Role of humic acids in the TiO2-photocatalyzed degradation of tetrachloroethene in water

Effects of humic acid fractions with different polarities on photodegradation of 2,4-D in aqueous environments

“…Subsequently, the fate of persistent toxic substances (PTS) in natural waters could be influenced significantly by HAs since the photochemically mediated processes are important in the transport and transformation of most PTS. Numerous studies have demonstrated that the effects of humic materials on the photodegradation of pollutants were complex, and HAs acted either as photosensitizers [5][6][7] or as inhibitors (light attenuating) [8,9] depending on their different functional groups [10,11].…”

Catalytic photodegradation of dyes by in situ zeolite-supported titania

“…This observed effect may be due to the fact that natural water may contain inorganic substance, such as phosphates, sulfates, chlorides, carbonates and nitrates, which are capable of being absorbed on the TiO 2 surface [37]. Furthermore, the presence of humic acid may also cause a negative effect by consuming the hydroxyl radical [38]. Fig.…”

Use of an integrated photocatalysis/hollow fiber microfiltration system for the removal of trichloroethylene in water

“…The TCE degradation efficiency reached more than 80% at an acidic pH level, while it decreased to approximately 60-65% at a neutral and alkaline pH region. Based on the findings reported elsewhere [10,18,33], the heterogeneous photocatalytic initiation (reactions (1)-(5)) and the proposed reductive degradation pathways (reactions (6)-(9)) are listed below: [CHCl CCl 2…”

“…The photocatalytic decomposition of many toxic organic contaminants such as cyanotoxin [13], humic substances [14,15], phenolic compounds [15], pesticides [16], endocrine disruptors [15], chlorinated compounds [15,17], and dyes [15] has been investigated with respect to the removal efficiency, reaction rate, and the formation of intermediates. Regarding organic pollutants, attempts have been made to decompose volatile organic compounds (VOCs) in a vapor phase rather than in an aqueous phase [18][19][20]. The vapor phase reaction, however, needs additional 0304 treatment for the VOCs present in an aqueous phase such as air stripping, so that the direct, effective degradation of VOCs in water or wastewater would be more attractive with regard to the process design and operations.…”