Investigating Removal Efficiency of Tetracycline Antibiotic from Aqueous Solutions Using Nanoclay Adsorbent and Study of Effective Parameters, Kinetic Models, and Adsorption Isotherms

Pharmaceutical contaminants are one of the most important environmental problems that must be cleared of aqueous environments before they enter the environment. Adsorption method is operationally easy and cost-effective if the adsorbent is not expensive. The purpose of this study is optimization the process of removal of tetracycline from aqueous solutions by nanoclay adsorbent and investigation the kinetics and adsorption isotherms. In this study, after preparing the nanoclay, optimization of parameters was done with Design Expert software. The parameters effect of pH, initial concentration and amount of adsorbent were investigated and SEM, XRD and FTIR analyzes were done to identify nanoclay properties. The optimal values ​​of parameters were pH equal to 9.5, adsorbent amount equal to 1.2 g and initial concentration equal to 21.15 mg /l at 25 °C, time of 30 min and stirring speed of 1000 rpm. The study of kinetic models and equilibrium isotherms showed that the adsorption follows the Pseudo-second Order (R2=0.999(   and   the Langmuir model, respectively. Under optimal condition, nanoclay as a low cost and environmentally friendly adsorbent has a good ability to adsorb tetracycline from aqueous solutions

Phenol removal by HRP/GOx/ZSM-5 from aqueous solution: Artificial neural network simulation and genetic algorithms optimization

In this study, horseradish peroxidase (HRP) and glucose oxidase (GOx) were immobilized on mesoporous ZSM-5 nanoparticles by using glutaraldehyde as cross linking agent, and the prepared biocatalyst was characterized using SEM and EDAX mapping analysis. The resulted HRP/GOx/ZSM-5 biocatalyst was used for phenol removal from aqueous solution. In order to prevent the deactivation of HRP in the presence of excess H2O2, required H2O2 was produced by GOx in situ to activate HRP, which led to an increase in removal efficiency of phenol about 30. Investigations on the removal efficiency of phenol for both immobilized and free enzymes indicated that immobilized enzymes have higher activity and less sensitivity to pH variation compared with free ones. In addition, the effect of parameters such as temperature, pH, HRP/GOx ratio, phenol and glucose concentration on the removal efficiency of phenol was investigated. Finally, an artificial neural network (ANN) was developed to model and express the relationship between removal efficiency of phenol and aforementioned parameters. The optimized values of parameters were determined by optimizing the resulted ANN model using genetic algorithm (GA). © 2018 Taiwan Institute of Chemical Engineer

Phenol removal by HRP/GOx/ZSM-5 from aqueous solution: Artificial neural network simulation and genetic algorithms optimization

In this study, horseradish peroxidase (HRP) and glucose oxidase (GOx) were immobilized on mesoporous ZSM-5 nanoparticles by using glutaraldehyde as cross linking agent, and the prepared biocatalyst was characterized using SEM and EDAX mapping analysis. The resulted HRP/GOx/ZSM-5 biocatalyst was used for phenol removal from aqueous solution. In order to prevent the deactivation of HRP in the presence of excess H2O2, required H2O2 was produced by GOx in situ to activate HRP, which led to an increase in removal efficiency of phenol about 30. Investigations on the removal efficiency of phenol for both immobilized and free enzymes indicated that immobilized enzymes have higher activity and less sensitivity to pH variation compared with free ones. In addition, the effect of parameters such as temperature, pH, HRP/GOx ratio, phenol and glucose concentration on the removal efficiency of phenol was investigated. Finally, an artificial neural network (ANN) was developed to model and express the relationship between removal efficiency of phenol and aforementioned parameters. The optimized values of parameters were determined by optimizing the resulted ANN model using genetic algorithm (GA). © 2018 Taiwan Institute of Chemical Engineer

Optimizing an electromagnetic wave absorber for bi-anisotropic metasurfaces based on toroidal modes

Abstract The design and optimization of an electromagnetic wave absorber for far-field wireless power transmission (WPT) is the subject of this research study. The goal of the research is to effectively absorb energy from ambient RF electromagnetic waves without the usage of a ground plane by employing metasurfaces with chiral components.By integrating trioidal moments into the design theory, the objective is to create a metasurface that functions in two frequency bands and produces high-quality resonance. The study also explores the dual non-homogeneity property of structures, polarization tensor coefficients, and the electromagnetic response of non-homogeneous metasurfaces. Based on the relative orientation of induced fields and moments, it delves deeper into the two basic possibilities for dual non-homogeneous elements. The development of chiral metasurfaces and the notion of electromagnetic chirality and its implications for polarization properties are introduced

Modification of bio-hydroxyapatite generated from waste poultry bone with MgO for purifying methyl violet-laden liquids

In the present work, biological hydroxyapatite (Bio-HAp) was generated from waste poultry bone and modified with magnesium oxide (MgO) nanoparticles (Bio-HAp/MgO) and used in the adsorption process of methyl violet (MV). The Bio-HAp and Bio-HAp/MgO mesoporous composites were characterized using physicochemical techniques. Bio-HAp and Bio-HAp/MgO composites had crystalline and mesoporous structures. The specific surface area of Bio-HAp/MgO mesoporous composites (14.7 m2/g) was higher and lower than that of Bio-HAp (4.6 m2/g) and MgO (154.9 m2/g), respectively. The effect of pH (2–10), temperature (25–45 °C), contact time (10–50 min), initial MV concentration (5–25 mg/L), and Bio-HAp/MgO quantity (0.5–2.5 g/L) on the adsorption efficiency was optimized through response surface methodology-central composite design (RSM-CCD). Among four isotherm models, the Freundlich isotherm (R2 > 0.98) was better matched with the equilibrium data. Based on the isotherm parameters (E, n, and RL), the MV adsorption process using Bio-HAp particles and Bio-HAp/MgO mesoporous composites is physical and desirable. The pseudo-second-order (R2 > 0.97) was more potent than the other models for modeling kinetic data. According to the thermodynamic investigation, the MV adsorption was an exothermic and spontaneous process. The mesoporous composite had good reusability to remove MV dye from liquid media up to 5 steps. Bio-HAp particles and Bio-HAp/MgO mesoporous composites were tested for treatment, which significantly reduced the dye content of the real sample. © 2020, Springer-Verlag GmbH Germany, part of Springer Nature

Enhancing the efficiency of recombinant hepatitis B surface antigen production in Pichia pastoris by employing continuous fermentation

The recombinant hepatitis B surface antigen (rHBsAg) is a protein-based vaccine which is mainly produced by Pichia pastoris (P. pastoris) in a high-cell-density fed-batch fermentation for large-scale production purposes. In this study, we compared the efficiency and productivity of a chemostat fermentation of P. pastoris for rHBsAg production with the conventional fed-batch fermentation process. For this purpose, we established chemostat fermentation of P. pastoris for rHBsAg production in bench-scale for two weeks. The specific and volumetric productivity for chemostat fermentation were 0.00468 mg HBsAg/g cell/h and 1.699 mg HBsAg/L/h, respectively. These parameters for fed-batch fermentation were 0.00456 mg HBsAg/g cell/h and 1.38 mg HBsAg/L/h, and by considering the downtime for harvesting and initiating the next run, these values dropped to 0.00375 mg HBsAg/g cell/h and 1.13 mg HBsAg/L/h, respectively. According to the PCR analysis, no genetic mutation and contamination were detected after approximately three weeks of fermentation process- including batch, fed-batch and chemostat fermentation. These results indicate large-scale production of rHBsAg in recombinant P. pastoris, using the chemostat operation mode is more cost-effective and time-sparing than the conventional fed-batch production system. Besides, common challenges such as contamination and mutation were absent in the continuous production of rHBsAg in P. pastoris. © 2018 Elsevier B.V