Heterogeneous Photocatalytic Pilot Plant for Cyanide Decontamination: A Novel Solar Rotary Photoreactor

Abstract

During the gold extraction in opencast mining, many hazardous substances, such as cyanide, are spilled into the water bodies. This study's aim was to develop a novel rotary photocatalytic TiO2-based reactor to remove cyanide from polluted water using a rotary concentrator photoreactor (RCPR). This pilot-scale reactor was tested with synthetic cyanide water at concentrations from 0.05 to 50 ppm, varying the pH and commercial TiO2 load. The optimal conditions from experimental data were 87.4% of cyanide removal and catalyst load of 0.30 g/L at pH 9.5. Further, samples of cyanide water from an opencast gold mine were treated, achieving removal of 68.7% after 240 min. Our value-added is the rotary motion of the set of four glass tubes, achieving satisfactory performance, which is promising for cyanide wastewater treatment with a more compact footprint than a standard compound parabolic collector (CPC) solar photoreactor. Thus, it was possible to reduce mass and heat transfer limitations with a simple design by considering this photoreactor as a photocatalytic process intensifier.