الفهرس 
INTRODUCTIONOnly 14 pages are availabe for public view
 |  | from | 68 |  |  |
| | | from | 68 | | |
Abstract
Copper is an example of heavy metal usually present in different types of industrial effluent. It is also responsible for environmental pollution and therefore, it should be removed from wastewater before being discharged into water. Different methods have been employed for this purpose. Adsorption and biosorption could be a good alternative technology. In recent years, there has been an increase in the use of biological materials including agricultural solid wastes as adsorbents for the removal of heavy metals. The advantage of using agricultural solid wastes is that it saves disposal costs while alleviating potential environmental problems. Agricultural by-products, such as peat, wood, pine park, banana pith, rice husk, wheat bran, peanut hull, wool, sunflower, grape stalks wastes, sugar beet pulp, olive mill solid residue, sawdust, leaves, walnut expeller meals, orange peel have been demonstrated to remove heavy metal ions from wastewater.
The aim of the present study is to assess the ability of low-cost adsorbents such as rice husk to adsorb Cu(II) from aqueous solution. The effect of initial concentration of copper ions, weight of sorbent, particle size of sorbent, pH of the solution, the solution temperature and contact time on the removal of Cu(II) was studied on the adsorption of copper ions from aqueous solution using unmodified rice husk.
The results showed that the most suitable temperature was 25°C and using particle size of 0.25 mm. Also, it was found that the best value of pH was 4 and adsorption at lower concentration (150 ppm) is favorable. The equilibrium time was found to be 30 min for all initial concentrations studied.
The equilibrium data were described by the Langmuir and Freundlich isotherm models depending on temperature to determine the best isotherm to correlate the experimental data, and it was found that both isotherms presented satisfactory results, while Langmuir isotherms presented better correlations. The maximum sorption capacity for Cu(II) was 25.57 mglg at 25°C.
Thermodynamics parameters of adsorption process (!J.C?, Mt’ and Mf’) were determined and the kinetic models (pseudo-first order and pseudo-second order) were also studied. A good correlation coefficient was obtained for pseudo second-order kinetic model. The values obtained for !J.S’ and Mt’ were negative while those obtained for !J.Go were positive. The data showed that the sorption process is non-spontaneous and exothermic in nature.