Photodegradation of 2,4-Dichlorophenol in Aqueous Systems under Simulated and Natural Sunlight

Abstract

The work presents results of studies on 2,4-dichlorophenol (2,4-DCP) degradation in aqueous solutions using photochemically initiated processes by simulated and natural sunlight. A number of possible substrate photodegradation routes were investigated, by both direct photolysis and photosensitized oxidation process. The major role of singlet oxygen in 2,4-DCP photodegradation was proved. Rose Bengal and derivatives of porphine and phthalocyanine were used as sensitizers. The influences of various process parameters on the reaction rate were investigated. On the basis of experimental data reaction rate constants of 2,4-DCP photosensitized oxidation were determined. The possibility of using natural sunlight to degrade 2,4-DCP in water in the middle latitudes was stated. The acute toxicity bioassay was conducted with the marine bacteriumVibrio fischerias a bioluminescent indicator. The obtained results encourage further research on this process.

Toxicity of aqueous mixture of phenol and chlorophenols upon photosensitized oxidation initiated by sunlight or vis-lamp

“…The experiments with sodium azide, well-known singlet oxygen ( 1 O 2 ) quencher, proved that 1 O 2 is responsible for phenol degradation (data not shown). This was in agreement with previous study in homogenous and heterogeneous photosensitized oxidation of 2,4DCP (Gryglik et al 2016; Gmurek et al 2017). It must be mentioned that phenolic compounds undergo faster degradation via 1 O 2 in dissociated form (Gryglik et al 2004; Miller 2005; Gmurek et al 2017).…”

Optimization of Heterogeneous Photosensitized Oxidation for Winery Effluent Treatment

“…The mixture of phthalocyanines showed the best removal of pollutants for a pH of 10, while aluminum phthalocyanines showed higher stability when exposed to visible light. Thus, Gryglik et al [25] studied the degradation of 2,4-dichlorophenol using homogeneous photosensitizers such as RB, AlPcS 4 , ZnPcS 4 , and meso-tetraphenylporphyrin-4,4 (TPPS 4 ) with pH and O 2 concentration variation. All of the studied photosensitizers presented a removal efficiency of 100%, except for ZnPcS 4 , which only removed 50% of this pollutant.…”

“…To our knowledge, this is the first paper to deal with the application of heterogenous photosensitized oxidation for effluent purification. Up to now, this process has been employed mainly for the model aqueous environment [16,25]. However, there is a lack of information about its applicability in a highly polluted environment.…”

Heterogeneous Oxidation of Phenolic Compounds with Photosensitizing Catalysts Incorporated into Chitosan

“…The acute toxicity was assessed using bioluminescent Vibrio fischeri bacteria, indicating lower toxicity than the parent compounds.Photosensitized oxidation is undoubtedly one of the most important photochemical methods, since it does not generate any additional pollutants [5]. Moreover, the advantage of photosensitized oxidation is the photooxidation of hard-degradable compounds by singlet oxygen generated in the presence of air and solar radiation [5][6][7], therefore, photosensitized oxidation is classified as a green chemistry process. Moreover, because the heterogeneous process is considered to leave no residue, no sludge is produced from the process.…”