생태융합환경공학연구실

논문 초록 (Abstract)

This study investigated the performance of calcium polysulfide (CPS) for immobilizing mixed heavy metals in
acidic–oxidizing groundwater collected from a smelting-impacted refinery in South Korea. A laboratory column
experiment was conducted using site-specific soil and groundwater to evaluate CPS transport, redox evolution,
metal precipitation, and hydraulic response under realistic geochemical conditions. The injection of CPS rapidly
established reducing and alkaline environments, promoting the precipitation of metal sulfides (MeS(s)), gypsum,
and secondary iron (hydr)oxides while inducing only moderate reductions in hydraulic conductivity. Massbalance
analyses demonstrated nearly complete cadmium sequestration and partial removal of zinc and magnesium,
governed primarily by sulfide affinity and solubility equilibria. Mineralogical and spectroscopic characterization
confirmed the formation of ZnS(s), CdS(s), and CaSO4⋅2H2O(s), whereas microbial community
profiling revealed enrichment of sulfur- and iron-metabolizing taxa within CPS-reactive zones, suggesting potential
microbial contributions to long-term stability. Compared with previous tests employing clean model
sands, the overall removal efficiency in site soil was lower, reflecting the effects of geochemical complexity,
competing ions, and localized precipitation. These findings demonstrate that the efficiency and longevity of CPS
treatment are controlled by the interplay among metal-specific thermodynamics, site mineralogy, and redox
buffering. The results highlight the importance of integrating mass-balance evaluation, mineralogical confirmation,
and microbial characterization to accurately assess in-situ performance and to optimize design parameters
for sustained sulfide-based remediation of mixed-metal contaminated groundwater.