Computational consideration on advanced oxidation degradation of phenolic preservative, methylparaben, in water: mechanisms, kinetics, and toxicity assessments

Occurrence, fate and risk assessment of parabens and their chlorinated derivatives in an advanced wastewater treatment plant

“…Excellent removal efficiencies (98.8-100%) were observed in the process of ozonation, which is in agreement with previous result that an amount of ozone could result in the removal of 99% of parabens in a short time [46]. The reaction kinetics and degradation mechanism of parabens during ozonation were investigated in several studies, and it has been shown that both hydroxyl radicals and hydrated electrons could rapidly react with parabens during this process [47][48][49]. Because of their high removal efficiencies in the conventional treatment, only a small fraction of parabens was further reduced by the ozonation.…”

“…All the ratios are much lower than 1, indicting that parabens and their chlorinated derivatives are not likely to produce biological effects at environmentally relevant levels in aquatic ecosystems. Taking into consideration the fact that several degradation products with higher toxicity than their parent parabens would form in the advanced oxidation [47,48], the risks of parabens, especially the degradation products, on organisms required further investigations.…”

Theoretical investigation on the kinetics and mechanisms of hydroxyl radical-induced transformation of parabens and its consequences for toxicity: Influence of alkyl-chain length

“…It have been demonstrated that computational approaches have provided important information on the reaction intermediates or active species involved in chemical reactions, which are necessary for the mechanism clarification but are difficult to be detected experimentally Fang et al, 2013). Also, theoretical calculations have successfully used to predict the toxicity assessments of EOCs in water (Gao et al, 2014aMadden et al, 2009).…”

Theoretical investigation on the role of mineral dust aerosol in atmospheric reaction: A case of the heterogeneous reaction of formaldehyde with NO 2 onto SiO 2 dust surface

“…Combined with the vibrational analysis, the nature of each point on the potential energy surface (PES) was characterized to confirm the calculated geometry corresponding to a saddle point with only one imaginary frequency or a local minimum without imaginary frequency. Intrinsic reaction coordinate (IRC) calculations (Gao et al, 2014) were performed to confirm that the transition state structures connected the reactants with products. The PES was further refined by MPWB1K/6-311þþG(3df, 3pd) level to yield more accurate energetic information.…”