A significant benefit of the floating composite material was its PR capability in turbid waste (TW). To simulate a TW stream, mixed waste from a floatation separation process was pre-treated in 1 mol L -1 KOH for 24 h at 80 °C and coarsely filtered through glass wool to produce a dark brown suspension which was then then spiked with 25 mg mL -1 EG as a substrate (Figure ). Vertically irradiated PR experiments (in triplicates) using 217 mL (1 cm deep, 217 cm 2 , 2 h, 1 mol L -1 KOH, 25 mg mL -1 EG, 12 mg mL -1 composite) of this TW+EG solution in the large reactor demonstrated that non-floating carbon nitride (CNx|Pt) was unable to produce a detectable quantity of H2 in a 2 h period, while floating HGM/CNx|Pt produced 503.2 ± 1.9 µmolH 2 m -2 h -1 under the same conditions (Figure ). Small-vial control experiments in well-mixed, side-illumination conditions where the light exposure to both catalysts was equal demonstrated that the CNx|Pt catalyst had approximately the same performance as HGM/CNx|Pt in both clear (EG only) and TW conditions (Figure , ESI).