ABSTRACT
Water and wastewater effluents contain a vast range of pharmaceutical chemicals. The present study aims to determine the potential of the advanced oxidation technology UV/H(2)O(2)/O(3) and its sub-processes (i.e. UV, UV/H(2)O(2), UV/O(3), O(3) and H(2)O(2)/O(3)) for the degradation of the antibiotics ciprofloxacin (CIP) and trimethoprim (TMP), and the antineoplastic drug cyclophosphamide (CPD) from water. Creating AOP conditions improved in most cases the degradation rate of the target compounds (compared with O(3) and UV alone). H(2)O(2) concentration was found to be an important parameter in the UV/H(2)O(2) and H(2)O(2)/O(3) sub-processes, acting as (â¢)OH initiator as well as (â¢)OH scavenger. Out of the examined processes, O(3) had the highest degradation rate for TMP and H(2)O(2)/O(3) showed highest degradation rate for CIP and CPD. The electrical energy consumption for both CIP and CPD, as calculated using the E(EO) parameter, was in the following order: UV > UV/O(3) > UV/H(2)O(2)/O(3) > O(3) > H(2)O(2)/O(3). Whereas for TMP O(3) was shown to be the most electrical energy efficient. Twelve degradation byproducts were identified following direct UV photolysis of CIP.
Subject(s)
Hydroxyl Radical , Ozone , Pharmaceutical Preparations/chemistry , Ultraviolet Rays , Water Pollutants, Chemical/chemistry , Bioreactors , Molecular Structure , Oxidation-Reduction , Waste Disposal, FluidABSTRACT
The photodegradation rate of sulphadimethoxine (SMT) in water was studied under polychromatic UV light, in a bench scale apparatus. SMT photolysis was carried out at pH levels of 2.5, 6.5 and 10 to study the impact of acid base properties on the degradation of SMT. The highest SMT photolysis fluence based rate was found at pH=2.5 (k=7.22x10(-4) cm2/mJ) and the lowest rate at pH=10 (k=4.72x10(-4) cm2/mJ), thus the reaction rate decreases with an increase in pH between pH values of 2.5-10. Results indicated that direct photolysis is not satisfactory for degradation of SMT by polychromatic UV lamp as a fluence of approximately 7,000 mJ/cm2 is needed to break down 99% of SMT at pH 6.5. The photodegradation products of SMT were studied at various pH values. Photodegradation of SMT results in dissimilar relative amounts of intermediates formed at different pH values which may exert a photon demand and impact on SMT photodegradation rate.
Subject(s)
Photolysis/radiation effects , Sulfadimethoxine/chemistry , Ultraviolet Rays , Water Pollutants, Chemical/chemistry , KineticsABSTRACT
A modified high performance liquid chromatography (HPLC) method for the quantification of vancomycin levels in plasma and tissues is described. The method uses solid phase extraction (SPE) of vancomycin from the samples and reversed phase HPLC with UV detection. The method was fully validated in terms of recovery, linearity, selectivity and various stability conditions. Vancomycin was determined in plasma samples obtained from 15 patients undergoing cardiopulmonary bypass, before and repeatedly during 12 h after drug administration. The vancomycin levels in plasma were measured by HPLC and by fluorescence polarization immunoassay (FPIA) (TDX). The following correlation was found: TDX = 0.84 HPLC + 1.04. The mean vancomycin levels in skin, fat, atrium, pericardium and sternum, before and after bypass, are reported.
