الفهرس 
IntroductionOnly 14 pages are availabe for public view
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Abstract
Water pollution is a serious environmental problem. Developing new generation of benign adsorbents satisfying several criteria required for real practical application is of great need. This work introduces an effort in this direction by introducing a number of novel magnetic nano adsorbents (NMNAs) for water treatment, this achieved by magnetization followed by functionalization of wood sawdust (WSD) which representing a natural and sustainable ligno-cellulosic polymer. The NMNAs were optimized to reduce calcium hardness, removal of some selected heavy metal ions and oil spills as well, from real water samples.
The thesis comprises four main chapters:
The first chapter is the Introduction. It includes the importance of dealing with water treatment for various purposes, whether reducing water hardness to be in accordance with international standards for drinking water specifications. In addition to water treatment for the purpose of removing inorganic pollutants, especially heavy metal ions and organic pollutants, especially oil spills. Thus it reviewed the different technologies developed in this regard especially adsorption which represent one of the best technologies due to its various advantages, when using biosorbents in general, and in particular agricultural wastes that have a unique chemical composition consisting of cellulose – hemi cellulose - lignin polymer.
The introduction also makes a spot light on the nano adsorbents considered in general as a new generation of adsorbents and the mod of obtaining them. Furthermore, magnetic nano adsorbent as more developed generation of adsorbents devoted for fast separation and preconcentration in comparison with conventional adsorbents
It also included the use of microwave solvent-less approach as a fast, green and benign mod for adsorbent surface functionalization.
The second chapter is the experimental part of thesis (materials, methods and instruments) it included:-
• The preparing solutions Ca(II), Cu(II), Zn(II), Ni(II), Fe(III), Cd(II) and Pb(II), and the mod of their determination and characterization of the NMNAs such as domestic microwave, FT-IR, XRD, SEM and TEM. In addition to automatic shaker, pH meter, Atomic absorption spectrophotometry, conductivity meter and TDS used during this study.
• The designed batch operation for optimized the highest efficiency of the NMNAs to work the targeted species, this include effect of pH, contact time, adsorbent dosage and adsorbate concentration. Thus, the two new magnetic nano adsorbents WSD@Fe3O4NPs-TA, WSD@Fe3O4NPs-CA were optimized for water softening, the other two NMNAs WSD@Fe3O4NPs/3-ATPS and WSD@Fe3O4NPs/5-ASA were optimized for removal of heavy metal ions Cu(II), Zn(II), Ni(II) and Fe(III), Cd(II), Pb(II), respectively and the last magnetic nano adsorbent Stearic acid (StA) WSD@Fe3O4NPs to produce WSD@Fe3O4NPs/StA was employed to remove oil spillage (crude oil and mineral oil used) from sea water surface.
• The real water samples used for application including two samples of ground water and Nile river water. In addition to two oil samples (used motor oil and crude oil).
• The source of raw wood sawdust (WSD) and the real water samples used to check the applicability of the NMNAs along with their regeneration studies after first use.
The third chapter is the results. It includes the results obtained after performing the experimental work and the significant of these results
Section I: Studies the reduce of water hardness resulting from increasing of Ca(II) ions concentration.
• Two novel magnetic nano composite adsorbents were successfully synthesized by covalently binding of tartaric acid (TA) and citric acid (CA) to wood sawdust coated magnetic nanoparticles (WSD@Fe3O4NPs) using green microwave solvent-less technique based on the following:-
- Fourier transform infrared (FT-IR) studies showed confirmation of grafting of both tartaric acid (TA) and citric acid (CA) on WSD@Fe3O4NPs surface by locating the characteristics (NــH) bending and (C=O) stretching of the amide group(ــNHــC=O( at 1567.30 and 1628.10 cm-1 for WSD@Fe3O4NPs-TA and 1575.34 and 1628.46 cm-1 for WSD@Fe3O4NPs-CA. In addition to the bands at 1439.85 cm-1, around 1735 cm-1 and at 1440 cm-1, 1709 cm-1 belonging to asymmetric CــO and symmetric C=O of unbound carboxyl groups in TA and CA, respectively. Furthermore the appearance of new stretch vibrations at 2852.24 and 2852.16 cm-1 in the spectra of WSD@Fe3O4NPs/TA and WSD@Fe3O4NPs/CA, respectively referring to propyl group incorporating the linker (3-APTS).
- XRD patters showed new diffraction lines located at 2θ = 20.216° and 17.233° for WSD@Fe3O4NPs-TA and at 2θ= 14.056°and 17.927° for WSD@Fe3O4NPs-CA.
- TEM analysis determined the nano particle size to be the range 14.6–18.8 nm for WSD@Fe3O4NPs, 28.2-34.6 nm for WSD@Fe3O4NPs-TA and 16.8-18.8 nm for WSD@Fe3O4NPs-CA. These results came to confirm that the two novel composites still keep their nano size properties after modification.
• The results of the initial study as a pH showed increasing in removal efficiency and calcium ion uptake up to maximum values of 84.70% for WSD@Fe3O4NPs-TA and 99% for WSD@Fe3O4NPs-CA at optimal pH 7.0 for both. By comparing with the parent WSD@Fe3O4NPs which has percentage of removal not more than 59.52 % to confirm the success of the modification process in increasing the efficiency of magnetic nanomaterials for removing Ca(II) ions from aqueous solutions.
• The maximum adsorption capacity of Ca(II) as a function of the mass of the adsorbent and shaking time was determined to be 18.4 mg/g using 0.4 g of WSD@Fe3O4NPs-TA with contact time 6.0 min. However, WSD@Fe3O4NPs-CA showed higher capacity value recorded to be 27.2 mg/g on using adsorbent dosage values 0.2 g and contact time 5.0 min. These results confirmed the strong effect of the size of the nanoparticles on the speed of extraction of Ca(II) ions and the results are in agreement with the number of carboxylic groups that present in citric acid.
• Ca(II) adsorption onto the novel magnetic nano adsorbents are in harmony with the Freundlich model where the R2 values recorded to be 0.9904 and 0.9998 for WSD@Fe3O4-TA and WSD@Fe3O4-CA, respectively emphasizing the variety of the functional groups on the surface of the two composites. Moreover, the kinetic data are well fitted with pseudo-second-order kinetic model with regression coefficient values of 0.9998 and 0.9902 for WSD@Fe3O4NPs-TA and WSD@Fe3O4NPs-CA, respectively.
• The comparing items of the newly synthesized magnetic nano composites adsorbents with other lingo-cellulosic bioadsobents ensured their advantages with respect to time required for the green synthetic methodology, fastness of Ca(II) uptake with superior magnetic separation along with relatively high removal efficiency.
• In situe desorption and regeneration studies showed results implying the stability and potential regeneration ability of the novel adsorbents for multiple times. The new adsorbents were successfully reused after desorbing of Ca(II) ions from the surface with 0.25M or 0.5M HCl for five successive cycles of adsorption-desorption batch operations. The properties of magnetic adsorbents allow them to be separated without the use of the usual filtering and sequencing separation techniques.
• The capability of the two novel magnetic nano adsorbents was checked for reduction of calcium hardness by application on real water samples including ground water GW1 (194), GW2 (680) and NRW (78) as mg/LCaCO3. After two consecutive batch operations values of calcium hardness decreased to be 46, 208 and 26 mg/L CaCO3, respectively on treating with magnetic nano adsorbent WSD@Fe3O4NPs-TA and reached the values 30, 146 and 20 mg/L CaCO3, respectively on using WSD@Fe3O4NPs-CA satisfying the WHO limits for drinking water. It should also be noticed that, this treatment process succeeded in reducing the values of total dissolved solids, electric conductivity and total alkalinity of the treated water samples if compared with the values before treatment.
Section II: The results of synthesis and optimization studies for remove of heavy metal ions from aqueous solutions
• Characterization of the two novel magnetic nano adsorbents WSD@Fe3O4NPs/3-ATPS and WSD@Fe3O4NPs/5-ASA confirmed the successful of their microwave synthetic methodology based on:-
- Fourier transform infrared (FT-IR) confirmed modification of WSD@Fe3O4NPs by anchoring the silylating agent 3-aminopropyletrimethoxysilane (3-ATPS) by locating two at 3328.51cm-1 and 1627.06 cm-1 ascribed to the N-H stretching vibration and NH2 bending mode of free NH2. In addition to the bands at 2852.98 cm-1 were attributed to CH2 of the alkylsilane. The new stretching vibration bands at 1650.02 cm-1 corresponding to carboxylic group with its C-O stretching at 1318.50 Cm-1 and strong NــH bending at 1491.70 cm-1 introduce strong evidence for the incorporation of 5-ASA modifier onto WSD@Fe3O4NP.
- The XRD patterns showed the appearance of new diffraction peaks centered at 2θ =7.649, 20.206, 21.331, 21.858 and 23.359 and for WSD@Fe3O4NPs/3-ATPS and at of 2θ = 7.47°, 14.175, 15.06°, 16.49°, 28.15 ° for WSD@Fe3O4NPs/5-ASA.
- TEM analysis determined the nano particle size for WSD@Fe3O4NPs/3-ATPS to be in the range 19.1-21.6 nm and 13.5-18.4 nm for WSD@Fe3O4NPs/5-ASA.