Conditions For Maximum Efficiency Research Articles

Predictive Modeling and Adsorption Behavior, Kinetics, and Thermodynamic Studies of <i>Anthocleista grandiflora </i>Leaf Extract for Corrosion Inhibition of Carbon Steel in Seawater

This study investigates the corrosion inhibition performance of Anthocleista grandiflora leaf (AGL) extract on carbon steel in seawater, considering the effects of temperature, immersion time, and inhibitor concentration. Predictive modeling, adsorption behavior, and the kinetics and thermodynamics of the inhibition process were examined. The weight loss technique,characterization techniques combined with response surface methodology (RSM), revealed that the AGL extract follows the Langmuir adsorption model, exhibiting physical adsorption with ΔG values between −16.24 to −15.49kJ/mol, indicating spontaneous and endothermic inhibition. The thermodynamic parameters entropy (−198.87 to −52.58 J/mol), enthalpy (20.42 to 53.42 kJ/mol), and activation energy (13.68 to 56.32 kJ/mol further support this. The corrosion reaction follows first-order kinetics, with the half-life decreasing as the rate constant and extract concentration increase.The SEM images revealed that the AGL extract formed a protective surface layer on the mild steel, effectively preventing pitting. This protective effect became more pronounced as the concentration of the extract increased. RSM optimization identified optimal conditions for maximum inhibition efficiency (98.70%) and corrosion rate (0.058 mm/y) at 800 ppm, 303 K, and 45 days, with a prediction accuracy of 95%, making it suitable for application in the oil and gas industry.

Optimization study of methylene blue dye adsorption on Chamaerops humilis fibers biosorption using a central composite design

This research explores the effectiveness of Chamaerops humilis (CH) fibers as a biosorbent for the adsorption of Methylene Blue (MB) dye from aqueous solutions. The fibers were characterized using X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FTIR). To optimize the dye removal process, a Design of Experiments methodology, specifically Central Composite Design (CCD), was applied. Factors such as solution pH, adsorbent dosage, contact time, and temperature were varied. The CCD analysis identified the optimal conditions for maximum removal efficiency (99.87 %) of a 10 mg/L MB solution, which were: 1.06 g/L of CH fiber dosage, pH 9.6, and a contact time of 60 min. The adsorption process aligned well with a pseudo-second-order kinetic model, and the maximum adsorption capacity of CH fibers was determined to be 9.422 mg/g. Thermodynamic parameters, including Gibbs free energy (ΔG°), enthalpy (ΔH°), and entropy (ΔS°) changes, were calculated, confirming that the adsorption is spontaneous and endothermic. The study highlights the potential of Chamaerops humilis fibers as an efficient and eco-friendly adsorbent for MB dye removal, offering a sustainable and cost-effective solution for wastewater treatment, particularly in industrial effluent management.

Exploring sustainable solutions: Utilizing recycled coffee grounds as a new bio‐adsorbent material for removal of Pb(II) ions from water

AbstractThis study investigates the potential of utilizing spent coffee grounds (SCG) treated with Ca(OH)2 as an adsorbent for the removal of lead (Pb(II)) ions from aqueous solutions. The SCG was subjected to sequential treatments, including washing, drying, sieving, and immersion in Ca(OH)2 solutions of varying concentrations. Adsorption experiments were conducted under different conditions to evaluate the efficiency of the adsorbent, including variations in contact time, solution pH, adsorbent dosage, temperature, and initial Pb(II) ion concentration. Characterization of the SCG before and after treatment was performed using Fourier transform infrared spectroscopy. The results revealed significant changes in the structural properties of the SCG after treatment with Ca(OH)2, leading to enhanced adsorption performance. The adsorption experiments demonstrated that the efficiency of Pb(II) ion removal was influenced by factors such as contact time, solution pH, adsorbent dosage, temperature, and initial Pb(II) ion concentration. Optimal conditions for maximum adsorption efficiency were identified as a contact time of 270 min, pH 6, adsorbent dosage of 1 g, and temperature of 313 K, resulting in a maximum adsorption capacity qmax of 18.69 mg g−1. The highest desorption rate was observed using HNO3, measured at 90.6%. The reusability efficiency of the adsorbent material was 87.98% in the first use, decreased to 75.41% after five reuses, and further reduced to 39.96% after ten reuses, indicating a decline in performance with repeated use. These findings highlight the potential of SCG as an effective and environmentally friendly adsorbent for the removal of potentially toxic elements from aqueous solutions.

Industrial park wastewater treatment using a combined sono-pulsed electrochemical-coagulation process

Maintaining sustainable water management practices, preserving ecosystems, and safeguarding public health has depend on the treatment of wastewater. It has a significant impact on reducing water pollution and protecting the water supplies. Sono-pulsed electrochemical oxidation (S-PEO) process is a wastewater treatment method that uses ultrasound (US) waves and electrochemistry to enhance the pollutant removal efficiency. This study aim is to investigate the mineralization of industrial park wastewater by using pulsed electrochemical oxidation (PEO) and a combination of sonolysis and pulsed electrochemical oxidation (S-PEO) processes. The research focuses on the percentage elimination of chemical oxygen demand (COD) and color, as well as the assessment of power consumption. The study considers the influence of experimental parameters like initial pH, electrolysis time, and current to find the optimum conditions for maximum percentage removal efficiency with minimization of power consumption. According to the study, the optimum values of responses for the S-PEO process were obtained at pH=7, electrolysis time=40 min, and current =0.5 Amp. The optimum values for the maximum removal percentages of the responses COD and color were 97.04 %, and 99.70 %, respectively. The minimum of power consumption for S-PEO was 0.19 kWh/m3. These results demonstrate that, the superior efficiency of the S-PEO process and its feasibility in the removal of industrial wastewater pollutants. Optimizing parameters like pH, time, and current intensity is crucial for optimal performance, reducing energy consumption and operational costs. The S-PEO technique eliminates pollutants from wastewater efficiently and effectively, making it the suitable process when compared to the others.

Catalytic green synthesis of Tin(IV) oxide nanoparticles for phenolic compounds removal and molecular docking with EGFR tyrosine kinase

In this study, tin dioxide nanoparticles (SnO2 NPs) were successfully synthesized through an eco-friendly method using basil leaves extract. The fabricated SnO2 NPs demonstrated significant adsorption capabilities for phenol (PHE), p-nitrophenol (P-NP), and p-methoxyphenol (P-MP) from water matrices. Optimal conditions for maximum removal efficiency was determined for each phenolic compound, with PHE showing a remarkable 95% removal at a 3 ppm, 0.20 g of SnO2 NPs, pH 8, and 30 min of agitation at 35 °C. Molecular docking studies unveiled a potential anticancer mechanism, indicating the ability of SnO2 NPs to interact with the epidermal growth factor receptor tyrosine kinase domain and inhibit its activity. The adsorption processes followed pseudo-second order kinetics and Temkin isotherm model, revealing spontaneous, exothermic, and chemisorption-controlled mechanisms. This eco-friendly approach utilizing plant extracts was considered as a valuable tool for nano-sorbent production. The SnO2 NPs not only exhibit promise in water treatment and also demonstrate potential applications in cancer therapy. Characterization techniques including scanning electron microscopy, UV–visible spectroscopy, Fourier transform infrared spectroscopy, X-ray diffraction spectroscopy (XRD), and energy-dispersive X-ray spectroscopy (EDAX) provided comprehensive insights into the results.

Synthesis and Characterizations of Molecularly Imprinted Polymer of Atrazine: Removal of Atrazine from Aqueous Samples

AbstractAtrazine (ATZ) is a widely used triazine herbicide in agriculture, however, it negatively affects the environment and human health. Therefore, a molecularly imprinted polymer (MIP) was employed for the selective removal of ATZ. In this study, MIPs were produced by precipitation polymerization using ATZ as the target molecule, methacrylic acid (MAA), acrylamide (AAm), and 2‐vinylpyridine (2VP) as functional monomers and ethylene glycol dimethacrylate (EGDMA) as cross‐linker, respectively. MIP characterizations were performed using Fourier Infrared spectroscopy (FTIR) and Field Emission Electron Microscopy (FESEM). The batch binding study revealed that MIP (2VP) exhibited the highest rebinding efficiency (88.44 %) among the MIPs. Furthermore, MIP (2VP) was analyzed by Energy‐Dispersive X‐ray spectroscopy (EDX), Brunauer‐Emmett‐Teller (BET) analysis, and thermogravimetric analysis (TGA). Adsorption studies revealed that the optimum conditions for maximum adsorption efficiency were 8 ppm ATZ solution at pH 7, using 0.3 g of MIP (2VP). MIP (2VP) demonstrated higher selectivity towards ATZ than the Ametryn (AME) a competitive interferent, with a relative selectivity coefficient of 2.77. MIP (2VP) successfully removed ATZ from distilled water (95.39 %), tap water (88.16 %) and river water (86.75 %). These findings contributed for the development of MIP for the removal of ATZ, which would be helpful in the protection of ecosystem and human health in future.

THEORY OF UNIFORM RISE/FALL OF A PHYSICAL BODY IN A MOVING MEDIUM

Well production collection and preparation systems play an important role in the separation of oil, gas and water. Proper control of the parameters of gas separators and settling tanks is a key task for their efficient operation. In this paper, the determination of the performance of separators and settling tanks is considered, and special attention is paid to the boundary conditions for maximum efficiency of the separation process. At the moment, the calculation of the performance of gas separators and various settling tanks is carried out according to formulas derived in the twentieth century, and the scientific world does not question their reliability or the reliability of their conclusion. And in order to either prove the reliability of these calculations, or to refute them, an analysis of work was carried out to determine the performance of separators and settling tanks. At the beginning of the work there is a description of how productivity is calculated in the modern world. After that, a discussion is held about the reliability of these calculations, where in the course of reasoning, logical arguments are given about the erroneous conclusions of past calculations. So it was found out that the main assumption in the previous calculations was the use of the absolute velocity of the body in determining the resistance force of the medium, while it was necessary to use the relative velocity of the body, namely the velocity of the body relative to the medium. The following are the new boundary conditions, the solution of this problem, and the conclusions obtained.But the most interesting are the further discussions in the work, during which answers to the questions are given: how and at what speed will the oil particle move in the gas environment of the gas separator at different ratios of forces acting on the particle. Thus, it was concluded that the relative velocity of a body floating freely in a liquid or gaseous medium always tends to a certain constant value, which is numerically equal to the critical velocity of the medium, that is, such a speed at which a particle of oil would be stationary relative to the earth with a moving medium. In this case, the absolute velocity of the body (particles of oil, water, gas) will be equal to the vector difference between the velocity of the medium and the critical velocity of the medium. Combining the obtained conclusions, a new theory about the motion of bodies in a moving medium is created.

A comparative and comprehensive study on robust silver-immobilized chitosan/carboxy methyl chitosan macromolecules for elimination of dyes

This study explores the potential of modified chitosan (CH) resulting from carboxy methyl (CM) group substitution in the chitosan skeleton, producing carboxy methyl chitosan (CMCH). Silver (Ag) was loaded to chitosan and modified chitosan (carboxy methyl substituted chitosan) supported on cellulose filter paper (FP) to tailor organic–inorganic macromolecule composites “Ag-Chi/CFP and Ag-CMCH/CFP” further applied as substantial composite for the reductive removal of methyl orange (MO) and rhodamine B (RB) dyes from wastewater. The synthesized catalyst was characterized via FTIR, 1H NMR, XRD, and SEM analysis. The degree of substitution was also measured, which was approximately 0.85. The reductive elimination efficiency of Ag-CMCH/CFP and Ag-Chi/CFP for MO dye was 95.31% and 88.85 %. In comparison, the elimination of RB was 98.28 and 94.04 %, respectively, in 16 min time, 0.6 mM Ag concentration, 40 mg/L, dye concentration and 0.3 M NaBH4 concentration. The synthesized catalysts were recycled three times. The degradation of MO and RB dyes using Ag-CMCH/CFP and Ag-Chi/CFP catalysts can be described by the first-order kinetic model. The determination coefficients (R2) and rate constants (k) values for MO degradation were found to be 0.9934 and 0.1736 s−1 for Ag-CMCH/CFP, and 0.9242 and 0.1001 s−1 for Ag-Chi/CFP, respectively. Similarly, for RB degradation, the R2 values were 0.9866 for Ag-CMCH/CFP and 0.9803 for Ag-Chi/CFP, with corresponding k values of 0.219 s−1 and 0.1548 s−1, respectively. The degradation process was optimized using response surface methodology (RSM) to determine the optimal conditions for maximum dye removal efficiency. The RSM models were statistically significant, as validated by ANOVA and correlation coefficient values. The F values of MO and RB models are significant as they have 2450.15 and 21999.37, respectively. The P value for both was <0.0001.

Effect of Light Intensity on Photosynthesis in Aquatic Plants in Australia

Purpose: The aim of the study was to investigate the Effect of Light Intensity on Photosynthesis in Aquatic Plants in Australia.&#x0D; Methodology: The study adopted a desktop methodology. Desk research refers to secondary data or that which can be collected without fieldwork. Desk research is basically involved in collecting data from existing resources hence it is often considered a low cost technique as compared to field research, as the main cost is involved in executive’s time, telephone charges and directories. Thus, the study relied on already published studies, reports and statistics. This secondary data was easily accessed through the online journals and library&#x0D; Findings: In the study examining the impact of light intensity on photosynthesis in Australian aquatic plants, key findings emerged. It was evident that light intensity played a crucial role, with higher light levels in shallower waters leading to increased photosynthesis rates. This underscored the significance of light as a primary determinant of photosynthesis in these ecosystems. Additionally, the study highlighted the impressive adaptability of Australian aquatic plants, some of which employed unique photo protective mechanisms to prevent photo inhibition under varying light conditions.&#x0D; Unique Contribution to Theory, Practice and Policy: Theory of Liebig's Law of the Minimum, Theory of The Beer-Lambert Law and Optimal Foraging Theory may be used to anchor future studies on the Effect of Light Intensity on Photosynthesis in Aquatic Plants in Australia. Develop practical guidelines for growers to optimize light conditions for maximum photosynthetic efficiency. Advocate for policies that recognize the significance of aquatic plants in maintaining healthy aquatic ecosystems. Promote the conservation and restoration of natural habitats for aquatic plants, especially in areas threatened by pollution or habitat destruction.&#x0D;

Assessing the biodegradation efficiency and underlying molecular pathway of strain AEPI 0–0: A newly isolated tetracycline-degrading Serratia marcescens

With the development of aquaculture and animal husbandry, the use of tetracycline antibiotics (TCs) has increased, thereby leading to negative impacts on naturally-occurring microbial communities. Microbial degradation is an effective and environmental friendly method to degrade TCs, but so far, very few cultured strains are suitable for this purpose. In this study, a bacterial strain, AEPI 0–0, with the potential to degrade TCs was isolated, with phylogenetic analysis subsequently classifying it as Serratia marcescens. The single factors that affected the strain’s degradation efficiency on TC-HCl were then studied using an orthogonal experimental design. The results showed that the biodegradation efficiency could reach about 85% on the 4th day, with the process following the degradation kinetic equation. Subsequently, RNA-seq was used and the differentially expressed genes（DEGs）were annotated and analyzed. The results showed that more genes were enriched in biological processes such as amino acid metabolism, carbohydrate metabolism, and cell membrane transport metabolism pathway. In addition, TetR family transcription factors may play an important role in the physiological process of AEPI 0–0 tolerance and degradation of tetracycline. In conclusion, a Serratia marcescens strain with high potential for TCs degradation was obtained, with the conditions for maximum degradation efficiency subsequently optimized, changes in the metabolic pathways were also preliminarily discussed. This strain could potentially be applied for the bioremediation of soil and water contaminated by TCs antibiotics. At the same time, this study also provides strains as well as theoretical support for microbial-based remediation of the environment.

Crystal violet removal using bimetallic Fe0–Cu and its composites with fava bean activated carbon

Nano zero-valent iron (nZVI), bimetallic nano zero-valent iron-copper (Fe0– Cu), and fava bean activated carbon-supported bimetallic nano zero-valent iron-copper (AC-Fe0-Cu) are synthesized and characterized using DLS, zeta potential, FT-IR, XRD, and SEM. The maximum removal capacity is demonstrated by bimetallic Fe0–Cu, which is estimated at 413.98 mg/g capacity at pH 7, 180 min of contact duration, 120 rpm shaking speed, ambient temperature, 100 ppm of C.V. dye solution, and 1 g/l dosage. The elimination capability of the H2SO4 chemical AC-Fe0-Cu adsorbent is 415.32 mg/g under the same conditions but with a 150 ppm C.V. dye solution. The H3PO4 chemical AC-Fe0-Cu adsorbent achieves a removal capacity of 413.98 mg/g under the same conditions with a 350 ppm C.V. dye solution and a 1.5 g/l dosage. Optimal conditions for maximum removal efficiency are determined by varying pH (3–9), time intervals (15–180 min), and initial dye concentrations (25–1000 ppm). Kinetic and isothermal models are used to fit the results of time and concentration experiments. The intra-particle model yields the best fit for bimetallic Fe0–Cu, H2SO4 chemical AC- Fe0–Cu, and H3PO4 chemical AC-Fe0-Cu, with corrected R-Squared values of 0.9656, 0.9926, and 0.964, respectively. The isothermal results emphasize the significance of physisorption and chemisorption in concentration outcomes. Response surface methodology (RSM) and artificial neural networks (ANN) are employed to optimize the removal efficiency. RSM models the efficiency and facilitates numerical optimization, while the ANN model is optimized using the moth search algorithm (MSA) for optimal results.

Study of the Influences of Fuel Utilization on Efficiency and Anode Safety at Different Fuel Flow Rates for Industrial-Size Solid Oxide Fuel Cell

Solid oxide fuel cell (SOFC) is regarded as a promising energy conversion technology that can directly produce electricity from chemical fuels without combustion. Commercialization of SOFC systems has already started with residential and industrial applications, and demonstrations for a broader range of uses have been carried out. However, the widespread commercialization of SOFC systems requires further improvements both in efficiency and durability. The efficiency of a single cell is affected by fuel utilization and voltage. In addition, high fuel utilization may cause an increase in concentration polarization or lead to local Ni oxidation of cell anode. Therefore, it is imperative to study the influence of fuel utilization on the cell's performance, efficiency, and anode safety. In this work, I-V curves at different fuel flow rates were tested. The fuel utilization and voltage corresponding to the peak power density at different flow rates were determined. Based on the gas conversion and diffusion resistance models, the area specific resistance behavior and the fuel utilization corresponding to the beginning of the concentration polarization zone were investigated. Besides, the effects of fuel utilization and cell voltage on local Ni oxidation were also studied. The results indicated that at a low fuel flow rate of 0.1-0.3 L/min, the fuel utilization corresponding to the peak power density condition (which is also the condition of maximum efficiency) was about 90%. Although a significant increase in concentration polarization occurred under such high fuel utilization, no Ni oxidation occurred due to the high voltage. However, at a high fuel flow rate of 0.8-1.0 L/min, the fuel utilization corresponding to the peak power density condition was about 70%. The low voltage led to local Ni oxidation before entering the concentration polarization zone. This finding provides an idea for choosing fuel utilization at different fuel flow rates to realize high efficiency and anode safety.

Extraction of cadmium from aqueous solutions by emulsion liquid membrane (ELM) using three different carriers dissolved in a 70:30 ratio of sunflower oil to kerosene

This study explores the use of novel green emulation liquid membranes (GELMs) for the simultaneous extraction and stripping of Cd (II) from aqueous solutions. A solute is transported through the membrane due to the presence of the carrier and then concentrated in the internal phase. Soybean, sunflower, corn, and canola oils were used to form green substitutes to petroleum-based organic diluents for use as GELMs. Bis-(2-ethylhexyl) phosphate (D2EHPA), tri-butyl- phosphate (TBP), and trioctylamine (TOA) were the extractants, span 80 was the emulsifier, and HCl or H2SO4 was used as the stripping agent. The best conditions for maximum extraction efficiency (98.68%), stripping efficiency (97.14%), and lowest membrane breakage (0.9%) were achieved using a mixture of sunflower oil and kerosene in the ratio of 70:30. The other optimum values of the variables were: 2% (v/v) Span 80, 10 min emulsification time, 12700 rpm emulsification speed, 400 rpm of agitation speed, 5% (v/v) D2EHPA, an external phase pH was 3.5, an internal phase of 0.25 M HCl, and 5:1 of the treat ratio (external phase to emulsion) at 10 min contact time. The synthesized membrane was reused eight times, with approximately the same efficiency and no significant breakage during the first seven cycles.

Effect and optimization of radial non-uniform porosity catalyst on SCR characteristics based on response surface method

Selective catalytic reduction (SCR) system is used to the denitration (de-NOx) of diesel engine exhaust after treatment. In this work, a three-dimensional SCR model with radial non-uniform distribution of catalysts is established to study the pressure drop and de-NOx performance. Firstly, the SCR converter model with uniform catalyst distribution is selected to verify its reliability. Then, the radius R1 and porosity ԑ1 of area 1, radius R2 and porosity ԑ2 of area 2 are selected as single factor variables to study the influence on the SCR system performance. Finally, response surface methodology (RSM) is employed to evaluate and optimize the above single factor parameters affecting de-NOx performance and pressure drop of SCR system. The results showed that the change of ԑ2 had the greatest impact on de-NOx efficiency and pressure drop. The optimum condition for maximum de-NOx efficiency was estimated at the R1 of 50 mm, R2 of 100 mm, porosity ԑ1 of 0.47 and porosity ԑ2 of 0.7. Under these conditions, the de-NOx efficiency by numerical simulation was 80.37 %, which was close to the predicted value (80.68 %), and the pressure drop was 218 Pa, which was close to the predicted value (246 Pa). Compared with the uniform distribution of catalysts, the de-NOx efficiency of the optimal Case of numerical simulation is increased by 3.74 %, and the pressure drop is reduced by 46 Pa. The research can provide theoretical and engineering references for the improvement of SCR catalyst coating process.

A sustainable system for decontamination of cephalexin antibiotic using electrocoagulation technology and response surface methodology

AbstractThe emergence of synthetic micropollutants in wastewater due to domestic and industrial use has presented new challenges for treatment processes. Among these pollutants, pharmaceutical and personal care products (PPCPs) are considered emerging contaminants due to their potential to enter drinking water sources. Antibiotics, in particular, are of significant concern due to their high consumption in veterinary and human applications. In this study, the electrocoagulation (EC) process is used as an efficient technique for the removal of cephalexin (CFX) from pharmaceutical wastewater. The study aims to explore the ability of the EC process to remove CFX and optimize its performance using the response surface method based on Central Composite Design (RSM‐CCD). The effects of initial CFX concentration, electrolysis time, initial pH, and electrode type (non‐insulated and insulated) were considered in the optimization process. This research is distinct as it examines the influence of key factors on the elimination of CFX. The results showed that electrolysis time had the most significant effect on CFX removal using the EC process. The analysis of variance (ANOVA) test was used to evaluate the importance of independent variables and their interaction. The optimal operating conditions for maximum removal efficiency (86.53%) were an initial CFX concentration, reaction time, and initial pH of 34 mg/L, 34.35 min, and 6.5, respectively, using an insulated electrode. Under these optimal conditions, predicted CFX removal was 93.54%. These findings demonstrate that RSM‐CCD is a useful tool for optimizing electrochemical removal processes for micropollutants such as CFX from wastewater streams. The study highlights the importance of considering electrode type in optimizing EC processes for micropollutant removal from wastewater.

Insights into the statistical physics modeling and fractal like kinetic approach for the adsorption of As(III) on coordination polymer gel based on zirconium(IV) and 2-thiobarbituric acid

A novel coordination polymer gel based on zirconium(IV) and 2-thiobarbituric (ZrTBA) was synthesized and explored its potential to remediate As(III) from water. Box-Behnken design with desirability function and genetic algorithm yielded the optimized conditions (initial concentration=194 mg L-1, dosage = 42.2 mg, time= 95 min and pH = 4.9) for maximum removal efficiency (99.19 %). The experimental saturation capacity for As(III) was 178.30 mg g-1. The steric parameter n > 1 of the best fitted statistical physics model: monolayer with two energies (R2 = 0.987–0.992) suggested multimolecular mechanism with vertical orientation of As(III) molecules onto the two active sites. XPS and FTIR confirmed the two active sites being zirconium and oxygen. The adsorption energies (E1 = 35.81–37.63 kJ/mol; E2 = 29.50–36.49 kJ/mol) and isosteric heat of adsorption indicated that physical forces governed the As(III) uptake. DFT calculations implied that the weak electrostatic interaction and hydrogen bonding were involved. The best fitted (R2>0.99) fractal like pseudo first order model established energetic heterogeneity. ZrTBA showed excellent removal efficiency in the presence of potential interfering ions and could be used up to 5 cycles of adsorption-desorption with < 8 % loss in the efficiency. ZrTBA removed ≥96.06 % As(III) from real water samples spiked at different levels of As(III).

Oil Removal from Polluted Seawater using Carbon Avocado Peel as Bio-Absorbent

Oil spills are a very dangerous occurrence for the marine ecosystem as the marine life-form's existence gets unnecessarily threatened. Since the exploration of oil from marine resources has become a must and oil spills end up occurring accidentally, as a result, it becomes important to employ various oil spill cleanup methods. The purpose of the current work was to evaluate the oil sorption capacity of dried carbonized avocado peel (AP) waste. AP was dried under the sun and microwaved to have the activated carbon AP. In this study, batch adsorption studies were conducted to remove different oil types (Crude oil, Diesel, Kerosene, and Gas oil) from polluted seawater using AP. The effect of various important parameters, namely, mixing time, adsorbent dose, oil dose, oil types, and reusability on the oil uptake, and their optimum conditions for maximum sorption efficiency was studied. Batch studies indicated that an adsorbent dosage of 7 g, mixing time of 20 minutes under a mixing rate of 45–50 revolutions/min, 1 g of oil and provides maximum oil removal efficiency in the present study. Based on the data fit result of the adsorption; the 7 g AP at 20 min (90%) had better oil retention than the 1.5 g (66%), 3 g (77%), and 5 g (82%) AP. The results indicated that the maximum oil adsorption percentage upon increasing the adsorbent dose (1.5 g, 3 g, 5 g, and 7 g peel) was 66-90% for Crude oil, 45-68% for Diesel, 35-56% for Kerosene, and 19-45% for Gas oil at 20 min using 1 gram oil. The results revealed that sorption capacity decreased as the oil got lighter. Increasing the oil dose reduce the adsorption capacity (Crude oil 90-66%, Diesel 64-45%, Kerosene 50-39%, and Gas oil 40-12%). The oil sorption capacities of the AP sorbents reduce gradually from 90-64% after 10 cycles, with about 72%, since the oleophilic nature of the peel surface was affected during the regeneration process. The kinetic data was analyzed for all adsorbent doses. The pseudo-first order kinetic model was found to agree well with then experimental data found. The result showed that AP biosorbent followed pseudo-first order kinetics. According to the results presented, the cheap efficient AP oil spill sorbent could be developed as a potential material to be used in seawater treatment for oil removal. The avocado carbon displayed excellent adsorption properties for the simulated seawater effluents containing oil.

Parametric analysis and optimization of a novel cascade compression-absorption refrigeration system integrated with a flash tank and a reheater

This article presents a novel cascade configuration for a compression absorption refrigeration system by combing a single effect absorption cycle with a reheater at the higher temperature circuit (HTC) and a modified vapor compression cycle with the flash tank at the lower temperature circuit (LTC). The proposed refrigeration system is investigated by the energy and exergy method, parametric analysis, and optimization by genetic algorithm for two different refrigerant pairs. At the LTC, the R41 refrigerant pair is employed whereas, lithium bromide solution (LiBr/H2O) and ammonia solution (NH3/H2O) are employed at the HTC. A detailed energy and exergy analysis is performed between the conventional and novel systems to illustrate the improvement achieved by the proposed system. Results suggest that at an evaporator temperature of −35 °C, using the combination of R41 and LiBr/H2O, the proposed system is capable to achieve 15.39% higher COP and exergetic efficiency than the conventional cascade absorption cycle. Furthermore, by employing R41-NH3/H2O combination under identical working conditions, the proposed system has achieved 18.49% higher COP and exergy efficiency than the conventional system. Additionally, a comparative parametric analysis between the two refrigerant pairs in the proposed system is conducted. The analysis suggests that R41-LiBr/H2O refrigerant pair has a significant advantage over the R41-NH3/H2O refrigerant pair. Lastly, the optimization of the proposed system is conducted by implementing the genetic algorithm to determine the optimal operating conditions for maximum COP and exergy efficiency.

Effects of Zr/(Sc+Zr) microalloying on dynamic recrystallization, dislocation density and hot workability of Al−Mg alloys during hot compression deformation

AbstractThe deformation behavior and microstructure characteristics of Al−6.00Mg, Al−6.00Mg−0.10Zr and Al−6.00Mg−0.25Sc−0.10Zr (wt.%) alloys were investigated by hot compression tests and electron microscopy methods. The results show that after deforming under the maximum processing efficiency condition (673 K, 0.01 s−1), dislocation densities of Al−6.00Mg, Al−6.00Mg−0.10Zr and Al−6.00Mg−0.25Sc−0.10Zr alloys are 2.68×1016, 8.93×1016 and 6.1×1017 m−2 respectively. Their dynamic recrystallization fractions are 19.8%, 15.0% and 12.7%, respectively. Kernel average misorientation (KAM) analyses indicate that dislocation accumulation near grain boundaries is enhanced by adding Zr or Sc+Zr. Besides, the established hot processing maps, based on the dynamic material model (DMM), reveal that the addition of Zr or Sc+Zr can reduce the range of low-temperature unstable domain but expand the unstable domain at high temperatures and high strains. The experimental results further verify that under the testing deformation condition, only the Al−6.00Mg−0.25Sc−0.10Zr alloy cracks at 773 K and 1s−1.

Removal of cutting oil from wastewater by utilization of novel adsorbent developed from teak leaf (Tectona grandis): equilibrium, kinetic, and thermodynamic studies

The disposal of oily wastewater is a severe environmental problem faced by the metalworking and automobile industries. When released into the environment, oil-contained wastewater severely threatens plant, animal, and human life. Adsorption has emerged as a unique technique, and using natural adsorbents makes it further cheap and more eco-friendly. Removal of both free and emulsified oil from wastewater by using biosorbents was looked upon as an alternative. The present research aims to develop a novel biosorbent from teak (Tectona grandis) leaves suitable for removing oil from wastewater. Batch Sorption studies were carried out by varying pH, sorbent dosage, contact period, mixing speed, and initial oil concentration. The optimum conditions for maximum adsorption efficiency were determined. The results showed that the adsorption of oil onto teak leaf (Tectona grandis) adsorbent follows Freundlich isotherm with a maximum sorption capacity of 10.115 mg/g and a pseudo-second-order kinetic model. The thermodynamic parameter (ΔH = 5033.75 KJ/mol) suggested oil adsorption’s spontaneous and endothermic nature onto the teak leaf (Tectona grandis) adsorbent. The best regeneration efficiency was achieved with 0.01 M HCl.