The geometry relaxation and photodeactivation from the S2 state of dibenzofuran studied by ultrafast spectroscopy

Dibenzofuran (DBF) has attracted much attention from scientists recently since it is applied as a photoluminescence material and pharmaceutically active compound. Since the polychlorinated derivatives are highly toxic and manifest photostability in the environment. Femtosecond transient absorption spectroscopy associated with quantum chemical calculations are employed to investigate the ultrafast excited state dynamics of dibenzofuran from the S2 state in 1,4-dioxane and ethanol, respectively. Following excitation at a wavelength of 266 nm, the S2 state is firstly populated in the Franck–Condon region and preserves the planar molecular structure of the ground state. The observed increase of the transient absorption spectra of the excited state within the first several picoseconds indicates a geometry relaxation occurring on the S2 potential energy surface. The subsequent kinetic traces of excited state absorption show that the S2 state in the adiabatic region decays to the S1 state through a fast internal conversion, followed by intersystem crossing to the T1 state with a decay time of tens and hundreds of picoseconds in ethanol and 1,4-dioxane, respectively. Finally, the deactivation processes from the S1 or T state are slow and take place on a time scale of about 20 ns.

Pharmaceutically Active Compounds Degradation Using Doped TiO2 Functionalized Zeolite Photocatalyst

The aim of this study was the investigation of photocatalytic degradation of pharmaceutically active compounds using doped TiO2 functionalized zeolite photocatalyst. Diclofenac (DCF), a non-steroidal anti-inflammatory drug, that represents a biorefractory micropollutant, was chosen as model of pharmaceutically active compound. The photocatalyst was Z-TiO2-Ag. The concentration of DCF in the working solutions was 10 mg/L,50 mg/L,100 mg/L and 200 mg/L and of photocatalyst 1 g/L in any experiments. The process was monitored by recording the UV spectra of the treated solutions and total organic carbon (TOC) determination. The UV spectra analysis and TOC removal proved that along the advanced degradation of DCF also a mineralization process occurred. The carried out research provided useful information envisaging the treatment of pharmaceutical effluents by photocatalysis.

Effect of Pharmaceutically Active Compound Nitroxoline on the Corrosion of Mild Steel in an Acidic Environment

The effect of Nitroxoline, antibiotic drug, was tested as a corrosion inhibitor for mild steel (MS) in an acidic environment by chemical method (mass loss measurement) and electrochemical methods such as electrochemical impedance spectroscopy and potentiodynamic polarization. The surface morphology of mild steel was investigated by scanning electron microscopy, energy dispersive X-ray spectroscopy, and atomic force microscopy techniques. From the chemical and electrochemical methods, the resistance of corrosion was increased with the addition of Nitroxoline concentration. Tafel curves indicate that the pharmaceutically active compound is a cathodic type inhibitor. An adsorption of Nitroxoline on the surface of mild steel was obeyed by Langmuir isotherm. SEM, EDX, and AFM techniques prove the adsorption process. All the obtained results confirmed that the investigated compound Nitroxoline acts as a good inhibitor for the corrosion of mild steel in an acidic environment.

Competitive adsorption of a pool of pharmaceuticals onto a raw clay mineral

The removal of a Pharmaceutically Active Compound (PhAC) pool using a well referenced clay mineral from Wyoming (SWy-2) as a geosorbent was studied for a better understanding of the environmental fate.

Rapid Screening Method for Detecting Ethinyl Estradiol in Natural Water Employing Voltammetry

17α-Ethinyl estradiol (EE2), which is used worldwide in the treatment of some cancers and as a contraceptive, is often found in aquatic systems and is considered a pharmaceutically active compound (PhACs) in the environment. Current methods for the determination of this compound, such as chromatography, are expensive and lengthy and require large amounts of toxic organic solvents. In this work, a voltammetric procedure is developed and validated as a screening tool for detecting EE2 in water samples without prior extraction, clean-up, or derivatization steps. Application of the method we elaborate here to EE2 analysis is unprecedented. EE2 detection was carried out using differential pulse adsorptive cathodic stripping voltammetry (DP AdCSV) with a hanging mercury drop electrode (HMDE) in pH 7.0 Britton-Robinson buffer. The electrochemical process of EE2 reduction was investigated by cyclic voltammetry at different scan rates. Electroreduction of the hormone on a mercury electrode exhibited a peak at −1.16±0.02 V versus Ag/AgCl. The experimental parameters were as follows: −0.7 V accumulation potential, 150 s accumulation time, and 60 mV s−1scan rate. The limit of detection was 0.49 μg L−1for a preconcentration time of 150 s. Relative standard deviations were less than 13%. The method was applied to the detection of EE2 in water samples with recoveries ranging from 93.7 to 102.5%.

Hydroxyl radical induced oxidation of theophylline in water: a kinetic and mechanistic study

Evidence is reported for the addition and hydrogen abstraction reactions of hydroxyl radicals with an important pharmaceutically active compound, theophylline.