and corresponding improvement in connective heat transfer. Since the boundary-layer thickness exceeded the nanoparticle diameter (30 nm), nanoparticles penetrated the interfacial film, inducing localized micro-convection and catalytic micro-mixing, which intensified interfacial heat transport. The experimentally determined Nusselt numbers showed strong agreement with the Xuan–Qiang correlation at 55 °C, suggesting that the nanoparticle volume fraction governs the catalytic interfacial heat-transfer mechanism.

The photodegradation of azithromycin present was carried out in water using H₂O₂ under UV irradiation. The reaction variables considered in this study were the amount of H₂O₂ solution and the initial concentration of azithromycin to evaluate the performance of the photodegradation process. The azithromycin degradation was not observed in the dark during stirring for 20 min. The study showed an efficient photodegradation of azithromycin using H₂O₂ as an oxidant in the presence of UV irradiation. The azithromycin degradation was altered significantly by the pH of the irradiated solution. The degradation was low at an acidic pH and showed an increasing trend as the pH changed to basic. The azithromycin degradation increased with a higher amount (higher concentration) of H₂O₂. The degradation of azithromycin decreased with a higher concentration of azithromycin in the reacting solution. The highest degradation of AZT was achieved in 1 h using a 1.0 ppm AZT solution containing 3 mL of H₂O₂. The experimental data obtained were well-fitted to zero-order reaction kinetics. The results of this study were found quite excellent. They showed 100% degradation in 1 h when compared with those reported in the literature, both with photocatalysis using nanomaterials and photolysis using light irradiation and/or H₂O₂. The UV/H₂O₂ system was found to be quite efficient for the photodegradation of azithromycin, and this system can be applied to degrade other organic pollutants present in industrial wastewater.

The photodegradation of azithromycin present was carried out in water using H2O2 under UV irradiation. The reaction variables considered in this study were the amount of H2O2 solution and the initial concentration of azithromycin to evaluate the performance of the photodegradation process. The azithromycin degradation was not observed in the dark during stirring for 20 minutes. The study showed efficient photodegradation of azithromycin using H2O2 as an oxidant in the presence of UV irradiation. The azithromycin degradation was affected significantly by the pH of the irradiated solution. The degradation was low at an acidic pH and showed an increasing trend as the pH changed to basic. The azithromycin degradation was increased with a higher amount (higher concentration) of H2O2. The degradation of azithromycin decreased with a higher concentration of azithromycin in the reacting solution. The highest degradation of AZT was achieved in 1 hour using a 1.0 ppm AZT solution containing 3 ml of H2O2. The experimental data obtained was well-fitted to zero-order reaction kinetics. The results of this study were found to be superior when compared with those reported in the literature, with photocatalysis using nanomaterials and photolysis using irradiation and H2O2. The UV/H2O2 system was found to be quite efficient for the photodegradation of azithromycin, and this system can be applied to degrade other organic pollutants present in industrial wastewater. To this point, such a study has not been reported specifically for AZT photodegradation.

The generation of H₂ via the catalytic hydrolysis of sodium borohydride (SBH) has promise as a practical and secure approach to produce H₂, a secure and environmentally friendly energy source for the foreseeable future. In this study, distinctive trimetallic NiCoPd nanoparticle-supported carbon nanofibers (NiCoPd tri-NPs@CNFs) is synthesized via sol-gel and electrospinning approaches. The fabricated trimetallic catalysts show an excellent catalytic performance for the generation of H₂ from the hydrolysis of SBH. Standard physicochemical techniques were used to characterize the as-prepared NiCoPd tri-NPs@CNFs. The results show that NiCoPd tri-NPs@CNFs is formed, with an average particle size of about 21 nm. When compared to NiCo bimetallic NP @CNFS, all NiCoPd tri-NPs@CNFs formulations demonstrated greater catalytic activates for the hydrolysis of SBH. The improved catalytic activity may be due in the majority to the synergistic interaction between the three metals in the trimetallic architecture. Furthermore, the activation energy for the catalytic hydrolysis of SBH by the NiCoPd tri-NPs@CNFs was determined to be 16.30 kJ mol⁻¹. The kinetics studies show that the reaction is of a first order with respect to the catalyst loading amount and a half order with respect to the SBH concentration [SBH].

In this study, 2D Co-B nanosheet-decorated 1D TiO₂ nanofibers (2D Co-B NS-decorated 1D TiO₂ NFs) are synthesized via electrospinning and an in situ chemical reduction technique. The as-prepared catalyst showed excellent catalytic performance in H₂ generation from sodium borohydride (SBH). When compared to naked Co-B nanoparticles, the catalytic activity of the 2D Co-B NS-decorated 1D TiO₂ NFs catalyst for the hydrolysis of SBH is significantly enhanced, as demonstrated by the high hydrogen generation rate (HGR) of 6020 mL min⁻¹ g⁻¹ at 25 °C. The activation energy of hydrolysis was measured to be 30.87 kJ mol⁻¹, which agreed with the reported values. The catalyst also showed good stability. Moreover, the effects of SBH, catalyst concentration, and temperature on the catalytic performance of 2D Co-B NS-decorated 1D TiO₂ NFs were studied to gain a comprehensive understanding of the dehydrogenation mechanism of SBH. Based on these findings, we conclude that 2D Co-B NS-decorated 1D TiO₂ NFs are effective catalytic materials for the dehydrogenation of SBH.

The present study involves the synthesis of photocatalytic composite nanofibers (NFs) comprising ilmenite nickel titanite-supported carbon nanofibers (NiTiO₃/TiO₂@CNFs) using an electrospinning process. The photocatalytic composite NFs obtained were utilized in hydrogen (H₂) production from the photohydrolysis of ammonia borane (AB). The experimental findings show that the photocatalytic composite NFs with a loading of 25 mg had a good catalytic performance for H₂ generation, producing the stoichiometric H₂ in 11 min using 1 mmol AB under visible light at 25 °C and 1000 rpm. The increase in catalyst load to 50, 75, and 100 mg leads to a corresponding reduction in the reaction time to 7, 5, and 4 min. The findings from the kinetics investigations suggest that the rate of the photohydrolysis reaction is directly proportional to the amount of catalyst in the reaction system, adhering to a first-order reaction rate. Furthermore, it was observed that the reaction rate remains unaffected by the concentration of AB, thereby suggesting a reaction of zero order. Increasing the reaction temperature results in a decrease in the duration of the photohydrolysis reaction. Furthermore, an estimated activation energy value of 35.19 kJ mol⁻¹ was obtained. The composite nanofibers demonstrated remarkable and consistent effectiveness throughout five consecutive cycles. The results suggest that composite NFs possess the capacity to function as a feasible substitute for costly catalysts in the process of H₂ generation from AB.

Rapid urbanization has negative effects on ecology, economics, and public health, primarily due to unchecked population growth. Sustainable building materials and methods are needed to mitigate these issues and reduce energy use, waste production, and environmental damage. This study highlights the potential of agricultural waste as a sustainable source of construction materials and provides valuable insights into the performance and benefits of using fired clay bricks made from pomegranate peel waste. In this study, fired clay bricks were produced using pomegranate peel waste as a sustainable building material. To optimize the firing temperature and percentage of pomegranate peel waste, a series of experiments was conducted to determine fundamental properties such as mechanical, physical, and thermal properties. Subsequently, the obtained thermal properties were utilized as input data in Design Builder software version (V.5.0.0.105) to assess the thermal and energy performance of the produced bricks. The results showed that the optimum firing temperature for the bricks was 900 °C with 10% pomegranate peel waste. The fabricated bricks reduced energy consumption by 6.97%, 8.54%, and 13.89% at firing temperatures of 700 °C, 800 °C, and 900 °C, respectively, due to their decreased thermal conductivity. CO₂ emissions also decreased by 4.85%, 6.07%, and 12% at the same firing temperatures. The payback time for the bricks was found to be 0.65 years at a firing temperature of 900 °C. These findings demonstrate the potential of fired clay bricks made from pomegranate peel waste as a promising construction material that limits heat gain, preserves energy, reduces CO₂ emissions, and provides a fast return on investment.

This study explores the potential for making lightweight bricks via the use of dry, pulverized spent mushroom materials (SMM) as a thermal insulator. There are five distinct replacement proportions of SMM that are used, and they range from 0% to 15% of the weight of the clay. The firing of the fabricated bricks at temperatures of 700, 800, and 900 °C led to the development of pores on the interior surface of the bricks as a consequence of the decomposition of SMM. The impact of SMM on the physicomechanical characteristics of fabricated bricks is assessed based on standard codes. Compressive strength, bulk density, and thermal conductivity decreased as the SMM content increased, reaching up to 8.7 MPa, 1420 kg/m³, and 0.29 W/mK at 900 °C and 15% substitution percentage. However, cold water absorption, boiling water absorption, linear drying shrinkage, linear firing shrinkage, and apparent porosity increased with the increase in SMM, reaching 23.6%, 25.3%, and 36.6% at 900 °C and 15% substitution percentage. In the study simulation model, there was a significant improvement in energy consumption, which reached an overall reduction of 29.23% and 21.49% in Cario and Jazan cities, respectively.

In this work we demonstrate one-pot glycidol synthesis, via trans-esterification between glycerol and dimethyl carbonate, by making use of commercially available sodium methoxide as a catalyst. An excellent glycerol conversion (99%) and remarkable glycidol yield (75%) was obtained using dimethyl carbonate/glycerol (molar ratio 2:1) in the presence of 3 wt% catalyst amount (with respect to glycerol weight) at 85 °C for a reaction time of 120 min. Sodium methoxide was recycled and reused twice with only a slight decrease in glycerol conversion. The water content of the glycerol reached 2.5 wt%; this did not reduce the glycerol conversion efficiency of the catalyst. A plausible mechanism for the trans-esterification involved in the preparation of glycidol was proposed.