Removal of Neutral Red Dye from Aqueous Solution by Adsorption onto Rice Bran

Abstract

This work is concerned with the study of locally available rice bran (Oryza sativa
L) as an adsorbent for the removal of neutral red dye from solution as low-cost adsorbent
in wastewater treatment for the removal of color which comes from textile dyes or other
industries.
Adsorption process were occurred at different acidity of solution (pH=3, 7, 11). The
experiments were repeated at different temperatures (20, 30, 40, 50°C) in order to
measure the thermodynamic parameters (ΔHº, ΔGº, ΔSº).
Rice bran showed good adsorption capacity against neutral red dye and can extract the
dye from aqueous solution. Adsorption isotherms of neutral red dye on bran from
aqueous solution obeyed Freundlich adsorption isotherm indicating the heterogeneity of
rice bran surface.
The tthermodynamic parameter values are calculated as follow:
ΔHº=-44.92 KJ.mol-1, ΔGº=-5.06 KJ.mol-1, ΔSº=-136.05 J.mol-1.ºK-1
In conclusion, adsorption of on rice bran is exothermic process with relatively high
thermodynamic parameters values. The adsorption enhanced by decreasing temperature
and with increasing acidity of the medium. It can be concluded from the results of the
present study that the process of adsorption of neutral red dye on rice bran may be used
effectively to remove the dye from aqueous medium.