Sonolytic and sonophotolytic degradation of Carbamazepine: Kinetic and mechanisms

Abstract

An in-depth investigation on the ultrasonic decomposition of Carbamazepine (CBZ), one of the most regularly identified drugs in the environment, was conducted. The effects of diverse variables were evaluated, such as frequency, power, solution pH, initial CBZ concentration and varied inorganic anions. Reaction order was determined on the basis of analyzing reaction kinetics of CBZ degradation. The sonophotolysis and photolysis of CBZ was also examined in this contribution. The influence of water composition on the sonolytic and sonophotolytic elimination of CBZ was analyzed. Additionally, 21 intermediates were identified during sonolytic degradation of CBZ based on LC/ESI-MS/MS analysis, among which two escaped from the detection in previous studies. Possible decay pathways were proposed accordingly. The epoxidation, cleavage of double bond, hydration, hydroxylation, ring contraction and intramolecular cyclization were believed to be involved in sonochemical degradation of CBZ.

Degradation of pharmaceuticals by ultrasound-based advanced oxidation process

“…On the same way, it is negatively charged at higher pH, and therefore, the negatively charged group would be more easily attacked by the hydroxyl radical (Wang et al 2013). However, in a similar type of study with carbamazepine, the degradation is reduced at 2, whereas other pHs (4.5-11) did not show any significant impact (Rao et al 2016).…”

“…The effect of frequency on the degradation of 162 lM carbamazepine at two frequencies such as 200 and 400 kHz was reported, and the maximum performance was at lower frequency. In this case, the degradation rate is decreased from 0.0028 to 0.00158 min -1 at these frequencies (Rao et al 2016).…”

“…Only the chloride ion shows a significant impact on the degradation of carbamazepine, and it is not influenced by other ions such as sulfate and nitrate ions. The chloride ion reduced the degradation rate (Rao et al 2016).…”

“…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 .…”

Removal of Pharmaceuticals from Wastewater by Intermittent Electrocoagulation

“…Therefore, high uptake of DCF can be observed due to the strong electrostatic attraction between DCF and these complexes. CBZ has a pKa 1 of 2.3 related to the protonation of the NH 2 group and pKa 2 of 13.9 related to the deprotonation of the amino group [33]. The structure of CBZ is in the molecular state at neutral pH and CBZ shows a hydrophobic property when it retains a molecular structure.…”