الفهرس 
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Abstract
Cleaner environment is the major requirement for smooth and better living of human beings. Of late, a rapid declination in environmental quality is observed globally. Of all, the critical requirement of living is water. Contamination of water can be highly noticed in emergent nations. Factors like population explosion, urbanization, rapid industrialization and various other harmful anthropogenic activities cause an increase in contamination of existing natural water resources thereby increasing water scarcity.
The wastewater may be contaminated with various inorganic as well as organic pollutants such as dyes, products from pharmaceutical, pesticides, personal care products (PCP), chemicals that may affect the endocrine process of organisms, surfactants, toxic metals etc. Out of this, water pollution caused by metal contamination which is a serious environmental problem because of the non biodegradability, high stability and solubility of these metals. Their environmental persistence disrupts biogeochemical cycles and damages food chain which in turn deranges the ecosystem.
This thesis contain four main chapters, their contents are summarized as follows:
Chapter 1:
This chapter is relative to general introduction about the assessment of chitosan for removing metallic ions and dyes from water and wastewater. Furthermore, the chemical modification of chitosan to get rid of the inherited limitations of chitosan as its solubility in acidic media that cannot be used as an insoluble adsorbent under these conditions beside its unsatisfactory mechanical properties and poor heat resistance, is reviewed. Also, this chapter is reviewing the magnetic introduction of magnetic material into chitosan to form magnetic chitosan (MC) that can have great applications in the field of pollutants removal due to the easy separation from the removal medium. Finally, the composites that can be formed from chitosan and activated carbon (biochar) from agricultural waste is discussed.
Chapter 2:
This chapter deals with the removal of Cr(VI) from water using the glutaraldehyde-crosslinked glycine modified chitosan resin. The adsorption of Cr(VI) onto glycine-modified crosslinked chitosan (GMCCR) resin has been investigated. Batch experiments were performed to examine kinetics, adsorption isotherm, pH effect, and thermodynamic parameters. The effect of pH for the adsorption of Cr(VI) was studied at range from 2 to 6 and the equilibrium was accomplished within 150 minutes and maximum removal was achieved under the optimum conditions at pH 3 . The result obtained from equilibrium adsorption studies are fitted Langmuir and Freundlich adsorption models and the data was found that the equilibrium data agreed very well with the Langmuir model . The maximum uptake was found to be 1.5 mmol/g (calc 1.75 mmol/g) at 250C. Thermodynamic parameters for the adsorption system were determined at 298 K, 308 K and 318 K (ΔH° =22.85 kJ•mol−1；ΔG° = −33.17 to −36.93 kJ•mol−1 and ΔS° = 188 J•K−1•mol−1). The positive values of ΔH° and ΔS° suggest an endothermic reaction and increase in randomness at the solid-liquid interface during the adsorption. The negative values of ΔG° indicating a spontaneous adsorption process. The kinetic process was described very well by a pseudo-second-order rate equation.
Chapter 3
In this Chapter, modified magnetic chitosan magnetic (glycine modified crosslinked chitosan (MGMCR)) resin was synthesized and its adsorption efficiency of Cd(II) ions has been investigated. Batch experiments were performed to study the effect of some parameters such as the initial Cd(II) concentration, pH value of the solution, adsorbent dose and the contact time on the adsorption process. The optimal pH for the adsorption of Cd(II) was found to be at 5 and the equilibrium was accomplished within 120 minutes. The result obtained from equilibrium adsorption studies are fitted in Langmuir and Freundlich adsorption models and the data was found to agree well with the Langmuir model. The maximum uptake was found to be 172 mg g-1 at 25 0C at pH 5.
Chapter 4
In this chapter, the biochar (activated carbon) from the Date Palm Mid Rib (DPLM) was prepared and characterized. The resulted Biochar was then grinded using mortar and pestle, sieved using laboratory sieve, the mesh size 250 – 500 µm was selected. This biochar was included in the synthesis of new composite adsorbents with or without magnetite.
Modified crosslinked chitosan/activated carbon (m-Cs@Ac) and magnetic modified crosslinked chitosan/ Fe3O4/activated carbon (Fe3O4@m-CS@AC) composites were prepared and characterized by FTIR, scanning electron microscopy (TEM), and scanning electron microscopy (SEM). The adsorption of the dye Congo red onto the composites was studied as a function of contact time, initial concentration of Congo red, adsorbent dosage, and pH of solution. Langmuir, Freundlich, and Tempkin adsorption isotherm models were studied and the experimental results were addressed by Langmuir isotherm model. The maximum adsorption capacity was 96.2 and 359.7 mg g−1 for m-CS@AC and Fe3O4@m-CS@AC, respectively, at 60 0C indicating high potential of Fe3O4@m-CS@AC in the adsorption of Congo red. A comparison of kinetic models showed that the overall adsorption process was best described by pseudo-second-order kinetic model. Thermodynamic analysis indicated an endothermic nature of adsorption and a spontaneous and favorable process. The m-CS/Fe3O4/AC might be a promising candidate of high efficiency, low cost and convenient separation under magnetic field.