Engineering and Technology Journal

The release of carbon dioxide from the combustion of fossil fuels and chimney emissions has emerged as the primary catalyst for global warming. The significant increase in emissions is due to various factors, including power plants that rely on fossil fuels, different industrial processes, and many other factors, all of which are the main causes of environmental pollution. The need has arisen to invent an effective way to reduce carbon dioxide emissions into the atmosphere, where scientists have reviewed several methods, such as transitioning to renewable energy, improving energy generation stations, and capturing carbon dioxide emissions. However, the optimal and most realistic choice is carbon capture and storage to preserve a green environment. Currently, there are three methods: pre-combustion capture, post-combustion capture, and oxyfuel combustion. Post-combustion capture is the most common system; among its various methods, absorption is considered one of the most common processes for gas capture. Absorption involves contact between a gas-liquid mixture to remove one of the gas components by dissolving it in a suitable liquid. The purpose of this review is to clarify the techniques of CO2 capture with a focus on the absorption process using the absorbent material (NaOH), as well as to identify other types of absorbent materials used in absorption processes and the effect of reactor structure on absorption performance in addition to the impact of reaction parameters on absorption efficiency

Fresh water is essential for life to continue on Earth. The accelerated growth of industrialization and globalization is to blame for the current apex of environmental problems. Heavy metals and organic pollutants discharged from industrial waste are extremely harmful at relatively minimal concentrations when tolerance levels are exceeded. They will lead to several diseases in humans. One method for treating wastewater is semiconductor photocatalysis. It depends mainly on the oxidation-reduction mechanism by holes and electrons, respectively, that are generated by the exposure of the semiconductor oxide into a source of photons. Pulsed laser ablation in liquid (PLAL) has attracted significant attention. Controlling the laser parameters is considered a green, competitive, and simple method to synthesize well-separated nanoparticles with a clean surface, small sizes, and numerous defects. ZnO semiconductor is considered cheap, not toxic, and more efficient at absorbing a large portion of the solar radiation spectrum with Eg =3.37 eV. These features give ZnO remarkable significance when used in biological and engineering applications. This short review article aims to know the advantages and challenges of using the PLAL technique in synthesizing ZnO and how to enhance the efficiency of inhibiting bacterial strains, cancer growth, and degradation of dyes using this material. We have found from this review that the size, shape, and zeta potential value govern the success of using ZnO nanomaterial in different applications. We also found an optimum value for ZnO's pulse duration and ablation time that can achieve the highest degradation efficiency.

Improving heat transfer efficiency in base fluids remains a key challenge in various thermal applications. To address this, several researchers have suggested the integration of nanoparticles into base fluids, leveraging recent advancements in nanotechnology to enhance performance. This study compares different types of nanoparticles and preparation methods for nanofluids and examines the impact of their properties on improving heat transfer. The convective heat transfer under a turbulent flow regime was studied experimentally and numerically in a copper tube used as a test section. Advanced measurement techniques were employed, including a Flux Teq LLC heat flux sensor mounted on the test section wall's inner surface to measure the instantaneous heat flux and inner surface temperature. Additionally, five T-type thermocouples were used to measure the bulk temperature. Three types of nanoparticles—titanium dioxide, copper oxide, and graphene nanoplates were used at three different concentrations (0.01, 0.02, and 0.03 vol. %) to prepare the nanofluids. The results of applying these nanofluids in the heat transfer process showed that the heat transfer coefficient increased with the concentration of nanoparticles. The greatest improvement was observed at a concentration of 0.03%, with heat transfer coefficient increases compared to the base fluid of 23.7%, 39.1%, and 68.25% for TiO₂, CuO, and GNP, respectively. Numerical results were obtained using COMSOL 5.6, a computational fluid dynamics (CFD) analytical program. The predicted and experimental values were compared to validate the model, showing good agreement between the results, though minor differences were observed. These findings highlight the potential of nanofluids as an innovative solution for advanced heat transfer applications, offering enhanced performance and energy savings

This study aims to employ an electrocoagulation reactor to treat petroleum effluent from a local plant and reduce dissolved solids (TDS) to suitable levels for reuse. A continuous reactor configuration featured a finned stainless steel cathode tube positioned between two cylindrical aluminum anodes. This study explored the influence of treatment duration (4–60 minutes), current density (0–6.0 mA.cm-2), and influent rate (50–150 ml/min) on the final TDS value. Flow rate increase correlated with increased final TDS values, while longer electrolysis durations and higher current densities led to decreased TDS levels. Optimized electrolysis conditions at 1 hour, 5 mA.cm-2, and 50 ml/min, with inner and outer anode consumptions of 0.18 g and 0.45 g, respectively, achieved a final TDS of 2000.45 mg/l, representing a reduction of 207.55 mg/l. The regression model, with a p-value of 0.0001, F-value of 219.37, and R2 of 99.75%, demonstrated the significance of the model components, indicating its robustness. The energy consumption was 3.65 kWh/m3, and the total operating cost was only 0.74 $ per m3. This study confirms the efficacy of the novel continuous reactor in managing petroleum wastewater under practical conditions with low consumption values of electrodes and electrical energy