Jo Dewulf

Heterogeneous Photocatalysis as an Advanced Oxidation Process for the Abatement of Chlorinated, Monocyclic Aromatic and Sulfurous Volatile Organic Compounds in Air: State of the Art

This review focuses on both fundamentals and applicability of heterogeneous photocatalysis as an advanced oxidation technology for degradation of volatile organic compounds (VOC) in air, with peer-reviewed literature data published since 1997 being the backbone of this article. Four key issues are covered. First, the underlying principles of heterogeneous photocatalysis are outlined using the band gap model. Second, a detailed overview is given of chlorinated, monocyclic aromatic and sulfurous VOC recently selected as target compounds in lab-scale photocatalytic degradation experiments. Data on reactor types, photocatalysts, reaction conditions, and reported results are tabulated. The third section deals with reaction products, analytical techniques used for separation and/or identification, proposed reaction pathways, and catalyst deactivation. Finally, effects of process parameters such as gas-phase pollutant and oxygen concentration, relative humidity, temperature, and light intensity on degradation kinetics are reviewed.

Fluoroquinolone antibiotics: an emerging class of environmental micropollutants.

The aim of this review paper is to provide a comprehensive overview of different chemical and environmental aspects concerning fluoroquinolone antibiotics as emerging contaminants. A literature survey has been performed based on 204 papers from 1998 to mid-2013, resulting in a dataset consisting out of 4100 data points related to physical-chemical properties, environmental occurrence, removal efficiencies, and ecotoxicological data. In a first part, an overview is given on relevant physical-chemical parameters to better understand the behavior of fluoroquinolones during wastewater treatment and in the environment. Secondly, the route of these antibiotics after their application in both human and veterinary surroundings is discussed. Thirdly, the occurrence of fluoroquinolone residues is discussed for different environmental matrices. The final part of this review provides a tentative risk assessment of fluoroquinolone compounds and their transformation products in surface waters by means of hazard quotients. Overall, this review shows that fluoroquinolone antibiotics have a wide spread use and that their behavior during wastewater treatment is complex with an incomplete removal. As a result, it is observed that these biorecalcitrant compounds are present in different environmental matrices at potentially hazardous concentrations for the aquatic environment. The latter calls for actions on both the consumption as well as the wastewater treatment aspect to diminish the discharge of these biological active compounds.

Anthropogenic volatile organic compounds in ambient air and natural waters: a review on recent developments of analytical methodology, performance and interpretation of field measurements.

Abstract This review focuses on a number of specific elements in recent developments of the analysis of volatile organic compounds (VOCs) in ambient air and natural waters. The first element that is discussed is the current status of the sampling methods. Recent advances in sorbent sampling, cryogenic sampling and the combination of both methods for sampling VOCs in ambient air are discussed. Next, some infrequently used sampling techniques are mentioned. As far as the analysis of VOCs in natural waters is concerned, the paper focuses on recent applications of liquid–liquid extraction and the dynamic headspace technique, and on new techniques such as the application of membranes. Secondly, the paper deals with the performance of the analytical techniques. General and specific elements affecting the analytical quality are discussed. In current measurements of VOCs in ambient air and natural waters, control of the analytical performance is not carried out in a systematic way. Finally, the possibilities of using the current techniques in field sample analyses are discussed. Information obtained using the analytical methods provides insights into the concentration levels of VOCs and their sources. By investigating relationships between concentration data of VOCs and environmental factors affecting these concentrations, it it now possible to explain observed variances in the concentrations of VOCs in the environment.

Measurement of Henry's law constant as function of temperature and salinity for the low temperature range

Abstract EPICS technique (Equilibrium Partitioning In Closed Systems) was further developed to study the gas-water equilibrium partitioning (Henrys law) of C1 and C2 organochlorines and monocyclic aromatic hydrocarbons in the low temperature range. Using this technique Henrys law constant was measured for 13 volatile organic compounds (VOCs) at the temperature range from 2 up to 25°C, and for salt concentrations from 0.0 up to 35.0 ppt (parts per thousand, kg m−3). The data obtained at 25°C, which could be compared, fit well with literature data. A double linear regression was made with Henrys law constant H as a function of the temperature and salinity. This relationship confirmed theoretical considerations. A comparison between H-values obtained for natural sea water and for artificial sea water were in most cases not significantly different, while the few significant differences did not seem to have a systematic deviation. This implies that for marine environments salinity and temperature are the main determining factors for Henrys law constants of VOCs and are sufficient to describe them.

Ozonation and advanced oxidation by the peroxone process of ciprofloxacin in water

A bubble reactor was used for ozonation of the antibiotic ciprofloxacin. Effects of process parameters ozone inlet concentration, ciprofloxacin concentration, temperature, pH and H(2)O(2) concentration were tested. Desethylene ciprofloxacin was identified, based on HPLC-MS analysis, as one of the degradation products. Formation of desethylene ciprofloxacin was highly dependent on pH, with the highest concentration measured at pH 10. Radical scavengers t-butanol and parachlorobenzoic acid were added in order to gain mechanistic understanding. Radical species other than hydroxyl radicals were suggested to occur at acidic pH which can explain fast ciprofloxacin ozonation at pH 3.

Renewables-based technology : sustainability assessment

Contributors. Foreword. Series Preface. Preface. List of Abbreviations. Part I: Renewables as a Resource and Sustainability Performance Indicators. 1 The Contribution of Renewables to Society (Goran Berndes). 2 The Potential of Renewables as a Feedstock for Chemistry and Energy (Wilfried G. J. H. M. van Sark, Martin K. Patel, Andre P. C. Faaij and Monique M. Hoogwijk). 3 Sustainability Performance Indicators (Alexei Lapkin). Part II: Relevant Assessment Tools. 4 Life Cycle Inventory Analysis Applied to Renewable Resources (Niels Jungbluth and Rolf Frischknecht). 5 Net Energy Balancing and Fuel-Cycle Analysis (Hosein Shapouri, Michael Wang and James A. Duffield). 6 Life Cycle Assessment as an Environmental Sustainability Tool (Adisa Azapagic). 7 Exergy (Jo Dewulf and Herman Van Langenhove). 8 Material Flow Analysis and the Use of Renewables from a Systems Perspective (Stefan Bringezu). 9 Ecological Footprints and Biocapacity: Essential Elements in Sustainability Assessment (William E. Rees). 10 The Sustainable Process Index (SPI) (Michael Narodoslawsky and Anneliese Niederl). Part III:Case Studies. 11 Assessment of Sustainable Land Use in Producing Biomass (Helmut Haberl and Karl-Heinz Erb). 12 Assessment of the Forest Products Industries (Klaus Richter, Frank Werner and Hans-Jorg Althaus). 13 Assessment of the Energy Production Industry: Modern Options for Producing Secondary Energy Carriers from Biomass (Andre Faaij). 14 Assessment of Biofuels (James A. Duffield, Hosein Shapouri and Michael Wang). 15 Assessment of Organic Waste Treatment (Jan-Olov Sundqvist). 16 Oleochemical and Petrochemical Surfactants: An Overall Assessment (Erwan Saouter, Gert Van Hoof, Mark Stalmans and Alan Brunskill). 17 Assessment of Bio-Based Packaging Materials (Andreas Detzel, Martina Kruger and Axel Ostermayer). 18 Assessment of Biotechnology-Based Chemicals (Peter Saling and Andreas Kicherer). 19 Assessment of Bio-Based Pharmaceuticals: The Cephalexin Case (Alle Bruggink and Peter Nossin). Part IV:Conclusions. 20 Conclusions (Jo Dewulf and Herman Van Langenhove). Index.

Illustrations towards quantifying the sustainability of technology

This paper attempts to quantify the sustainability of technological processes. It is based on thermodynamics with energy carriers and materials (products, waste, etc.) expressed in the same calculable quantity–exergy (Joule). The results have three considerations. One factor reflects to that extent renewable resources are used. In addition, the technological efficiency has to be accounted for as it affects sustainability. Finally, the results take into account the generation of waste products and the exergy required for converting the waste into products which are harmless or assimilable in the ecosphere. The proposed measure of sustainability has been illustrated for two types of products. In the first illustration, ethanol production was studied. Two routes were investigated, one starting from fossil oil and the other from agricultural products. Additionally, a route based on the synthesis from carbon dioxide and hydrogen was examined, in which hydrogen was generated by splitting water with electricity from photovoltaic solar energy conversion. The second product studied was electricity, generated from the combustion of natural gas or from photovoltaic solar energy conversion. The merit of the obtained results are that they treat technological sustainability not only in qualitative but also in quantitative terms. The insights obtained can help to account for sustainability in the development of new concepts of chemical technology.

Influence of pH on the sonolysis of ciprofloxacin: biodegradability, ecotoxicity and antibiotic activity of its degradation products.

The presence of antibiotics in the aquatic environment has raised concerns due to the potential risk for the emergence or persistence of antibiotic resistance. Antibiotics are often poorly degraded in conventional wastewater treatment plants. In this study, sonolysis at 520 kHz and 92 W L(-1) was used for the degradation of the fluoroquinolone antibiotic ciprofloxacin. In a first experiment at pH 7, 57% of the ciprofloxacin (15 mg L(-1)) was degraded after 120 min of ultrasonic irradiation at 25 degrees C. pH proved to be an important parameter determining the degradation rate, since the pseudo first order degradation constant increased almost fourfold when comparing treatment at pH 7 (0.0058 min(-1)) and pH 10 (0.0069 min(-1)) with that at pH 3 (0.021 min(-1)). This effect can be attributed to the degree of protonation of the ciprofloxacin molecule. The BOD/COD ratio of the solutions, which is a measure for their biodegradability, increased from 0.06 to 0.60, 0.17, and 0.18 after 120 min of irradiation depending on the pH (3, 7, and 10, respectively). The solution treated at pH 3 can even be considered readily biodegradable (BOD/COD>0.4). The antibiotic activity against Escherichia coli (G-) and Bacillus coagulans (G+) of the treated solutions also reduced after sonolysis. The highest decrease was again found when irradiated at pH 3. In contrast, ecotoxicity of the solutions to the alga Pseudokirchneriella subcapitata increased 3- to 10-fold after 20 min of treatment, suggesting the formation of toxic degradation products. The toxicity slowly diminished during further treatment.

Analysis of volatile organic compounds using gas chromatography.

The focus of this review is the analysis of volatile organic compounds (VOCs) by gas chromatography (GC) in the field of environmental, food, flavour and fragrance, medical and forensic sciences. New trends in sample injection, separation and detection are covered, including multi-dimensional and high-speed GC. Attention is drawn to a growing interest in quality assessment. From the review, it is clear that it remains a challenge to generate multi-component gaseous standards of VOCs at ppbv and pptv.

Determination of Henry's law coefficients by combination of the equilibrium partitioning in closed systems and solid-phase microextraction techniques

This paper describes the determination of Henrys law coefficients by means of the EPICS (equilibrium partitioning in closed systems) technique in combination with SPME (solid-phase microextraction). The use of solid-phase microextraction-sampling allowed us to extend the possibilities of the equilibrium partitioning in closed systems technique with respect to the range of Henrys law coefficients which can be measured. Whereas the equilibrium partitioning in closed systems technique is limited to determine air–water equilibrium partitioning of volatile compounds with Henrys law coefficients of at least 0.06 (dimensionless), the current method allowed to measure coefficients between 0.0023 and 13.5. In this way Henrys law coefficients of 20 compounds, being in a range covering five orders of magnitude, were measured with relative standard deviations between 1.0 and 19.8% (mean standard deviation: 5.7%; median of standard deviations: 4.8%, n=99). Several types of compounds were examined i.e. aliphatic hydrocarbons, monocyclic and polycyclic aromatic hydrocarbons, chlorinated and fluorinated compounds, ethers and esters, biphenyl and N-containing compounds, including compounds for which availability of experimental Henrys law coefficients is limited. Measurement of the equilibrium partitioning in the 2 to 25°C range allowed to establish relations of Henrys law coefficient as a function of temperature.