Design Of Response Surface Methodology Research Articles

Selective and invisible separation and determination of Rhodamine B in diverse industrial samples using aqueous biphasic switchable hydrophilicity solvent-like based microextraction method

An effective and selective aqueous biphasic switchable hydrophilicity solvent-like based microextraction method (ABSHS-ME) combined with UV–vis spectrophotometry was established for the first time to monitor Rhodamine B (RhB) at 550 nm in soaps, lipsticks, anti-freezes and match tips. RhB was extracted firstly as its invisible form into immiscible hydrophobic phase and then converted to its UV–vis active form using acidified ethanol. The essential extraction parameters (pH, SHS volume, and vortex time) were optimized by Box-Behnken Design of Response Surface Methodology. Quadratic model with R2 = 0.9893 was found as favourable chemometric design for ABSHS-ME method. Preconcentration factor was obtained to be 25. Effect of matrix ions and dyes were examined in detail. 7 and 24 µg/L of Rhb were determined for limit of detection and limit of quantitation, respectively. RhB was determined linearly between 24 and 2500 µg/L. Relative standard deviations were lower than 7 %. ABSHS-ME method was validated determining the RhB concentrations of industrial samples with analyte addition-recovery tests. RhB contents of the real samples analyzed were found between 0.26–1.07 µg/g and 1.53–4.73 µg/mL with recovery values ranging from 95 to 101 %. The environmentally friendly index of the method was evaluated using the new generation AGREE tool.

Parametric analysis, modeling and optimization of the process parameters in electric discharge machining of aluminium metal matrix composite

Optimizing electric discharge machining (EDM) for aluminum/SiCp metal matrix composites poses challenges due to intricate machine parameters and process complexity, impacting process economy and elevating product costs. The research aims to find the optimal combination of process parameters which include pulse on-time, pulse current, duty cycle (%), gap voltage, sensitivity and flushing pressure for EDM of Al/SiCp-MMC using a copper electrode for the selected response factors such as material erosion rate and surface roughness, Ra. The experiments were designed using the central composite design of response surface methodology and an advanced optimization technique known as Teaching–learning-based optimization (TLBO), is applied to find the optimal combination of process parameters to obtain maximum material erosion rate subject to the desired range of surface roughness (SR), Ra. The combination of the high pulse on-time (i.e. 150 μs) and high pulse current (i.e. 12A) results in high material removal rate with deep craters on the machined surface clearly visible in SEM images contrasting the minimized surface roughness at lower values of pulse on-time (50 μs) and the pulse current (4A). Pulse on - time (Ton) is found to be the most significant factor for material erosion rate and surface roughness with percentage contribution of 70.86 and 54.9 respectively for optimization of the response. The regression models were developed at 95% confidence level for material removal rate and surface roughness with R2 value of 0.93 and 0.95 respectively signifying high degree of accuracy in predicting the response. Confirmation tests conducted to check the adequacy of the established models revealed that the percentage error between the predicted and experimental responses is found to be within acceptable levels. Electron discharge machining of the aluminium metal matrix composite at the optimized conditions could provide economical aspect in the aerospace and automobile industry.

Optimization of Ultrasound-enhanced Subcritical Water Hydrolysis of Oil Palm Empty Fruit Bunch for the Production of Fermentable Sugar

To enhance the hydrolysis to produce fermentable sugar, oil palm empty fruit bunch (OPEFB) has undergone ultrasonication pretreatment prior to subjection to subcritical water hydrolysis. This work aims to optimize the effect of temperature, reaction time, and the concentration of sodium dodecyl sulfate (SDS) as the surfactant, with the primary aim of maximizing sugar production in the subcritical water hydrolysis process applied to oil palm empty fruit bunch (OPEFB). The pretreatment process conditions were optimized using response surface methodology of the central composite design (RSM–CCD). The experimental design includes three factors and levels, with a range of 180–220 °C temperature (X1), 60–80 minutes process time (X2), and 1–5% w/w SDS concentration (X3), an α value of 1.68, and reducing sugar concentration (g/L) as response (Y1). The optimum condition for subcritical water hydrolysis of OPEFB was obtained at 208 °C, 78 minutes, and 2.6% w/w SDS concentration with an expected yield of 6.09 g/L. As a result, reducing sugar produced by enzymatic hydrolysis increased by 324.7% compared to raw OPEFB, with sugar yield of 45.64% after 36 hours. Along these, changes in crystallinity, chemical composition, lignocellulosic functional groups, and morphology were analyzed to determine the impact of the pre-treatment on OPEFB.

Enhanced removing of cyanobacterium by NZVI coupled with H2O2: Influencing factors and removal mechanisms

AbstractAs advanced oxidation processes (AOPs) is considered to be a highly effective approach for degrading organic pollutants, the simultaneous coagulation and oxidation process by the Fenton‐like reaction of nanoscale zero‐valent iron (NZVI) and hydrogen peroxide (H2O2) is investigated to eliminate the harmful cyanobacterium Microcystis aeruginosa in this study, and the process conditions are optimized using the central composite design of response surface methodology (RSM); in addition, the removal efficiency of M. aeruginosa (in terms of chlorophyll a, Chl a) and the verifications of the antioxidant abilities, as well as extracellular organic matters (EOM) and intracellular organic matters (IOM) are investigated under the optimized conditions. Results indicate that H2O2 concentration is the key factor affecting the Chl a removal efficiency, and the maximum Chl a removal reaches 98.10% under the optimized conditions: NZVI concentration 62.82 mg L−1, H2O2 concentration 54.2 mmol L−1, pH 4.38 and rotating speed 67 rpm. The high correlation coefficient (R2 > 0.80) of analysis of variance (ANOVA) demonstrates the RSM model is extremely significant and suitable for experimental results. Moreover, the total organic carbon (TOC) and fluorescent substances (soluble cyanobacteria metabolic byproducts, aromatic proteins II, humic and fulvic acid‐like compounds) for both EOM and IOM are enhanced removal. It is speculated the removal mechanisms of the Fenton‐like process of NZVI/H2O2 for cyanobacterium belongs to the combined actions of the oxidation of Fe(II)/H2O2 and the coagulation of Fe(III), which destroy the defense system and result in the removal of M. aeruginosa.

Effect of grinding media shape on the particle size distribution of UG2 ore using the response surface methodology central composite design

In this study, the effects of truncated ellipsoids and cubes on the particle size distribution of a UG2 ore were compared to the spheres using the response surface methodology for experimental design, modeling, and optimization. The response surface methodology demonstrated that it can be useful in optimizing grinding operations. It provides lenses to see and analyze the behavior of the ball filling, interstitial filling, and % solids parameters which are complex and interactive, and their effects on the production of the desired product (−75 µm) for different grinding media. Spherical grinding media outperformed truncated ellipsoids and cubes, producing the highest amount of the desired size class (82.58%), followed by 80.41% for truncated ellipsoids and 77.07% for cubes. Spheres also consumed the least power followed by cubes and lastly truncated ellipsoids. The differences in optimal grinding conditions were attributed to different contact mechanisms, surface area, and load behavior of the grinding media.

Box–Behnken modeling of biodiesel production from Botryococcus braunii microalgae

AbstractThis research aimed to model and optimize the growth factors and enhance the lipid yield from Botryococcus braunii microalgae, and to design a system for obtaining biodiesel from these lipids as this does not compromise food security. Botryococcus braunii, grown on a modified Chu‐13 medium, reached the stationary phase after 27 days with a maximum cell count of 265 × 104 cells mL−1 after 27 days and maximum biomass yield of 725 mg L−1 after 30 days on modified Chu‐13 medium, which was higher than growth on Basal SAG medium. The maximum lipid content (18.47%) and lipid yield (4.46 mg L−1day) were obtained when B. braunii was cultivated on modified Chu‐13 medium after 30 days. Gas chromatography (GC) analysis for the lipids indicated that the highest percentages of SFAs (51.03%) and lowest percentages of monounsaturated fatty acids (MUFAs) (36.47%) and polyunsaturated fatty acids (PUFAs) (12.49%) were obtained by culturing B. braunii on modified Chu‐13 medium. The effect of different growth parameters (N2 level, NaHCO3, and CO2 concentrations) on growth yield was modeled by using D‐optimal design response surface methodology (RSM).

Using predictive models unravel the potential of titanium oxide-loaded activated carbon for the removal of leachate ammoniacal nitrogen.

The TiO2 nanocomposite efficiency was determined under optimized conditions with activated carbon to remove ammoniacal nitrogen (NH3-N) from the leachate sample. In this work, the facile impregnation and pyrolysis synthesis method was employed to prepare the nanocomposite, and their formation was confirmed using the FESEM, FTIR, XRD, and Raman studies. In contrast, Raman phonon mode intensity ratio ID/IG increases from 2.094 to 2.311, indicating the increase of electronic conductivity and defects with the loading of TiO2 nanoparticles. The experimental optimal conditions for achieving maximum NH3-N removal of 75.8% were found to be a pH of 7, an adsorbent mass of 1.75mg/L, and a temperature of 30°C, with a corresponding time of 160min. The experimental data were effectively fitted with several isotherms (Freundlich, Hill, Khan, Redlich-Peterson, Toth, and Koble-Corrigan). The notably elevated R2 value of 0.99 and a lower ARE % of 14.61 strongly support the assertion that the pseudo-second-order model compromises a superior depiction of the NH3-N reduction process. Furthermore, an effective central composite design (CCD) of response surface methodology (RSM) was employed, and the lower RMSE value, precisely 0.45, demonstrated minimal disparity between the experimentally determined NH3-N removal percentages and those predicted by the model. The subsequent utilization of the desirability function allowed us to attain actual variable experimental conditions.

Optimization, Sodium Hydroxide and Plantain Fibres: Mechanical Properties of Unsaturated Polyester Composites for Transtibial Prosthetic Socket

Low mechanical behaviors of natural fibres in the reinforcement of polymer composites have remain an issue of concern. This study is aimed at investigating the effect of NaOH treatment on the mechanical properties of plantain fiber for the transtibial prosthetic sockets made of polyester resin. Plantain fiber was extracted from the plantain bast using water retting techniques. The fibres were modified using alkaline treatment method of 5 – 25% for variable time of 30 to 150 minutes. It was optimized using 3-level Factorial design (3-LCD) of response surface methodology based on tensile properties of treated fibres. The polyester composites of plantain and glass fibers were prepared using hand-layup techniques. Instron Universal testing machine-3369 model was used to determine the tensile and impact properties of fibers and polyester composites. Rockwell hardness tester-RBHT/S-39 model was used to determine the hardness property. The optimum process conditions of 5 % NaOH for 119 minutes improved plantain fiber tensile strength, modulus, strain, energy, and extension by improved by 102.03, 208.07, 9.70, 210.52 and 205.73 %, respectively. The ultimate tensile strength and modulus was obtained at 10 and 12.5% fiber loading. The hardness and impact strength of NaOH modified unsaturated polyester composites was marginally more than 3.51 and 10.69% of glass fiber reinforced unsaturated composites, respectively, at 12.5% fiber loading. FTIR analysis revealed the improvement in mechanical properties. Thus, NaOH modified plantain fiber unsaturated polyester composites serves as a better alternative for making transtibial prosthetic socket.

Novel nanohybrid iron (II/III) phthalocyanine-based carbon nanotubes as catalysts for organic pollutant removal: process optimization by chemometric approach.

In the present study, two iron phthalocyanine (FePc)-based nanocatalysts were synthesized and fully characterized. The carbon nanotubes (CNT) functionalized in an easy way with either Fe(II)Pc or Fe(III)Pc exhibit a very good catalytical activity. The activity in real wastewater effluent was comparable with the activity in distilled water. The procedure of modeling and optimizing with the assistance of chemometrics, utilizing design of experiments (DOE) and response surface methodology (RSM), revealed the conditions of optimum for decaying Reactive Yellow 84 on the nanocatalysts FePc_CNT. These optimal conditions included a catalyst dose of 1.70 g/L and an initial concentration (C0) of 20.0 mg/L. Under the indicated optimal conditions, the experimental findings verified that the removal efficiency was equal to Y = 98.92%, representing the highest observed value in this study. Under UVA light, after only 15 min of reaction, over 94% of dye was removed using both catalysts. The reuse experiments show that the activity of both nanohybrid material based on FePc-CNT slightly decreases over four consecutive runs. The quenching experiments show that RY84 was removed through radical pathways (O2•- and •OH) as well as non-radical pathways (1O2 and direct electron transfer).

Optimization of non-thermal plasma process to remove methyl blue towards application in wastewater treatment

This study was carried out to optimize the treatment process of methyl blue (MB) in aqueous solution using dielectric barrier discharge (DBD) plasma and experiments were designed by using response surface methodology and central composite design (RSM-CCD). Four independent factors such as plasma power, liquid flow rate, air flow rate, and exposure time were investigated. According to the analyzed results of RSM, the experimental data is best fitted with a model of the quadratic polynomial with regression coefficient values of more than 0.9 for all responses. At optimal degradation conditions, the plasma power, liquid flow rate, air flow rate, and exposure time were 100 W, 1.5 lpm, 6 lpm, and 108.8 minutes respectively and the concentration of methyl blue was reduced to 95.8% with a concentration of 1.06 ppm. The degradation of methyl blue followed kinetic reaction rate was r = 1.6 10-3[MB]2.2.

Bioactive Compound Extraction of Hemp (Cannabis sativa L.) Leaves through Response Surface Methodology Optimization

Hemp, commonly known as Cannabis sativa L., is a medicinal plant species of the Cannabaceae family. For the efficient extraction of C. sativa leaves using the conventional stirring process with water as the solvent, three crucial extraction parameters (i.e., extraction duration, liquid–solid ratio, and temperature) were investigated through the response surface methodology (RSM). The concentrations of the extracted bioactive compounds (polyphenols, ascorbic acid, and carotenoids) showed significant variations in the RSM design points, suggesting the importance of finding the optimal extraction conditions in which liquid–solid ratio and extraction temperature were found to have the highest impact. Further analysis was conducted on the optimal extract employing several assays to determine their polyphenol content, total carotenoid content, color evaluation, anti-inflammatory activity, and antioxidant capacity through FRAP, DPPH, and H2O2 assays. Α low extraction time (30 min) at 50 °C and a high liquid–solid ratio (50:1) were required for the highest possible yield of polyphenols. The total polyphenol content was determined to be 9.76 mg gallic acid equivalents/g under optimum conditions, with pelargonin being the most abundant polyphenol (1.51 mg/g) in C. sativa extracts. Ascorbic acid was measured at 282.23 μg/g and total carotenoids at 356.98 μg/g. Correlation analyses revealed that anti-inflammatory activity was negatively correlated with specific polyphenols. As determined by DPPH (27.43 μmol ascorbic acid equivalents (AAE)/g), FRAP (49.79 μmol AAE/g), and H2O2 (230.95 μmol AAE/g) assays, the optimized aqueous extract showed a high antioxidant capacity. Furthermore, it demonstrated considerable anti-inflammatory activity at 17.89%, with the potential to increase to 75.12% under particular extraction conditions. Given the high added-value of the aqueous extracts, the results of this study highlight the potential utility of C. sativa leaves as a source of health-improving antioxidant compounds in the pharmaceutical and food industries.

Design of experiment (DOE) and process optimisation of palladium catalysed biphenyl synthesis

ABSTRACT The effects of time, temperature and catalyst concentration were investigated for an optimised condition of biphenyl synthesis by Suzuki-Miyaura cross-coupling reactions by Neolyst catalysts. The optimisation process was analysed using Box Behnken Face-Centred Experimental Design in Response Surface Methodology (RSM). The design was employed to derive a statistical model for the effect of parameters studied on the yield of biphenyl. The coefficient of determination, r 2 was 0.9883% after model reduction. With an optimum time of 6.63 h, a temperature of 73°C and with minimum catalyst concentration of 0.013 mol% gives the optimum conditions for the maximum yield of biphenyl.

DEVELOPMENT AND OPTIMIZATION OF SUPER SATURABLE SELF-NANO EMULSIFYING DRUG DELIVERY SYSTEM FOR DASATINIB BY DESIGN OF EXPERIMENT

Objective: In current research, Self-Nanoemulsifying Super Saturable Drug Delivery Systems S‑SNEDDS was formulated to attain superior drug dissolution and stability. Methods: Using saturated solubility, capryol ® 90, cremophor®-EL, and transcutol HP were used to make S-SNEDDS. Its composition was optimized using the ternary phase diagram. Using the central composite design of Response Surface Methodology, dasatinib-SNEDDS developed responses for droplet size (Y1), polydispersity index (Y2), and % drug released in 15 min (Y3). Various Precipitation Inhibitors were added to optimize SNEDDS (S3) to make S-SNEDDS and evaluate. Results: The optimum formulation was S3, with a particle size of 128 nm and zeta potential of-21 mV. Methylcellulose was shown better supersaturation than other inhibitors. The optimized formulation (F3) was more stable than ordinary SNEDDS due to its more significant zeta potential (-25 mV) and lower particle size (128 nm). Dasatinib was shown to be amorphous in S-SNEDDS using Differential Scanning Calorimetry and X-ray Powder Diffraction. F3 had a higher 90 min release rate (>99%) than pure drug dispersion (26%) and SNEDDS formulation (95%). Conclusion: The results concluded that S-SNEDDS formulation successfully enhanced the dissolution and stability of dasatinib.

Using Response Surface Methodology Approach to Modeling and Optimization of the Combustion Process in Cement Kiln

AbstractIn this study, this process has been modeled and optimized using the design of experiment technique and response surface methodology (RSM). The RSM was employed to optimize the combustion process in the cement kiln. Kiln feed (X1 = 160–190 t h−1), fan speed (X2 = 840–870 rpm), kiln rotational speed (X3 = 2.8–3.4 rpm), kiln fuel rate (X4 = 3800–4150 L h−1), calciner fuel rate (X5 = 5700–6200 L h−1), pressure of kiln inlet (X6 = 98–102 Pa), and limestone saturation factor (LSF) (X7 = 94–95.8 %) as independent variables were investigated. The carbon monoxide and the kiln body temperature in RSM were considered as response variables. The absolute average error in the model predictions for the combustion process in the cement kiln, for the kiln body's temperature, is about 1.6 % and for carbon monoxide is about 15.5 %.

Green DES based microextraction method for monitoring brilliant black BN (E151) in diverse food matrices

A green deep eutectic solvent (DES) based microextraction method was established for separation and spectrophotometric determination of E151 in food matrices. DES composed of tetra pentyl ammonium bromide and 1-octanol (1:5) was used. Important analytical microextraction parameters including pH, volume of DES and time of vortex mixing were optimized using Box-Behnken design of Response Surface Methodology. The other variables including composition ratio of DES and sample volume were optimized by one variable at a time optimization process. The method exhibited linear behaviour for E151 having concentration range between 132–12000 µg/L with 30 preconcentration factor. The relative standard deviation, detection limit and quantitation limit were determined to be 5 %, 40 and 132 µg/L, respectively. The scores of analytical greenness and applicability for the method were determined to be 0.69 and 62.5, respectively. pK values of E151 were determined. Extraction mechanisms of E151 were elucidated. The method was applied to foodstuffs and water samples to determine their E151 contents by analyte addition recovery tests with recovery values ranging between 94–103 %.

Cd2+ removal efficiency of activated carbon from Prosopis juliflora: Optimization of preparation parameters by the Box-Behnken Design of Response Surface Methodology

The study focuses on the preparation of activated carbon from Prosopis juliflora (PJAC) wood by pyrolysis and chemical activation. The objective is to assess its effectiveness as an adsorbent for synthesizing a composite adsorbent coating (CAC) for Cadmium (Cd2+) removal from aqueous solution. The effect of preparation factors related to Cd2+ removal efficiency was assessed. The Design of Experiments (DoE) for the adsorption of Cd2+ on the PJAC were done using the Box-Behnken Design (BBD) of the Response Surface Methodology (RSM) (Design Expert software version 11). The influence of impregnation ratio (IR), carbonization time (t), and carbonization temperature (T) on the Cd (II) percent (%) removal was evaluated. The response surface graphs in 3D were also generated for the response variable, and the higher R2 coefficient values were fitted into the polynomial quadric model. The results indicated that all the variable preparation factors were significant in the Cd2+ removal by PJAC with carbonization temperature being the most significant. At the optimum conditions i.e. impregnation ratio (1.8), carbonization temperature (595 °C) and carbonization time (174 min), the model predicted a 99.9 % Cd2+ removal efficiency while the adsorption experiment obtained a 96.7 % removal efficiency, respectively. Later, the morphological and chemical properties of the PJAC prepared with optimal parameters were analyzed using different characterization techniques including SBET, SEM-EDX, pHPZC, FTIR and XRD. The SEM images revealed a rough and porous morphological surface with an SBET of 600.4 m2/g and a near neutral pHPZC of 6.92. The XRD pattern indicated the crystalline nature of the prepared adsorbent. The pre and post adsorption FTIR spectrum of the PJAC demonstrated a distinct difference with the latter showing a reduction in peak intensity and height. These results underpin the potential of utilizing invasive plants like Prosopis Juliflora as adsorbents for heavy metal removal.

Effective and selective Type V deep eutectic solvent based microextraction of E127 in foodstuffs and drugs

The effective and selective deep eutectic solvent (DES) based microextraction method was developed for the first time, using new generation Type V DES for the separation and determination of E127 (erythrosine) in foodstuffs and drugs. Dicyclohexylamine and diphenylamine were mixed at 1:5 mole ratio to create the DES. The essential parameters (pH, DES volume and vortex time) were optimized using Box-Behnken Design of Response Surface Methodology. The quadratic microextraction approach was favorable chemometric model design (R2=0.9945) for the method. The limits of detection and quantitation were determined to be 23 and 78µg/L, respectively. E127 was enriched to be thirty-fold at the optimum conditions. The concentrations of E127, ranging between 0.078 and 4.0µg/mL, were linearly determined using the equation A=62.114C+3.8 (R2=0.9989). The interference effect of ions and dyes was investigated in detail. The relative standard deviation was lower than 6% throughout the experiments. Analyte addition-recovery tests were applied to the real samples for determination of their E127 concentrations. The method was validated by calculating microextraction recoveries obtained from spiked tests. E127 contents of foodstuffs and drugs were determined between 8.8 and 42.4µg/g, with recovery values ranging from 94 to 102%. AGREEmethod and AGREEprep tools were used to define environmentally friendly index of the method.

Adsorptive removal of perfluorooctanoic acid from aqueous matrices using peanut husk-derived magnetic biochar: Statistical and artificial intelligence approaches, kinetics, isotherm, and thermodynamics

Removal of perfluorooctanoic acid (PFOA) from water matrices is crucial owing to its pervasiveness and adverse ecological and human health effects. This study investigates the adsorptive removal of PFOA using magnetic biochar (MBC) derived from FeCl3-treated peanut husk at different temperatures (300, 600, and 900 °C). Preliminary experiments demonstrated that MBC600 exhibited superior performance, with its characterization confirming the presence of γ-Fe2O3. However, efficient PFOA removal from water matrices depends on determining the optimum combination of inputs in the treatment approaches. Therefore, optimization and predictive modeling of the PFOA adsorption were investigated using the response surface methodology (RSM) and the artificial intelligence (AI) models, respectively. The central composite design (CCD) of RSM was employed as the design matrix. Further, three AI models, viz. artificial neural network (ANN), support vector machine (SVM), and adaptive neuro-fuzzy inference system (ANFIS) were selected to predict PFOA adsorption. The RSM-CCD model applied to optimize three input process parameters, namely, adsorbent dose (100-400 mg/L), pH (3-10), and contact time (20-60 min), showed a statistically significant (p<0.05) effect on PFOA removal. Maximum PFOA removal of about 98.3% was attained at the optimized conditions: adsorbent dose: 400 mg/L, pH: 3.4, and contact time: 60 min. Non-linear analysis showed PFOA adsorption was best fitted by pseudo-second-order kinetics (R2=0.9997). PFOA adsorption followed Freundlich isotherm (R2=0.9951) with a maximum adsorption capacity of ∼307 mg/g. Thermodynamics and spectroscopic analyses revealed that PFOA adsorption is a spontaneous, exothermic, and physical phenomenon, with electrostatic interaction, hydrophobic interaction, and hydrogen bonding governing the process. A comparative analysis of the statistical and AI models for PFOA adsorption demonstrated high R2 (>0.99) for RSM-CCD, ANN, and ANFIS. This research demonstrates the applicability of the statistical and AI models for efficient prediction of PFOA adsorption from water matrices using MBC (MBC600).

Optimizing Ultrasound-Assisted Extraction of Bioactive Compounds from Canthium horridum Blume Leaves Utilizing Polyols: A Study on Skin-Related Activities

The focus on reducing organic solvent usage, owing to their negative environmental and health impacts, is driving a search for innovative green alternative solvents in academia and industry. Canthium horridum Blume (CH) exhibits many therapeutic activities, including antioxidant and anti-inflammatory efficacy. The objective of this study is to evaluate the optimal solvent concentration using a simplex-lattice design with an aqueous-polyols mixture and to optimize the parameters for extracting bioactive compounds and antioxidant activities from ultrasound-assisted extraction (UAE) of CH leaves through central composite design (CCD) in response surface methodology (RSM). This study examines the total phenolic content (TPC), antioxidant activities, comparison of different extraction conditions, identification of bioactive compounds, cell cytotoxicity, cellular antioxidant activity, and melanin content reduction efficacy of the extracts. According to the findings from the simplex-lattice model, the ideal solvent composition consisted of 32.57%w/w butylene glycol, 32.92%w/w glycerine, and 34.51%w/w water. Furthermore, based on the response model, optimal extraction conditions were identified as a 15-minute extraction time and a solvent-to-sample ratio of 32.94:1. In comparison to alternative extraction methods, ultrasonic-assisted extraction using the aqueous-glycerine-butylene glycol (GB-UAE) extract resulted in notably elevated TPC and antioxidant responses (p<0.05). Major antioxidant bioactive compounds included 4-(Butoxymethyl) phenol, 3-O-Caffeoyl-4-O-methylquinic acid, Quercetin 3-(2G-glucosylrutinoside), 2,4-Dihydroxybenzoic acid and other bioactive compounds. The GB-UAE extract revealed greater cell viability than UAE using ethanol (EtOH-UAE) extract in both cytotoxicity and cellular antioxidant assays at the same concentration. Additionally, it exhibited comparable melanin content reduction efficacy at a higher concentration compared to that of EtOH-UAE extract. The researcher anticipates that the current study will advance the utilization of an aqueous-polyols system for extracting bioactive compounds extending beyond CH leaves. Although the potential applications of CH leaves in cosmetics and pharmaceutical formulations have been identified, further comprehensive mechanistic and clinical studies are required to fully understand their effects.

Multiparameter optimization of non-thermal plasma-driven synthesis of carbohydrate-stabilized rhenium nanoparticles towards enhancement of their catalytical activity for reduction of nitroaromatic compounds

This study aims to optimize the synthesis of carbohydrate-stabilized rhenium nanoparticles (ReNPs) utilizing cold atmospheric pressure plasma (CAPP), specifically direct current atmospheric pressure glow discharge (dc-APGD), hypothesizing that controlling synthesis parameters will enhance catalytic efficiency in the reduction of nitroaromatic compounds (NACs). The dc-APGD system operated in flowing liquid cathode (FLC-dc-APGD) and flowing liquid anode (FLA-dc-APGD) modes. Design of experiments (DOE) and response surface methodology (RSM) were employed for the first time to optimize ReNPs synthesis. This included optimizing the concentration of ReO4- in ReNPs precursor solution, solution flow rate as well as discharge current. ReNPs were characterized using high-resolution transmission electron microscopy (HRTEM), dynamic light scattering (DLS), and X-Ray photoelectron spectroscopy (XPS). In turn, optical emission spectroscopy (OES) was employed for the identification of reactive species generated in plasma phase that contributed to the synthesis of ReNPs. The resultant sizes, surface charges, and phase compositions were linked with synthesis parameters and then with catalytic activities revealed by the variety of ReNPs. HRTEM photomicrographs revealed spherical and spherical-like morphologies of obtained ReNPs synthesized using FLC-dc-dc-APGD and FLA-dc-APGD modes with the actual sizes of 7.28 ± 2.90nm and 3.24 ± 0.57nm, respectively. Optimized conditions yielded ReNPs with exceptional catalytic activity, reducing 94.9% (FLC-dc-APGD) and 90.5% (FLA-dc-APGD) of 4-nitrophenol (4-NP) with the apparent rate constants (k1) 0.269 and 0.107min-1, respectively. Further, the conversions of 90% were achieved over FLC-dc-APGD-based ReNPs for nitrobenzene (NB), 2,4,6-trinitrophenol (2,4,6-TNP), 2,4-dinitrophenol (2,4-DNP), and 4-nitroaniline (4-NA). In these cases, the k1 values were 0.235, 0.174, 0.070, 0.001min-1 for, respectively. The results allowed to find a correlation between ReNP size distribution, oxidation state, and catalytic activity that suggested a potential for tailored Re nanocatalysts in environmental remediation.