Degradation Pathway Of Volatile Organic Compounds Of Bitumen In The Presence Of Sulfur-Doped Phenol-Rich Bio-Oils

We have developed an efficacious methodology for degradation of volatile organic compounds (VOCs) from the matrix of bitumen under visible-light conditions which time dependent density functional theory (TD-DFT) analysis supports the degradation of VOCs by sulfur-doped phenol-rich bio-oil (S_۴^∙-WPn (n = ۱–۳)) prepared by C−S coupling reaction. This method involves two sequential reactions where the degradation of the VOCs is followed by sulfur-doped phenol-rich bio-oil (S_۴^∙-WPn (n = ۱–۳)) with C−S coupling reaction.This study examines how sulfur-doped phenol-rich bio-oil (S_۴^∙-WPn (n = ۱–۳)) reduces the emission of the VOCs from the bitumen matrix. To do so, we have evaluated the degradation pathway of two bitumen VOCs (Benzoic acid and Benzofuran) by S_۴^∙-WPn . TD–DFT results indicate that the S_۴^∙-WPn have the potential to retain these VOCs in the bitumen matrix. Our calculations also predict that the reaction of tetrameric radical sulfur (S_۴^∙) with bio-oil (WPn) and subsequent VOCs could accelerate the degradation of VOCs while diminishing bitumen aging. To gain insight into the C–S cross-coupling mechanism, we have performed UV–Vis spectroscopic measurements for VOCs and VOCs-S_۴-WPn compounds. TD–DFT calculations also predicted a significant red shift in UV-Vis spectroscopic absorption spectrum at ۴۰۰ nm albeit with a weaker absorption when S_۴^∙-WPn and VOCs reacted and these peaks resulted from the degradation of VOCs. The study outcomes show the efficacy of sulfur-doped phenol-rich bio-oils in the degradation of selected VOCs.An interesting phenomenon was found that UV-Vis spectroscopic absorption red shift (~۲۰۰ nm) occurs after the C−S coupling reaction between S_۴^∙-WPn and VOCs. The absorption spectral of (VOCs-S_۴-WPn) has been red-shifted to nearly ۴۰۰ nm. The red shift enhanced the ability of these VOCs compounds to absorb light at a wavelength higher than ۲۰۰ nm, thereby favoring the direct photodegradation of VOCs compounds.

کلیدواژه ها:

Volatile Organic Compounds ، Bitumen ، Degradation ، Phenol ، Sulfur ، Ultraviolet Aging.