Ultrasonic degradation of sulfadiazine in aqueous solutions

Abstract

Advanced oxidation methods, like ultrasound (US), are a promising technology for the degradation of emerging pollutants in water matrices, such as sulfonamide antibiotics. Nevertheless, few authors report the degradation of sulfonamides by high-frequency US (>100 kHz), and limited information exist concerning the use of ultrasonic-driven processes in the case of sulfadiazine (SDZ). In this study, SDZ degradation was investigated with the aim to evaluate the influence of initial concentration, pH and US frequency, and power. Ultrasonic frequencies of 580, 862, and 1,142 kHz at different power values and SDZ initial concentrations of 25, 50, and 70 mg L(-1) were used. The results show that SDZ degradation followed pseudo first-order reaction kinetics with k values and percent removals decreasing for increasing solute initial concentration. Higher SDZ percent removals and removal rates were observed for the lowest operating frequency (580 kHz), higher dissipated power, and in slightly acidic solution (pH 5.5). Addition of the radical scavenger n-butanol confirmed that hydroxyl radical-mediated reactions at the interface of the cavitation bubbles are the prevailing degradation mechanism, which is directly related to the pKa-dependent speciation of SDZ molecules. Finally, addition of H2O2 had a detrimental effect on SDZ degradation, whereas the addition of the Fenton reagent showed a positive effect, revealing to be a promising alternative for the removal of sulfadiazine.

Sonolysis and sono-Fenton oxidation for removal of ibuprofen in (waste)water

“…According to its low volatility and low water solubility (see Table 1), IBP degradation mechanism may correspond to a radical attack at the bubble surface. In order to confirm this hypothesis, two types of radical scavengers, namely n-butanol and acetic acid, were added to the IBP solution before 20 kHz sonolysis: n-butanol is a short chain alcohol with only partial solubility in water (log K ow = 0.88) known to be an effective % OH scavenger for the gaseous region and/or the interfacial region of the collapsing bubble [22,36], while fully miscible acetic acid (log K ow = −0.17) reacts with % OH in the solution bulk [37]. As shown in Fig.…”

“…Several works have investigated the coupling of ultrasound and Fenton oxidation for the elimination of various organic compounds such as dyes, phenolic compounds and pesticides [13,19,20], and more recently pharmaceuticals [21][22][23]. However, to our knowledge, this latter mechanism (Eq.…”

Degradation of pharmaceuticals by ultrasound-based advanced oxidation process

“…The degradation of 25 mg L -1 of sulfadiazine, acetaminophen and levodopa at three frequencies such as 574, 860 and 1134 kHz was reported. The degradation is maximum at lower frequency used in the system for sulfadiazine (Lastre-Acosta et al 2015), whereas in the case of levodopa and acetaminophen, the degradation rate is comparable at frequencies 574 and 860 kHz and lower degradation is reported at high frequency (Isariebel et al 2009). The degradation of atenolol at concentration 10 -5 M was reported at four frequencies such as 200, 350, 620 and 1000 kHz.…”

“…The degradation of carbamazepine, ciprofloxacin, sulfadiazine, acetaminophen, levodopa, diclofenac and atenolol was reported at various frequencies (De Bel et al 2011;Isariebel et al 2009;Lastre-Acosta et al 2015;Nejumal et al 2014;Rao et al 2016). The degradation of 15 mg L -1 is found to be maximum at 544 kHz with a rate constant of 0.0067 min -1 .…”

“…It has higher hydrophobic character in the neutral form (at pH 5.5), and it can easily diffuse to the negatively charged hydrophobic interface of liquid-gas cavitation microbubbles, where they can accumulate and be degraded by Á OH and by pyrolysis. At alkaline pH, the hydrophilicity increases and thereby reduces the chance of accumulation in the interface (Lastre-Acosta et al 2015). Due to the same reason, maximum performance in the ultrasonic degradation of dicloxacillin was obtained at pH 3 compared to 5.7 and 9 (Villegas-Guzman et al 2015).…”