Sorption and water distribution performances of a geosynthetic sheet used in naturally contaminated soils management

A novel hydrotalcite-coated geosynthetic sorption sheet shows potential for managing geogenic contamination in excavated soils and rocks. Employed in an attenuation layer, it retains contaminants in leachate before infiltration into surrounding soil. This study evaluates the arsenic (As) sorption efficiency and water distribution performance of this geosynthetic material to assess its field applicability. Batch experiments were conducted across a pH range of 3–9, temperatures of 5–40 °C, and with co-existing ions (HCO₃⁻, SO₄²⁻ at 0–500 mg/L). Results demonstrated effective removal of both As(III) and As(V), with higher efficiency for As(V). While pH, co-existing ions, and temperature had minimal effect on As(V) removal, they significantly influenced As(III) removal. Specifically, As(III) sorption efficiency decreased by 15 % as pH decreased from 9 to 3. The presence of HCO₃⁻ and SO₄²⁻ reduced As(III) removal due to competition for sorption sites. Removal efficiency slightly improved at 40 °C due to the endothermic nature of the sorption process. Soil tank experiments indicated that soil particle size was the dominant factor controlling water retention and drainage patterns. Coarse sand promoted concentrated flow, while finer sands enhanced retention and dispersion. The geosynthetic sorption sheet showed only a limited hydraulic influence under the tested conditions.