Preparation Of Activated Carbons From Coal Heavy Component And Their Adsorption Properties

China’s industrial development has been rapid,but it is also faced with a serious problem of water pollution.A large number of phenolic wastewater,dye wastewater and heavy metal wastewater have caused certain harm to the environment.Therefore,it is very important to find an economic and effective treatment method for wastewater.Activated carbon is prepared by using the heavy group separated from the whole components of Tongting coal as the precursor.Compared with the raw coal,there are a lot of cracks on the surface of heavy group.These cracks make it easier for the activator to enter the raw material for activation,so as to prepare activated carbon with larger specific surface area and higher adsorption capacity.In this paper,first of all,choose different activator to activate heavy group,on a visit to select the best activator on the basis of different activation process conditions on the properties of activated carbon adsorption of methylene blue and phenol,finally explores the different adsorption conditions,activated carbon adsorption of methylene blue,phenol and the heat of adsorption kinetics of hexavalent chromium aqueous solution.The pore structure of the activated carbon prepared by direct carbonization with phosphoric acid,zinc chloride and potassium hydroxide and the adsorption capacity of phenol and methylene blue were compared.The results show that potassium hydroxide is the best activator among several activation methods.The specific surface area of potassium hydroxide is up to 3682m2/g,the adsorption capacity of methylene blue solution of 2000 mg/L is 1979 mg/g,the adsorption rate is 98.95%,and the adsorption capacity of phenol of 120 mg/L is99.19 mg/g,the adsorption rate is 82.66%.Secondly with potassium hydroxide as activator,explores the preparation process conditions for the pore structure and adsorption properties of activated carbon,the activation temperature is too low,activator ratio is too low,the activation time is too short,can cause activated carbon is not fully activated,activation temperature,ratio of activator is too high and activation time is too long,can cause activated carbon aperture to collapse.The results showed that when the activation temperature was 750 o C,the ratio of base to carbon was 4:1,and the activation time was 1 h,the activated carbon had the maximum specific surface area and the best adsorption effect for methylene blue,with the specific surface area up to 3752 m2/g,the adsorption capacity for methylene blue solution of 2000 mg/L was as high as 1996.74 mg/g,and the adsorption rate was as high as 99.84%.However,when the alkali to carbon ratio was 2:1,the adsorption capacity of phenol reached the maximum,107.08 mg/g for 120 mg/L phenol solution,with an adsorption rate of 89.23%.When the specific surface area of activated carbon was the maximum,the adsorption capacity of phenol was 103.57 mg/g,with an adsorption rate of 86.31%.The results show that the adsorption of methylene blue by activated carbon is mainly affected by the pore structure,while the adsorption of phenol by activated carbon is not only affected by the pore structure,but also affected by the surface functional groups of activated carbon.Finally,the prepared activated carbon was used as adsorbent to adsorb phenol,methylene blue and hexavalent chromium solution,and the influence of adsorption conditions on adsorption performance was investigated.The results show that the adsorption rate of activated carbon for each adsorbate is fast,and the equilibrium can be reached in about five minutes.With the increase of temperature,the adsorption capacity of the prepared activated carbon for phenol and hexavalent chromium solution decreased,and its adsorption isotherm met Freundlich isothermal adsorption model,while the adsorption capacity of methylene blue solution increased,and its isothermal adsorption line met Langmuir isothermal adsorption model.It has good adsorption performance for phenol and hexavalent chromium under acidic conditions,and good adsorption performance for methylene blue under alkaline conditions.The adsorption kinetics of activated carbon for each adsorbate accords with quasi-second-order kinetics,and the adsorption process is not controlled by a single adsorption rate.In this paper,super high specific surface area activated carbon was prepared from coal group heavy materials with excellent adsorption performance,which provided a new way for non-fuel utilization of coal.