The Performance Of Modified Oil Shale Ash In The Treatment Of Heavy Metal Wastewater With High Salinity Near Shore

Marine heavy metal pollution mainly comes from industrial waste generated in human industrial production,agricultural waste generated in agricultural production,and various types of domestic waste generated in human life.Heavy metal pollution will not only affect the animals and plants in the ocean,but also cause irreversible harm to the human body.Conventional methods for the treatment of heavy metal pollutants in water bodies,such as biological methods,chemical methods,ion exchange methods,etc.,have the disadvantages of causing secondary pollution and not easy to recycle.Therefore,we choose better-recovered adsorption that does not cause secondary pollution.law.However,the manufacturing cost of adsorbents with higher adsorption efficiency is relatively high,so the preparation of relatively cheap adsorbents with high adsorption rate has become the focus of research.Oil shale resource is a very important resource.Mining a large amount of oil shale also brings a large amount of by-product oil shale ash.The oil shale ash has the characteristics of loose porosity and high porosity,which can be Used as a raw material for the preparation of adsorbents.In this paper,the oil shale ash produced in the production process of thermal power plants in Huadian area of Jilin Province was used as the main raw material,and the acid-base modification was carried out to obtain two kinds of adsorbents.The two prepared adsorbents were used to adsorb Pb²⁺heavy metal ion wastewater respectively.The main research contents are summarized as follows:1.The oil shale ash residue is calcined at high temperature and treated withω（50%）HNO₃ or 3mol/L Na OH.Among the two synthetic adsorbents,the adsorbent treated with alkali has the highest adsorption efficiency.The analysis results proved that the composition of the prepared acid-base modified oil shale ash samples did not change,only the surface morphology changed and became rougher;the prepared acid-base modified oil shale ash samples had higher The larger specific surface area of unmodified oil shale ash is beneficial to the adsorption of heavy metal ions.Among them,the specific surface area of the alkali-modified oil shale ash adsorbent is larger.2.The study of factors affecting the efficiency of the adsorption test shows that the best temperature for the adsorption of heavy metal ions Pb²⁺by the oil shale ash-based adsorbent is 308K;the best dosage of the alkali-modified oil shale ash adsorbent is 15 g/L;The adsorption rate of the sample increases with the increase of the initial concentration;the optimal p H for the adsorption of Pb²⁺by alkali-modified oil shale ash is 6;with the increase of the salt content in the heavy metal wastewater,the removal rate of Pb²⁺by the adsorbent Significantly down.3.The adsorption of heavy metal ions Pb²⁺by alkali-modified oil shale ash residue is relatively better in accordance with the Langmuir adsorption isotherm equation;the equilibrium adsorption capacity of the adsorbent for heavy metal ions Pb²⁺is179.34mg/g;the pseudo-second-order kinetic equation can better describe the entire adsorption process.The adsorption process is an endothermic process,and the high temperature is conducive to the spontaneous progress of the adsorption process.Further analysis can be concluded that the adsorption mechanism of heavy metal cation Pb²⁺on the adsorbent is:surface precipitation,physical adsorption,and chemical adsorption.