Isolation of sugarcane amino acids from aqueous solution by ARHA

Abstract

In this research work, adsorption of sugarcane amino acids on activated rice husk ash (ARHA) has been studied. The pore distribution of the ARHA falls between macroporous and mesoporous domains. The BET surface area of the ARHA was typically found as SBET = 16.48 m2/g. The adsorption properties of studied sugarcane amino acids depend on several factors such as pKa, functional group present, polarity, molecular weight, size and solution condition such as pH, ionic strength and adsorbed concentration. Adsorption was found to increase markedly with increase in ionic strength from 0.02 to 0.1 M suggesting a role for the hydrophobic force in this adsorption process. Adsorption was reduced substantially by the addition of urea; therefore, hydrogen bonding seems to play an important role in this adsorption process. ARHA was characterized by FT-IR, SEM and BET techniques for its use for selective adsorption for sugarcane amino acids from their aqueous solutions. Typical Langmuirian (L2) type adsorption isotherms were observed and adsorption mechanism has been proposed. Thermodynamics parameters of the adsorption process have also been evaluated. This study showed that the ARHA could be employed as low- cost and effective adsorbent for the removal of sugarcane amino acids.