Photocatalytic degradation of phenolic syntan using TiO2 impregnated activated carbon

Investigations were carried out to study the photocatalytic degradation of phenolic syntan (PS), a widely used environmentally polluting chemical in the leather tanning industry. Photocatalytic inactive commercial TiO2 was used as the precursor for the preparation of TiO2 impregnated activated carbon (Ti-AC) photocatalyst. Experiments were conducted by varying the concentrations of PS solution (50–1000 mg/l), pH (2.5–10) and time intervals to optimize the working parameters. A 254 nm UV light was used throughout the study. The effect of PS degradation using Ti-AC was also compared with direct UV photolysis. The Ti-AC was characterized using X-ray Diffraction (XRD), Diffuse Reflectance Spectroscopy (DRS), Scanning Electron Microscopy (SEM) and energy dispersive X-ray analysis (EDX) to determine the structural, optical, surface morphology and elemental analysis respectively. X-ray studies revealed the formation of catalytically active anatase phase in Ti-AC. Photodegradation of PS was examined by chemical oxygen demand (COD) method. PS degradation occurred at both the extreme end of acidic and alkaline pH conditions. However, the percentage degradation was comparatively higher at pH 2.5. The photodegradation followed pseudo first order kinetics. UV–Visible studies substantiated the occurrence of bathochromic and hyperchromic effects as a result of ring opening in the PS molecule.

The anatase phase TiO2 impregnated in activated carbon (Ti-AC) was synthesized. The higher degradation percentage of phenolic syntan was achieved by Ti-AC compared to photolysisFigure optionsDownload high-quality image (75 K)Download as PowerPoint slideResearch highlights
► A bio-refractory chemical (phenolic syntan) was degraded using Ti-AC.
► The photoactive anatase phase was formed in Ti-AC on heat treatment, confirmed by surface morphological studies.
► The effect of pH, concentration and light intensity were optimized using UV light in the presence and absence of Ti-AC.
► The degradation profile shows that Ti-AC exhibits great influence on phenolic syntan.