Sunlight-induced catalytic activity of CaBi4Ti4O15 for binary dye degradation

This study explores a practical approach for treating dye effluent via photocatalysis. Unlike most published research, which typically conducts experiments using photocatalytic reactors with a single-model dye. This investigation examines photocatalysis under sunlight irradiation with both singular and binary model dyes. The study utilizes a CaBi4Ti4O15 catalyst prepared by the solid-state method and tested with single Methylene Blue dye, Rhodamine B dye, and their mixture (binary dye). The catalyst was characterized using X-ray diffraction spectroscopy, Raman spectroscopy, and X-ray photoelectron spectroscopy. The Brunauer-Emmett-Teller (BET) method indicated that the catalyst has a specific surface area of 1.94 m2/g, while the Tau'c plot revealed an indirect bandgap of 3.23 eV. The degradation efficiencies through the poled catalyst were notable, achieving 68 % and 65 % for singular Methylene Blue and Rhodamine B dyes, respectively, and 55 % and 35 % for Methylene Blue and Rhodamine B in the binary dye mixture. Initial photocatalytic experiments were conducted under UVbulb irradiation, with activity further enhanced through Corona poling of the catalyst. The enhanced rate constants were 0.005 min-1 and 0.004 min-1 for singular Methylene Blue and Rhodamine B dyes, respectively. For the binary dye mixture, the poled catalyst showed rate constants of 0.0035 min-1 and 0.00175 min-1 for Methylene Blue and Rhodamine B, respectively. Later under sunlight irradiation, the poled catalyst demonstrated rate constants of 0.013 min-1 and 0.0135 min-1 for single Methylene Blue and Rhodamine B dyes, respectively, and 0.01 min-1 and 0.0095 min-1 for Methylene Blue and Rhodamine B in the binary dye mixture.