Development of an automated low-cost photoreactor with integrated control, monitoring, and sampling modules

Photocatalysis is an innovative technology with high potential in environmental pollution management, clean energy production, and chemical synthesis. Photoreactor systems have been developed in recent years, featuring various designs and capabilities that enhance their efficiency and adaptability for diverse applications. However, their lack of automation and real-time monitoring limits the optimal performance of photocatalytic processes. This study presents a novel, automated, modular, low-cost photoreactor for photocatalytic processes on a laboratory scale. This system offers programmable and easily exchangeable LED arrays with real-time control of irradiation, temperature, and pH using low-cost sensors, and remote operation via an open-source control interface. In addition, the photoreactor incorporates an automatic sampling and dosing unit that enables controlled reagent addition and sample withdrawal during experiments, facilitating real-time kinetic analysis and advanced experimental protocols. The platform's performance and versatility are demonstrated through photocatalytic degradation experiments using Rhodamine B as a model pollutant. Bismuth ferrite (BiFeO₃) was selected as a benchmark photocatalyst due to its growing research interest and promising visible-light activity. Comparative experiments conducted against a reference photoreactor show that the presented system achieves degradation efficiencies comparable to those of the reference photoreactor under controlled conditions. The integrated online monitoring of temperature and pH proved effective in registering consistent operational conditions, providing a significant advantage for reaction control. The automatic sampling and dosing module was validated using a portable low-cost photometer, yielding removal results that aligned with those from a reference spectrophotometer. Unlike previously reported self-assembled photoreactors, the proposed platform integrates programmable LED irradiation, real-time pH and temperature monitoring, automated dosing and sampling, remote operation, and online analytical capability within a single low-cost modular system.