3D printed photoreactor with immobilized graphitic carbon nitride: A sustainable platform for solar water purification

[Display omitted] •g-C3N4/chitosan hydrogel beads (GCHBs) were developed for water purification.•A compound parabolic collector photoreactor was fabricated via 3D printing.•The photocatalytic system is promising for micropollutant removal.•Global drinking water production was estimated to show system practicality.•Research outcome provides a sustainable platform for small-scale water treatment. Solar-energy-enabled photocatalysis is promising for sustainable water purification. However, photoreactor design, especially immobilizing nano-sized photocatalysts, remains a major barrier preventing industrial-scale application of photocatalysis. In this study, we immobilized photocatalytic graphitic carbon nitride on chitosan to produce g-C3N4/chitosan hydrogel beads (GCHBs), and evaluated GCHB photoreactivity for degrading phenol and emerging persistent micropollutants in a 3D printed compound parabolic collector (CPC) reactor. The CPC photocatalytic system showed comparable performance with slurry reactors for sulfamethoxazole and carbamazepine degradation under simulated sunlight, and it maintained the performance for contaminant removal in real water samples collected from water/wastewater treatment plants or under outdoor sunlight irradiation. Global drinking water production was estimated for the CPC system, and it holds promise for small-scale sustainable water treatment, including, but not limited to, the production of high-quality potable water for single houses, small communities, rural areas, and areas impacted by natural disasters in both developed and developing countries.