Simultaneous mitigating membrane fouling and eliminating emerging contaminants through the innovative application of an amorphous-tricobalt tetrasulfide/peroxymonosulfate process in the treatment of micro-polluted surface water.

Membrane fouling and insufficient capacity in removing emerging contaminants (ECs) represent two significant challenges hindering the widespread adoption and application of ultrafiltration (UF) technology. Herein, an amorphous tricobalt tetrasulfide/peroxymonosulfate (amorphous-CoS/PMS) process was innovatively proposed as pre-treatment technology prior to UF to address these issues. Neither PMS nor amorphous-CoS alone achieved the desired objectives in experiments involving individual typical natural organic matters (NOMs) or NOMs mixtures. In NOMs mixture experiments, the introduction of PMS alone slightly alleviated membrane fouling through increasing the energy barrier for NOMs particle adsorption onto the membrane. Meanwhile, the introduction of amorphous-CoS alone induced a significant scouring effect, hindering the deposition of NOMs particles on the membrane surface. Moreover, simultaneously introducing the amorphous-CoS and PMS achieved the desired objectives for tackling both challenges. Surface-bound radicals and sulfate radical played a dominant role in these achievements, while hydroxyl radical, singlet oxygen, and electron transfer contributed secondarily. These reactive oxygen species significantly reduced the molecular weight and content of NOMs and ECs, thereby substantially alleviating membrane fouling and altering its dominant fouling form from cake filtration to pore blocking. Notably, the pre-oxidation process exhibited excellent versatility in different micro-polluted surface waters with varying NOMs concentration, water hardness, and ECs type. This study provides valuable data support for the application of the amorphous-CoS/PMS process in UF field and offers indispensable guidance towards water security objectives.