생태융합환경공학연구실

논문 초록 (Abstract)

This study investigated the inhibition potential and repeated-use stability of a functional zeolite medium in which quaternary ammonium compounds (QACs) were immobilized on the zeolite surface through a Sol-Gel process. The prepared QACs-coated Zeolite was applied to Microcystis aeruginosa (M. aeruginosa) under laboratory-scale conditions, and its performance was evaluated based on visual changes, chlorophyll-a (Chl-a), phycocyanin (PC), pH, pseudo-first-order decay constants (k), surface characterization (SEM, EDS, and FT-IR), TOC-based leaching assessment, and microcystin analysis. The results showed that the QACs-coated Zeolite treatment promoted visible discoloration of the suspension. Compared with uncoated zeolite and sodium silicate-coated zeolite, the QACs-coated Zeolite induced greater reductions in both Chl-a and PC, with PC showing a more sensitive response. The pseudo-first-order decay analysis also indicated that the apparent pigment decay rate increased with increasing QACs coating concentration. In repeated-use experiments using the same medium for three consecutive cycles, similar trends were maintained, suggesting that the material retained a certain level of reactivity under repeated-use conditions. SEM, EDS, and FT-IR analyses suggested the formation of an organic-inorganic composite coating layer on the zeolite surface. TOC-based indirect estimation showed that Sol-Gel-coated samples exhibited lower leaching tendencies than the simply impregnated sample, implying that the Sol-Gel network may suppress the release of QACs into water to some extent. In addition, six major microcystin congeners were below the detection limit in all treatment conditions. Overall, the QACs-coated Zeolite showed the potential to induce pigment reduction, flocculation, and sedimentation of M. aeruginosa, while maintaining a certain degree of reactivity during repeated use. The Sol-Gel immobilization approach also appeared advantageous over simple impregnation in terms of leaching stability. However, because this study mainly relied on pigment-based indicators and qualitative observations, further studies are needed to evaluate cell viability, toxin partitioning, direct QACs quantification, ecotoxicological safety, and field-scale applicability.