Zakaria Al-Qodah

Adsorption of dyes using shale oil ash

Abstract The adsorption of reactive dyes on shale oil ash has been investigated during a series of batch adsorption experiments.The adsorption isotherm data were fitted to Langmuir isotherm. The two-resistance mass transfer model has been developed based on the film resistance and homogeneous solid phase diffusion. A computer program has been developed to estimate the theoretical concentration-time dependent curves and to compare them with the experimental curves by means of the best-fit approach. The model predicts that the external mass transfer coefficient K was not affected by varying the initial dye concentration, but it increases when the agitation speed and temperature was raised. The diffusion coefficient D was found to increase when the initial dye concentration, and temperature was raised.

Production and characterization of granular activated carbon from activated sludge

In this study, activated sludge was used as a precursor to prepare activated carbon using sulfuric acid as a chemical activation agent. The effect of preparation conditions on the produced activated carbon characteristics as an adsorbent was investigated. The results indicate that the produced activated carbon has a highly porous structure and a specific surface area of 580 m 2 /g. The FT-IR analysis depicts the presence of a variety of functional groups which explain its improved adsorption behavior against pesticides. The XRD analysis reveals that the produced activated carbon has low content of inorganic constituents compared with the precursor. The adsorption isotherm data were fitted to three adsorption isotherm models and found to closely fit the BET model with R 2 equal 0.948 at pH 3, indicating a multilayer of pesticide adsorption. The maximum loading capacity of the produced activated carbon was 110 mg pesticides/g adsorbent and was obtained at this pH value. This maximum loading was found experimentally to steeply decrease as the solution pH increases. The obtained results show that activated sludge is a promising low cost precursor for the production of activated carbon.

Enhancement of COD-Nutrients Removals and Filterability of Secondary Clarifier Municipal Wastewater Influent Using Electrocoagulation Technique

The present work studied experimentally the variations of some characteristics of the mixed liquor solution in wastewater treatment plants (WWTPs) under the effect of electrocoagulation (EC) technique. Unlike conventional methods, electrocoagulation was performed using cylindrical perforated iron electrodes to achieve a good distribution of the applied DC field onto the municipal wastewater. Effects of electrocoagulation time, applied voltage gradient, and aeration on the mixed liquor characteristics were considered. The study figured out the dependency of the local pH and oxidation potential reduction (OPR) values, near anode and cathode on these operational conditions. It was found that electrocoagulation process reached steady state conditions in no more than 60 minutes. At high voltage gradient (6 V/cm), the steady removal efficiencies of COD and nutrients exceeded 89%. While aeration showed moderate influence on removal efficiencies and wastewater sludge filterability, it significantly affected the pH and ORP near the electrodes especially at the low voltage gradient. Results also indicated that the sludge filterability was improved notably by increasing the voltage gradient to have minimal levels of specific-resistance to filtration (SRF).

Copper Adsorption on Chitosan-Derived Schiff Bases

The adsorption of Cu(II) ions onto the chitosan derived Schiff bases obtained from the condensation of chitosan with salicyaldehyde (polymer I), 2,4-dihydroxybenzaldehyde (polymer II) and with 4-(diethylamino) salicyaldehyde (polymer III) in aqueous solutions was investigated. Batch adsorption experiments were carried out as a function of contact time, pH, and polymer mass. The amount of metal-ion uptake of the polymers was determined by using atomic absorption spectrometry (AAS) and the highest Cu(II) ions uptake was achieved at pH 7.0 and by using sodium perchlorate as an ionic strength adjuster for polymers I, II, and III. The isothermal behavior and the kinetics of adsorption of Cu(II) ions on these polymers with respect to the initial mass of the polymer and temperature were also investigated; adsorption isothermal equilibrium data could be clearly explained by the Langmuir equation. The experimental data of the adsorption equilibrium from Cu(II) solution correlates well with the Langmuir isotherm equation.

Hydro-thermal behavior of magnetically stabilized fluidized beds

Abstract Three different magnetic particles have been used to investigate the effect of a transverse magnetic field on the hydrodynamic and thermal behavior of a gas-fluidized bed, with an immersed heating spherical surface. The effects of gas superficial velocity and magnetic field intensity on the boundaries of the flow regimes and bed porosity have been studied to explain the behavior of the radial temperature distribution and the local heat transfer coefficient at different radial positions in the bed. In the present study, three correlations for the minimum fluidization velocity U mf , the minimum stabilization intensity B msi , and Nuselt number (Nu) are proposed.

Modeling of antibiotics production in magneto three-phase airlift fermenter.

A mathematical model is developed to describe the performance of a three-phase airlift reactor utilizing a transverse magnetic field. The model is based on the complete mixing model for the bulk of liquid phase and on the Michaelis-Menten kinetics. The model equations are solved by the explicit finite difference method from transient to steady state conditions. The results of the numerical simulation indicate that the magnetic field increases the degree of bioconversion. The mathematical model is experimentally verified in a three-phase airlift reactor with P. chrysogenum immobilized on magnetic beads. The experimental results are well described by the developed model when the reactor operates in the stabilized regime. At relatively high magnetic field intensities a certain discrepancy in the model solution was observed when the model over estimates the product concentration.

Heavy metal ions removal from wastewater using electrocoagulation processes: A comprehensive review

ABSTRACT A vast number of publications have investigated the application of electrocoagulation (EC) process in heavy metal ions removal from wastewaters. Most of these studies were simple lab-scale using synthetic wastewater with the absence of holistic and systematic approach to consider the process complexity. This comprehensive review considers the fundamental aspects of EC processes such as mechanisms, kinetic models, and isotherm models used by different researchers. Furthermore, the impact of the main design and process operational parameters on the removal efficiency is discussed and analyzed. Many concluding remarks and perspectives are stated to give insights for possible future investigations.

Separation of yeast cells from aqueous solutions using magnetically stabilized fluidized beds

Aims:  To separate Saccharomyces cerevisiae cells from aqueous solutions using magnetically stabilized fluidized beds (MSFB) that utilize a horizontal magnetic field, and to study the effect of some parameters, such as bed porosity and height, liquid flow rate and inlet concentration on cell removal efficiency and breakthrough curves.

Application of Magnetically Stabilized Fluidized Beds for Cell Suspension Filtration from Aqueous Solutions

Abstract A magnetically stabilized fluidized bed (MSFBs) utilizing a transverse magnetic field was used to retain cells from cell suspension. The magnetic field permits bed expansion without mixing of the magnetic particles. The bed porosity increased by 75% when the magnetic field intensity increases to 110 mT. The effect of the magnetic field, suspension flow rate, bed height, initial concentration, and pH on the breakthrough curves was studied. According to the experimental results, increasing the initial concentration, flow rate, and pH leads to early breakthrough and inefficient deposition. Additionally, increasing the field intensity and bed height delays the breakthrough point.

The Effect of Magnetic Field on Local Heat Transfer Coefficient in Fluidized Beds With Immersed Heating Surface

Five different magnetic particles have been used to investigate the effect of a transverse magnetic field on the thermal behavior of a gas fluidized bed, with an immersed heating spherical surface. The effects of gas superficial velocity and magnetic field intensity on the behavior of the temperature distribution and the local heat transfer coefficient at different radial and axial positions in the bed was investigated. In the present study a correlation relating Nusselt number to the magnetic field intensity is proposed.