Studies On Adsorption Of Heavy Metals In Solution By Actived Carbon

The actived carbon is a kind of good adsorbents, which having the higher specific surface areas and chemistry stability. There are many advantages in the removing heavy metals in the industry waste water by using the technique of the actived carbon adsorption . Because it needs simple equipment, small covering area and do not produce the second pollution,the application of this method has increased in home and abroad. Because the principle of the adsorption in removing heavy metals between aqueous and waste water. Therefor, the study of removing heavy metals in solution by actived carbon can help the treatment of removing the heavy metals in industry waste water and present a valuable reference for research on the disposing of metals in solution using actived carbon adsorption method.In this thesis, the author investigated the effect of heavy metals adsorption , adsorption characteristic in adsorbing arsenic in aqueous , presented the adsorption heavy metals technology using actived carbon and in the certain degree discussed the adsorption mechanism of adsorbing arsenic in aqueous from the thermodynamics and dynamics two aspects through three experiments which are the static adsorption experiment in discharge the mental heavy metals copper, lead and arsenic in industry waste water ; the static adsorption experiment in adsorbing arsenic in aqueous ;the modification experiment of chemical properties on actived carbon surface and adsorption performance to adsorb arsenic after surface modification.Examining the results of technology experiments, the author found two primary conclusions as follows:(l)Actived carbon can adsorb the mental heavy metals in nonferrous metallurgy waste waters and the adsorption time last short time. After half-hours adsorbed , the concentration of arsenic in aqueous can reduce to 0.063mg/L,far below the standard(0.5mg/L).But the copper and lead concentration in solution can not meet the standard.But when the solution pH is altered, the adsorption effects to copperhead and arsenic are all good. The efficiency of the copper, lead and arsenic removal can come up to 99.33%,89.13% and 99.91%.(2)The solution's pH is one of the mental affect factors in adsorption. At the lowpH , the adsorption efficiency of the copper lead and arsenic is high but the higher pH make against adsorption efficiency and when the pH is about 4 , the adsorption effect is satisfied.The conclusions of the static adsorption experiment in adsorbing in aqueous are that the after adsorption ,the concentration of arsenic in water can reduce from 2.0mg/L to a level lower than 0.01 mg/L , and the higher arsenic concentration, the more amount adsorbed; that category of actived carbon and form of arsenic in water are two main factors affecting the adsorption. The higher specific surface areas, the higher efficiency and when the form of arsenic in aqueous is in HAsO2, the amount of arsenic is adsorbed; that when the pH is low , the adsorption efficiency of arsenic is high but the higher pH make against adsorption efficiency and when the pH is between 3.5-4.5 , the adsorption effect is almost highest. Furthermore, the granularity and the dosage of actived carbon the ionic strength of solution and temperature can also affect the adsorption efficiency. The results of experiments tell us that when the granularity of actived carbon is between 160~200, the adsorption efficiency is almost highest. That the more amount of actived carbon, the higher efficiency before the adsorption get to equilibrium. That the higher ionic strength of solution is, the lower the efficiency and low temperature is help to adsorption but high against. The adsorption can give out heat but the value is only 18.142Kj/mol. NaOH can be used in the actived carbon desorption, after adsorption. Furthermore, after surface modification of actived carbon using the heavy nitric acid, the adsorption effect of the actived carbon to arsenic in water become lower. This illustrates that the increased acidic functional groups on the surface of the carbons can n...