Applied Chemical Engineering (Transferred)

Abstract

This studyinvestigates the efficacy of photocatalytic degradation process using TiO₂-UV configuration for treatment of waste water containing textile dye Acid Yellow 36 (AY36).Acid Yellow 36 dye was degraded using catalyst TiO₂ in analkaline medium of pH8.0.A dose of 0.25g of TiO₂ was used for 88.4% degradation of initial concentration of 20mg/l AY36 dye in 28 hrs. The effect of parameters such as pH, initial dye concentration, amount of TiO₂used, and exposure to UV light/irradiation on degradation of AY36 was investigated.Further it was observed that suspended TiO₂ in dye solution shows more effective results towards dye degradation, than embedded TiO₂ in the form of alginate beads. The study concluded that photocatalytic degradation is a potential tool for degradation of azo dyes.

Abstract The topological entropy HS of all 2907 convex 4- to 9-atomic polyhedral clusters has been calculated from the point of different symmetrical positions of the atoms. It shows a general trend to drop with growing symmetry of clusters with many local exceptions. The topological entropy HV of the same clusters has been calculated from the point of different valences (chemical bonds) of the atoms. It classifies the variety of clusters in more details. The relationships between the HS and HV entropies are discussed.

Abstract

In this work, ZnO nanostructures are electrodeposited on ITO conducting substrate prepared from chloride baths. The influence of concentration of Zn²⁺ on the electrochemical characteristics has been studied using cyclic voltammetry (CV) and chronoamperometry (CA) techniques. The Mott–Schottky measurements demonstrate an n-type semiconductor character for all samples with a carrier density varying between 1.47 × 1,018 cm⁻³ and 3.14 × 1,018 cm⁻³. Scanning electron microscopy (SEM) show arrays of vertically aligned ZnO nanorods (NRs) with good homogeneity. X-ray diffraction spectra demonstrate that films crystalline with the Würtzite structure with preferential (002) crystallographic orientation having c-axis perpendicular to the substrate. The high optical properties of the ZnO NRs with a low density of deep defects was checked by UV-Vis transmittance analyses, the band gap energy of films varies between 3.3 and 3.4 eV with transparency around 80-90%.

Abstract

In oil industry microbiologically influenced corrosion plays a key role since it costs a lot of money yearly. This kind of corrosion is mainly induced by the microbial biofilms occurring on the metal surface and their metabolites that modify the electrochemical conditions from metal-solution interface. This study focused on the evaluation of the antimicrobial activity of essential oil of Lippiagracilis Schauer over Clostridium bifermentans isolated from ballast of ship transporter of crude oil as well as against fungi occurring on microbial biofilms. Additionally, it was evaluated the influence of the essential oil on the corrosion of AISI 1020 carbon steel by electrochemical and gravimetric techniques. A minimum inhibitory concentration of the 20.0 μg·L^-1 was obtained for the essential oil over the C. bifermentans that was the same used for investigating the biocide activity against fungal biofilms for different contact time. Results showed that colony former unit (CFU) for fungi reduced to zero after 120 minutes exposition to the essential oil. Also, the essential oil of L. gracilis Schauer showed a quite good potential to control effectively the growth of C. bifermentans. Electrochemical polarization and gravimetry assays showed that essential oil of L. gracilis Schauer at concentration of 60 µg·L^-1 was efficient to inhibit the corrosion of AISI 1020 carbon steel. L. gracilis Schauer essential oil acted as a powerful biocide.

Abstract

A selective, high yielding and convenient method for deprotection of tert-butyldimethylsilyl ether (TBS) using catalytic amount of ZnBr₂and N-chlorosuccinimide in methanol/DCM as solvent at room temperature is described. The methodology iseconomical, robust, clean, rapid, high yielding and highly selective in for deprotection of TBS ether.Methodology is applicable for deprotection of acetonide also.