Publications by authors named "C Bradu"

8 Publications

Biosorbents from Plant Fibers of Hemp and Flax for Metal Removal: Comparison of Their Biosorption Properties.

Molecules 2021 Jul 10;26(14). Epub 2021 Jul 10.

Laboratoire Chrono-Environnement, Faculté des Sciences & Techniques, UMR 6249, Université Bourgogne Franche-Comté, 16 route de Gray, 25000 Besançon, France.

Lignocellulosic fibers extracted from plants are considered an interesting raw material for environmentally friendly products with multiple applications. This work investigated the feasibility of using hemp- and flax-based materials in the form of felts as biosorbents for the removal of metals present in aqueous solutions. Biosorption of Al, Cd, Co, Cu, Mn, Ni and Zn from a single solution by the two lignocellulosic-based felts was examined using a batch mode. The parameters studied were initial metal concentration, adsorbent dosage, contact time, and pH. In controlled conditions, the results showed that: (i) the flax-based felt had higher biosorption capacities with respect to the metals studied than the hemp-based felt; (ii) the highest removal efficiency was always obtained for Cu ions, and the following order of Cu > Cd > Zn > Ni > Co > Al > Mn was found for both examined biosorbents; (iii) the process was rapid and 10 min were sufficient to attain the equilibrium; (iv) the efficiency improved with the increase of the adsorbent dosage; and (v) the biosorption capacities were independent of pH between 4 and 6. Based on the obtained results, it can be considered that plant-based felts are new, efficient materials for metal removal.
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http://dx.doi.org/10.3390/molecules26144199DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8303383PMC
July 2021

Sorption of 4-n-nonylphenol, 4-n-octylphenol, and 4-tert-octyphenol on cyclodextrin polymers.

Environ Sci Pollut Res Int 2021 May 20. Epub 2021 May 20.

Chrono-environnement, Université Bourgogne Franche-Comté, UMR 6249, 16 route de Gray, 25000, Besançon, France.

Alkylphenols are industrial pollutants commonly present in wastewater. They are difficult to eliminate by conventional treatment processes, ending up in the sludge of wastewater treatment plants. In this study, we propose to use cross-linked cyclodextrin-based polymers (ECP) as sorbents to treat three alkylphenols, namely, one nonylphenol (4-n-NP) and two octylphenols (4-n-OP and 4-tert-OP), present in aqueous solution by a batch method. The experiments were carried out with five cyclodextrin polymers (α-ECP, β-ECP, γ-ECP, α,β,γ-ECP, and HP-β-ECP). Sorption results showed that all polymers, with the exception of α-ECP, had high sorption capacities between 60 and 100% of the alkylphenols in the concentration range studied (between 25 and 100 μg/L). In all cases, HP-β-ECP has shown the highest removals, regardless of the structure of the molecule. The order obtained was HP-β-ECP >> β-ECP ~ α,β,γ-ECP >> γ-ECP > α-ECP. The 4-tert-OP compound was the best adsorbed, regardless the material and the solution studied. Sorption results also indicated that (i) the sorption efficiency decreased with the increasing of alkylphenol concentration; (ii) sodium chloride had a strong negative effect on the sorption process; and (iii) the performance remained unchanged after five sorption-regeneration cycles. The main sorption mechanism of alkylphenols occurring in ECP was the inclusion within the cyclodextrin cavities. The obtained results proved that cyclodextrin polymers could serve as efficient sorbents for the removal of alkylphenols from real effluents.
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http://dx.doi.org/10.1007/s11356-021-14435-yDOI Listing
May 2021

A review on non-thermal plasma treatment of water contaminated with antibiotics.

J Hazard Mater 2021 09 22;417:125481. Epub 2021 Feb 22.

GREMI, UMR 7344, Université d'Orléans, CNRS, Orléans, France.

Large amounts of antibiotics are produced and consumed worldwide, while wastewater treatment is still rather inefficient, leading to considerable water contamination. Concentrations of antibiotics in the environment are often sufficiently high to exert a selective pressure on bacteria of clinical importance that increases the prevalence of resistance. Since the drastic reduction in the use of antibiotics is not envisaged, efforts to reduce their input into the environment by improving treatment of contaminated wastewater is essential to limit uncontrollable spread of antibiotic resistance. This paper reviews recent progress on the use of non-thermal plasma for the degradation of antibiotics in water. The target compounds removal, the energy efficiency and the mineralization are analyzed as a function of discharge configuration and the most important experimental parameters. Various ways to improve the plasma process efficiency are addressed. Based on the identified reaction intermediates, degradation pathways are proposed for various classes of antibiotics and the degradation mechanisms of these chemicals under plasma conditions are discussed.
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http://dx.doi.org/10.1016/j.jhazmat.2021.125481DOI Listing
September 2021

Characterization of the chemical activity of a pulsed corona discharge above water.

Chemosphere 2019 Dec 9;236:124302. Epub 2019 Jul 9.

Department of Plasma Physics and Nuclear Fusion, National Institute for Lasers, Plasma and Radiation Physics, Atomistilor Str. 409, P.O. Box MG-36, Magurele, Bucharest, 077125, Romania. Electronic address:

A pulsed corona discharge above liquid combined with ozonation has been investigated for the degradation of organic pollutants in water, as well as regarding the generation of several oxidizing species: ozone in gas phase, hydrogen peroxide and hydroxyl radicals in the liquid. A considerable improvement in the energy efficiency for organic compounds removal has been observed when reducing the width of the discharge pulses. This finding was correlated with the efficient formation of oxidizing species in case of short pulses. Recycling of the effluent gas from the plasma also enhances contaminants degradation. This was mainly attributed to an in situ peroxone process, i.e. the reaction between plasma-generated O and HO, forming highly reactive OH radicals, largely responsible for organic compounds degradation. This assumption is supported by the decline in O and HO concentrations and simultaneous increase in OH concentration detected in plasma-ozonation experiments as compared to results obtained with plasma alone.
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http://dx.doi.org/10.1016/j.chemosphere.2019.07.033DOI Listing
December 2019

Degradation of the chlorophenoxyacetic herbicide 2,4-D by plasma-ozonation system.

J Hazard Mater 2017 Aug 23;336:52-56. Epub 2017 Apr 23.

University of Bucharest, Faculty of Chemistry, Department of Organic Chemistry, Biochemistry and Catalysis, Bd. Regina Elisabeta 4-12, 030016, Bucharest, Romania.

A novel advanced oxidation process based on the combination of ozonation with non-thermal plasma generated in a pulsed corona discharge was developed for the oxidative degradation of recalcitrant organic pollutants in water. The pulsed corona discharge in contact with liquid, operated in oxygen, produced 3.5mgL ozone, which was subsequently introduced in the ozonation reactor. The solution to be treated was continuously circulated between the plasma reactor and the ozonation reactor. The system was tested for the degradation of 2,4-dichlorophenoxyacetic acid (2,4-D) and considerably improved performance as compared to ozonation alone, both with respect to the removal of the target compound and to mineralization. The apparent reaction rate constant for 2,4-D removal was 0.195min, more than two times higher than the value obtained in ozonation experiments. The mineralization reached more than 90% after 60min treatment and the chlorine balance confirms the absence of quantifiable amounts of chlorinated by-products. The energy efficiency was considerably enhanced by shortening the duration of the discharge pulses, which opens the way for further optimization of the electrical circuit design.
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http://dx.doi.org/10.1016/j.jhazmat.2017.04.050DOI Listing
August 2017
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