COMPARATIVE ADSORPTION STUDY ON RICE HUSK AND RICE HUSK ASH BY USING AMARANTHUS GANGETICUS PIGMENTS AS DYE

Abstract

Low cost adsorbents such as Rice Husk (RH) and Rice Husk Ash (RHA) were used for removing dyes from aqueous medium and later Linear, Langmuir and Freundlich adsorption isotherms have been verified by using adsorption data. RH was activated by treating with nitric acid and RHA was prepared from RH by dolomite process. Natural dyes were extracted from the vegetable Amaranthus gangeticus by using a standard method. The removal efficiency of adsorbents was measured for the variation of parameters pH, contact time and adsorbents concentration. It has been noted that after changing time for same amount of adsorbent (1g/100ml) and dyes (10 ml) RH gave no efficiency trend but increased to 43.91% whereas for RHA efficiency was gradually increased to 59.62%. A reverse trend was noted when adsorption amounts were changed and others were put constant where RHA efficiency gradually increased to 99.30% but RH gave no trend with highest efficiency was close to 61.85%. The RH removal efficiency was good for pH 11 close to 62.86% and it was continuous from 3.95% at pH 2. Alternately, RHA gave 80.21% at pH 2 and later was decreased to 1.5% at pH 9 and again increased from pH 11. It is noted that RHA removal efficiency is better than RH and adsorptions are well fitted with isotherms.