Predicting adsorption of aromatic compounds by carbon nanotubes based on quantitative structure property relationship principles

Abstract Quantitative structure property relationship (QSPR) models were developed to predict the adsorption of aromatic compounds by carbon nanotubes (CNTs). Five descriptors chosen by combining self-organizing map and stepwise multiple linear regression (MLR) techniques were used to connect the structure of the studied chemicals with their adsorption descriptor (K�) using linear and nonlinear modeling techniques. Correlation coefficient (R2) of 0.99 and root-mean square error (RMSE) of 0.29 for multilayered perceptron neural network (MLP-NN) model are signs of the superiority of the developed nonlinear model over MLR model with R2 of 0.93 and RMSE of 0.36. The results of cross-validation test showed the reliability of MLP-NN to predict the K� values for the aromatic contaminants. Molar volume and hydrogen bond accepting ability were found to be the factors much influencing the adsorption of the compounds. The developed QSPR, as a neural network based model, could be used to predict the adsorption of organic compounds by CNTs. © 2015 Elsevier B.V

Electrochemical synthesis of copper carbonates nanoparticles through experimental design and the subsequent thermal decomposition to copper oxide

A copper anode was used in sodium carbonate solutions to prepare nanoparticles of copper carbonates. To reach the best results, the parameters affecting the preparation procedure were evaluated and optimized based on the Taguchi robust design (TRD), and it was found that the size of the resulting copper carbonates particles could be managed by applying optimal values of parameters such as electrolysis voltage, carbonate concentration, stirring rate and the temperature. To evaluate how significantly the factors influence the size of the particles, analysis of variance (ANOVA) was used, and the results indicated that the electrolysis voltage, carbonates concentration, and stirring rate affect the dimensions of the particles to a high degree. The optimal conditions were also evaluated. Further, the copper carbonate particles were used as the precursor in a solid-state thermal decomposition reaction intended for forming nanostructured CuO particles. All products were studied through SEM, XRD, TG-DTA, and FT-IR techniques and also those of optimal properties were evaluated as photocatalytic species for application in the UV-induced degradation (UVID) of methylene blue (MB). © 2019 IOP Publishing Ltd

Facile chemical synthesis of cobalt tungstates nanoparticles as high performance supercapacitor

Cobalt tungstate (CoWO4) nanoparticles were synthesized by a chemical precipitation reaction in aqueous ambient involving direct addition of cobalt ion solution to the solution of tungstate reagent. Optimization of the synthesis procedure was carried out using Taguchi robust design as statistical method. In order to controllable, simple and fast synthesis of CoWO4 nanoparticles, effects of some synthesis conditions such as reagents concentrations (i.e., cobalt and tungstate ions), flow rate of cobalt feeding and temperature of the reactor on the particle size of synthesized CoWO4 were investigated by the aid of an orthogonal array (OA9). The results of optimization process showed that CoWO4 nanoparticles could be prepared by controlling the effective parameters and at optimum conditions of synthesis procedure, the size of prepared CoWO4 particles was about 55� nm. Chemical composition and microstructure of the prepared CoWO4 nanoparticles were characterized by means of XRD, SEM, TEM, FT-IR spectroscopy, UV�Vis spectroscopy and fluorescence. The supercapacitive behavior of the CoWO4 electrode has been investigated by cyclic voltammetry, galvanostatic charge/discharge and electrochemical impedance spectroscopy. The CoWO4 electrode indicates high specific capacitance of 378� F� g�1 at scan rate of 2� mV� s�1 in 2.0� M H2SO4 electrolyte. Therefore, the prepared electrode could be potential electrode materials for supercapacitors. Moreover, an excellent rate performance, good capacitance retention (~95.5� ) was also observed during the continuous 4000 cycles. �© 2016, Springer Science+Business Media New York

In vitro antibacterial property assessment of silver nanoparticles synthesized by Falcaria vulgaris aqueous extract against MDR bacteria

Silver nanoparticles (AgNPs) were fabricated in the presence of Falcaria vulgaris aqueous extract as a biosynthesis method without utilizing any surfactant or template. AgNPs were prepared under different synthesis conditions such as silver ion concentration and the amount of plant used for the extraction, reaction duration and temperature for the extraction. The effect of these variables on the size of resulted AgNPs was examined, and operation conditions were optimized statistically with analysis of variance (ANOVA) to describe the role of these variables in tuning the size of AgNPs. The results of ANOVA displayed the optimum conditions for the synthesis procedure that resulted in AgNPs with the average size of 28 ± 8 nm. Furthermore, the growth of AgNPs was monitored by UV-Vis spectroscopy, and they were characterized using TEM, SEM, X-ray diffraction, and FT-IR spectroscopy. Finally, in vitro antibacterial activity of the AgNPs showed the maximum inhibition zone alongside Staphylococcus aureus (ATCC 25923) and lowermost inhibition zone touching E. coli (MDR). The minimum inhibitory concentration (MIC) for the AgNP-Fv was in a range between 0.535 and 0.001 µg/ml. According to the results, the ATCC bacteria were more sensitive to AgNP-Fv compared to multiple-drug resistance bacteria, except for Pseudomonas aeruginosa (MDR). Figure not available: see fulltext.. © 2019, Springer Science+Business Media, LLC, part of Springer Nature