Preparation Of Carbon-based Composites And Their Adsorption Properties For Heavy Metal Ions And Organic Dyes In Waste Water

Since the entry of the twentieth century,industry,agriculture,science and other fields of technology have made great progress with the accelerated pace of reform and opening up in China.Especially the development of the industrial level,it improves the level of our economy at the same time causes various problem of environmental pollution,such as industrial waste water.It contains heavy metal ions and organic dyes which can indirectly harm to the human health through different ways.Heavy metal ions Cr（Ⅵ）has strong toxicity which can cause carcinogenic mutations.It has been listed as one of the eight largest chemical substances which endangers the human health.The organic dyes rhodamine B（RhB）and methylene blue（MB）has complex structure which is difficult to handle thoroughly.Therefore,the appropriate way to handle the pollutants in industrial waste water which can ensure human health and has great significance.The adsorption method has many advantages,such as simple equipment,wide application range,good treatment effect,recyclable use of adsorbent and little secondary pollution.In this paper,the carbon composites with adsorption properties are prepared.The adsorption properties of Cr（VI）,RhB and MB in organic waste water were also studied.The main results are as follows:1.The waste cinder in boiler room was modified by HCl.Fe₃O₄/modified cinders were prepared by in situ hydrothermal method.The SEM,XRD,XPS,FT-IR and BET were used to characterize the microstructure and mechanical properties of the composites.The effects of the amount of adsorbent,the time of adsorption,the pH value and the initial concentration of Cr（Ⅵ）solution on the adsorptive capacity of Cr（Ⅵ）adsorbent were investigated.The results showed that the optimum conditions for the adsorption reaction were as follows:the amount of adsorbent was 1.5 g,the adsorption time was 60 min,and the pH value of Cr（Ⅵ）solution was 3.00.The adsorption of Cr（Ⅵ）on Fe₃O₄/modified cinder is consistent with pseudo-second-order kinetics.After 5 successive adsorption/regeneration cycles,the adsorption rate of the adsorbent was more than 90%.The Fe₃O₄/modified cinder has better regeneration potential.And the magnetic properties of iron oxide itself are embodied in the separation of the composite material easily and after treatment.2.The montmorillonite/carbon sphere composites were prepared by solvothermal method which used the montmorillonite,cetyltrimethylammonium bromide（CTAB）and glucose as the precursor,surfactant and carbon source,respectively.The microstructure and mechanical performances of the composites are characterized by SEM,XRD,XPS,FT-IR and BET.The effects of the amount of adsorbent,the time of adsorption,the pH value and the initial concentration of RhB solution,the adsorption temperature on the adsorptive capacity of RhB adsorbent were investigated.The optimum conditions for the adsorption reaction were as follows:the amount of adsorbent was 0.3 g,the adsorption time was 15 min,the pH value of RhB solution was 5.00,and the adsorption temperature was 45℃.The adsorption of RhB on montmorillonite/carbon sphere is more consistent with Langmuir model.The adsorption thermodynamics parameters indicate that the adsorption of RhB on montmorillonite/carbon sphere is spontaneous and endothermic mainly by physical adsorption.The adsorption of RhB on montmorillonite/carbon sphere is more consistent with pseudo-second-order kinetics.The adsorption rate of the adsorbent was about 90%after five successive adsorption/regeneration cycles.The montmorillonite/carbon sphere has a good potential of regeneration and reuse.3.The porous carbon material was prepared by calcination at a high temperature of 500 ℃using C6H12O6 as carbon source and soluble inorganic salt sodium chloride as a template.The SEM,XRD,XPS,FT-1R and BET were used to characterize the microstructure and mechanical properties of the porous carbon material.The effects of the amount of adsorbent,the adsorption time,the pH value and the initial concentration of MB solution,the adsorption temperature on the adsorption performance were investigated.The best conditions of this adsorption reaction were as follows:the quality of this adsorbent was 0.0075 g,the time of this adsorption reaction was 2 min,the pH value of the MB solution was 6.00,and the temperature of this adsorption reaction was 25℃.This adsorption reaction is consistent with the Langmuir model.The adsorption thermodynamics parameters show that this adsorption reaction is spontaneous and exothermic reaction based on physical adsorption.The adsorption of MB on porous carbon is more consistent with pseudo-second-order kinetics.After 5 successive adsorption/regeneration cycles,the adsorption rate of the material was decreased,but the primary performance of the porous carbon was better than 100%.