Study On Adsorption Of Dye Compounds By Biochar And Actived Carbon

With the rapid development of textile industry, the treatment of dye-containing wastewater has been a major environmental concern. The dyes in wastewater possess complex structures and stable properties,which are difficult to degrade in the environment. Therefore, it would do serious harm to public health when discharged into the environment.Biochar(BC) with many porous structures and surface functional groups is widely used for the removal of pollutants. It is cheaper and easier to get from the environment compared with activated carbon(AC).This study will discuss the differences of adsorption characteristics between BC and AC, and the feasibility of BC for waste water pollution removing is investigated.The adsorption of malachite green(MG) and Acid OrangeⅡ(AOⅡ)on wood-based BC and AC were investigated in this study. Effect of adsorption time, oscillation intensity, temperature, p H and ion strength were investigated through the equilibrium adsorption test to explore their adsorption behaviors and mechanism. The main results are listed asfollows:1. As pH increased from 3 to 9, the adsorption amount of MG on BC and AC increased while the adsorption amount of AOⅡ decreased. The appropriate salt concentration is beneficial for removal of MG and AOⅡ.Oscillation intensity does no effect on adsorption.All the adsorption isotherms could be well described with the Langmuir and Freundlich equation. With temperature increasing from 10 to 40℃, the adsorption amount of MG and AOⅡ on BC increased, while those on AC decreased.2. The adsorption thermodynamics showed that the △H0and △G0ofadsorption of MG and AOⅡ on BC is positive and negative respectively,which suggested the adsorption progress is a spontaneous endothermicprocess. The △H0and △G0 of adsorption of MG and MG and AOⅡ on AC was negative and positive respectively, which suggested the adsorption progress is a non-spontaneous exothermic process.3. The adsorption kinetic process of MG and acid AO Ⅱ on two adsorbents can be divided into two stages which called rapid and slow adsorption. The adsorption process fitted well with the secondary reactionkinetics model.