High performance membrane filtration coupled with PMS/CoFe2O4 catalytic degradation for dyes

Abstract

Catalytic oxidation of contaminants by peroxomonosulfate (PMS) was coupled with membrane filtration to realize high-performance removal of dyes. CoFe2O4 (CFO) was enwrapped and cross linked in calcium alginate (CaAlg) to form CFO−CaAlg composite membrane. The introduction of CFO could not only activate PMS, but also enhanced the stability, hydrophilic property and crosslinking degree of the composite membrane. The final removal rate was enhanced greatly benefiting from the synergistic effect of filtration and catalytic degradation. The removal rate increased from 75% (filtration) to 98% by coupling with catalytic degradation. More importantly, purified water could be obtained immediately instead of waiting for purifying the whole feed solution due to the superiority of cross flow filtration. Radicals quenching and electron spin resonance (ESR) analysis experiment confirm that SO4· − contributed 25% and 1O2 contributed 75% in catalytic degradation. The composite membrane was effective for different type of dyes and could be reused only being backwashed by purified water because the catalyst CoFe2O4 could recover from Co3+ to Co2+ by itself during the process. This study opens a new path of rapid water purification and immediate drinking water supply.