Activated persulfate by chelating agent Fe·/complex for in situ degradation of phenol: intermediate identification and optimization study

Research on Chemical Intermediates - Due to its high toxicity, phenol is classified as a priority. In this paper, the removal of phenol from aqueous solutions was investigated using EDTA and...     

Design,synthesis, activity evaluation and QSAR studies of novel antimalarial 1,2,3-triazolo-β-lactam derivatives

This paper describes the synthesis of some new β-lactam derivatives containing the 1,2,3-triazole moiety. All the compounds were evaluated for their in vitro antimicrobial and antimalarial activities. Moderate to excellent antimalarial activities were encountered. The results showed that compounds 5a, 5c, 5f, 5i exhibited the most potent antimalarial activity with IC₅₀ values of 0.85, < 0.97, < 0.97, 1.81 µM against chloroquine-resistant P. falciparum K1 strain. A QSAR study highlights the structure–activity relationships that correlate the observed antimalarial activities with changes in the compounds’ structural features.     

Numerical study of aerosol particle deposition in simple and converging-diverging micro-channels with a slip boundary condition at the wall

The design of micro-devices involving aerosol transport requires the study of the deposition of aerosols in micro-channels. In this study, the slip and no-slip boundary conditions for the gas flow regime were applied to the Navier-Stokes equations to obtain the particle deposition in simple and converging-diverging micro-channels. The equation of particle motion included inertial, viscous, Brownian, and gravity terms. It was found that the ratio of gravity to inertial effects controls the deposition of particles with diameters of 0.1-1 μm, and the ratio of diffusion to inertial effects controls the deposition of particles with diameters of 0.01-0.001 i~m. Comparison between the no-slip and slip flow regimes showed that the deposition of 0.1- to 1-μm-diameter particles was less and the deposition of 0.01- to 0.001-1μm-diameter particles was greater for the slip flow regime. There was no significant difference between slip and no-slip flow regimes for the deposition of 0.01- to 0.1-μm-diameter particles. Finally, it was shown that the stagnated gas in the corners of the converging-diverging micro-channel produced similar gas velocity profiles under the slip and no-slip flow regimes.     

Application of LDOS and multipole expansion technique in optimization of photonic crystal designs

We introduced a procedure of using local density of states for increasing the quality factor and Purcell factor of photonic crystal cavities. We used multipole expansion method for accurate calculation of local density of photonic states, stationary field profile, Q-factor, mode volume and Purcell factor of photonic crystal cavities. We found out that the quality factor exponentially increases with the number of additional photonic crystal layers around the cavity while the mode frequencies stay unchanged. We also demonstrated the method in studying the defect mode??s behavior in photonic crystal cavities and showed that high Q-factor, small mode volume and high Purcell factor could be obtained with optimization of geometrical parameters of first neighboring layer.     

Comparative study of Box–Behnken,central composite,and Doehlert matrix for multivariate optimization of Pb (II) adsorption onto Robinia tree leaves

A comparative study of Box–Behnken, central composite, and Doehlert matrix was performed on the adsorption of Pb (II) by Robinia tree leaves in a batch system. As a case study, uptake capacity (q) and removal efficiency (R) of Pb (II) biosorption have been evaluated with all theses approaches. The advantages and limitations of these different response surface techniques have been experimentally considered. The results show the different statistical predictability of Doehlert matrix and Box–Behnken design at 95% confidence level comparable with some extent with that of central composite design at some extreme conditions. An environmental and economical comparison was also carried out between individual and simultaneous optimization of removal efficiency (R) and uptake capacity (q) using desirability function. Optimization of q proves only to have advantages over R or simultaneous optimization of R and q in this particular biosorption process. Copyright © 2013 John Wiley & Sons, Ltd.     

Theoretical calculation and prediction for experimental design to obtain spin crossover complexes

DFT methods were utilized to study SCO complexes. [Fe(2btz)₂(NCX)₂] (2btz = 2,2′‐bithiazoline, X = S ( 1 ) and Se ( 2 )), [Fe(phen)₂(NCX)₂] (phen = 1,10‐phenantroline, X = S ( 3 ) and Se ( 4 )), and [Fe(bpy)₂(NCS)₂] ( 5 ) (bpy = 2,2′‐bipyridine) compounds, which have experimentally shown SCO behavior, were calculated. B3LYP, B3LYP*, OPBE, and OLYP with 6‐31G* and 6‐311 + G** basis sets were employed to calculate the ΔE_HS/LS energy gap as a clue to find complexes with SCO behavior. It is found that calculated result by B3LYP* with c₃ = 0.14 and OPBE methods and 6‐31G* basis set are in agreement with experimentally observed SCO complexes. Then, newly designed Fe(N‐N)₂(X)₂ complexes, where N‐N are bidentate nitrogen donor chelating ligands and X= SCN^‐, SeCN^‐, Cl^‐, Br^‐, I^‐, were chosen to see their potential to be SCO compounds. ΔE_HS/LS for potential SCO complexes are estimated from 0.8 to 6.5 kcal/mol in B3LYP* and 0.6–5.7 kcal/mol in OPBE. These calculations suggest [Fe(bpy)₂(NCSe)₂], [Fe(5dmbpy)₂(NCS)₂], and [Fe(3‐BrPhen)₂(NCSe)₂] compounds have the ability to show SCO behavior. © 2016 Wiley Periodicals, Inc.     

Photocatalytic reduction of nitro aromatic compounds to amines using a nanosized highly active CdS photocatalyst under sunlight and blue LED irradiation

A variety of aromatic nitro compounds were chemoselectively reduced to the corresponding anilines using conveniently prepared nanosized CdS as a photocatalyst under the sunlight and blue LED irradiation. The results demonstrated that synthesized CdS nanostructures have the potential to provide a promising visible light driven photocatalyst for chemoselective reduction of nitro aromatics in the presence of nitrile and carbonyl groups to the corresponding amines under both sunlight and blue LED irradiation. Photoreduction of nitro aromatics by the prepared nanosized CdS with high surface area was faster than when using the commercially available CdS under both sunlight and LED irradiation. Nanosized CdS photocatalyst was prepared by a simple method without any capping agent. X-ray diffraction (XRD), energy dispersive spectrometry (EDAX), transmission electron microscopy (TEM), scanning electron microscopy (SEM), N₂ absorption—desorption, diffuse reflectance spectroscopy (DRS), and flat band potential methods were employed for the characterization, which revealed that the prepared CdS nanoparticles have a well-resolved cubic structure with the size of around 10–30 nm and a band gap of 2.37 eV.     

Nano TiO2 Modified Carbon‐ceramic Electrode and Its Application for Electrocatalytic Oxidation of NADH

The electrocatalytic oxidation of nicotinamide adenine dinucleotide (NADH) was studied on nanoTiO₂ modified sol‐gel electrode, using cyclic voltammetry, chronoamperometry and differential pulse voltammetry as diagnostic techniques. It is demonstrated that TiO₂ nanoparticles on sol‐gel network catalyze the oxidation of NADH in the absence of any electron transfer mediators. Effect of various parameters such as pH, scan rate, TiO₂ percentage on the response of modified electrode was studied. In addition, scanning electron microscopy (SEM) was used to characterize the surface morphology of the spots. A dynamic range between 0.5–50 μM with detection limit of 0.35 μM was obtained with DPV studies. This method was successfully used for determination of NADH in cucumber cotyledons samples. The electrode showed relatively good stability over more than 2 months.