Ahmad Tariq Jameel

Synthesis and Characterization of Carbon Nanofibers Grown on Powdered Activated Carbon

Carbon nanofibers (CNFs) were synthesized through nickel ion (Ni2+) impregnation of powdered activated carbon (PAC). Chemical Vapor Deposition (CVD) using acetylene gas, in the presence of hydrogen gas, was employed for the synthesis process. Various percentages (1, 3, 5, and 7 wt. %) of Ni2+ catalysts were used in the impregnation of Ni2+ into PAC. Field Emission Scanning Electron Microscope (FESEM), Fourier Transform Infrared (FTIR) Spectroscopy, Energy Dispersive X-Ray Analyzer (EDX), Transmission Electron Microscopy (TEM), Thermal Gravimetric Analysis (TGA), zeta potential, and Brunauer, Emmett, and Teller (BET) were utilized for the characterization of the novel composite, which possessed micro and nanodimensions. FESEM and TEM images revealed that the carbonaceous structure of the nanomaterials was fibrous instead of tubular with average width varying from 100 to 200 nanometers. The PAC surface area increased from 101 m2/g to 837 m2/g after the growth of CNF. TGA combustion temperature range was within 400°C and 570°C, while the average zeta potential of the nanocomposite materials was −24.9 mV, indicating its moderate dispersive nature in water.

Lead Sorption by Carbon Nanofibers Grown on Powdered Activated Carbon — Kinetics and Equilibrium

Carbon nanofibers (CNFs) were synthesized by using a safe and less hazardous method, compared to using floating catalysts in chemical vapor deposition (CVD) process. This process used C2H2 as carbon source and oil palm kernel shell-based powdered activated carbon (PAC) as cheap solid substrate. Use of nickel (Ni2+) impregnated PAC as fixed substrate for the synthesis of CNF is one of the novelties of the research work accomplished by the authors. The PAC–CNFs porous nanocomposite product was used for the sorption of lead ions (Pb2+) from synthetic aqueous solution. Kinetics of Pb2+ adsorption and isotherms were investigated by varying initial concentration of lead and contact time. PAC–CNFs were found to remove Pb2+ better at acidic pH of about 5.5. Langmuir and Freundlich isotherms were applied to the sorption equilibrium data to find the best fitted model. Langmuir isotherm model with R2 = 0.965 fitted the adsorption data better than the Freundlich isotherm. The kinetic processes of Pb2+ adsorption on CNFs were investigated by applying different kinetic models, namely zero-order, pseudo-first-order and pseudo-second-order. The pseudo-second-order rate equation exhibited the best results with R2 = 0.999, qe = 74.79 (mg/g) and K2 = 0.029 (min ⋅ g/mg). The novel nanocomposite product seemed to have the potential to remove Pb2+ ions from aqueous solution.

Optimization of oil extraction from Pitanga (Eugenia uniflora L.) leaves using simplex centroid design

ABSTRACT Simplex centroid design (SCD) was employed to optimize the mixing of petroleum ether, n-hexane, methanol and ethanol for the extraction of oil (PLO) from Pitanga (Eugenia uniflora L.) leaves, via Soxhlet extraction. The highest yield (54%) of Pitanga leaf oil (PLO) was obtained with 100% ethanol and the lowest yield (16%) from the mixture of methanol (33.3%)/hexane (33.3%)/ethanol (33.3%). The coefficient of determination (R2) of the model equation obtained was 0.91, while the adjusted R2 and predicted R2 were 0.8729 and 0.951, respectively. The saponification value (S.V.), iodine value, acid value and free fatty acid (FFA) are 35.34 mgKOH/g, 72.97 mgI2/g oil, 32.41 and 16.30 mgKOH/g, respectively.

Numerical simulation of non-isothermal thin liquid film flow on inclined plane using an implicit finite difference scheme

The classical problem of the stability and dynamics of thin liquid films on solid surfaces has been studied extensively. Particularly, thin liquid films subjected to various physico-chemical effects such as thermocapillarity, solutal-Marangoni and evaporative instabilities at the film surface has been the focus of research for more than two decades. Various flow configurations of thin film such as thin film on plane, inclined, and wavy surfaces has been the subject of recent investigations. An inclined film compared to a horizontal film, also experiences the gravity force which may significantly influence the nonlinear dynamics of the film coupled with other forces. In this research, we attempt to study the stability and dynamics of thin liquid films subjected to thermocapillarity and evaporative instabilities at the free surface besides instability owing to ubiquitous van der Waals attraction, using numerical simulations. For a Newtonian liquid, flow in thin liquid film on a planar support and bounded by a passive gas, is represented by Navier-Stokes equation, equation of continuity and appropriate boundary conditions. The external effects are incorporated in the body force term of the Navier-Stokes equation. These governing equations are simplified using the so called long-wave approximation to arrive at a nonlinear partial differential equation, henceforth called equation of evolution (EOE), which describes the time evolution of the interfacial instability in the film caused by internal and/or external effects. Efficient numerical method is required for the solution of the equation of evolution (EOE) in order to comprehend the nonlinear dynamics of the thin film. Here we present the results of our numerical simulation using Crank-Nicholson implicit finite difference scheme applied to the thin film model incorporating instabilities owing to gravity, evaporation and thermo-capillarity. Comparison of our results with those obtained from Spectral method, show remarkable agreement for most of the cases investigated.

Unconventional Method for Monitoring of Waste Cooking Oil Transesterification

A technique to monitor transesterification of waste cooking oil (WCO) is presented. The technique was developed based on analogue signal from WCO, fatty acid methyl ester (FAME) and commercial palm oil (CPO). A low-pass filter design for the photodiode was used to obtain the characteristic analog signal generated by these oil samples and the signal was correlated to absorbance spectra of the oils using data from Fourier transform infrared (FTIR) equipment. A match was made between the analogue signals of the oil samples and calibrated against the FTIR spectra at 95% confidence level. Depletion of WCO during transesterification in a batch reactor correlated with the time observed for peak yield during biodiesel production. The results of the technique are discussed as a possible way to monitor transesterification process in a batch reactor.