An analysis of the absorption of alkyl benzene sulphonate by algal residues

The extraction of agar-agar from Gracilaria debilis produced a residue which was examined as a potential biosorbent for the removal of linear alkyl benzene sulphonate (LAS) from aqueous solution. Tests were carried out at 25 degrees C and a range of pH values. The results were analysed as Langmuir isotherms. The compliance between the data and the theoretical equation was good and the results indicated that the adsorption was favoured by lower pH values. The maximum adsorption capacity was 76 . 34 mg g(-1). This needs to be compared with a value of 75 . 85 mg g(-1) determined previously for the adsorption of a branched chain alkyl benzene sulphonate by activated carbon. The rates of LAS removal were also measured and it was found that the rates were increased by lowering the pH.