Correlating the chemical and spectroscopic characteristics of natural organic matter with the photodegradation of sulfamerazine

Abstract

The role of aquatic natural organic matter (NOM) in the removal of contaminants of emerging concern has been widely studied. Sulfamerazine (SMR), a sulfonamide antibiotic detected in aquatic environments, is implicated in environmental toxicity and may contribute to the resistance of bacteria to antibiotics. In aquatic systems sulfonamides may undergo direct photodegradation, and, indirect photodegradation through the generation of reactive species. Because some forms of NOM inhibit the photodegradation there is an increasing interest in correlating the spectroscopic parameters of NOM as potential indicators of its degradation in natural waters. Under the conditions used in this study, SMR hydrolysis was shown to be negligible; however, direct photolysis is a significant in most of the solutions studied. Photodegradation was investigated using standard solutions of NOM: Suwannee River natural organic matter (SRNOM), Suwannee River humic acid (SRHA), Suwannee River fulvic acid (SRFA), and Aldrich humic acid (AHA). The steady-state concentrations and formation rates of the reactive species and the SMR degradation rate constants (k1) were correlated with NOM spectroscopic parameters determined using UV-vis absorption, excitation-emission matrix (EEM) fluorescence spectroscopy, and proton nuclear magnetic resonance ((1)H NMR). SMR degradation rate constants (k1) were correlated with steady-state concentrations of NOM triplet-excited state ([(3)NOM(∗)]ss) and the corresponding formation rates ((3)NOM*) for SRNOM, SRHA, and AHA. The efficiency of SMR degradation was highest in AHA solution and was inhibited in solutions of SRFA. The steady-state concentrations of singlet oxygen ([(1)O2]ss) and the SMR degradation rate constants with singlet oxygen (k1O2) were linearly correlated with the total fluorescence and inversely correlated with the carbohydrate/protein content ((1)H NMR) for all forms of NOM. The total fluorescence and EEMs Peak A were confirmed as indicators of (1)O2 formation. Specific ultraviolet absorbance at 254 nm (SUVA254) and aromaticity showed potential correlations with the steady-state concentrations of hydroxyl radical ([HO]ss) and the corresponding formation rates (HO).

Triplet state dissolved organic matter in aquatic photochemistry: reaction mechanisms, substrate scope, and photophysical properties

“…27 More recently, Grebel et al 17 made an in depth study of the reaction of HDA with 3 CDOM*, and this work has sparked the use of HDA as both a quencher of 3 CDOM* and a molecular probe to quantify its concentration. [28][29][30][31][32][33][34][35][36][37][38][39][40][41][42] In a similar way, isoprene (E T ¼ 251 kJ mol À1 ) 25,43 has been effectively used as a triplet quencher, providing evidence for the involvement of 3 CDOM* in the oxidation of mefenamic acid, 44 some sulfa drugs, 45,46 and the amino acids tryptophan, methionine, and tyrosine. 47 Dienes have not only been used as probe molecules.…”

Terephthalate Probe for Hydroxyl Radicals: Yield of 2-Hydroxyterephthalic Acid and Transition Metal Interference

“…increased from 4 -7.5). As both the high (Son et al 2015, Batista et al 2016, Gonzalez et al 2017) and low (Huang et al 2013, Paušová et al 2015, Tafer et al 2016 values have been taken up in the literature, we attempt to address the discrepancy.…”

Fluorescence analysis allows to predict the oxidative capacity of humic quinones in dissolved organic matter: implication for pollutant degradation

“…It shows that C1 had common features with C2, and C5 with C6. Previous works reported that the formation rate of singlet oxygen was coupled to the abundance of humic-like components emitting at long wavelength for DOM of both marine (Timko et al 2014;Bai et al 2018) and terrestrial origin (Batista et al 2016;Coelho et al 2011). Compared to these works, we were able to identify the moieties involved in the correlation, and we propose that C4 and C7 could be attributed to the reduced forms of quinonic humic-like components (Cory and McKnight 2005).…”

“…Previous works have shown that the capacity of DOM to generate reactive species under solar irradiation could be predicted measuring its absorbance properties (Dalrymple et al 2010;Mckay et al 2017;Peterson et al 2012;Palma et al 2020). Previous works also suggested that correlations may exist between DOM photoreactivity and fluorescence parameters (Coelho et al 2011) or individual fluorescent components identified by deconvolution of the three-dimensional spectra by parallel factor analysis (PARA-FAC, Timko et al 2014;Bai et al 2018;Batista et al 2016).…”