Fig. 2: Architecture and control framework of the automated purification system.

a 3D-rendered representation of the fully automated purification device connected to a clean water supply (reverse osmosis unit) and a GO dispersion container. The equipment is controlled via a touchscreen interface, which displays real-time process data. Waste is collected in a separate container. b Cut-away view highlighting the placement of pumps P₁/P₂ (water handling), pump P₄ (GO recirculation), solenoid valves V₁/V₂, the electronics back-panel, and the dual power supplies. c Exploded view of the membrane module assembly, showing: internal support plate, membrane sheets, external fixing plates, and PEEK connectors for fluid routing. d Control topology. A Raspberry Pi drives the graphical user interface and closed-loop logic, while an Arduino handles real-time sensor acquisition (conductivity probe κ₁, level sensor L₁) and actuators toggling via a relay module. An emergency-stop (E-Stop) switch cuts-off 12 V power from all actuators. e Schematic diagram of the fluidic circuit, highlighting the purification tank. Pumps and valves regulate the flow of water and GO dispersion through the membrane module. Pump 4 enables internal recirculation of GO, while Pumps 1–3 control water flow. f Operating principle of the joint processes that work in the unit: tangential flow across the membrane (left) minimizes fouling, maintains a high diffusive flux and permits scaling of the system; conventional dialysis (right) is driven by the concentration gradient of the species between the dispersion and water.