الفهرس | Only 14 pages are availabe for public view |
Abstract Removal of heavy metals from liquid waste effluents is an important environmental concern in treatment process of hazardous wastes. During the last decades, considerable effort have been directed towards the development and improvement of materials to be used for removal or decontamination of hazardous waste such as ion exchange materials, ion exchange membranes, ceramic materials, …etc. This work handles the treatment of hazardous wastes using functionalized hydrophilic hydrogels by the polymerization of acrylic acid, acrylamide, vinyl alcohol individually and in a binary mixture using gamma irradiation as initiator. Further chemical modification to the functional groups of the prepared copolymers carried out to meet the requirements for their applications in waste treatment. The preparation conditions of the hydrogel composite copolymers such as monomer or binary monomer concentration, radiation dose, solvent and inhibitor concentration and reagents used for the preparation process, was investigated. The FTIR spectroscopy, Thermal gravimetric analysis (TGA), Differential thermal Analysis (DTA) and swelling behavior studies have been applied for the characterization of the prepared hydrogels. It was found that the maximum metal ions uptake by hydrogels is ordered in sequence as (Cr3+> Co2+> Ni2+) and it depends on the type of hydrogels is ordered in sequence of P(AAm/VA) > P(AAm/AAc) > P(Sty./AAc) polymeric hydrogels. The metal uptake for all metal ions and copolymers kinds achieved maximum value at around pH=5 after this point adsorption begins to decrease. The prepared hydrogels are considered as additional materials to be used for safety treatment of hazardous liquid waste. The chemical behavior of Co2+, Ni2+ and Cr3+ is similar to Co60, Ni58 and Cr52. In this study it is considered that under the same conditions, the removal of Co60, Ni58 and Cr52 from liquid radioactive waste will be similar to cobalt, nickel and chromium ions. Key words: Acrylic acid, Styrene, Acrylamide, Vinyl alchol, Hazardous waste, Absorption, Cr, Co, Ni, Radioactive waste, Hydrogels, copolymers. |