Adsorption Of Cations And Anions By Calcined Hydrotalcite Supported On Activated Carbon

At present,Ozone Oxidation Technology(OOT)has become one of the mainstream technologies for drinking water treatment.With the increasing use of OOT in the advanced treatment of drinking water,its research has become more in-depth.The by-product bromate produced by this technology in the disinfection of drinking water has also attracted the attention of scientists.As a potentially dangerous carcinogen,bromate severely harms human health.Therefore,it is necessary to study how to control and remove these bromate by-products generated during ozone oxidation.In addition to bromate,the presence of a large number of calcium and magnesium ions will increase the hardness of the water body,thus forming scale,causing damage to the water supply system,and in the thermal application of water,consume more energy.The long-term consumption of these over-hardened waters will also harm human health and thus have a negative impact on human production and life.In the treatment process of industrial water and high-salt wastewater,high calcium and magnesium ions will also cause many hazards such as sedimentation,blockage,etc.in the subsequent water treatment process.Therefore,effectively softening water bodies will contribute enormous value in terms of economy and health.The high cost and process complexity of the anion bromate and cation calcium and magnesium ions are solved for the existing water treatment multi-set processes.In view of this situation,this paper proposes a new technology to remove bromate and calcium and magnesium from the composite material of activated carbon supported hydrotalcite.In this paper,four kinds of Hydrotalcite Supported on Activated Carbon materials were prepared by the equal volume impregnation method,and the composite adsorbents CLDHs/AC were obtained after calcination at high temperature.The composites were characterized by SEM,XRD,EDS and BET techniques.In order to study the adsorption properties of materials,kinetic experiments,adsorption equilibrium experiments,thermodynamic experiments and regeneration experiments were carried out.The study of the adsorption of bromate on CLDHs/AC shows that the kinetic experimental data fit the pseudo-second-order kinetic model and the Langmuir model is more suitable for describing the equilibrium adsorption experiment,which is an endothermic and chemisorption-based adsorption process.Regeneration experiments show that the composites can be recycled at least 3 times.The maximum saturated adsorption at 50? is 60.02 mg/g.Studies on the adsorption of calcium and magnesium by CLDHs/AC show that the pseudo-second-order model can better describe the kinetic data of calcium and magnesium;the equilibrium study shows that the adsorption of calcium and magnesium on the composite material is in accordance with the Langmuir model,The maximum adsorption amounts of calcium and magnesium were 215.98 and 101.32 mg/g,respectively.The thermodynamic analysis showed that the adsorption of calcium and magnesium on the composite was spontaneous and endothermic.Regeneration experiments show that,CLDHs/AC has good reusability,at least three times more than recycling.In summary,CLDHs/AC has potential applications for the treatment of wastewater containing BrO3-,Ca2+ or Mg2+ because of its high efficiency,easy operation and low cost.