Column removal of methylene blue using activated carbon derived from water spinach (Ipomoea aquatica)

Abstract

This study investigated column and batch sorption of methylene blue from solution using activated carbon produced from water spinach. The equilibrium data of the batch sorption process was analyzed using Langmuir and Freundlich isotherm models and the monolayer sorption capacity (441 mg/g) obtained from the Langmuir plot was compared with the column sorption capacity (456 mg/g) obtained from the BDST model plot. The effect of three process variables (carbon bed height, initial methylene blue concentration and flow rate) on the dynamic sorption of methylene blue on carbon was studied using breakthrough curve. From the BDST model analysis it was found that; an increase in dye concentration from 200 to 300 mg/l increased the column sorption capacity (N0) from 371 to 478 mg/g while an increase in flow rate from 2 to 6 ml/min decreased the column sorption capacity (N0) from 456 to 253 mg/g respectively. The correlation coefficient (R2) values obtained from the BDST model plots were generally very high with values ranging from 0.99 to 1.000 indicating the validity of the BDST model for the present system. 

Keywords: Activated carbon, Basic Blue-9, BDST, Column removal, Water spinach.