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The advanced treatment of polluted liquid streams containing traces of pharmaceutical compounds is a major issue, since more and more effluents from pharma labs and wastewaters containing the excretions of medically treated humans and animals are discharged in the conventional wastewater treatment plants without previous effective treatments. Ibuprofen is a widely used non-steroidal anti-inflammatory drug (NSAID), which explains why it is found in wastewaters so often. In this paper, the removal of IBP from simulated water streams was investigated by using a lab-scale experimental device, consisting of a batch reactor equipped with a lamp emitting monochromatic UV light at a fixed wavelength (254 nm) and various intensities. Three sets of experiments were carried out: the first to study IBP concentration as a function of time, at different volumes of treated solutions (V = 10–30 mL); the second to explore the effect of pH on IBP degradation as a function of time (pH = 2.25–8.25) and the third to evaluate the effect of different UV light intensities on IBP degradation (E = 100–400 mJ m−2). The IBP initial concentration (IBP 0) was varied in the range 30–60 mg L−1. The results obtained show that the concentration of IBP decreases along with treatment time, with a negative effect of the treated volume, i.e. smaller volumes, such as lower liquid heights, are more easily degraded. Moreover, the higher the pH, the better the IBP degradation; actually, when pH increases from 2.25 to 6.6 and 8.25, the IBP concentration, after an hour of treatment, decreases respectively to 45, 34 and 27 % of its initial value. In addition, as the intensity of light increases from 100 to 400 mJ m−2, the IBP concentration decreases to 34 % of its initial value. A reaction scheme is put forward in the paper, which well describes the effects of volume, pH and light intensity on the IBP degradation measured experimentally. Moreover, the IBP degradation by-products have been identified.

A major environmental concern has recently developed due to emerging pollutants (EC) that are nowadays being detected in the effluents of municipal and industrial wastewater treatment plants (WWTP) at very low concentrations, thanks to improved analytical techniques. Pharmaceutical compounds (PhACs) are some of the most hazardous EC. These compounds can be retained into the water cycle (from users to WWTP, and then to water sources by discharge) virtually endlessly. Thus innovative solutions are required, such as the advanced oxidation processes (AOP). Among them, combined treatments based on UV light appear to be eco-friendly, giving very interesting removal efficiencies if opportunely devised. In this paper, the removal of diclofenac, a widely used non-steroidal anti-inflammatory drug (NSAID), from synthetic water streams was explored by using a lab-scale experimental device, consisting of a batch reactor equipped with a lamp emitting monochromatic UV light at fixed wavelength and intensity (254 nm; 400 mJ m–2). The experimental tests have been carried out to evaluate the effect of treatment time and to verify the possibility of further degrading the obtained compound. The preliminary results confirm what has been recently and unexpectedly found in literature, that is the formation of a dimer during the first minutes of photolysis, carbazole, a very stable coloured intermediate. A major environmental concern has recently developed due to emerging pollutants (EC) that are nowadays being detected in the effluents of municipal and industrial wastewater treatment plants (WWTP) at very low concentrations, thanks to improved analytical techniques. Pharmaceutical compounds (PhACs) are some of the most hazardous EC. These compounds can be retained into the water cycle (from users to WWTP, and then to water sources by discharge) virtually endlessly. Thus innovative solutions are required, such as the advanced oxidation processes (AOP). Among them, combined treatments based on UV light appear to be eco-friendly, giving very interesting removal efficiencies if opportunely devised. In this paper, the removal of diclofenac, a widely used non-steroidal anti-inflammatory drug (NSAID), from synthetic water streams was explored by using a lab-scale experimental device, consisting of a batch reactor equipped with a lamp emitting monochromatic UV light at fixed wavelength and intensity (254 nm; 400 mJ m(-2)). The experimental tests have been carried out to evaluate the effect of treatment time and to verify the possibility of further degrading the obtained compound. The preliminary results confirm what has been recently and unexpectedly found in literature, that is the formation of a dimer during the first minutes of photolysis, carbazole, a very stable coloured intermediate.

In this work, an experimental and modeling analysis of the adsorption of four aromatic compounds (i.e., toluene, naphthalene, o-xylene and ethylbenzene) onto a commercial activated carbon is carried out. The aim is to assess the suitability of the adsorption process for the treatment of polluted groundwater, also when a multiple contamination is detected. Batch adsorption tests from simulated polluted groundwater are performed in single-compound systems and in two binary systems (i.e., toluene + naphthalene and o-xylene + ethylbenzene), at constant temperature (20°C) and pH (7). Experimental results in single-compound systems reveal that all of the analytes are significantly adsorbed on the tested activated carbon. In particular, toluene and naphthalene adsorption capacities are the highest and of similar value, while for o-xylene and ethylbenzene, the performances are lower. The adsorption of these compounds seems to be influenced by a combined effect of several parameters, such as hydrophobicity, molecule size, structure of the molecule, etc. Experimental results in binary systems show a different behavior of the two systems, which confirms their complexity and explains the interest in these complex adsorption systems. In particular, toluene and naphthalene are mutually competitive, while in the case of o-xylene + ethylbenzene, only the former undergoes competitive effects. The analysis of the entire experimental data set is integrated with a dedicated modeling analysis using the extended Langmuir model. For both single-compound and binary systems, this model provides acceptable results, in particular for low equilibrium concentrations, like those more commonly found in groundwater, and for the compounds involved in adsorptive competitive effects. © 2014 by the authors.

The presence of trace of pharmaceutical compounds (PhACs) in groundwater and in drinking and superficial waters is a major public health concern. Recently, various advanced treatment technologies have been studied to remove these kinds of pollutants; among them, combined treatments based on UV light appear to be more eco-friendly and with very interesting removal efficiencies if properly modified. In this paper, the removal of Ibuprofen (IBP) from synthetic water streams was investigated by using a lab-scale experimental device consisting of a batch reactor equipped with a lamp emitting monochromatic UV light (254 nm; 400 mJ m−2). The IBP initial concentration (C IBP 0 ) was 45.9 mg L−1. Two sets of experiments were carried out; the first one was aimed at studying the IBP concentration as a function of time, at different volumes of treated solution; the second one was aimed at exploring the effect of pH on IBP degradation as a function of time. The results obtained show that the concentration of IBP decreases along with treatment time, with a negative effect of the treated volume, i.e., smaller volumes, that is lower liquid heights, are more easily degraded. Moreover, the higher the pH, the better the IBP degradation; actually when pH increases from 2.25 to 5.51 and finally to 8.25, the IBP concentration, after an hour of treatment, decreases respectively to 45, 34, and 27 % from its initial value. A reaction mechanism is suggested, which well describes the effects of volume and pH on the experimentally measured IBP degradation.

Ibuprofen (IBP) is an anti-inflammatory drug whose residues can be found worldwide in natural water bodies resulting in harmful effects to aquatic species even at low concentrations. This paper deals with the degradation of IBP in water by hydrodynamic cavitation in a convergent-divergent nozzle. Over 60% of ibuprofen was degraded in 60 min with an electrical energy per order (EEO) of 10.77 kWh m-3 at an initial concentration of 200 μg L-1 and a relative inlet pressure pin = 0.35 MPa. Five intermediates generated from different hydroxylation reactions were identified; the potential mechanisms of degradation were sketched and discussed. The reaction pathways recognized are in line with the relevant literature, both experimental and theoretical. By varying the pressure upstream the constriction, different degradation rates were observed. This effect was discussed according to a numerical simulation of the hydroxyl radical production identifying a clear correspondence between the maximum kinetic constant kOH and the maximum calculated OH production. Furthermore, in the investigated experimental conditions, the pH parameter was found not to affect the extent of degradation; this peculiar feature agrees with a recently published kinetic insight and has been explained in the light of the intermediates of the different reaction pathways. Ibuprofen (IBP) is an anti-inflammatory drug whose residues can be found worldwide in natural water bodies resulting in harmful effects to aquatic species even at low concentrations. This paper deals with the degradation of IBP in water by hydrodynamic cavitation in a convergent-divergent nozzle. Over 60% of ibuprofen was degraded in 60 min with an electrical energy per order (E-EO) of 10.77 kWh m(-3) at an initial concentration of 200 mu g L-1 and a relative inlet pressure p(in) = 0.35 MPa. Five intermediates generated from different hydroxylation reactions were identified; the potential mechanisms of degradation were sketched and discussed. The reaction pathways recognized are in line with the relevant literature, both experimental and theoretical. By varying the pressure upstream the constriction, different degradation rates were observed. This effect was discussed according to a numerical simulation of the hydroxyl radical production identifying a clear correspondence between the maximum kinetic constant k(OH) and the maximum calculated (OH)-O-center dot production. Furthermore, in the investigated experimental conditions, the pH parameter was found not to affect the extent of degradation; this peculiar feature agrees with a recently published kinetic insight and has been explained in the light of the intermediates of the different reaction pathways. (C) 2015 Elsevier B.V. All rights reserved.

This work is an experimental analysis of o-xylene and ethylbenzene adsorption onto a commercial activated carbon in both single-compound and binary systems. The effect of temperature and salinity was assessed for single-compound systems, confirming that the adsorption of these analytes is an exothermic phenomenon occurring in active sites other than those where ionic substances are adsorbed. The estimate of the isosteric heat of adsorption allowed demonstrating that there are no lateral interactions between o-xylene and ethylbenzene molecules and that the Langmuir model can be used for data interpretation. Adsorption tests in binary systems showed that o-xylene adsorption is affected by the presence of ethylbenzene, while the adsorption capacity of ethylbenzene remains unchanged in both single-compound and binary systems. Finally, based on a modelling analysis of the binary systems, the Langmuir multicomponent model appears to be a statistically reliable tool for o-xylene binary data prediction, while the Langmuir single-compound model is suitable for the prediction of ethylbenzene binary data, in line with the experimental evidence showing the absence of any competition phenomena.