Box-Behnken Experimental Design Methodology Research Articles

Type-II surface heterojunction of bismuth-rich Bi4O5Br2 on nitrogen-rich g-C3N5 nanosheets for efficient photocatalytic degradation of antibiotics

• A highly solar active N-rich g-C 3 N 5 /Bi 4 O 5 Br 2 heterostructure was synthesized. • The interlayer stacking and extra N in triazine decreased the CB of N-rich g-C 3 N 5. • The matched energy band structure offered remarkable charge separation. • The role of promoted charge separation exceeds the extended visible utilization. • The degradation pathway and toxicity evolution of sulfathiazole were revealed. A novel g-C 3 N 5 /Bi 4 O 5 Br 2 surface heterojunction was developed via in-situ growth of Bi-rich Bi 4 O 5 Br 2 on g-C 3 N 5 nanosheets. The optimal composite achieved 3.6- and 16.0- times of sulfathiazole (STZ) degradation activity when compared with pristine Bi 4 O 5 Br 2 and g-C 3 N 5 . The interlayer stacking morphology and extra nitrogen in triazine units significantly narrowed the conduction band of g-C 3 N 5 , which greatly promoted its visible utilization; while the bismuth-rich property of Bi 4 O 5 Br 2 prolonged the excited charge carrier lifetime. Both photoluminescence and electrochemical impedance spectroscopy analysis demonstrated that the type-II surface heterojunction (g-C 3 N 5 /Bi 4 O 5 Br 2 ) offered remarkable charge transfer and separation due to the matched energy band structure. The STZ degradation mechanism and pathways were proposed based on experiments and density functional theory calculation, and the contribution of reactive species for STZ degradation followed the order of O 2 ∙ - > h + > OH. Moreover, the toxicity evolution of STZ was evaluated, suggesting that sufficient mineralization is required to ensure safe discharge. The Box-Behnken experimental design methodology study revealed that g-C 3 N 5 /Bi 4 O 5 Br 2 exhibited high reactivity for antibiotics degradation under different water matrix. This study suggested that g-C 3 N 5 /Bi 4 O 5 Br 2 has great application potential for cost-effective remediation of persistent organic contaminants by using solar light.

Facile fabrication of BUC-21/Bi24O31Br10 composites for enhanced photocatalytic Cr(VI) reduction under white light

Abstract In this study, the Bi24O31Br10 nanosheets were successfully synthesized using hydrothermal method. Subsequently, series binary BUC-21/Bi24O31Br10 composites were fabricated by facile ball-milling method. The results suggested that the introduction of a specific quality of Bi24O31Br10 on the surface of BUC-21 could enhance the utilization efficiency of white light and suppress the photo-induced carriers recombination to promote the photocatalytic efficiency. The BB-100 (the mass ratio of BUC-21/Bi24O31Br10 being 1) exhibited the best performance, in which 99.9% Cr(VI) ions were photoreduced into Cr(III) upon the white light irradiation within 120 min. As well, the influences of small organic acids, initial pH, light intensities along with the co-existing matters on the Cr(VI) removal were investigated. Furthermore, the Box-Behnken experimental design methodology proved that the photoreduction process was significantly influenced by the co-existing inorganic anions and negatively charged dissolved organic matters (DOM). After 4-run recycling for the adsorption-photoreduction of Cr(VI) experiments, the BB-100 still exhibited satisfied reduction activity with good stability and reusability. A possible reaction mechanism was proposed and clarified through the electrochemical determination, time-resolved photoluminescence decay spectra, active species trapping experiments, electron spin resonance analyses (ESR) and density functional theory (DFT) calculation.

Silver nano-rods: Simple synthesis and optimization by experimental design methodology

In this article, Box–Behnken experimental design methodology was successfully used to consider the effects of silver (Ag) ion concentration and temperature of reaction together with the interaction between Ag+ and reducing agent (hydrazine) concentration on the yield of Ag nano-rods. The statistical and variance analysis was presented, which indicated the factors with higher influence over the model response. By applying such model, the optimum conditions for effective factors were determined for obtaining Ag nano-rods with yield per volume 0.6–0.7, which was at Ag+ concentration of 0.19 g/ml, molar ratio between surfactants of 1, concentration of hydrazine of 0.5 g/ml and nano-rods formation temperature of 90 °C, and was found to give 0.55 g/ml varied from predicted values which was 0.7g/ml with Ag nano-rod outer diameter of 59–73 nm.

Predictive control of CO2 emissions from a grate boiler based on fuel nature structures using intelligent neural network and Box-Behnken design

Abstract The aim of this research was to predictive control of CO2 emissions by modelling the correlations between fuel nature structure (elementary composition) and CO2 emissions from a grate boiler. Back Propagation Neural Network (BPNN) coupled with Genetic Algorithms (GA), which facilitates the learning algorithms to figure out the local minimum deviation, is employed to map the highly nonlinear relationships between elements such as C, H and O in fuels and final CO2 emission. A total of 15,000 training and testing data come from the recordings of a grate boiler within six months. And the predicted CO2 emissions based on fuel nature structure matched the measured data with fairly good agreement. Finally, the Box-Behnken experimental design methodology was used to extract the mathematical expression between elements in fuels and CO2 emission. Consequently, by knowing the C, H and O composition in fuels, the CO2 emission can be well forecasted, in such way, it is sensible to optimize the future fuel nature structure in order to achieve clean carbon footprint and control the CO2 emissions.

Box–Behnken experimental design for preparation and optimization of the intranasal gels of selegiline hydrochloride

Selegiline hydrochloride (SL) is chosen as an adjunct for the control of clinical signs of Parkinsonian patients. The aim of the present work is to develop and optimize thermosensitive gels using Pluronic (F-127) for enhancing transport of SL into the brain through the nasal route. SL gels were prepared using a cold method and the Box–Behnken experimental design methodology. Drug (SL), gelling agent (F-127), and emulsifier (Propylene glycol, PG) were selected as independent variables, while the gelation temperature, gel strength, pH, gel content, and gel erosion were considered as dependent variables. For further understanding of the interaction between the various variables, contour plots and surface plots were also applied. Selected formulations, like S10 (contain 25 mg SL, 20 g F-127, and 1 g PG) and S14 (contain 50 mg SL, 18 g F-127 and 1 g PG), had a clear appearance in the sol form, with gelling temperature of the nasal gel ranging between 33 and 34, respectively. The gel strength of the formulations varied from 4.67 and 0.68 mm and the drug content was 100%. The pH of the formulations ranged between 6.71 and 7.11. Detachment force was acceptable (63.69–244.16 N/cm2) to provide prolonged adhesion. In vitro, drug release studies showed that the prepared formulations could release SL for up to 8 h. Permeation flux for the S10 gel was 0.0002 mg/min/cm2. Results demonstrated that the potential use of SL gels can enhance the therapeutic effect of SL through the intranasal administration.

Preparation, evaluation and optimization of nanoparticles composed of thiolated triethyl chitosan: A potential approach for buccal delivery of insulin

In the present work, insulin nanoparticles composed of thiolated N-triethyl chitosan (TEC-Cys), as a new derivative, were synthesized and characterized by the 1H-NMR. Triethyl chitosan (TEC) was thiolated with l-Cysteine (Cys) by the formation of an amide bond between the residual primary amino group of quaternized chitosan and carboxylic group of Cys. Then, the nanoparticles were prepared by the polyelectrolyte complexation (PEC) method. The preparation of the nanoparticles was optimized using the Box-Behnken experimental design methodology. The independent factors were pH of the polymer solution, a concentration ratio of polymer/insulin and stirring rate, while the dependent factors were size, poly dispersity index (PdI), zeta potential and entrapment efficiency (EE%). The values of 126.9 nm, 0.26, 24.6 mV and 97.8% for the particle size, PdI, zeta potential and EE%, respectively, showed proper physicochemical properties for the TEC-Cys nanoparticles (19% degree of quaternization and 165 μmole thiol group/gram of polymer). Furthermore, the morphology of the nanoparticles was studied using scanning electron microscopy (SEM), which revealed separate, spherical, and non-aggregated nanoparticles. The in vitro release of insulin from the nanoparticles was carried out in phosphate buffer solution (PBS) with pH = 7.4 and showed 98% drug release within 480 min. Finally, the permeability of the insulin nanoparticles was done through rabbit buccal mucosa as an ex vivo study and represented that the permeability of insulin can reach 96% in 480 min. Tissue viability was assessed using a MTT (3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyltetrazolium bromide) biochemical assay and showed no significant cytotoxic effect for rabbit buccal mucosa. According to our results, the TEC-Cys nanoparticulate system can be a good approach for buccal delivery of insulin.

Optimization of copper extraction from spent LTS catalyst (CuO–ZnO–Al2O3) using chelating agent: Box-behnken experimental design methodology

The objective of the present work is to investigate the extraction of copper from spent low temperature Shift catalyst using EDTA, as chelating agent and optimization of the parameters that influence the extraction of copper. Response surface methodology was applied for designing the experiment and to determine the optimal experimental conditions. Most influencing parameters such as concentration of EDTA, solid to liquid ratio and particle size of catalyst were optimized based on 3 factors 3 levels box behnken design which requires 15 run of experiments for designing a response surface. The high value of regression coefficient R 2 (0.981) indicates a good correlation between predicted and experimental response, which confirms the acceptability of the proposed model.The optimum conditions were found as—concentration of EDTA: 0.5889 M, solid to liquid ratio: 0.02 and particle size: 90 μm. Under these optimum conditions, the experimental value of extraction of copper was estimated as 94.5% which seems very close to predicted response.

How chemical and physical mechanisms enable the influence of the operating conditions in a photocatalytic indoor air treatment device to be modeled

The photocatalytic degradation of toluene in indoor air conditions was performed in a closed-loop multi-pass photocatalytic reactor using the Box-Behnken experimental design methodology. The objective of this work was to rigorously determine a kinetic model in order to understand the behavior of the reactor in real indoor air conditions and to relate the kinetic parameters to physical and chemical mechanisms. Three main parameters were studied: initial toluene concentration, light irradiance and air stream velocity. The experimental results were used to calculate the single-pass removal efficiency for different operating conditions and to establish a relationship between the single-pass removal efficiency, light irradiance and air stream velocity. This relationship was integrated into an overall reaction rate law based on the Langmuir-Hinshelwood mechanism. The kinetic model obtained was then validated for various experimental conditions.

Box-Behnken experimental design for preparation and optimization of ciprofloxacin hydrochloride-loaded CaCO3 nanoparticles

The purpose of this study was to prepare and optimize ciprofloxacin hydrochloride loaded-CaCO3 nanoparticles, using a chemical precipitation method and the Box-Behnken experimental design methodology (using Minitab 16). The molar ratio of CaCl2:Na2CO3 (X1), the concentration of drug (X2) and the speed of homogenization (X3) were selected as independent variables while the particle size and entrapment efficiency were considered as dependent variables. Contour plots and surface plots were used for further understanding of the interaction between the different variables. The results indicated that the speed of homogenization was the main contributing variable for particle size; while, in the case of entrapment efficiency, the drug concentration showed the major role. The optimum values for the molar ratio of CaCl2:Na2CO3, the concentration of drug and the speed of homogenization were found to be 1:1 ratio in mole, 2.18 g/dl and 12,000 rpm, respectively, when entrapment efficiency and particle size were predicted as 37.99% and 107.26 nm, respectively. It was concluded that chemical precipitation technique alongside the Box-Behnken experimental design methodology are fast and useful methods for preparation and optimization of drug incorporated calcium carbonate nanoparticles.

Application of Box–Behnken design to prepare gentamicin-loaded calcium carbonate nanoparticles

The aim of this research was to prepare and optimize calcium carbonate (CaCO3) nanoparticles as carriers for gentamicin sulfate. A chemical precipitation method was used to prepare the gentamicin sulfate-loaded CaCO3 nanoparticles. A 3-factor, 3-level Box–Behnken design was used for the optimization procedure, with the molar ratio of CaCl2: Na2CO3 (X1), the concentration of drug (X2), and the speed of homogenization (X3) as the independent variables. The particle size and entrapment efficiency were considered as response variables. Mathematical equations and response surface plots were used, along with the counter plots, to relate the dependent and independent variables. The results indicated that the speed of homogenization was the main variable contributing to particle size and entrapment efficiency. The combined effect of all three independent variables was also evaluated. Using the response optimization design, the optimized Xl–X3 levels were predicted. An optimized formulation was then prepared according to these levels, resulting in a particle size of 80.23 nm and an entrapment efficiency of 30.80%. It was concluded that the chemical precipitation technique, together with the Box–Behnken experimental design methodology, could be successfully used to optimize the formulation of drug-incorporated calcium carbonate nanoparticles.