Study Of Adsorption Property About Rice Husk Ash And Modified Rice Husk Ash

This study dealed with the adsorption characteristics of phenol and Cd2+onto rise husk ash. And rice husk ash (RHA) was dealed with hydrofluoric acid and sodium hydroxide (RHA/HF、RHA/NaOH).The BET analysis of RHA/HF and RHA/NaOH showed an increase in total pore volume and specific surface area compared to RHA, especially RHA/HF.The specific surface area of RHA、RHA/NaOH and RHA/HF were114.6m2/g、289m2/g and492.7m2/g respectively. FTIR and XRD showed there were silica and carbon in RHA,and silicia was almost entirely removed in RHA/HF and partly in RHA/NaOH.Adsorption studys of phenol on rice husk ash showed that, the optimum pH for the adsorption was found to be3and the temperature was15℃. Maximum uptake was obtained at adsorbent dose of20g/L. At optimum condition of pH,contact time, temperature and adsorbent dosage level removal efficiency of62.51%for inital phenol concentration of15mg/L. The Langmiur isotherm was found to be better than the Freundlich isothem and the experimental data were better described by pesudo first model as evident from correlation coefficient values R. For the adsorption studys of phenol on RHA/HF, maximum uptake was obtained when the dose was10g/L and when the intital concentration of phenol was100mg/L, the removal efficiency was97.24%. The adsorption of phenol on RHA/HF was also fitted to the Langmiur isotherm and pesudo first adsorption kinetics model.The equilibrium time for adsorption of Cd2+from aqueous solutions was achieved within2h of contact time. The optimum pH for the adsorption was found to be5and maximum uptake was obtained at RHA dose of20g/L,which may be considered as optimum adsorbent dosage level at the specified conditions. When the initial Cd2+concentration was20mg/L, the removal efficiency was96.9%and the residual Cd2+concentration in the solution was0.62mg/L,which corresponded with IS:10500.