Experimental Study On Activated Carbon Adsorption And Desorption Of Aluminum

With the increasing standards of water purity and increasing water pollutions,the traditional purification process of water is difficult to meet the drinking standard of living.As an advanced water treatment unit,active carbon basin is studied deeply and is used in water purification process.Generally speaking,the average aluminum concentration of water has decreased by 50% after filtering in the carbon basin. Actually,the aluminum concentration of water from the carbon basin is obviously higher than sedimentation from original water,which occurs in some individual tank after running long-time.And the increasing of pH value will activate this process. With the special characteristic of active carbon basin,the experimental study is performed for absorption and desorption of aluminum using active carbon with considering the influencing factor for aluminum concentration in process of water purification in this article.Firstly,according to the survey and the experiment research of the influencing factor in the water purification process,the conclusion is that the concentration of aluminum is impacted by pH value and the dosage of coagulant and coagulant-aids.Secondly,based on absorption theory,the absorption corresponding experiment is performed according to different initial aluminum concentration,the dosage of adsorbent,temperature,time and pH value.The experiment result shows that high dosage of absorbent and high initial aluminum concentration results in low absorption capacity;the adsorption effect elevates along with the temperature enhance.The adsorption process divides into two periods:earlier,mid and late;after adsorption equilibrium,the rate of adsorption keeps same regardless of lengthening the adsorption time under same condition.pH value is an important carbon absorption efficiency factor of aluminum; the neutral condition adsorption effect is worst.Finally,based on desorption theory, the desorption corresponding experiment is performed according to concentration of desorbing,the category of desorbing, desorbing temperature,time and pH value after the adsorption equilibrium.The conclusion is that the increasing desorbing effect with increasing temperature;the desorption process is divided into three period:initial,medium-term,and late.When being balance,no matter how to extend the time of desorbing, the rate of desorption will not change;pH value is the main factor in the process of carbon desorbing aluminum.The effect of desorption is better with acidic and alkaline but the neutral condition is worst;The effect of five kind of strippants(NaAC,NaHCO3,Na2CO3, Na3PO4,NaOH),NaOH are the best for the activated charcoal desorption aluminum;in six density of NaOH(0.01mol/L,0.05mol/L,0.10mol/L,0.20mol/L,0.50mol/L, 1.0mol/L),the effect of 0.20mol/LNaOH is best for the activated charcoal desorption aluminum.The experiment results will have great value on controlling the aluminum concentration of water from the active carbon basin.