Peroxymonosulfate-activated molecularly imprinted bimetallic MOFs for targeted removal of PAHs and recovery of biosurfactants from soil washing effluents

• A novel catalyst named Al/Co-MOFs@MIP was synthesized to active PMS. • Higher stability, better catalytic performance and excellent selective recognition of Al/Co MOFs@MIP. • Selective degradation of phenanthrene in soil washing effluents was achieved for biosurfactant recovery. • Non-radical and radical mechanisms were involved in Al/Co-MOFs@MIP/PMS system. Treatment of washing effluents containing high concentrations of surfactants and PAHs remains a critical challenge in surfactant-enhanced soil washing processes. In this study, bimetallic metal–organic frameworks modified with molecularly imprinted polymers, named Al/Co-MOFs@MIP have been synthesized to activate peroxymonosulfate (PMS) at the first time for targeted degradation of phenanthrene from soil washing effluents for biosurfactant recovery. The Al/Co-MOFs@MIP has higher stability, better catalytic performance and excellent selective recognition. The Al/Co-MOFs@MIP has significantly enhanced adsorption of phenanthrene. Electrostatic interactions and functional groups binding between phenanthrene and specific recognition sites led to better selective recognition. Targeted adsorption of phenanthrene caused closer distance between free radicals and pollutants which resulted in higher degradation efficiency. Phenanthrene adsorbed on the Al/Co-MOFs@MIP surface consumes free radicals, thus reducing the attack of oxidative free radicals on rhamnolipids. The EPR and quenching experiments indicated that although both free radicals and non-free radicals made contributions to the degradation of phenanthrene. Phenanthrene is attacked and oxidized by SO 4 Â · - and 1 O 2 through two pathways, including oxalic acid loss, ring cleavage and mineralization. This study indicated that selective phenanthrene degradation could be realized in Al/Co-MOFs@MIP/PMS system due to the synergetic effects including selective adsorption and catalysis of the material.