Controllable Preparation Of New Sulfur-doped Attapulgite Composites And Their Adsorption Properties For MB,Pb²⁺ And Cu²⁺

With the rapid development of chemical industry,the damage of waste water pollution has become increasingly concerned environmental problems.The treatment of water pollution has caused widespread concern among researchers.The natural attapulgite is a resource-rich,easy-to-exploit and low-cost clay mineral.After attapulgite is calcined,the adsorption active site can be increased.Then,the structural modification of attapulgite can improve the adsorption performance by doping with sulfur-containing substances.In this thesis,attapulgite was roasted at a certain temperature,and the high concentration Na₂S solution was used to obtain composite materials through hydrothermal process.A series of test methods including infrared spectroscopy?FT-IR?,X-ray diffraction?XRD?,scanning electron microscopy?SEM?and thermogravimetric analysis?TGA?were used to characterize attapulgite before and after sulfur doping.The results showed that attapulgite was successfully doped with SO₄^2-and the morphology and structure of attapulgite changed obviously.Taking the cationic dye methylene blue?MB?,heavy metal ions Pb²⁺and Cu²⁺as adsorption objects,the influences of contact time,solution pH value,initial concentration of solution and other factors on the adsorption rate were investigated.The results showed that the adsorption rate of the attapulgite composite prepared with0.5 mol/L sodium sulfide by hydrothermal process for MB solution was as high as99.86%.After five times of adsorption-desorption experiments,the adsorption rate reached 89.01%,the desorption rate reached 87.23%.The maximum adsorption rate for Pb²⁺was 84.43%.After five times of adsorption-desorption experiments,the adsorption rate was 68.7%,and the desorption rate was 65.34%.The adsorption rate for Cu²⁺was 70.09%.After five times of adsorption-desorption experiments,the adsorption rate was 55.78%,and the desorption rate was 53.79%.The adsorption results of sulfur-doped attapulgite composites for MB,Pb²⁺and Cu²⁺were suitable for the pseudo-second order kinetic equation and the Langmuir adsorption isotherm equation.The results show that the new sulfur-doped attapulgite composites can be used as an adsorbent for removing organic dyes and heavy metal ions in solution,and the removal effect of organic dyes is better.