Removal of BTEX from water system by synergistic flocculation of biosurfactant and iron salt.

The adsorption micelle flocculation (AMF) effect of biosurfactants (rhamnolipids, RL) and polymerized ferric sulfate (PFS) on the removal of low molecular weight benzoic acid (benzoic acid and p-methyl benzoic acid) and phenol (2,4-dichlorophenol and bisphenol A) organics was investigated. The coexistence system of RL and organic matter was constructed, and the effects of pH, Fe concentration, RL concentration and initial concentration of organic matter on the removal effect were discussed. For benzoic acid and p-methyl benzoic acid, the increase of Fe and RL concentrations was beneficial to their removal rates under weak acidic conditions, and the removal rate of the coexistence system was higher for methyl benzoic acid (87.7 %) than for benzoic acid (78.6 %), which might be attributed to the stronger hydrophobicity of the coexistence system for methyl benzoic acid; while for 2,4-dichlorophenol and bisphenol A, pH and Fe concentration changes had less effect on the removal rate, but the increase in RL concentration was favorable to the removal rate, which was 93.1 % and 86.7 % for BPA and 2,4-dichlorophenol, respectively. These findings provide feasible ideas and directions for the removal of organics by AMF using biosurfactants.