Adsorption Characteristics Of Orange Ⅱ Dye In Water By Modified Activated Carbons

With the development of dyes and dyeing industry, its production wastewater hasbecome the main sources of water pollution. Decolorization of dye wastewatertreatment has always been a problem, although many but have certain limitation.Activated carbon is a class of developed pore structure and high specific surface areasolid materials. Because it is in a wide range of efficient adsorption of the adsorbate andeasy to operate,it is widely used in water treatment industry. This is a very promisingtechnology.In this article, using granular activated carbon as adsorbent, activated carbon’sremoval and adsorbent characteristics toward anionic Orange Ⅱ dye in water havebeen studied through a batch of experiments. The result show that:The adsorptionkinetic of granular activated carbon for Orange Ⅱ dye that concentration were200,300,400mg·L^-1followed the first order reaction kinetics model of dC/dt=-K（C-Ce）.The parameter k[min^-1] were0.03852,0.02033,0.015; Concentration of Orange Ⅱdecreased with time, and the stable value of concentration is Ce, Cewere5.52,11.54,23.53. The isothermal adsorption process can be a good description of the Langmuirmodel of q=qmbCe/（1+bCe）,R2>0.9.The pH value and ionic strength are importantfactors of adsorption of Orange Ⅱ by granular activated carbon. The maximumadsorption capacity values of system when the pH was2is higher than the values ofsystem when the pH was4to1016%²7%;When the pH value was4to10,themaximum adsorption capacity values were closer to each other,the difference betweenthe maximum adsorption capacity value and the minimum adsorption capacity valuewas9.2%. With the increase of ionic strength, the adsorption was improved. Changingthe ionic strength with NaCl, When the ionic was0to0.1mol·L^-1, the differencebetween the maximum adsorption capacity value and the minimum adsorption capacityvalue was10.2%.Six different kinds of activated carbon were obtained by soaking in nitric acidsolution and microwave high-temperature modification.The concentration of Orange Ⅱwere100³00mg·L^-1.Using the behaviors of adsorption by specific ionic strength andpH value,explored the effect of the modification conditions on the adsorption.In theadsorption experiment of Orange Ⅱ, when the ionic was0.001mol·L^-1,the maximumadsorption capacity values of1#⁶#AC were13.28,12.22,15.04,14.30,11.73, 16.66mg·L^-1. Descending order of adsorption capacity is:6#>3#>4#>1#>2#>5#.WhenpH=6,the maximum adsorption capacity values of1#⁶#AC were12.91,12.24,13.22,13.70,12.00,14.88mg·L^-1. Descending order of adsorption capacity is:6#>4#>3#>1#>2#>5#.Compare the5#AC and6#GAC,the pore structure similar to each other and thespecific surface area of5#AC is slightly larger than6#AC, but the effect of adsorptionis a difference of24%⁴2%. This shows that,specific surface area and pore size, porevolume can not be good characterization of adsorption of Orange Ⅱ by activatedcarbon. The nature of surface functional groups has an important influence on theadsorption, the total proportion of oxygen functional groups in the order of:6#（28.89%）>3#（26.84%）>2#（22.50%）>1#（21.21%）>4#（20.12%）>5#（17.70%）. In general, thetotal content of oxygen-containing groups more, the better the adsorption effect ofOrange Ⅱ by activated carbon.