Afrasyab Khan

Recent developments in immobilizing titanium dioxide on supports for degradation of organic pollutants in wastewater- A review

This review focuses on the various types of supports used for immobilization of titanium dioxide nanomaterial catalyst for degradation of organic pollutants in wastewater. Several supports suitable to particular immobilization technique used for the degradation of pollutants in wastewater streams are explained. In general, a coating of catalyst on supports is carried out either by physical (e.g., thermal treatment) or by chemical (e.g., sol–gel). Among a range of the supports used, some of the prominent ones include glass, silica, activated carbon, stainless steel, cellulose, clay. Also, characterization methods in use such as X-ray diffraction, transmission electron microscope, scanning electron microscope, and UV-spectroscopy are discussed. The operating parameters such as temperature for the selected immobilization techniques are also explained.

Modeling and optimization of photocatalytic treatment of pre-treated palm oil mill effluent (POME) in a UV/TiO2 system using response surface methodology (RSM)

Abstract This study aimed at the degradation of COD, BOD and Color present in palm oil mill effluent (POME) using UV/TiO2 system. A Statistical tool called face-centered central composite design has been run through response surface methodology by the use of design expert software to model and optimize the photodegradation process. The SEM average size of the synthesized TiO2 particle is 100 nm and this confirm that it is anatase. The prominent peak as reveal by XRD occur at 22.3° and this indicates that TiO2 formed is anatase. The FTIR results shows a peak value of 1,406.50 and 1,452.50 cm−1 indicating that the TiO2 anatase is formed while nonappearance of the peak at 2,900 cm−1 indicates that the all organic compounds have been removed after calcination. The three models developed for the three pollutants are non-significant as revealed from the Prob > F values of 0.0584 for COD, 0.0612 for BOD and 0.4239 for color and this confirms that proposed models fit the experimental data. The optimum conditions for the three parameters are 5.50 for initial pH, 4.84 mg for catalyst dosage and 42.86 min for time and the percentage removal of the COD, BOD, and color are within the range of 59.43–96.81%, 48.05–102.68% and 60.63–94.29% respectively. Regression analysis obtained through analysis of variance provided significant quadratic polynomial with the coefficient of determination R2 = 0.9646, 0.9496 and 0.9223 for COD, BOD, and Color removal respectively.

CFD based Hydrodynamic Parametric study of inclined injected Supersonic steam into subcooled water

Hydrodynamic parametric study of the supersonic steam injection into subcooled water is investigated.The phenomenon of direct-contact condensation, used in steam driven jet injectors, nuclear reactor emergency core cooling systems and direct-contact heat exchangers was investigated computationally by injecting an inclined steam jet without the presence of non condensable gases using a supersonic nozzle submerged in subcooled water. Ansys Fluent based Euler-Euler multiphase model is used. The angle of inclination is varied from 450 to 00 with a decrement of 200 for each computation with the constant inlet pressure of 7 bars and water temperature of 300C. It was found that the temperature and pressure near the nozzle exit showing an abrupt height with the instantaneous condensation upon venting. The hydrodynamic Gaussian profile width is more in the case of vertical injection as compare to the inclined injection which depict the effect of static water fluid pressure and gravity on pressure head and temperature.