Preparation, characterization, and photocatalytic performance of a PVDF/cellulose membrane modified with nano Fe3O4 for removal of methylene blue using RSM under visible light.

In this work, a polymeric membrane-based polyvinylidene fluoride coated with cellulose and loaded with iron oxide nanoparticles (PVDF/cellulose/Fe3O4) was synthesized and was characterized using FESEM, XRD, AFM, and contact angle measurements. The activity and modification of the PVDF/cellulose/Fe3O4 membrane under visible light for the removal of methylene blue were studied using the central composite design. The effect of influential variables such as pH, methylene blue concentration, amount of Fe3O4 in the membrane, and irradiation time on MB removal was investigated. Analysis of variance was used to determine the significance of experimental factors and their interactions. About 72.5% methylene blue removal using the PVDF/cellulose/Fe3O4 membrane under visible light was achieved at optimum conditions of a pH of 9, methylene blue concentration of 600 mg L-1, Fe3O4 amount of 0.03 g, and irradiation time of 117 min. Finally, results confirmed that the proposed membrane has good performance for methylene blue removal under visible light.

Optimization of synergic antibacterial activity of Punica granatum L. and Areca nut (P.G.L.A.N) extracts through response surface methodology.

The primary objective of this study was to evaluate the use of natural compounds as opposed to chemical preservatives. This study employed response methodology to evaluate the synergistic antibacterial effect of Areca nut and Punica granatum L. extract. Independent variables included extract type (Punica granatum L., Areca nut, and their mixture), solvent (water, ethanol, methanol), bacterial type (S. aureus, Salmonella, E. coli), and extract concentration (1, 10, 100 mg/L). The sensitivity was determined using the disk diffusion method, and the diameter of the inhibitory zone was measured. On the specified bacteria, the MIC (minimum inhibitory concentration) and MBC (minimum bactericidal concentration) of each extract were ascertained using the serial dilution method. This study revealed the existence of beneficial synergistic effects between the two extracts. Results indicated that the ethanolic extracts of Punica granatum L. and Areca nut had a synergistic effect on E. coli.

Antibacterial activity of Punica granatum L. and Areca nut (P.A) combined extracts against some food born pathogenic bacteria.

The antibacterial effects of combined extracts of Punica granatum L. and Areca nut (P.A) against resistant bacteria, a gram-positive bacterium, Staphylococcus aureus and three gram-negative bacteria, Escherichia coli, Salmonella, and Enterobacter aerogenes, in individual and biofilm forms was studied. Antibacterial activity was studied using disk diffusion method, microbroth dilution, and microtiter plate methods. Given the disc diffusion test (Minimum Inhibitory Concentration (MIC) and Minimum Bactericidal Concentration (MBC)), the extracts had inhibitory effects on the individual forms of bacteria. However, the ethanolic extract had greater effectiveness than the methanolic extract. Generally, ethanol efficiently extracts flavonoids and their glycosides, catechol and tannins. This fact due to the ethanol polarity that is equal 0.654. The results indicated that the ability of extracts in inhibiting the formation of biofilms, destruction of biofilms, and prevention of metabolic activity of bacteria had a direct relationship with concentration and the highest inhibitory was seen on Staphylococcus aureus (98.98%), Staphylococcus aureus (94.98%), and Enterobacter aerogenes (88.55%). Based on the results, the P.A. combined extract can be used as an alternative combination with the ability to inhibit antibiotic-resistant bacteria in single and biofilm forms.

Preparation and characterization of graphitic carbon nitrides/polyvinylidene fluoride adsorptive membrane modified with chitosan for Rhodamine B dye removal from water: Adsorption isotherms, kinetics and thermodynamics.

In the present study, a PVDF/g-C3N4/chitosan (PCC) membrane was used for the removal of Rhodamine B from aqueous solutions. Water flux for PCC membrane decreased from 49.87% to 14.76% by the addition of chitosan from 2% to 4%. Afterward, batch adsorption conditions were optimized for a PVDF/g-C3N4/chitosan membrane applying Box-Behnken design algorithm. The maximum RB removal efficiency was 72.74% at 2 mg/L of initial RB concentration, pH = 3, 2 g of g-C3N4 and 3% of chitosan at the optimum conditions. The Freundlich isotherm and pseudo-second order models were satisfactorily describing the equilibrium and kinetic of adsorption, respectively. Thermodynamic parameters were disclosed that the adsorption of RB onto PCC was exothermic (ΔH° = -21.35 kJ mol-1) and spontaneous (ΔG° < 0) with the generation of energy (ΔS° = +92.42 kJ mol-1) at the interface of solid/liquid. Thus, this novel membrane could be employed as an effective adsorbent to remove of RB dye from aqueous solutions.

Evaluation of Antibacterial Activity of Aqueous, Ethanolic and Methanolic Extracts of Areca Nut Fruit on Selected Bacteria.

Today, the tendency to use of natural preservatives to increase food security has expanded. In the present study, antibacterial effects of Areca Nut fruit extracts were evaluated against Staphylococcus aureus, Escherichia coli, Salmonella enterica, and Enterobacter aerogenes bacteria using agar disc diffusion technique. Methanol, ethanol, and water were used as solvents for extraction by maceration method, and extracts were analyzed by GC-MS. The antibacterial activity was evaluated using microtiter broth dilution method to determine minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC). Results revealed that all ATCC strains were significantly inhibited by ethanolic and methanolic extracts. Escherichia coli produced a significantly larger zone of inhibition for Gentamicin (35 ± 0.65 mm) and Penicillin (25 mm ± 0.56), while Enterobacter aerogenes produced smaller zone of inhibition for Gentamicin (20 ± 0.87 mm) and Penicillin (15 ± 0.87 mm). Also, methanolic extract had considerable antibacterial activity with MIC value of 1.56 mg/mL against Escherichia coli. All of extracts were used to evaluate antibacterial effects in prepared cake, and as a result, all pathogenies were the most sensitive by methanolic extract in 100 mg/L of concentration except Escherichia coli that were more sensitive by ethanolic extract. In conclusion, the Areca Nut fruit extracts may be used as a natural preservative in food industries. Future studies should focus on the effect of Areca Nut fruit extracts in bakery and drinking industries.

The synthesis, characterization and applications of poly[N-isopropylacrylamide-co-3-allyloxy-1,2-propanediol] grafted onto modified magnetic nanoparticles.

In this paper, a novel method is investigated for the extraction, determination, and delivery of ceftazidime in simulated gastric and real biological fluids such as serum plasma and urine in in vitro drug delivery systems. A new polymer as a nano-sorbent was synthesized by the surface grafting of [N-isopropylacrylamide-co-3-allyloxy-1,2-propanediol] onto modified magnetic nano-particles by 3-mercaptopropyltrimethoxysilane and it was characterized by FT-IR, CHN, SEM, TEM, VSM, TGA, and zeta potential analyses. The effects of main parameters such as pH, reaction time, temperature, and solvents were evaluated for ceftazidime removal. The results indicate that the newly synthesized polymer can be successfully applied for biomedical applications and drug delivery.

Optimization of operational variables and kinetic modeling for photocatalytic removal of Direct Blue 14 from aqueous media by ZnS nanoparticles.

Zinc sulfide nanoparticles (ZnS-NPs) were synthesized via a simple and facile co-precipitation method and were characterized by X-ray diffraction (XRD), field emission scanning electron microscopy (FE-SEM) and diffuse reflectance spectroscopy (DRS). Photocatalytic activity of synthesized nanoparticles was evaluated in removal of double azo dye Direct Blue 14 (DB14) from aqueous media. Optimization of photocatalytic removal of DB14 was studied using response surface methodology (RSM). Based on the results, DB14 removal efficiency increased with increasing intensity and duration of UV light irradiation, whereas the higher pH and higher initial dye concentration were unfavorable. Under optimum conditions (initial DB14 concentration =10 mg L-1, ZnS-NPs amount = 0.7 g L-1, pH = 3.5, UV light intensity =16 W m-2, and irradiation time = 48 min), dye removal efficiency reached up to 88.26%. In continuation of our researches, non-linear regression analysis was used to development a kinetics model based on the Langmuir-Hinshelwood model and an empirical equation was obtained for estimation of apparent pseudo-first-order rate constant (kap) as a function of the operational variables. Findings indicated a high similarity was between the model prediction and experimental results.

Novel ZnS/Carbon Nanofiber Photocatalyst for Degradation of Rhodamine 6G: Kinetics Tracking of Operational Parameters and Development of a Kinetics Model.

A novel nanocomposite in the role of photocatalyst was prepared by composition of zinc sulfide (ZnS) nanoparticles with carbon nanofibers (CNFs) and was characterized. The XRD, EDX, and FE-SEM analysis revealed that ZnS is successfully embedded in CNFs matrix. The DRS results indicated that supporting of ZnS by CNFs led to a decrease of the band gap energy. The photocatalytic degradation of a hazardous xanthine dye, Rhodamine 6 G (Rh-6G), by the prepared ZnS/CNFs composite was examined from the kinetics point of view. Nonlinear regression analysis was used to develop a mathematical kinetics model based on the Langmuir-Hinshelwood mechanism, and an empirical equation was obtained for the estimation of apparent pseudo-first-order rate constant (kap ) as a function of operational parameters (viz. initial dye concentration, ZnS/CNFs content, pH, and irradiation intensity). Based on the results, kap increased with an increase ZnS/CNFs content, pH, and UV light intensity, whereas it decreased by increasing the initial Rh-6G concentration. Moreover, a new kinetics model was obtained based on proposed elementary steps to determine kap . In the final stage of the work, intermediate materials produced within photocatalytic degradation of Rh-6G dye were detected by GC-MS analysis.

Fabrication of sulfated nanofilter membrane based on carboxymethyl cellulose.

The aim of this study is to prepare sulfated carboxymethyl cellulose (SCMC) nanofilter membrane using sulfur trioxide pyridine complex (SO3/pyridine) as sulfating agent and glutaraldehyde (GA) as a crosslinking agent onto polysulfone supporting membrane. The prepared nanofilter was characterized by Fourier transform infrared spectroscopy, X-ray diffraction, scanning electron microscopy, atomic force microscopy and zeta potential. To evaluate the prepared nanofilter, various amounts of SO3/Pyridine were used and efficiency of them was investigated. The results showed that increasing the sulfate groups raised the flux from 13.87 to 29.54 L/(m2·h-1), whereas percentage rejection was increased during the separation of salt aqueous solutions and then decreased. It can be concluded that, SCMC-GA-2 (with molar ratio of SO3/pyridine to CMC of 1) shows high separation efficiency in acidic conditions and improves the hydrophilicity and charge density of the filter.

Application of central composite design and artificial neural network in modeling of reactive blue 21 dye removal by photo-ozonation process.

The present study deals with use of central composite design (CCD) and artificial neural network (ANN) in modeling and optimization of reactive blue 21 (RB21) removal from aqueous media under photo-ozonation process. Four effective operational parameters (including: initial concentration of RB21, O(3) concentration, UV light intensity and reaction time) were chosen and the experiments were designed by CCD based on response surface methodology (RSM). The obtained results from the CCD model were used in modeling the process by ANN. Under optimum condition (O(3) concentration of 3.95 mg L(-1), UV intensity of 20.5 W m(-2), reaction time of 7.77 min and initial dye concentration of 40.21 mg L(-1)), RB21 removal efficiency reached to up 98.88%. A topology of ANN with a three-layer consisting of four input neurons, 14 hidden neurons and one output neuron was designed. The relative significance of each major factor was calculated based on the connection weights of the ANN model. Dye and ozone concentrations were the most important variables in the photo-ozonation of RB21, followed by reaction time and UV light intensity. The comparison of predicted values by CCD and ANN with experimental results showed that both methods were highly efficient in the modeling of the process.

The antioxidant, general toxicity and insecticidal activities of Nepeta scrophularioides Rech. f. extracts in different developmental stages.

The essence of the present study is to focus on the antioxidant, general toxicity and insecticidal properties of the extracts of Nepeta scrophularioides Rech.f. during different developmental (vegetative, flowering, post-flowering) stages. The samples were subjected to screening for their possible antioxidant activities by using 2, 2-diphenyl-1-picrylhydrazyl (DPPH) assay. The extracts of the flowering and the post-flowering stages showed higher antioxidant activity than those from the vegetative stage. The MeOH extracts of N. scrophularioides in different development stages were tested for cytotoxicity by brine shrimp toxicity assay. The result obtained for the bio assay was found to be significantly lethality. Among the samples, the extracts of flowering stage were found to be the most active with a LC50 value of 0.078 mg/mL. All three extracts showed significant insecticidal activity at the concentration of 20 mg/mL dose of test sample after 24 h. The extracts of vegetative and post-flowering were the most potent samples.

Comparison of 4-chloro-2-nitrophenol adsorption on single-walled and multi-walled carbon nanotubes.

The adsorption characteristics of 4-chloro-2-nitrophenol (4C2NP) onto single-walled and multi-walled carbon nanotubes (SWCNTs and MWCNTs) from aqueous solution were investigated with respect to the changes in the contact time, pH of solution, carbon nanotubes dosage and initial 4C2NP concentration. Experimental results showed that the adsorption efficiency of 4C2NP by carbon nanotubes (both of SWCNTs and MWCNTs) increased with increasing the initial 4C2NP concentration. The maximum adsorption took place in the pH range of 2-6. The linear correlation coefficients of different isotherm models were obtained. Results revealed that the Langmuir isotherm fitted the experimental data better than the others and based on the Langmuir model equation, maximum adsorption capacity of 4C2NP onto SWCNTs and MWCNTs were 1.44 and 4.42 mg/g, respectively. The observed changes in the standard Gibbs free energy, standard enthalpy and standard entropy showed that the adsorption of 4C2NP onto SWCNTs and MWCNTs is spontaneous and exothermic in the temperature range of 298-328 K.