The effect of natural organic compounds on the adsorption of toluene and ethylene benzene on MWCNT

Purpose The present study aimed to investigate the effect of humic acid (as a NOM model) on the adsorption capacity of MWCNT. Methods Ethyl benzene and toluene were removed from aqueous solution and adsorbed on multi walled carbon nanotubes in batch adsorption experiments at the presence of different concentrations of humic acid. Results The results showed that the highest adsorption of multi walled carbon nanotubes was 72 mg/g for ethyl benzene and 35 mg/g for toluene in an aqueous solution without humic acid. Langmuir isotherm model and pseudo-second-order kinetic model were the predominant models of adsorption process. Pre-loading of humic acid on MWCNT reduced the adsorption capacity of MWCNT from 14 mg/g to 8 mg/g for toluene and from 25 mg/g to 10 mg/g for ethyl benzene, when the experiments were conducted with MWCNT pre-loaded by humic acid from 0 to 30% . Conclusions The batch adsorption experiments showed that the presence of dissolved humic acid in the aqueous environment slightly affected the adsorption of ethyl benzene and toluene by MWCNT but, Pre-loading of humic acid on MWCNT could reduce the adsorption capacity of multi walled carbon nanotubes.