LIGNIN VALORIZATION: OPTIMIZING PHOTOCATALYSIS PROCESS FOR ENHANCED LIGNIN DEGRADATION

Abstract

This thesis investigates the photocatalytic degradation of lignin using the Photocatalysis process, aiming to elucidate optimal conditions for lignin valorization. The study investigates the impact of hydrogen peroxide (H2O2) and ferrous sulfate (FeSO4.7H2O) concentrations on lignin degradation efficiency. In respect to H2O2 concentration with time variation results show that the highest efficiency is achieved at 50 minutes and 150 mM H2O2 but the lignin degraded compounds are detected at 30mM and 50mM. The study also reveals increasing lignin degradation with FeSO4.7H2O concentration over time keeping H2O2 concentration constant at 50 mM , highlighting the complexity of the degradation process .The maximum degradation is achieved at 0.5 gm FeSO4.7H2O concentration at 60 min with 50mM H2O2 .Response surface methodology (RSM) modeling shows a curvilinear relationship with 33.04% degradation between time and H2O2 concentration and nonlinear relationship with 93.71% degradation between FeSO4.7H2O with time keeping constant H2O2 concentration. Furthermore, under optimized conditions of H2O2 and FeSO4.7H2O, varying lignin concentrations still resulted in lignin degradation, highlighting the robustness of the photocatalytic process. UPLC-MS-QTOF analysis reveals the presence of lignin-derived compounds like Syringaldehyde, p-Coumaric acid, Cinnamic Acid etc. Overall, this thesis provides valuable insights into the optimization of photocatalytic conditions for lignin degradation.