Study On Adsorption Of Heavy Metal Copper Ions By Nano-Magnesium Hydroxide

In recent years,with the increasingly serious environmental pollution caused by heavy metal ions and the enhancive consciousness of environmental protection,nanometer magnesium hydroxide powder materilas have been extensively concerned and researched as a "green environmental protection" adsorbent.However,due to the high surface energy of nanometer magnesium hydroxide,the structure is extremely unstable and is easily to agglomerate.Therefore,it is necessary to modify the surface of nano-sized magnesium hydroxide to enhance its dispersibility and oil hydrophobicity,so as to adsorb the heavy metal effectively.According to the modification method of nano-magnesium hydroxide,adsorption mechanism and data simulation theory,the details of this thesis is as follows:1.The surface of magnesium hydroxide was modified with silane couper KH-560,titanate coupler HY-201 and sodium stearate respectively.In addtion,the effects of modification time,modification temperature,modifier dosage and stirring rate on the modification effect of nano-magnesium hydroxide were investigated.The results showed that the dispersibility and hydrophobicity of the modified nano-magnesium hydroxide particles were significantly improved.Based on the comparison and analysis of the effect of nano magnesium hydroxide under different technological conditions,it indicated that the best modifier is the titanate coupler HY-201 and the optimum modification conditions were obtained,which are as follows: modifier dosage is 1.5 wt%,modification temperature is 80℃,modification time is 15 min,and stirring rate is 600 rpm.2.The adsorption of heavy metal copper ions was studied by using nano-magnesium hydroxide as adsorbent before and after modification.The effects of adsorbent concentration,adsorption time,p H value of solution and adsorption temperature on the adsorption process were investigated.And the optimum conditions were obtained under the conditions at p H= 6,adsorbent dosage of 3g/L,adsorption time of 15 min and temperature of 298 K.By comparing the adsorption effect of nano-magnesium hydroxide on copper ions with or without modification,it was found that the removal rate of copper ions after modification was better than that before modification.The thermodynamics and kinetics of the adsorption process were studied.Experimental results revealed that the adsorption of copper ion by adding nano-magnesium hydroxide follows Langmuir equation.And the maximum adsorption capacity of copper ions before and after the modification of nano-magnesium hydroxide were 43.48 mg/L and 45.47 mg/L,respectively.The thermodynamic studies show that the adsorption is a physical,spontaneous and endothermic process and the gibbs free energy ΔG decreases with the increase of temperature.The kinetics experiments show the adsorption is a pseudo-first order kinetic and the adsorption rate is controlled by the diffusion of particles and the adsorption of surfactants on the surface.3.The BP network structure with additional momentum was studied and constructed.By comparing the predicted values with the experimental values,the results show that the BP network model can predict and the average relative error is smaller or equal to 3.27%.