Box-Behnken Model Research Articles

Biosorption of Zn(II) on the different Ca-alginate beads from aqueous solution

The performance of a new biosorbent system, consisting of a fungal biomass immobilized within an orange peel cellulose absorbent matrix, for the removal of Zn 2+ heavy metal ions from an aqueous solution was tested. The amount of Zn(II) ion sorption by the beads was as follows; orange peel cellulose with Phanerochaete chrysosporium immobilized Ca-alginate beads (OPCFCA) (168.61 mg/g) > orange peel cellulose immobilized Ca-alginate beads (OPCCA) (147.06 mg/g) > P. chrysosporium (F) (125.0 mg/g) > orange peel cellulose (OPC) (108.70 mg/g) > plain Ca-alginate bead (PCA) (98.26 mg/g). The Zn 2+ concentration was 100 to 1000 mg/L. The widely used Langmuir and Freundlich isotherm models were utilized to describe the biosorption equilibrium process. The isotherm parameters were estimated using linear and non-linear regression analysis. The Box–Behnken model was found to be in close agreement with the experimental values, as indicated by the correlation coefficient value of 0.9999.

Optimization of enzymatic hydrolysis of triglycerides in soy deodorized distillate with supercritical carbon dioxide

Enzymatic hydrolysis of triglycerides of soy deodorized distillate (DOD), using immobilized Candida rugosa lipase under supercritical carbon dioxide (SC-CO 2) medium, was carried out. Optimization of the reaction parameters using response surface methodology based on Box-Behnken model at three levels of pressure (120–180 bar), temperature (40–60 °C) and moisture content (40–80% of triglyceride content) for maximum hydrolysis of triglycerides was arrived by multilinear regression of the experimental results. The optimum conditions for maximum degree of triglyceride hydrolysis (94%) were found to be: pressure of 180 bar, temperature of 43 °C and moisture content of 40% to the triglyceride content. Maximum degree of hydrolysis was achieved with short incubation time of 1.5 h under SC-CO 2. Whereas conventional method of hydrolysis in hexane under similar reaction conditions of temperature, moisture and enzyme concentration, needs 5 h to achieve 88% of triglyceride hydrolysis.

Electrochemical removal of chromium from wastewater by using carbon aerogel electrodes

A study has been carried out to determine the feasibility of electrochemical removal of chromium ions from industrial wastewater using carbon aerogel electrodes. In this work the effect of key variables including pH (2–7), concentration 2–8 (mg/l), and charge 0.3–1.3 (A h) was determined. The metal ion removal was significantly increased at reduced pH and high charge conditions. The metal concentration in the wastewater can be reduced by 98.5% under high charge (0.8 A h) and acidic conditions (pH 2). The effect of the independent parameters—pH, effluent concentration and charge on the percentage removal was depicted by a quadratic equation obtained using Box–Behnken model. The regression analysis gave a R 2 value of 0.9469 shows a close fit between the experimental results and the model predictions. The model was further used to optimise the parameters to maximise the percentage Cr-removal to more than 98%.

Microbiological degradation of phenol using mixed liquors of Pseudomonas putida and activated sludge

This work investigated the biodegradation potential of phenol using mixed liquors of Pseudomonas putida (ATCC 31800) and activated sludge. Experiments were made as a function of solution pH (6–10), temperature (30–36 °C), nitrogen source (NH 4) 2SO 4 (0.5–0.8 g/l), and carbon source glucose (0.5–0.8 g/l). Response surface methodology by the Box–Behnken model was used to examine the role of four process factors on phenol degradation. It was shown that a second-order polynomial regression model could properly interpret the experimental data with an R 2-value of 0.9997 and an F-value of 3605.45, based on which the maximum degradation of phenol was estimated up to 80.1% within the range examined. Interactions between process parameters and each significance effect on phenol degradation were also discussed.

Design of experiments in the biodegradation of phenol using immobilized Pseudomonas pictorum (NICM-2077) on activated carbon

Pseudomonas pictorum (NICM-2077) immobilized on various matrices are used to protect the microbes from confronting shock loads of concentrated phenol. The cells were immobilized in activated carbon and were used in biodegradation of phenol. Biodegradation of phenol using immobilized Activated Carbon matrix played an important role in reducing the toxicity of phenol. The degradation was carried and using the Box-Behnken model and analysis of variance have been applied to the experimental degradation studies. Response surface method with three levels of phenol concentration (0.200, 0.400, 0.600 g/l), activated carbon (0.5, 1.0, 1.5 g/l) and pH (7, 8, 9) were used in the identification of significant effects and interactions in the biodegradation studies. Phenol removal rate increases especially when the degradation medium was supplemented with utilizable carbon sources. A first-order polynomial regression model, which was used at first for analysis of the experiment had a significant lack of fit. Therefore, linear and quadratic terms were incorporated into the regression model through variable selection procedures. Effect of incubation phenol concentration, activated carbon and pH were significant. The predicted values using Box-Behnken model was found to be in close agreement with the experimental values, as indicated by the correlation coefficient values of 0.9463.