Applied Chemical Engineering

Abstract In recently few years, application of membrane technologies in sea water desalination is increased compared to other desalination technologies. Electrodialysis membrane technology is still limited in seawater desalination due to the high operation cost and its limitations for high salty water. Electrodialysis desalination cost is proportional to the amount of salt, which must be carried out through the membrane. Seawater desalination with high salt content of NaCl (42 g/L) was applied using IonTech electrodialysis unit. Partial desalination process was studied in two separate experiments, batch and continuous operation. Operation parameters like voltage applied, electrolyte concentration and time of desalination were studied under batch mode process. Continuous operation process was carried out to confirm the partial desalination process of electrodialysis. The limited current density is determined, 1.49 A/m 2  and 1.15 A/m 2  for theoretical and experimental, respectively. The specific energy consumption was calculated, 7.15 kWh/m 3 . 

Abstract The acquisition of new materials for the manufacturing of high efficiency and low-cost photovoltaic devices has currently become a challenge. Thin films of CuInGaSe and CdTe have been widely used in solar cell of second generation, achieving efficiencies about 20 %; however, the low abundance of In and Te as well as the toxicity of Cd is  the primary obstacles to their industrial production. Compounds such as Cu 2 ZnSnS 4 , Cu 2 ZnSnSe 4  and Cu 2 ZnSn(SSe) 4  have emerged as an important and less costly alternative for efficient energy conversion in the future. In addition, these compounds have the required characteristics to be used as an absorber material in solar cells (band-gap close to 1.4 eV, an absorption coefficient greater than 10 4  cm -1  and a p-type conductivity). In this work, we present a study of the structural, compositional, morphological and optical properties of Cu 2 ZnSnS 4 thin films deposited by spray pyrolysis technique as well as their dependence on temperature.

Abstract A technique has been developed to detect and determine multi heavy metals simultaneously in a water sample. Hydride generating technique was implemented to convert the analyte which present in the water sample (liquid phase) into another form with an improved separation coefficient, called “derivative”. This process occurred without changing the original chemical structure. Derivatives were separated from the liquid phase by applying custom made gas-liquid separator (GLS), operated with oscillation. Separated species then transferred into a die-electric barrier discharge (DBD) plasma atomizer where a fragmentation of the analyte into free atoms is occurred. The generated atoms were detected by emission spectroscopy. The presented technique was applied for detection of individual and multi heavy metals simultaneously in water sample and proved useful in terms of reducing the effect of the hydrogen generated, through the process, on suppressing the atoms signal in the DBD atomizer.

Abstract Thin films of un-doped and doped a-Se with Dysprosium rare - earth ions have been prepared by the thermal evaporation technique. The optical transmission spectra of the investigated films have been measured in a wide spectral range and used to calculate the linear optical constants together with the optical energy gap of studied films. The observed decrease in the values of the energy gap against the increase of the Dysprosium (Dy) content in a-Se films has been explained using Mott and Davis Model and in terms of electronegativity difference of the constituent atoms. Furthermore, the dispersion of nonlinear parameters such as second - order refractive index and nonlinear absorption coefficient (two-photon absorption coefficient) of investigated films are presented and discussed.

Abstract In the current research, the vegetable oil based polyurethane nanocomposite (PUNC) adhesive was prepared using transesterified castor oil (CO) based polyol, partially biobased aliphatic isocyanate (PBAI) and organically modified montmorillonite nanoclay (Closite 30B). The transesterified CO was synthesized by reacting CO with ethylene glycol, which was confirmed using proton nuclear magnetic resonance ( 1 HNMR) analysis. Further, the prepared polyurethane (PU) and its nanocomposite adhesive with specific NCO: OH molar ratio 1.3:1 was confirmed by Fourier transform infrared spectroscopy (FTIR) analysis. The increasing of wt% of nanoclay loading level up to 3% into PU matrix increased the lap shear strength of the adhesive systems. Subsequently, the effect of polyurethane nanocomposite adhesives on the bonding strength of wood-to-wood and aluminum-to-aluminum substrate was studied using lap shear strength test. The nanoclay was observed to effectively intercalate into the polymer matrix. Moreover, the phase separation in PU and PUNC adhesive was studied using atomic force microscope (AFM) and differential scanning calorimetry (DSC) analysis.

Abstract This article studies a new green eco-friendly TLC (thin layer chromatography) using silica gel and polyaniline modified silica gel as stationary phase in combination with ethyl acetate (EA), n-butyl acetate (BA) and butane-1-ol (BO) solutions as mobile phase for the comparative study of migration behaviour of organic dyes to identify the most suitable thin layer chromatographic system for the resolution of co-existing dyes. Better separation efficiency was observed by modifying silica gel with polyaniline as compared to pure silica stationary phase. Densitogrpahic presentation of separations achieved on polyaniline modified silica gel Pani@SG-EB1 was also presented. The thin layer chromatographic system comprising of polyaniline modified silica gel Pani@SG-EB1 as stationary phase and n-butyl acetate:DDW, 5:5 as green mobile phase was observed to be the most favourable for the separation of various combinations of three or four-component mixtures of organic dyes viz. methyl thymol blue, tartrazine, carmoisine, rose bengal, amidoblack 10B, bromopyrogallol red and 4-nitrobenzene dizonium tetrafluoroborate. The effect of presence of cations and anions on separation trend was also examined and the limits of detection of the separated organic dyes were estimated. Fourier transform infrared spectroscopy (FTIR), x-ray diffraction (XRD), scanning electron microscopy (SEM) and transmission electron micrograph (TEM) studies were undertaken to characterize silica gel and modified silica gel (stationary phase). The developed method has been successfully applied for the identification of carmoisine in Solvin cold DS syrup and tartrazine in MefastTM syrup.