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Go to Editorial ManagerThe adsorption characteristics of Nickel (II) onto Iraqi Bentonite clay from aqueous solution have been investigated with respect to changes in pH of solution, adsorbent dosage, contact time and temperature of the solution. The maximum removal efficiency of Nickel (II) ions is 96% at pH=6.5 and exposure to 100 g/L adsorbent. For the adsorption of Nickel (II) ions, the Freundlich isotherm model fitted the equilibrium data better than the Langmuir isotherm model. Experimental data are also evaluated in terms of kinetic characteristics of adsorption and it was found that the adsorption process for Ni+2 ions follows well pseudo-second-order kinetics. Thermodynamic functions, the change of free energy (?G°), enthalpy (?H°) and entropy (?S°) of adsorption are also calculated for Nickel (II) ions. The results show that the adsorption of the Nickel (II) ions on Iraqi Bentonite is feasible and exothermic at (20-50) °C.
Gait analysis can be described as a field of biomechanical engineering dealing with the subject of human locomotion. This study aimed to identify the effect of Ilizarov on gait when the presence the above-knee prosthesis. The study was made on a 50-year-old male patient was underwent correction right tibia with Ilizarov fixation due to war accident in July 2012. Also, this accident led to trans-femoral amputation. Two-dimensional gait system of a synchronized 25 Hz camera with an AMTI force platform was use for measuring gait kinematics and kinetics data while walking at a self-selected speed. These data can be used as standard measures in pathology studies, as input to theoretical joint models, and as input to mechanical joint simulators treated with Ilizarov and prosthetics.
Biodiesel produced from vegetable oils is a good alternative clean diesel. The present study was conducted because there are some variations or contradictions in literature on the use of CaO heterogeneous catalyst. In this study, biodiesel was produced from sunflower vegetable oil and methanol in presence of commercial calcium oxide catalyst in batch mechanical stirrer reactor. The effect of three operating conditions, methanol mole ratio (4-12), reaction time (0.5-2.5 h) and catalyst amount (2-10 %), on the yield of biodiesel was studied at constant reaction temperature of 60 oC. Response surface methodology (RSM) was used with central composite design (CCD) of experiments. Polynomial correlation was found for the dependent variable of the process (yield of biodiesel), satisfactorily predicted at 95% confidence level. The optimum yield biodiesel was about 98% and at operating condition of methanol ratio 10, reaction time 2 h and catalyst amount 8 %. The reaction time was found to be the most effective operating condition. Kinetics study of the process showed that first order reaction with triglyceride concentration and zero order with methanol concentration gave best fit with the experimental data, triglyceride with a reaction rate constant k= 1.53 h-1.
In this study, low cost biosorbent ? inactive biomass (IB) granules (dp=0.433mm) taken from drying beds of Al-Rustomia Wastewater Treatment Plant, Baghdad-Iraq were used for investigating the optimum conditions of Pb(II), Cu(II), and Ni(II) biosorption from aqueous solutions. Various physico-chemical parameters such as initial metal ion concentration (50 to 200 mg/l), equilibrium time (0-180 min), pH (2-9), agitation speed (50-200 rpm), particles size (0.433 mm), and adsorbent dosage (0.05-1 g/100 ml) were studied. Six mathematical models describing the biosorption equilibrium and isotherm constants were tested to find the maximum uptake capacities: Langmuir, Freundlich, Redlich–Peterson, Sips, Khan, and Toth models. The best fit to the Pb(II) and Ni(II) biosorption results was obtained by Langmuir model with maximum uptake capacities of 52.76 and 36.97 mg/g for these two ions respectively. While for Cu(II) the corresponding value was 38.07 mg/g obtained with Khan model. The kinetic study demonstrated that the optimum agitation speed was 400 rpm, at which the best removal efficiency and/or minimum surface mass transfer resistance (MSMTR) was achieved. A pseudo-second-order rate kinetic model gave the best fit to the experimental data (R2=0.99), resulting in mass transfer coefficient values of 42.84× , 1.57× , and 2.85× m/s for Pb(II), Cu(II), and Ni(II) respectively. The thermodynamic study showed that the biosorption process was spontaneous and exothermic in nature.
This work investigated the removal of the reactive green (R.G) dye from wastewater using the photo-Fenton process. Batch experiments were carried out to research the role of the Impacts of operating parameters. The dosage of H2O2; dosage Fe+2; pH; temperature, and irradiation time were examined. Maximum decolorization efficiencies green dye were achieved at the [H2O2]=100 ppm; [Fe2+]=20 ppm; pH 3; temperature=56 °C and irradiation time=90 min. This research focuses on modeling, kinetics and thermodynamics of the removal of pollutant (reactive green dye) of water. The results showed that the decolorization kinetic of R.G followed pseudo-first-order reaction kinetic. Also the thermodynamic parameters ?G?, ?H? and ?S? were determined using the Van't Hoff equation for the oxidation processes. The changes in Gibbs free energy showed the oxidation process under normal conditions is non-spontaneous.