Study On Removal Of U(Ⅵ)、Pb(Ⅱ)from Wastewater By Tobacco Scrap

In the process of cigarette production,a large amount of tobacco is generated.At present,the tobacco generated during the production of cigarettes is generally treated as garbage,landfilled or incinerated,which results in waste of resources and also leads to certain environmental pollution.If it is applied to the removal of heavy metals in wastewater,it can provide new ideas for the treatment of heavy metal polluted wastewater.In this dissertation,static adsorption experiments were carried out on the end of the cigarette produced during the cigarette production process.The amount of tobacco added,the p H of the solution,the adsorption time,the initial concentration and the temperature were observed to adsorb U(Ⅵ)and Pb(Ⅱ),the condition experiment was conducted in the experiment,the experimental parameters of each condition were obtained,and the spectrophotometric method and the flame atomic absorption method were used to measure and obtain experimental data.The kinetics and thermodynamic equations were used to analyze the experimental data and to study the adsorption properties of U(Ⅵ)and Pb(Ⅱ)adsorbed on the tobacco.Fourier transform infrared spectroscopy(FTIR),scanning electron microscopy(SEM)and X-ray energy dispersive spectroscopy(EDS)were used to characterize the end of the tobacco,and the mechanism of adsorption of U(Ⅵ)and Pb(Ⅱ)was discussed.The main conclusions are:(1)The experimental results show that when the temperature is 30 °C,the amount of fume is 4 g/L,the solution p H is 5,the concentration of U(Ⅵ)is 20 mg/L,and the adsorption time is 100 min.The best results.The adsorption process fits the pseudo-second-order kinetics model(R2≈1)and the Langmuir isotherm model(R2≈1).It can be seen that the adsorption of U(Ⅵ)by the end of the process,the chemical adsorption plays a key role and belongs to the homogeneous adsorption.Scanning electron microscopy,X-ray diffraction,infrared spectroscopy and other results show that the tobacco has a good adsorption effect on U(Ⅵ).After adsorbing U(Ⅵ),the surface morphology tends to be flat and interacts with U(Ⅵ).The groups are mainly hydroxyl and carboxyl groups.(2)The experimental results show that when the temperature is 25 °C,the amount of fume is 2 g/L,the p H of the solution is 6,the concentration of Pb(Ⅱ)is 20 mg/L,and the adsorption time is 60 min,the end of tobacco absorbs Pb(Ⅱ).The best results.The adsorption process fits the pseudo-second-order kinetics model(R2≈1)and the Langmuir isotherm model(R2≈1).It can be seen that the adsorption of Pb(Ⅱ)by the cigarette tobacco plays a key role in chemical adsorption and is uniform adsorption.Scanning electron microscopy,X-ray diffraction,infrared spectroscopy and other results showed that the end of the tobacco has a good adsorption of Pb(Ⅱ).After adsorption of Pb(Ⅱ),the surface morphology tends to be flat and interacts with Pb(Ⅱ).The groups are mainly hydroxyl and carboxyl groups.(3)During the process of sorption of U(Ⅵ)and Pb(Ⅱ)in the solution,UO22+ and Pb2+ come into contact with the surface of the tobacco,and the surface hydroxyl and carboxyl groups react with UO22+ and Pb2+,and the surface H+ and UO22+,respectively.Pb2+ undergoes ion exchange,which enriches UO22+ and Pb2+ on the surface of the tobacco.