الفهرس 
Chapter 1 IntroductionOnly 14 pages are availabe for public view
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Abstract
Organic compound-containing wastewater is produced in huge amounts by many industrial plants, which should be treated before discharging as the organic pollutants are highly undesirable pollutants from the environmental point of view. Treatment of this wastewater is very costly. Sugar industry is one of the largest chemical industrial sectors in Egypt.
In this thesis, three different treatment techniques have been investigated to treat real beet sugar mill effluent. The first one was adsorption technique by using an activated carbon obtained from graphitization and chemical treatment of the rice husk (ACRH). The second one was a new electrochemical technique by using an electromagnetic field-enhanced novel tubular electrocoagulation cell as an effective and low-power treatment process. The third technique was a microbial fuel cell (MFCs) is a new bio electrochemical device that aims to generate electricity utilizing electrons obtained from microorganisms’ digestion of organic substances. Accordingly, if industrial wastewater could be utilized in the MFCs, a double benefit would be obtained, renewable energy generation with simultaneous wastewater treatment.
During adsorption studies, it was found that the adsorption of phenol (as a model for the organic pollutant) is high 145 mg per g of ACRH, and the adsorption capacity in the intraparticle structure is 180% higher than adsorption on the external surface of the activated carbon from rice husk and the experimental results proved that intraparticle diffusion is the controlling step.
To enhance the treatment of real industrial wastewater effluents, a new design of an electromagnetic field-enhanced electrochemical cell consisting of a tubular screen roll anode and two cathodes (an inner and outer cathode) has been used. The treatment of real beet sugar mill effluent by the electrocoagulation process has been studied. Different parameters have been investigated, like current density (CD), effluent concentration, NaCl concentration, rpm, number of screen layers per anode, and the effect of the addition of an electromagnetic field. The results showed that: under the optimum conditions of CD at 3.13 Am-2, two screens per anode, NaCl concentration of 12 g/l, and rotation speed at 120 rpm, the percentage of color removal was 85. 5 % and the electrical energy consumption was 3.595 kWh/m3. In addition, the presence of electromagnetic field enhanced the energy consumption for the wastewater treatment by accelerating the coagulation step as indicated by simulation results. Numerically, applying the magnetic field resulted in performing a color removal efficiency of 97.7 % using a power consumption of 2.569 kWh/m3 which is considered a distinct achievement in industrial wastewater treatment process. This design has proven to be a promising one for continuous treatment of industrial effluents and to be a possible competent to the currently available techniques due to the high removal efficiency and low energy consumption.
In MFC technique, a novel carbon nanofibers-decorated graphite rods are introduced as effective and low-cost anodes for industrial wastewater-driven microbial fuel cells. Carbon nanofibers deposition on the surface of the graphite rods could be performed by electrospinning of polyacrylonitrile/N,N‒dimethylformamide solution at 6.42 KV using the rod as nanofiber collector. Vacuous drying followed by graphitization under inert atmosphere results in formation of carbon nanofiber layer on the surface of the used graphite rods. The experimental results indicated that at 10 min electrospinning time, the proposed graphite anode reveals very good performance compared to the commercial anodes. Typically, the generated power density from sugarcane industry wastewater-driven air cathode microbial fuel cells were 13±0.3, 23±0.7, 43±1.3 and 185±7.4mW/m2 using carbon paper, carbon felt, carbon cloth and graphite rod coated by 10- min electrospinning time carbon nanofibers anodes, respectively. The distinct performance of the proposed anode came from creating 3D carbon nanofiber layer filled with the biocatalyst. Moreover, to annihilate the internal cell resistance, a membrane-less cell was assembled by utilizing poly(vinylidene fluoride) electrospun nanofiber layer-coated cathode. This novel strategy inspired a highly hydrophobic layer on the cathode surface preventing water leakage to avoid utilizing the membrane. However, in both of anode and cathode modifications the electrospinning time should be optimized; the best results were obtained at 5 and 10 min for the cathode and anode, respectively.
Overall, the developed magnetic field-enhanced novel tubular electrodes electrocoagulation cell and carbon nanofibers decorated graphite rode-based microbial fuel cell performed distinguished and low-cost treatment of the sugar industry wastewater. Typically, a strong saving in the required electrical energy with a maximization of the color removal efficiency could be achieved in the electrocoagulation-based technique. Moreover, in the developed MFC, electrical power was generated from the wastewater with simultaneous treatment.