الفهرس 
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Abstract
Food security continues to be a major issue in the world, as the global population grows and certain resources become increasingly scarce. The agricultural industry is heavily reliant on fertilizers containing phosphorus to ensure healthy crop yields that feed the world. However, there are growing concerns about the availability of these fertilizers and the environmental impact from their production. Phosphate fertilizer industries produce a particular kind of effluent which is highly acidic and contains significant amounts of pollutants such as fluoride and phosphate. The high content in these pollutants and the enormous daily flow-rate of fertilizer industry wastewater from phosphate fertilizers production lead to the discharge of several thousand tons of these pollutants per year. Accordingly, there is an increasing demand for treatment of wastewaters from phosphate fertilizer industry to make water for agricultural and industrial reuses. In this regards, the present work aimed to develop cost effective and efficient method for phosphate industry wastewater treatment.
The present thesis is composed of a three main chapters, each of which can be summarized as follow:
THE FIRST CHAPTER:
This chapter concern with a full literature survey for the different approaches for phosphate fertilizers industry wastewater treatment. The main points that have been discussed through this chapter can be summarized as follow:
Overview of the world fertilizers demand 120
Summary and conclusions
Phosphate rock
World Production of Phosphate Rocks
Phosphate resource in Egypt
Overview on phosphate fertilizer manufacturing facilities.
Wastes in phosphate fertilizers industry.
Reviewing of the different techniques concerning the Wastewater treatment such as Coagulation and Flocculation method, precipitation method, electrochemical method, Sedimentation and flotation, Biological method, Membranes Technology, Disinfection method and Sorption method.
THE SECOND CHAPTER:
The utilized chemicals, reagents, materials, apparatus, instruments and equipment were stated. It could be summarize the experiments which have been done in this work as follow:
Characterization of the utilized natural Na-bentonite sample.
Study the factors affecting the sorption of iron, fluoride, phosphate and COD and TSS from wastewater sample which include; shaking time, solution pH, reaction temperature, liquid/ solid ratio, and mechanical stirring speed.
Characterization of the activated carbon working sample.
Investigate the variables affecting iron, fluoride, phosphate and COD and TSS adsorption from wastewater such as; shaking time, solution pH, reaction temperature, liquid/ solid ratio, and mechanical stirring speed.
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Summary and conclusions
THE THIRD CHAPTER:
The results of experimental work were declared and discussed through this chapter which consists of four main parts. Both parts one and two covers the characterization of the utilized natural Na-bentonite sample and its subsequent utilization in iron, fluoride, phosphate and COD and TSS sorption. The third and fourth parts of this chapter concern with characterization of activated carbon and its applications in batch iron, fluoride, phosphate and COD and TSS adsorption from wastewater sample.
The first part
The following analyses have been carried out for the prepared bio-charcoal, hydrochloric and nitric acids activated charcoal: XRD, XRF, FT-IR, Surface as well as the cross section morphology and BET. The obtained results can be summarized as the following; The XRD peaks clear that the clay is composed primarily of montmorillonite (mainly sodium bentonite). XRF results show that Na-bentonite sample is composed mainly of silicon dioxide, aluminum oxide, and iron oxide, in addition to sodium, potassium, calcium, and magnesium oxides. The obtained analysis confirmed that the natural bentonite sample belongs to Na-bentonite category. FTIR spectra indicates quartz admixture in the sample, which has been confirmed by X-ray diffraction extensively. The surface morphology show loose aggregates with a porous structure, and the aggregated particles are of various shapes and sizes having crystalline features. The specific surface area (SBET) and the total pore volume (VT) of the clay sample were 33.02 m2/g, 0.0583cc/g respectively.
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Summary and conclusions
The second part
This part includes the application of natural Na-bentonite (Na-
B) for iron, fluoride, phosphate and COD and TSS adsorption from wastewater. The effect of different factors on the sorption process namely; shaking time, amount of the added Na-B (g/ L), solution pH, mixing stirring speed and temperature have been investigated. The obtained data clarify that the preferred experimental conditions were picked as following; shaking time of 60 min, room temperature and added sorbent amount of 1.0 g/ L. With regard to the aforementioned conditions; iron, fluoride, phosphate and COD and TSS sorption efficiencies were 80.5, 60.3, 36.6, 71.4, and 60.5% respectively.
The kinetic terms of adsorption process were analyzed using the pseudo-first order, pseudo-second order, and Morris-Weber models. The thermodynamics analysis for iron, fluoride, phosphate and COD and TSS adsorption results showed that the removal process had been of an endothermic behavior. Simultaneously, the thermodynamics parameters ∆H and ∆S showed positive values that could confirm the endothermic nature of the adsorption process. On the other hand, ∆G was found to be negative value which refers to the execution of a spontaneous process.
In the third part
This part is concerning with the characterization of the utilized activated carbon (AC) by XRD, FT-IR, Scan Electron Microscope (SEM) and BET. The obtained results can be summarized as following; FT-IR spectra reflect the existing function groups in the activated carbon structure. The surface properties of AC were as following;
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Summary and conclusions
surface area of 1171m2/ g, total pore volume of 0.55cm3/g and average pore radius of 1.12 nm. The inner morphologies of AC exhibited loose aggregates with a porous structure. Moreover, it is clear that the carbon surface is smooth and distributed with small pores. XRD spectrum confirm the presence of carbonaceous structures.
The fourth part
This part deals with the application of the activated carbon for iron, fluoride, phosphate and COD and TSS removal from phosphate industries wastewater. The impact of various parameters on the adsorption process such as; shaking time, amount of the added carbon (g/ L), solution pH, stirring speed, and temperature have been studied.
The obtained results indicate that the adsorption process using AC has got an equilibrium state after 30 min. Moreover, the obtained data show that about 34.2, 75.4, 80.4, 81.4, and 87.5% of iron, fluoride, phosphate, and COD and TSS respectively could be adsorbed from the wastewater sample using activated carbon applying the following conditions; shaking time 30 min; solution pH of 4, sorbents dose of 2.0 g/ L; and room temperature. The experimental data were tested through different kinetic model expressions. The acquired data were successfully modeled using the pseudo second order. The thermodynamic parameters (ΔH, ΔS and ΔG) of the presented adsorption process indicate that iron, fluoride, phosphate and COD and TSS removal has been endothermic, physical and spontaneous.
In conclusion, the obtained data indicated that activated carbon is highly effective for wastes adsorption from phosphate industries wastewater, than Na-bentonite. In addition, by applying subsequent
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Summary and conclusions
double stage treatment process (Na-bentonite followed by activated carbon), the wastewater stream could be recycled inside the phosphate fertilizer plan as (gas scrubbers –mixers-in granulation process) which contributes to environmental as well as water security.