الفهرس 
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Abstract
The thesis aims to prepare some layered double hydroxides using co-precipitation method. The prepared layered double hydroxides were investigated by using different instrumentals. The fabricated layered double hydroxides were also used as adsorbents for the removal of some organic dyes from wastewater. This thesis consists of three main chapters.
Chapter (1): Introduction
It includes brief about water pollution, sources of pollution and its harms on living things, as well as the different methods used to purify polluted water. It includes the definition of layered double hydroxides and the different methods used in their preparation, as well as the different applications of layered double hydroxides. This chapter also includes a literature survey on the previous work performed on layered double hydroxides and their different applications in water purification and other various fields. It contains the literature survey on the previous work for the removal of sunset yellow and amaranth dyes.
Chapter (2): Experimental
This chapter contains the practical part of this thesis. Also, this chapter includes complete description of the materials, reagents, equipment and the methods which used for the preparation of Mg/Al, Zn/Al and Zn/Mg-Al layered double hydroxides by a co-precipitation method. It also includes the description of the instrumental tools such as (TG- DTA, XRD, FTIR, HR-TEM, FE-SEM, surface area and UV-Vis spectrophotometer. It also contains the explanation for the batch method which used for the removal of organic dyes from water using the fabricated adsorbents. It also includes the explanation for various factors that influencing the removal efficiency.
Chapter (3): Results and discussion
This chapter contains the discussion of the extracted result and data from experimental work. It divided into two main parts: characterization of the fabricated material (first part) and their application in the removal of pollutants as organic dyes from water.
Part 1: characterization part
The first part describes the characterization of the synthesized various layered double hydroxides (Mg/Al, Zn/Al and Zn/Mg-Al) by using co-precipitation method. The produced layered double hydroxides were characterized by different tools such as (Thermal analysis, X-ray diffraction, Fourier transforms infrared analysis, Scanning electron microscopy, transmission electron microscopy, surface area determination and UV-Vis spectrophotometer).
The extracted results showed that the preparation of the Mg/Al, Zn/Al and Zn-Mg/Al layered double hydroxides were prepared using co-precipitation method. The obtained peaks in XRD patterns indicated for the formation of Mg/Al, Zn/Al and Zn-Mg/Al layered double hydroxides in the crystalline form. The crystallite size of the obtained M1, M2 and M3 samples, determined to be 15.12 nm, 11.13 nm and 7.54 nm, respectively. Also, the crystallite size of the fabricated Z1, Z2 and Z3 samples calculated to be 13.23 nm, 12.3 nm and 10.93 nm, respectively. from XRD peaks of Zn-Mg/Al layered double hydroxide (ZM1, ZM2, ZM3, ZM4 and ZM5 samples), the crystallite size determined to be 14.85 nm, 10.95 nm, 10.40 nm, 10.10 nm and 10.00 nm, respectively.
FTIR spectra of the fabricated layered double hydroxides showed the characteristic peaks at 3000-3800 cm-1, 1640-1645 cm-1 related to the stretching and bending of hydroxides or/ and water molecules inside the obtained layered double hydroxide. Also, FTIR spectra appeared that peaks in the range of 1365-1400 cm-1 and 400-900 cm-1 related to the presence of nitrate groups, Mg-O, Zn-O and Zn-O-Mg inside the formation of layered double hydroxide.
The transmission electron microscopy revealed the presence of crystalline complete and non-complete spherical shapes with hard agglomeration. The average of particles sizes of Mg/Al, Zn/Al and Zn-Mg/Al layered double hydroxides determined to be 45 nm, 72 nm and 76 nm for M3, Z3 and ZM3, respectively. Micrographs of SEM for M3, Z3 and ZM3 samples appeared the presence of sheets shaped with different grain sizes. The grain size determined from SEM images to be 64 nm, 133 nm and 72 nm for M3, Z3 and ZM3samples. Energy dispersive spectroscopy (EDX) and EDX-elemental mapping appeared for the presence of four (Mg, Al, O, N), four (Zn, Al, O, N) and five (Mg, Zn, Al, O, N) elements for M3, Z3 and ZM3 samples, respectively.
The Surface of the synthesized layered double hydroxides characterized using Brunner-Emmett Teller (BET) and Barrett-Joyner-Halenda (BJH) methods. For the calculations of the surface area, pore volume and pore diameter were calculated, respectively. According to the extracted data from isotherm curves, the surface area determined to be 24.88, 22.17 and 20.30m2/g for Mg/Al, Zn/Al and Zn-Mg/Al layered double hydroxide samples, respectively. Also, the extracted data from pore size distribution, the pore size in the range of 2-50 nm, due to the formation of mesopores structure of the synthesized LDH samples.
Part 2: Application part
The second part includes the explanation of the extracted adsorption data for the removal of sunset yellow and amaranth dyes using the fabricated Mg/Al, Zn/Al and Zn/Mg-Al layered double hydroxides. This part includes the results and discussion of the factors affecting the removal of the selected dyes under study from aqueous solutions such as pH, contact time, initial dye concentration, adsorbent dose, ionic strength and temperature. The optimum conditions for the adsorption process were extracted from the experimental data.
In case of sunset yellow dye, the optimum pH for the adsorption of sunset yellow dye was found to be 7 for the obtained Mg/Al, Zn/Al and Zn/Mg-Al layered double hydroxides. The contact times for the adsorption process of sunset yellow dye using Mg/Al, Zn/Al and Zn/Mg-Al layered double hydroxides were found to be between 30-60 min. The amount of dose for the adsorption of sunset dye using Mg/Al, Zn/Al and Zn/Mg-Al LDH were determined to be 50 mg and removal is 99.2%, 99.7% and 99.6%, respectively. The dye removal decreased with the increasing the amount of KCl using the synthesized Mg/Al, Zn/Al and Zn/Mg-Al layered double hydroxides. The dye removal increased with raising the temperature for all the synthesized samples. The adsorption data followed well the Langmuir isotherm model for all the prepared Mg/Al, Zn/Al and Zn/Mg-Al layered double hydroxides. The adsorption of the sunset yellow dye fitted the pseudo second order model using Mg/Al, Zn/Al and Zn/Mg-Al layered double hydroxides. The adsorption of sunset yellow dye showed spontaneous, physiorption and endothermic process using the Mg/Al, Zn/Al and Zn/Mg-Al layered double hydroxides as adsorbents. The adsorption capacities of Mg/Al, Zn/Al and Zn/Mg-Al layered double hydroxide samples for removal sunset yellow dye were found to be 209, 96 and 120 mg/g, respectively.
In case of amaranth dye, the optimum pH for the adsorption process was found to be 7 for the obtained Mg/Al, Zn/Al and Zn/Mg-Al layered double hydroxides. The contact times for the adsorption of amaranth dye using Mg/Al, Zn/Al and Zn/Mg-Al layered double hydroxides were found to be between 30-60 min. The amount of dose for the adsorption of sunset dye using Mg/Al, Zn/Al and Zn/Mg-Al LDH were determined to be 50 mg 99.5%, 99.53 % and 99.5%, respectively. The dye removal decreased with increasing the amount of KCl using the synthesized Mg/Al, Zn/Al and Zn/Mg-Al layered double hydroxides. The dye removal increased with raising the temperature for all the synthesized layered double hydroxides samples. The adsorption data followed well the Langmuir isotherm model for all the prepared Mg/Al, Zn/Al and Zn/Mg-Al layered double hydroxides. The adsorption of the sunset yellow dye fitted the pseudo second order model using Mg/Al, Zn/Al and Zn/Mg-Al layered double hydroxides. The adsorption of amaranth dye showed spontaneous, physiorption and endothermic process using the Mg/Al, Zn/Al and Zn/Mg-Al layered double hydroxides as adsorbents. The adsorption capacities of Mg/Al, Zn/Al and Zn/Mg-Al layered double hydroxide samples for removal amaranth dye were found to be 174, 69 and 93 mg/g, respectively.