Activity

The aqueous extract synthesized using the biomass, Ziziphus spina-christi, was applied to protect the surface of aluminium under acidic environment. The influence of extract concentration (0-0.14 mg/ml), contact time (2-8 h) and temperature (303.15-313.15 K) on the inhibition efficiency was studied. Langmuir isotherm fitted well to the experimental observations (R2 > 0.960) confirmed the monolayer attachment of inhibitors. The values of activation energy observed in this study suggests that the inhibition process to be surface interaction-based process. Thermodynamic parameters confirmed the process as feasible and exothermic. Potentiodynamic polarization and Electrochemical impedance spectroscopy studies are conducted to study the mechanism of corrosion. The electrochemical corrosion kinetics was studied using current density-potential curves and the Tafel constants (βa and βc) were calculated as 154.42 and 128.35 mV, at 0.14 mg/mL of inhibitor concentration. 20-Hydroxyecdysone ic50 The biomass-based corrosion inhibitor was characterized using scanning electron microscope and attenuated total reflection techniques.Membrane bioreactor technology includes the integration of biological wastewater treatment and physical separation by membrane filtration. When analyzing the system performance, efficiency of biological processes, physical separation and membrane fouling must be taken into consideration. Over the years, mathematical modelling of wastewater treatment has evolved and is being used extensively to optimize the performance of treatment systems. A Number of attempts have been made towards the development of mathematical models for membrane bioreactors and most of these models have not considered the effect of soluble microbial products on membrane fouling. Also the effect of periodic membrane cleaning was neglected. In this study, an integrated mathematical model was developed for the membrane bioreactor. A biological model based on activated sludge processes (extended with biopolymer kinetics) and a physical model with cake layer kinetics and membrane fouling have been combined. In order to overcome the drawbacks of previous attempts of modelling, the influence of soluble microbial products and extracellular polymeric substances are considered in the model integration. Further, the physical processes of the sludge removal and membrane cleaning which have strong influence on membrane fouling are considered in the model. “AQUASIM”, a computer program for the identification and simulation of aquatic systems, was used for solving the processes. Calibrated and validated model enables the prediction of the system performance and membrane fouling under different operating conditions.3D-particulate and 1D-fiber structures of multiferroic bismuth ferrite (BiFeO3/BFO) and their composites with 2D-graphene oxide (GO) have been developed to exploit the different scheme of interfacial engineering as 3D/2D and 1D/2D systems. Particulates and fibers of BFO were developed via sol-gel and electrospinning fabrication approaches respectively and their integration with GO was performed via the ultrasonic-assisted chemical reduction process. The crystalline and phase formation of BiFeO3 and GO was confirmed from the XRD patterns obtained. The electron microscopic images revealed the characteristic integration of 3D particulates (with average size of 100 nm) and 1D fibers (with diameter of ~150 nm and few μm length) onto the 2D GO layers (thickness of ~27 nm). XPS analysis revealed that the BFO nanostructures have been integrated onto the GO through chemisorptions process, where it indicated that the ultrasonic process engineers the interface through the chemical modification of the surface of these 3D/2D and 1D/2D nanostructures. The photophysical studies such as the impedance and photocurrent measurements showed that the charge separation and recombination resistance is significantly enhanced in the system, which can directly be attributed to the effective interfacial engineering in the developed hetero-morphological composites. The degradation studies against a model pollutant Rhodamine B revealed that the developed nanocomposites exhibit superior photocatalytic activity via the effective generation of OH radicals as confirmed by the radical analysis studies (100% degradation in 150 and 90 min for 15% GO/BFO particulate and fiber composites, respectively). The developed system also demonstrated excellent photocatalytic recyclability, indicated their enhanced stability.This study aimed to produce a clean energy, hydrogen, and to remove pollutants simultaneously in water by photoelectrochemical (PEC) method. The photo-anode of cuprous oxide modified titanate nanotube arrays (Cu2O/TNTAs) was synthesized by using lactic acid, green tea, and coffee as reductants individually. The characterizations of Cu2O/TNTAs were performed by ultraviolet-visible diffuse reflectance spectroscopy (UV-vis DRS), field emission scanning electron microscope (FE-SEM), X-ray photoelectron spectroscopy (XPS), and X-ray diffraction (XRD) to investigate the physical and chemical properties such as structure, crystallization, element contents, and optical performance. The electrochemical analyses of Cu2O/TNTAs showed the photo-current of Cu2O/TNTAs-t (using green tea as reductant) was 2.4 times higher than pure TNTAs, illustrating the effective separation of electron-hole pairs after Cu2O modification. The photoelectrochemical performances of Cu2O/TNTAs-t and Cu2O/TNTAs-c (using coffee as the reductant) were better than Cu2O/TNTAs-L (using lactic acid as the reductant) in terms of photo-current density, Ibuprofen degradation, and hydrogen generation, implying that depositing Cu2O on TNTAs can significantly improve the electron mobility by reducing the recombination rate of electron-hole pairs, which is beneficial to simultaneously ibuprofen degradation and hydrogen production.Arsenic oxyanions are toxic chemicals that impose a high risk to humans and other living organisms in the environment. The present study investigated indigenous heterotrophic bacteria in the tailings dam effluent (TDE) of a gold mining factory. Thirty-seven arsenic resistant bacteria were cultured on Reasoner’s 2A agar supplemented with arsenic salts through filtration. One strain encoded as PMS5 with the highest resistance to 140-mM sodium arsenite and 600-mM sodium arsenate in tryptic soy broth was selected for further investigations. According to phenotypic examinations and 16S rDNA sequence analysis, PMS5 belonged to the genus Alishewanella and was sensitive to most of the examined antibiotics. The biosorption and bioaccumulation abilities of arsenic salts were observed in this isolate based on Scanning Electron Microscopy (SEM) with Energy Dispersive X-Ray Analysis (EDX) and biosorption and bioaccumulation data. PMS5 was also found to cause the volatilization and biotransformation of arsenic oxyanions through their oxidation and reduction.