الفهرس 
Title pageOnly 14 pages are availabe for public view
 |  | from | 90 |  |  |
| | | from | 90 | | |
Abstract
Water is essential for life and its quality is important in our lives because it is essential to support physiological activities of any biological cell. Contamination of water by toxic materials such as heavy metals and pesticides are global problems that are a growing threat to the environment Conventional methods used for the removal of toxic metal ions usually include chemical precipitation, reverse osmosis, electrodeposition,ion exchange, evaporation, etc.However, most ofthese methods are ineffective and/or very expensive, especially in removing heavy metal ions from very dilute solutions. Adsorption technology is one of the most popular methods to control these pollutants. However, the adsorption efficiency, selectivity, equilibrium time, regeneration and stability usually depend on the materials used as adsorbents. Efficiency of conventional adsorbents is usually limited by the surface area or active sites, the lack of selectivity, and the adsorption kinetics. Nanotechnology offers leapfrogging opportunities to water and wastewater. This capability results from the fact that at the nanoscale (1–100 nm) materials can display dramatically different physical and chemical properties from their bulk counterparts. Nano-adsorbents are highly efficient due to their extremely high specific surfacearea and associated sorption sites, short intraparticle diffusion distance, and tunable pore size and surface chemistry. One of the low-cost and effective adsorbents is chitosan. It is a type of natural polyaminosaccharide, synthesized from the deacetylation of chitin with the advantages of the widespread abundance, high safety, low toxicity, good chemical reactivity and chemical and physical versatilities.
The nanomaterials from chitosan and chitosan-ZnO composites were prepared to remove heavy metals and pesticides, respectively from simulated wastewater.The prepared nanomaterials were characterized using Transmission Electron Microscope (TEM) and Scanning Electron Microscope (SEM) to determine the morphology and the topography of nanoparticles, the crystallinty and characteristic peaks were studied using X-Ray diffraction (XRD) and Fourier Transformer Infrared Spectroscopy (FT-IR) was used to identify the functional groups and chemical bonding of the materials. SEM analysis and TEM images showed that porous and spherical shape of prepared nanomaterials with diameter ranging from 40 nm and 55 nm for CSNPs and CS-ZnONCs, respectively. The XRD characteristic peaks that appeared at 2θ values is 10.67 and 19.99 for chitosan nanoparticles and these peaks are very weak in the spectrum of the CS–ZnONCs and new peaks of 31.7, 34.4, 36.2, 47.4, 56.5, 62.72, 66.4, 67.9 and 68.9appeared which identifying to the presence ofZnO.While FTIR determine presence the peaks of O-H, NH2, C=O, (CH2)n , C-O, P-O, P=O and O-Zn-O indicating the successful formation of CSNPs and CS–ZnONCs.
Heavy metals from Cu(II) and Zn(II) were chosen as heavy metals to study the removal efficiency of CSNPs. Simulated water in batch experiments were performed to investigate pH, contact time and initial concentration on the adsorption process. 0.1 g CSNPs was added to 50 ml Cu(II) solutions with 10,30,50,80 and 100 ppm and the same batch experiments were repeated for Zn(II), for Cu(II) the equilibrium was obtained within 210 min at pH=5 while for Zn(II) for the equilibrium was obtained within 60 min at pH=7. Pseudo-first-order and pseudo-second-order were applied to investigate the kinetic data. It was found that kinetic data is well fitted to pseudo-second-order. Adsorption isotherms were studied by the aid of Langmuir and
Freundlich. Although both of them show a great consistence with data, Langmuir isotherm showed the best fitting for Cu(II) and Zn(II).
While For pesticide removal, Stock solution of 0.2 ppm of lambda cyhalothrin pesticide was prepared to achieve the adsorption experiment. Adsorption applications for removal of pesticide were conducted. The optimum conditions, including pH, adsorbent dose, agitating time and the initial concentration of pesticide for the adsorption of pesticide by chitosan loaded with zinc oxide nanoparticles beads were investigated. Results showed that 0.7 g of the CS-ZnONCs for 90 min and pH 7, could remove 97% of the pesticide from lambda cyhalothrin solution (25 ml, 0.2 mg L-1), using HPLC at 230 nm.