Study On The Modification Of Oil Shale Ash To Prepare Of Absorbent And Its Adsorption Characteristics

At present, there are increasing more and more concerns about the utilization of oil shale as an alternative source of energy due to the rich reserves. A large quantity of oil shale ash is generated annually in the combustion of oil shale for electricity generation because of oil shale with low-oil content and high-ash content. While oil shale is only utilized to produce electricity, a large quantity of oil shale ash is dumped in landfills as waste and not proposal. It is not only a waste of resource but also it may cause a serious environmental problem. This is due to that oil shale ash is potentially hazardous heavy pollutants containing a variety of heavy metal trace elements and various mineral.Based on oil shale ash from the thermal power plant located in Huadian of Jinlin province, China, the physical and chemistry characteristics of oil, the key parameters of conversion of oil shale ash into NaX zeolite and the adsorption characteristics of Ni²⁺ from wastewater by oil shale ash and zeolite were studied systematically.The physical and chemistry characteristics of oil shale ash such as the chemical composition, the mineral composition, BET specific surface area, BJH cumulative pore area, BJH cumulative pore volume were obtained by a series of testing methods such as XRD, XRF, SEM, BET specific surface area and BJH pore distribution, and the testing results were obtained to provide a basis of conversion of oil shale into zeolite.An alkali fusion and hydrothermal synthesis method was studied to converse of oil shale ash into NaX zeolite. The parameters of synthesis zeolite such as H₂O/Na₂O, Na₂O/ SiO₂ molar ration, synthesis time and synthesis temperature on the process of synthesis of zeolite were discussed and the key parameters were obtained and optimized to achieve the best synthetical conditions. The physical and chemistry characteristics of zeolite were tested and it was found that the synthesis zeolite was a promising and efficient adsorbent with high adsorption capacity.The adsorption characteristics of Ni²⁺ from wastewater by oil shale ash and zeolite were studied by a series of batch adsorption experiments. Effects of various parameters such adsorbent dose, pH, temperature, initial concentration, adsorption time were investigated, and the theoretical analysis of the adsorption kinetics, adsorption thermodynamics, Langmuir and Freundlich adsorption isotherm were utilized to fit the process of adsorption. It was showed that the process of adsorption was fitted to the Pseudo frist order kinetics model, Pseudo second order kinetics model and Elovich kinetics model, and the process of adsorption was a non-spontaneous process, and both the Langmuir model and Freundlich model were utilized to fit the process of adsorption with R² >0.98 in all cases.