Occurrence of the Antimicrobials Sulfamethoxazole and Trimethoprim in Hospital Effluent and Study of Their Degradation Products after Electrocoagulation

Abstract

In this study, an investigation was carried out into the occurrence of sulfamethoxazole (SMX) and trimethoprim (TMP) in the effluent of the university hospital (HUSM) of the UFSM. The degradation of these antimicrobials by the electrocoagulation (EC) process was also examined, in both the aqueous solution and hospital effluent, and a study was conducted in order to identify the subproducts formed. The experiments were optimized through factorial planning and, also, checked by response surface methodology. The best conditions for EC (achieving 58.0% of chemical oxygen demand (COD) reduction) were obtained by using 13 mA cm À2 , 500 mg L À1 of NaCl, and 30 mm of interelectrode distance. The quantification of SMX (27.8 mg L À1 ) and TMP (6.65 mg L À1 ) in the hospital effluent, and the identification of the degradation products were carried out through liquid chromatography-mass spectrometry quadrupole linear and ion trapping with electrospray ionization (LC-ESI-MS/MS_QTrap). Removals of 88.0% (degradation only) and 33.0% (adsorption only) were achieved for aqueous solutions of SMX and TMP, respectively, under optimized conditions. In hospital effluent samples, fortified with additions of SMX and TMP, corresponding removals of 16.0% (degradation) and 28.0% (adsorption) were achieved. This suggests that the EC process is efficient in degrading SMX in aqueous solution, although the same was not the case with TMP. The degradation products of SMX were identified (m/z 256.0 and 288.5); however, only the latter is mentioned in the literature. Toxicological aspects were not considered in this study.

A Preliminary Study on the Occurrence of Pharmaceutically Active Compounds in Hospital Wastewater and Surface Water in Hanoi, Vietnam

“…The recoveries of PhACs were determined by comparing the concentrations of the spiked water samples (1 mg/L of PhACs) before and after SPE extraction. In this study, the surrogate standard (2,3-DPAA) and internal standard (Chry-d 12 ) was added to the sample before the whole analytical procedure so as to compensate for the losses for acidic and neutral PhACs during sample preparation procedure, respectively. Absolute and relative recoveries for selected PhACs were in the ranges from 67 to 93% and from 95 to 107%, respectively.…”

Removal of nonsteroidal anti-inflammatory drugs (NSAIDs) by electrocoagulation–flotation with a cationic surfactant

“…The removal efficiency of diclofenac by flotation in a high-grease wastewater reached 20%~40%, and removal of ibuprofen was about 10%~20%. In addition, Martins et al [30] indicated that hospital wastewater had a large amount of organic compounds and a complicated matrix, so pharmaceuticals may be adsorbed or attached to other species or structures, which decreased the removal efficiency.…”

“…Ren et al found that the removal efficiencies of berberine hydrochloride (a broad-spectrum antibiotic) with iron electrodes reached over 80% [28]. According to Martins et al study, the reduction of the concentration of sulfamethoxazole by electrocoagulation-flotation process with aluminum electrodes was over 80% [30].…”

“…This method has also been successfully applied to treat wastewater containing such pharmaceuticals as salicylic acid [27], 4 berberine hydrochloride [28,29], and some antibiotics [30]. Chou et al indicated that over 80% of salicylic acid compounds were removed with aluminum electrodes [27].…”

Removal of Pharmaceuticals from Wastewater by Intermittent Electrocoagulation

“…About 80% of 30 mg/L AMX was eliminated from aqueous solution after 4 h in a non-optimized electrochemical cell at 2.45 V potential using an iron anode and titanium plates as the anode and cathode, respectively [25]. In another study [26], the reduction of the concentration of sulfamethoxazole by the electrocoagulation-flotation process with aluminum electrodes was over 80%.…”