Chlorophyll-sensitized phenolic resins for the photocatalytic degradation of methylene blue and synthetic blue wastewater

A novel method was proposed to incorporate chlorophyll molecules into the phenolic resins for the photocatalytic degradation of methylene blue and synthetic blue wastewater (a mixture used as a disinfectant in airplanes, trains, and ships). A solvent-extraction method was employed for obtaining chlorophyll molecules. About 90% of the obtained chlorophyll was successfully incorporated into the phenolic resin via the Fischer esterification reaction. In addition, FTIR and UV-Vis spectrophotometry confirmed the immobilization of chlorophyll into the polymer. Although the studied photocatalysts showed the same energy gap (about 2.16 eV) and electrochemical potentials (around -0.425 V and 1.950 V), the sensitized material achieved a higher photocatalytic degradation of methylene blue in alkaline and acidic conditions. In addition, the effective photocatalytic mechanism model demonstrates the selective anion radical attack of methylene blue. Interestingly, the photocatalytic degradation of synthetic blue wastewater shows a contradictory behavior compared to the methylene blue experiments. It was enhanced at acidic conditions, reached complete decolorization, and 40% of TOC removal after 6 h of continuous irradiation. In conclusion, photocatalysis was employed to degrade synthetic blue wastewater for the first time, showing a well-functionality on a full irradiated stirred tank with the chlorophyllsensitized phenolic resin. [GRAPHICS] .

Automated summary

A novel method incorporating chlorophyll molecules into phenolic resins for photocatalytic degradation showed higher efficiency in degrading methylene blue under alkaline and acidic conditions. The photocatalytic degradation of synthetic blue wastewater demonstrated contradictory behavior compared to methylene blue experiments, being more effective in acidic conditions.