Study On Adsorption Properties Of Nano TiO₂/Fe₃O₄ Attapulgite Clay For Inorganic Ions And Organic Compounds

In recent years,the use of natural non-metallic mineral adsorption treatment of washing sewage,printing and dyeing wastewater is a hot topic in the study of environmental protection,especially the water environment deteriorating,a large number of containing heavy metal ions and difficult to be biodegradation of the mixed wastewater continuously discharged into water today.Attapulgite clay is a kind of functional material which has the function of environmental remediation and purification.As adsorption material,attapulgite clay has high porosity,large surface area,there may be different types of adsorption centers,and it is widely used in water treatment also because of its low price and abundant resources,high adsorption capacity and renewable advantages.In this paper,attapulgite clay was purified and activated by acidification to obtain the purified attapulgite clay,and then the TiO₂/Fe₃O₄ attapulgite clay with different components was prepared by using nano TiO₂ and Fe₃O₄ as the matrix.Scanning electron microscopy?SEM?was used to observe the changes of morphology of attapulgite clay before and after loading,and it was found that the form of the rod like crystal of the modified attapulgite clay was dispersed and dissociated.Electron spectroscopy?EDS?was used to characterize and analyze the changes of components before and after loading.The adsorption behavior of Cr?VI?,phosphate and methylene blue in simulated wastewater solution on accurate configuration was studied by controlling the loading conditions and adsorption conditions,including the ratio of TiO₂ / Fe₃O₄ / attapulgite clay,the dosage of adsorbent,the temperature,the value of pH,adsorption time,initial concentration of adsorbate and other factors,to study the composite properties of the adsorption and photocatalytic performance..The experimental results show that the adsorption capacity of Cr?VI?,phosphate and methylene blue can be greatly improved under the optimized experimental conditions.3/4-composite materials on the adsorption of the optimal conditions of Cr?VI?were as follows: 1.00 mg/L concentration,adsorbent dosage is 0.6g,adsorption time 90 min,temperature 20 ?,the value of pH is 6.0⁷.0,the adsorption rate reached 86.46%;3/4-composite materials on the adsorption of the optimal conditions of phosphate were as follows: 2.00 mg/L concentration,adsorbent dosage is 0.6g,adsorption time 120 min,temperature 20?,the value of pH is 7.0⁸.0,the adsorption rate reached 90.37%;2/4-composite materials on the adsorption and degradation of methylene blue in the optimal conditions: the concentration of 15.00 mg/L,the adsorbent dosage was 0.4 g,adsorption time 60 min,temperature 20?,the value of pH is about 9.0,the adsorption rate reached 97.15%.The desorption experiments showed that the composite materials had recycle capacity for Cr?VI?,phosphate and methylene blue adsorbents,and the adsorption rate after ten times still was more than 42.8%.The adsorption thermodynamics and adsorption kinetics models of the composites were studied,and found that the adsorption was in accordance with the quasi-second order kinetic equation,the adsorption process of the composites is controlled by two aspects: particle diffusion?PDC?and chemical reaction?CRD?,and the fitting degree was highert of the Freundlich and Langmuir models and the adsorption was multilayer adsorption and monolayer adsorption coexist;The adsorption process is self releasing thermal reaction and mainly physical adsorption,but there are also ion exchange adsorption and chemical adsorption.