Isotherms, kinetics and thermodynamic mechanism of methylene blue dye adsorption on synthesized activated carbon.

The treatment of methylene blue (MB) dye wastewater through the adsorption process has been a subject of extensive research. However, a comprehensive understanding of the thermodynamic aspects of dye solution adsorption is lacking. Previous studies have primarily focused on enhancing the adsorption capacity of methylene blue dye. This study aimed to develop an environmentally friendly and cost-effective method for treating methylene blue dye wastewater and to gain insights into the thermodynamics and kinetics of the adsorption process for optimization. An adsorbent with selective methylene blue dye adsorption capabilities was synthesized using rice straw as the precursor. Experimental studies were conducted to investigate the adsorption isotherms and models under various process conditions, aiming to bridge gaps in previous research and enhance the understanding of adsorption mechanisms. Several adsorption isotherm models, including Langmuir, Temkin, Freundlich, and Langmuir-Freundlich, were applied to theoretically describe the adsorption mechanism. Equilibrium thermodynamic results demonstrated that the calculated equilibrium adsorption capacity (qe) aligned well with the experimentally obtained data. These findings of the study provide valuable insights into the thermodynamics and kinetics of methylene blue dye adsorption, with potential applications beyond this specific dye type. The utilization of rice straw as an adsorbent material presents a novel and cost-effective approach for MB dye removal from wastewater.

Optimization of oil industry wastewater treatment system and proposing empirical correlations for chemical oxygen demand removal using electrocoagulation and predicting the system's performance by artificial neural network.

The alarming pace of environmental degradation necessitates the treatment of wastewater from the oil industry in order to ensure the long-term sustainability of human civilization. Electrocoagulation has emerged as a promising method for optimizing the removal of chemical oxygen demand (COD) from wastewater obtained from oil refineries. Therefore, in this study, electrocoagulation was experimentally investigated, and a single-factorial approach was employed to identify the optimal conditions, taking into account various parameters such as current density, pH, COD concentration, electrode surface area, and NaCl concentration. The experimental findings revealed that the most favorable conditions for COD removal were determined to be 24 mA/cm2 for current density, pH 8, a COD concentration of 500 mg/l, an electrode surface area of 25.26 cm2, and a NaCl concentration of 0.5 g/l. Correlation equations were proposed to describe the relationship between COD removal and the aforementioned parameters, and double-factorial models were examined to analyze the impact of COD removal over time. The most favorable outcomes were observed after a reaction time of 20 min. Furthermore, an artificial neural network model was developed based on the experimental data to predict COD removal from wastewater generated by the oil industry. The model exhibited a mean absolute error (MAE) of 1.12% and a coefficient of determination (R2) of 0.99, indicating its high accuracy. These findings suggest that machine learning-based models have the potential to effectively predict COD removal and may even serve as viable alternatives to traditional experimental and numerical techniques.

Theoretical study on the physical properties of synthesized SrMO3 (M = Hf and Pt) oxide perovskites using DFT.

We investigated the physical behavior of SrMO3 (M = Hf and Pt) compounds, which are strontium-based oxide perovskites. We utilized the WIEN2k software to simulate and investigate their physical properties. The structural stability of SrHfO3 and SrPtO3 was verified using the Birch-Murnaghan equation of states for optimization. We also checked the elastic stability through the computation of elastic constants using the IRelast software. Our results indicate the stability of these compounds and showed their anisotropic, ductility, scratch-resistive, and plastic strain-resistant characteristics. Using the TB-mBJ potential approach, we determined that SrHfO3 is an insulator, whereas SrPtO3 is a metal in nature. The density of states computations was used to find the band structure as well as the contribution of different electronic states. Optical property research was conducted using the band gap energies of these substances. Our findings suggest that these crystals have low energy absorption and reflectivity of up to 65%, making them suitable for use in high-frequency UV devices. Specifically, SrHfO3 is more transparent before the energy point 2.80 eV, while the compound SrPtO3 after 6.50 eV to 12.0 eV and SrHfO3 from 12.0 and 14.0 eV. This study represents the first DFT-based investigation of these discussed crystals according to the best of our knowledge.

Emerging Developments in Separation Techniques and Analysis of Chiral Pharmaceuticals.

Chiral separation, the process of isolating enantiomers from a racemic mixture, holds paramount importance in diverse scientific disciplines. Using chiral separation methods like chromatography and electrophoresis, enantiomers can be isolated and characterized. This study emphasizes the significance of chiral separation in drug development, quality control, environmental analysis, and chemical synthesis, facilitating improved therapeutic outcomes, regulatory compliance, and enhanced industrial processes. Capillary electrophoresis (CE) has emerged as a powerful technique for the analysis of chiral drugs. This review also highlights the significance of CE in chiral drug analysis, emphasizing its high separation efficiency, rapid analysis times, and compatibility with other detection techniques. High-performance liquid chromatography (HPLC) has become a vital technique for chiral drugs analysis. Through the utilization of a chiral stationary phase, HPLC separates enantiomers based on their differential interactions, allowing for the quantification of individual enantiomeric concentrations. This study also emphasizes the significance of HPLC in chiral drug analysis, highlighting its excellent resolution, sensitivity, and applicability. The resolution and enantiomeric analysis of nonsteroidal anti-inflammatory drugs (NSAIDs) hold great importance due to their chiral nature and potential variations in pharmacological effects. Several studies have emphasized the significance of resolving and analyzing the enantiomers of NSAIDs. Enantiomeric analysis provides critical insights into the pharmacokinetics, pharmacodynamics, and potential interactions of NSAIDs, aiding in drug design, optimization, and personalized medicine for improved therapeutic outcomes and patient safety. Microfluidics systems have revolutionized chiral separation, offering miniaturization, precise fluid control, and high throughput. Integration of microscale channels and techniques provides a promising platform for on-chip chiral analysis in pharmaceuticals and analytical chemistry. Their applications in techniques such as high-performance liquid chromatography (HPLC) and capillary electrochromatography (CEC) offer improved resolution and faster analysis times, making them valuable tools for enantiomeric analysis in pharmaceutical, environmental, and biomedical research.

Different Dimensionalities, Morphological Advancements and Engineering of g-C3 N4 -Based Nanomaterials for Energy Conversion and Storage.

Graphitic carbon nitride (g-C3 N4 ) has gained tremendous interest in the sector of power transformation and retention, because of its distinctive stacked composition, adjustable electronic structure, metal-free feature, superior thermodynamic durability, and simple availability. Furthermore, the restricted illumination and extensive recombination of photoexcitation electrons have inhibited the photocatalytic performance of pure g-C3 N4 . The dimensions of g-C3 N4 may impact the field of electronics confinement; as a consequence, g-C3 N4 with varying dimensions shows unique features, making it appropriate for a number of fascinating uses. Even if there are several evaluations emphasizing on the fabrication methods and deployments of g-C3 N4 , there is certainly an insufficiency of a full overview, that exhaustively depicts the synthesis and composition of diverse aspects of g-C3 N4 . Consequently, from the standpoint of numerical simulations and experimentation, several legitimate methodologies were employed to deliberately develop the photocatalyst and improve the optimal result, including elements loading, defects designing, morphological adjustment, and semiconductors interfacing. Herein, this evaluation initially discusses different dimensions, the physicochemical features, modifications and interfaces design development of g-C3 N4 . Emphasis is given to the practical design and development of g-C3 N4 for the various power transformation and inventory applications, such as photocatalytic H2 evolution, photoreduction of CO2 source, electrocatalytic H2 evolution, O2 evolution, O2 reduction, alkali-metal battery cells, lithium-ion batteries, lithium-sulfur batteries, and metal-air batteries. Ultimately, the current challenges and potential of g-C3 N4 for fuel transformation and retention activities are explored.

Thermodynamics Investigation and Artificial Neural Network Prediction of Energy, Exergy, and Hydrogen Production from a Solar Thermochemical Plant Using a Polymer Membrane Electrolyzer.

Hydrogen production using polymer membrane electrolyzers is an effective and valuable way of generating an environmentally friendly energy source. Hydrogen and oxygen generated by electrolyzers can power drone fuel cells. The thermodynamic analysis of polymer membrane electrolyzers to identify key losses and optimize their performance is fundamental and necessary. In this article, the process of the electrolysis of water by a polymer membrane electrolyzer in combination with a concentrated solar system in order to generate power and hydrogen was studied, and the effect of radiation intensity, current density, and other functional variables on the hydrogen production was investigated. It was shown that with an increasing current density, the voltage generation of the electrolyzer increased, and the energy efficiency and exergy of the electrolyzer decreased. Additionally, as the temperature rose, the pressure dropped, the thickness of the Nafion membrane increased, the voltage decreased, and the electrolyzer performed better. By increasing the intensity of the incoming radiation from 125 W/m2 to 320 W/m2, the hydrogen production increased by 111%, and the energy efficiency and exergy of the electrolyzer both decreased by 14% due to the higher ratio of input electric current to output hydrogen. Finally, machine-learning-based predictions were conducted to forecast the energy efficiency, exergy efficiency, voltage, and hydrogen production rate in different scenarios. The results proved to be very accurate compared to the analytical results. Hyperparameter tuning was utilized to adjust the model parameters, and the models' results showed an MAE lower than 1.98% and an R2 higher than 0.98.

Advanced Photocatalytic Treatment of Wastewater Using Immobilized Titanium Dioxide as a Photocatalyst in a Pilot-Scale Reactor: Process Intensification.

In many nations, particularly those experiencing water scarcity, novel approaches are being applied to clean wastewater. Heterogeneous photocatalysis is the most widely used of these approaches because it entails the decomposition of organic molecules into water and carbon dioxide, which is a more ecologically benign process. In our study, we studied the photocatalytic degradation process on the effluent flumequine. This treatment is made through a solar pilot reactor in the presence of immobilized titanium dioxide with three light intensities and two types of water as solvents. A variety of factors that might influence the rate of deterioration, such as flow rate, light intensity, and initial concentration, have been investigated. The maximal degradation of flumequine was achieved at more than 90% after 2.5 h under optimal conditions (an initial concentration of 5 mg/L, three lamp light intensities, and a flow rate of 29 L/h). By combining the oxidized agent H2O2 with this process, the photocatalytic activity was improved further to 97% under the same conditions. The mineralization of this product has also been tested using total organic carbon (TOC) analysis. A high mineralization rate has been recorded at around 50% for a high initial concentration (20 mg/L) at a flow rate of 126 L/h. The results demonstrated the highly effective removal of flumequine and the efficacy of this photocatalytic system.

Synthesis, structural, and opto-electrochemical properties of cobalt aluminate type spinel and its use with ZnO for Cr(VI) photoreduction.

The discovery of the occurrence of inorganic pollutants in surface waters is identified in the system assessment quality. The most harmful elements are pesticides, persistent organic pollutants, pharmaceuticals, personal care products, and heavy metals are still dangerous to the environment due to their general uses. Chromate has the largest concentration compared to the other metals in the wastewater industries. This work evaluates the application of the spinel p-CoAl2O4 as a photocatalyst prepared by the nitrate synthesis process to reduce Cr(VI), a hazardous metal for the environment. The photocatalyst was characterized using thermal analysis (TG), X-ray diffraction, UV-diffuse reflectance spectroscopy, scanning electron microscopy, fluorescent X-ray, Fourier transform infrared spectroscopy, electrical conductivity, and photoelectrochemically. The results showed that the efficiency of optimum reduction of Cr(Vl) to Cr(IIl) photoreduction is more effective (77%) for pH = 3.6 than that at high pH values up to 8 (7%). Moreover, the effect of the hetero-system CoAl2O4/ZnO on photocatalytic efficiency was investigated. The photocatalytic activity increases up to 99% with 1 g L-1, a total catalyst dosage over the hetero-system CoAl2O4/ZnO at a ratio of 75%/25%. This data is better relative to CoAl2O4 or ZnO alone. The Cr(VI) photoreduction activity improvement was caused by the best separation and the photogeneration of electron-hole on the CoAl2O4/ZnO surfaces. Finally, the Lagergren pseudo-first-order and the Langmuir-Hinshelwood models fit well the experimental kinetics.

Recent progress in air treatment with combined photocatalytic/plasma processes: A review.

Nowadays, air pollution is an increasingly important topic, as environmental regulations require limiting pollutant emissions. This problem requires new techniques to reduce emissions by either improving the current emission control systems and processes or installing new hybrid treatment systems. These are of broad diversity, and every system has its advantages and disadvantages. The tendency is, accordingly, to combine various techniques to achieve more acceptable and suitable treatment. Recent studies suggest that the combination of photocatalysis and plasma in a reactor can offer attractive pollutant treatment efficiency with a minimum of partially oxidized by-products than that of these processes taken separately. However, there is little review of the capability of this pairing to treat different brands of pollutants. Besides, available data concerning reactor design with flows treated 10 to 1000 times higher than those studied at the lab scale. This review paid particular attention to determine the reaction mechanisms in terms of engineering and design of combination reactors (plasma and catalysis). Likewise, we developed the effect of critical parameters such as pollutant load, relative humidity, and flow rate to understand the degradation kinetics of specific pollutants individually by using plasma and photocatalysis. Additionally, this review compares different designs of cold plasma reactors combination with heterogeneous catalysis with special attention on synergistic and antagonistic effects of using plasma and photocatalysis processes at the laboratory, pilot, and industrial scales. Therefore, the elements discussed in this review stick well to the first theme on pollution prevention of the special issue concerning pollution prevention and the application of clean technologies to promote a circular (bio) economy.

Phytochemical characterization, and antioxidant and antimicrobial activities of essential oil from leaves of the common sage Salvia officinalis L. from Abha, Saudi Arabia.

Background: The composition and activities of essential oil of common sage from Saudi Arabia have not yet been reported. Objectives: To analyze the composition and antibacterial and antioxidant activities of essential oil from leaves of the common sage Salvia officinalis L. from Abha, Saudi Arabia. Methods: Essential oil was extracted from the leaves of S. officinalis by hydrodistillation, and its composition was analyzed using gas chromatography and mass spectrometry. Phenolics and flavonoids were determined using gallic acid and quercetin standards. Antioxidant activity was determined using a 2,2-diphenyl-1-picrylhydrazyl radical scavenging method. Activity against various gram-positive and gram-negative bacteria was determined by disk diffusion and microdilution. Results: The yield of essential oil was 3.24 ± 0.55% (w/dry weight). Major compounds identified were camphor (20.3%), 1,8-cineole (15.0%), α-thujone (14.9%), viridiflorol (9.9%), carvone (6.2%), and ß-thujone (5.7%). Phenolic content was 134.3 ± 17.61 µg/mL and flavonoid content was 119.5 ± 18.75 µg/mL. Antioxidant IC50 was 970 ± 5.5 µg/mL. The highest gram-positive antibacterial activity was for Bacillus subtilis and the highest gram-negative activity was for Escherichia coli. Minimum inhibitory concentrations ranged from 62.2 ± 3.9 to 1398.1 ± 50.7 µg/mL for gram-positive bacteria and from 323.4 ± 69.5 to 968.4 ± 120.6 µg/mL for gram-negative bacteria. Minimum bactericidal concentrations ranged from 120.3 ± 7.6 to 1387.4 ± 161.8 µg/mL for gram-positive bacteria and from 386 ± 8.3 to 1225.2 ± 100.9 µg/mL for gram-negative bacteria. Conclusions: Essential oil of S. officinalis L. from Abha, Saudi Arabia, showed compositional, antioxidant, and antibacterial properties generally consistent with essential oil of S. officinalis L. from other locations as reported in the literature.