Miniaturised coiled flow inverter for continuous, rapid and high-efficiency removal of pharmaceutical pollutants from hospital wastewater

Miniaturised wastewater treatment equipment that operates in continuous mode offers advantages such as improved mixing, shorter treatment times, and reduced footprint compared to conventional batch systems. These features are particularly relevant for treating hospital wastewater (HWW) contaminated with pharmaceuticals. In this study, a miniaturised continuous adsorption system based on a coiled flow inverter (CFI) is evaluated as a novel platform for PPCP removal. Triamterene, a diuretic commonly detected in HWW, was selected as a model compound and removed using graphene oxide (GO) as the adsorbent under continuous-flow conditions. The effects of flow rate (10–135 mL/min), initial triamterene concentration (1–250 mg/L), GO dosage (0.2–2 mg/mL), and pH (2−10) were investigated. Rapid adsorption was observed, with up to 99% removal achieved within 40 s, and a maximum adsorption capacity of 822 ± 0.07 mg/g. Removal efficiency showed minimal sensitivity to flow rate over the tested range. Under identical batch conditions, commercial activated carbon achieved only ∼14% removal. GO retained over 90% removal efficiency after 10 adsorption-desorption cycles, indicating good reusability. When applied to real HWW samples, the system achieved >90% triamterene removal within one minute. Overall, this study demonstrates the feasibility of integrating GO adsorption with CFI hydrodynamics for rapid, continuous PPCP removal and provides a foundation for further optimisation and scale-up.