Multistage Adsorption–Filtration of Cow’s Milk for Heavy Metal and Radionuclide Removal with Preservation of Milk Quality

This study evaluated a modular sorbent-based filtration system for reducing heavy metals and anthropogenic radionuclides in cow milk and assessed changes in selected physicochemical parameters. Taurite (shungite), natural zeolite, and coconut-shell activated carbon 207C were tested in single- and multicolumn configurations at 100 and 150 cm3 per sorbent layer. Pb and Cd reduction were evaluated in fortified milk, while pre-existing 137Cs and 90Sr were assessed in milk from two locations. Milk-quality parameters were measured in separate milk batches. At 150 cm3 per layer, taurite→activated carbon reduced Pb and Cd by approximately 90.6% and 91.9%, respectively, to 0.032 and 0.025 mg/kg. Under the 150 cm3 radionuclide-testing conditions, zeolite→activated carbon reduced 137Cs and 90Sr by 75.73% and 73.97%, yielding residual activities of 0.2534 and 0.1123 Bq/kg. The complete three-stage configurations achieved approximately 79.9% and 77.7% reductions, respectively. In the separate quality assessment, taurite→activated carbon produced limited changes in basic composition and viscosity, whereas zeolite-containing configurations caused greater decreases in Na and K. Radionuclide results were interpreted within each source-specific series because milk source and sorbent loading varied simultaneously. Overall, the findings demonstrate substantial laboratory-scale contaminant reduction and support selecting sorbent configurations according to contaminant type, with taurite→activated carbon providing a favourable balance across the separately assessed removal and milk-quality criteria.