Synthesis of nickel ferrite nanoparticles as an efficient magnetic sorbent for removal of an azo-dye: Response surface methodology and neural network modeling

In this research, nickel ferrite (NiFe2O4) nanoparticles (NFNs) are prepared through coprecipitation method, and applied for adsorption removal of a model organic pollutant, methyl orange (MO). The characterization of the prepared NFNs was performed using scanning electron microscopy (SEM), X-ray diffraction (XRD), vibrating sample magnetometer (VSM) and transmission electron microscopy (TEM). Optimization and modeling of the removal of MO applying NFNs were performed via central composite design (CCD) and the influential parameters including nano-sorbent amount, dye initial concentration, contact time and pH were considered as input variables for CCD. A dye removal percentage of 99 % was achieved under the optimum condition established for MO removal that was in agreeing with the predicted value. Additionally, multi-layer artificial neural network (ML-ANN) was applied to acquire a predictive model of MO removal. The isothermal investigation of MO adsorption was performed by developing Langmuir, Freundlich and Temkin models, and results showed that experimental data were best fit in Freundlich model. Based on the adsorption kinetics studies, the pseudo-second-order kinetic model was the best model to describe the adsorption mechanism of MO onto NFNs

A green approach for the synthesis of silver nanoparticles using Lithospermum officinale root extract and evaluation of their antioxidant activity

Recently, the synthesis of silver nanoparticles has become an important subject in the bionanotechnology field. Many different chemical and physical methods could be used for silver nanoparticles synthesis, but they are limited due to the usage of toxic chemicals and the production of dangerous by-products. However, the usage of plant extract for silver nanoparticles synthesis is a green single-step method without using toxic chemicals. Herein, silver nanoparticles were synthesized using Lithospermum officinale root aqueous extract and their antioxidant activity was evaluated in vitro. The results showed that 1 ml of the extract could reduce 9 ml of silver ions (1 mM) to silver nanoparticles by heating the reaction mixture (60 ºC) for 6 hours at pH 7.0. The synthesized silver nanoparticles were detected by UV–Vis spectroscopy, TEM, FT-IR, DLS, and XRD. The synthesized silver nanoparticles spectrum had a maximum peak at 390nm, and TEM analysis indicated spherical particles, higher stability (zeta potential: -15.3 mV) and an average size of 7 nm. The antioxidant activity of the synthesized silver nanoparticles was 0.07 mg/ml compared to L. officinale root aqueous extract (0.142 mg/ml) which indicated higher antioxidant activity. So, it is concluded that the synthesized silver nanoparticles could be considered a clinical therapeutic potential due to its antioxidant property

Enhancing photocatalytic activity of zinc oxide nanoparticles by a ‎non-thermal atmospheric pressure plasma

In this work, plasma has been used as a simple, very fast, low energy and efficient method for modification of the zinc oxide nanopowder to improve its photocatalytic activity. Zinc oxide is one of the effective photocatalysts in degradation of the organic contaminants, e.g. dyes. The purpose of the zinc oxide photocatalyst modification is to reduce the band gap and thus to increase its photocatalytic activity in the visible light range. To achieve nitrogen-doped zinc oxide nanoparticles (N-Doped ZnO), the zinc oxide nanopowder was suspended in melamine solution, as nitrogen precursor, and then treated with a non-thermal atmospheric pressure plasma. Different concentrations of melamine and different times of plasma exposure were considered for optimizing the nitrogen-doped zinc oxide structure. The photocatalyst properties of the pure zinc oxide and optimized nitrogen-doped zinc oxide samples were investigated by XRD, FESEM, EDX, BET, DRS and PL analyses. The photocatalytic activity of the pure zinc oxide nanopowder and plasma-treated samples were performed in the photocatalytic degradation of methylene blue dye contaminant. The degradation efficiency of methylene blue by the pure zinc oxide was 71.7%. By applying plasma to the zinc oxide nanopowder for 5 minutes with a concentration of 500 mg/L of melamine solution, the degradation efficiency was enhanced to 90%. According to the results, it can be seen that the plasma treatment has succeeded in the nitrogen doping process to the zinc oxide structure and improved its photocatalytic activity

Optimization of lysine production in Corynebacteriumglutamicum ATCC15032 by Response surface methodology

Introduction:Lysine is an essential amino acid and has importance in food and pharmaceutical industry. Nowadays, there are different methods such as genetic and growth media optimization to enhance the lysine production. One of the useful methods in optimization of growth media is the response surface methodology. Materials and methods: In this study, lysine was produced by wild type of Corynebacterium glutamicum ATCC15032 and the production increased by response surface methodology. After selection of M9 culture media as a basic culture media, the effect of different factors such as carbon (glucose), nitrogen (ammonium sulphate) sources and methionine, as an additive, were studied on the lysine production. Then, the culture media and the time of incubation were optimized by response surface methodologyforlysine production. Results: The results showed that in M9 culture media, the amount of the produced lysine was 0.7 milligram per liter. In the optimized culture media (by response surface methodology) which has 14% glucose, 5% ammonium sulphate and 5mM methionine, lysine was produced up to 0.98 gram per liter after 2.5 days incubation. Pareto analysis indicated that methionine is the most effective factor in the lysine production. Finally, the results of granulation showed that the optimum condition for granulation of culture media (containing lysine) was achieved by adding starch, ammonium sulphate and sodium chloride in low pH and 100 °C. Discussion and conclusion: According to the results, the proposed culture media by response surface methodology causes 1400 times increase in the lysine production compared with M9 culture media and methionine had an important role in the production of lysine, probably by inhibiting the other metabolic pathway which has common metabolic precursor with lysine production metabolic pathway

Assessment of environmental applicability of TiO2 coated self-cleaning glass for photocatalytic degradation of estrone, 17 beta-estradiol and their byproducts

WOS: 000510854900005Optimization of photocatalytic degradation of two natural estrogenic compounds, estrone (El) and 17 beta-estradiol (17 beta-E2) in aqueous medium was performed on TiO2 coated Pilkington Activ (TM) self-cleaning glass as a novel approach to eliminate free nano-TiO2 releasing to the intended environment after treatment. the active glass was characterized by Atomic Force Microscopy (AFM), X-ray diffraction (XRD), and Raman spectroscopy to characterize the TiO2 nanoparticles. the main purposes were mineralization of target compounds in the treated water during the photocatalytic reaction and also to investigate the oxidation by products. Response Surface Methodology (RSM) has been applied to optimize the photocatalytic degradation by changing time, pH, and light intensity as effective factors. According to the results, time was the more effective parameter. the maximum efficiency degradation was achieved in alkaline media. Due to interactive effects between variable factors, 1 mg/L aqueous solution of El and 17 beta-E2 in water was totally decomposed by TiO2 photocatalyzed reactions under UV-C irradiation of 10.08 W/m(2) for 52.49 min at pH 9.42. Results of GC-MS analysis were introduced 17-deoxy Estrone and 2-Hydroxyestradiol as intermediate products for El and 17 beta-E2, respectively. All of the peaks finally disappeared after 170 min. Optimized conditions were applied for real sample of wastewater, presenting 30.40% and 56.84% in the efficiency degradation of El and 17 beta-E2, respectively.Ege University Scientific Research (BAP)Ege University [2017/SUF/014]This study is partially funded by Ege University Scientific Research (BAP) (Project No.: 2017/SUF/014). Authors acknowledge Dr. Ozan Unsalan (Ege University, Department of Physics) for help with the analysis of Raman spectrums. Golnar Matin thank Prof. Yury Gogotsi (A.J. Drexel Nanotechnology Institute, Drexel University) for his kind comments and suggestions on characterization of TiO2 nanocrystals coated on the glass

Abatement efficiency and fate of EPA-Listed PAHs in aqueous medium under simulated solar and UV-C irradiations, and combined process with TiO2 and H2O2

WOS:000605750200003Photolytic degradation of dissolved compounds of 16 EPA-Listed PAHs in aqueous medium, exposed to ultraviolet/ titanium dioxide (UV-C/TiO2), xenon light/ titanium dioxide (Xe/TiO2), xenon light/ hydrogen peroxide (Xe/H2O2) and ultraviolet/ hydrogen peroxide (UV-C/H2O2) was studied. The compounds which detected above detection limit of applied analytical method and instrument include: naphthalene (Nap), acenaphthylene (Acy), acenaphthene (Ace), fluorene (Flu), fluoranthene (Fln) and pyrene (Pyr) survived. A time-course experiment (0, 1, 2, 5, 12 min) was performed to determine the fate of PAHs profile along treatments. After accomplishment of the removal process Sigma(6) PAHs ranked as follow: UV-C/TiO2 > Xe/TiO2 > UV-C > Xe > Xe/H2O2, and UV-C /H2O2 with estimated values of 76.38, 23.02, 22.55, 2.78, 0.00 and 0.00% of the concentration values at the beginning of the treatment, respectively. High efficiency of Xe/H2O2 treatment process (100.00%) at the end of treatment and the structure of residual PAHs which changed to the lighter compounds (2,3-ringed PAHs) before accomplishment of the removal process were proven. Generally, low resistance of Fln to all treatment conditions was observed. Total removal of Nap was considered to be a characteristic PAH compound for completion of the removal of PAHs. Mutate of parent PAH compounds and intermediates were analyzed by gas chromatography-mass spectrometry (GC-MS) and the results suggest the evaluating the toxicity of the treated water due to by-product formation concerns.Ege University Scientific Research (BAP)Ege University [2017/SUF/014]This study was partially funded by Ege University Scientific Research (BAP) (Project No.: 2017/SUF/014). Authors acknowledge Dr. Ozan Unsalan (Ege University, Department of Physics) for his help with the analysis of Raman spectra. Navid Kargar and Golnar Matin thank Prof. Yury Gogotsi (A.J. Drexel Nanotechnology Institute, Drexel University) for his useful comments and suggestions on characterization of TiO2 nanocrystals

Performance of chitosan based nanocomposite hollow fibers in the removal of selenium(IV) from water

Fe3O4-chitosan nanocomposite hollow fibers were prepared via impregnation of Fe3O4 nanoparticles on dry-wet spun chitosan hollow fibers (CS-HFs) and its performance in the removal of selenium(IV) from water was investigated. The prepared nanocomposite was characterized using XRD, SEM and TEM analyses confirming the formation of Fe3O4 nanoparticles throughout the heterogeneous surface of CS-HFs. Response surface methodology (RSM) was utilized to optimize Se(IV) adsorption and investigate operational parameters including nanocomposite amount, Se(IV) concentration, pH and contact time. The polynomial second order regression, which is conventionally developed in RSM for describing the process, did not accurately fit the experimental data owing to significant lack of fit. However, in modified polynomial third order regression, all model evaluation criteria had been confirmed the accuracy of the developed model. The adsorption of Se(IV) on prepared Fe3O4-CS HFs followed from pseudo-second-order kinetics with participating both intraparticle and boundary layer diffusion in the rate-controlling step

Improving photocatalytic activity of the ZnS QDs via lanthanide doping and photosensitizing with GO and g-C3N4 for degradation of an azo dye and bisphenol-A under visible light irradiation

In this research, insertion of Gd ions (2 wt%) into the crystalline lattice of the ZnS QDs enhanced the photocatalytic activity of the QDs. In addition, the influence of graphene oxide (GO) and graphitic carbon nitride (g-C3N4) was assessed on the photocatalytic activity of the ZnS QDs through degradation of acid red 14 (AR14) and bisphenol-A (BA) under visible light. Higher photocatalytic degradation efficiency (97.1% for AR14 and 67.4% for BA within 180 min) and higher total organic carbon (TOC) removal (67.1% for AR14 and 59.2% for BA within 5 h) was achieved in the presence of ZnS QDs/g-C3N4 compared with ZnS QDs/GO nanocomposite. Finally, the Gd-doped ZnS QDs were hybridized with g-C3N4 as optimal support to fabricate a potent visible-light-driven photocatalyst for the decomposition of organic contaminants. The maximum photocatalytic degradation of 99.1% and 80.5% were achieved for AR14 and BA, respectively, in the presence of Gd-doped ZnS QDs/g-C3N4 nanocomposite. The photosensitization mechanism was suggested for the improved photocatalytic activity of the ZnS QDs/GO, ZnS QDs/g-C3N4, and Gd-doped ZnS QDs/g-C3N4 nanocomposites under visible light. © 2022 Elsevier Lt