Efficient removal of phenol compounds from water environment using Ziziphus leaves adsorbent

© 2020 Elsevier B.V. Industrial processes generate toxic organic molecules that pollute environment water. Phenol and its derivative are classified among the major pollutant compounds found in water. They are naturally found in some industrial wastewater effluents. The removal of phenol compounds is therefore essential because they are responsible for severe organ damage if they exist above certain limits. In this study, ground Ziziphus leaves were utilized as adsorbents for phenolic compounds from synthetic wastewater samples. Several experiments were performed to study the effect of several conditions on the capacity of the Ziziphus leaves adsorbent, namely: the initial phenol concentration, the adsorbent concentration, temperature, pH value, and the presence of foreign salts (NaCl and KCl). The experimental results indicated that the adsorption process reached equilibrium in about 4 h. A drop in the amount of phenol removal, especially at higher initial concentration, was noticed upon increasing the temperature from 25 to 45 °C. This reflects the exothermic nature of the adsorption process. This was also confirmed by the calculated negative enthalpy of adsorption (−64.8 kJ/mol). A pH of 6 was found to be the optimum value at which the highest phenol removal occurred with around 15 mg/g at 25 °C for an initial concentration of 200 ppm. The presence of foreign salts has negatively affected the phenol adsorption process. The fitting of the experimental data, using different adsorption isotherms, indicated that the Harkins-Jura isotherm model was the best fit, evident by the high square of the correlation coefficient (R2) values greater than 0.96. The kinetic study revealed that the adsorption was represented by a pseudo-second-order reaction. The results of this study offer a basis to use Ziziphus leaves as promising adsorbents for efficient phenol removal from wastewater

Développement d'un bioréacteur biphasique pour la dégradation du phénanthrène par Mycobacterium 6PY1 sp.

The overall objective outlined in the work of this thesis is to evaluate the potential of a two-phase partitioning bioreactor TPPB supplemented with an aeration system equipped with static mixers, for the biodegradation of phenanthrene (Polycyclic Aromatic Hydrocarbon model). Preliminary steps were devoted to the physiological adaptation of the Mycobacterium sp. 6PY1 in sole subtrate system and to the optimisation of the operating conditions. The fundamental results gained in these preliminary steps were applied to phenanthrene degradation in the TPPB combined with the aeration system involving static mixers. It was found that this system is efficient for complete phenanthrene degradation. Furthermore, integrating static mixers in the indicated system enhances both the biodegradation rate by 15% and the biomass production by 21%.L'objectif général de cette étude consistait à évaluer le potentiel d'un bioréacteur biphasique couplé avec un dispositif d'aération utilisant des mélangeurs statiques, pour la biodégradation du phénanthrène (hydrocarbures aromatiques polycycliques modèle). Des mesures préliminaires ont été consacrées à l'adaptation physiologique de Mycobacterium sp. 6PY1 dans un système à un seul substrat et à l'optimisation des conditions opératoire. Les résultats fondamentaux acquis au cours de ces étapes préliminaires ont été appliqués à la dégradation de phénanthrène dans le bioréacteur biphasique combiné avec le système d'aération des mélangeurs statiques. Il a été constaté que ce système est performant pour la dégradation du phénanthrène. En outre, l'intégration des mélangeurs statiques dans le système biphasique améliore à la fois la vitesse de biodégradation (+15%) et la production de biomasse (+21%).GRENOBLE1-BU Sciences (384212103) / SudocSudocFranceF

Enhancement of mass transfer characteristics and phenanthrene degradation in a two−phase partitioning bioreactor equipped with internal static mixers

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Optimization and modeling of phenanthrene degradation by Mycobacterium sp. 6PY1 in a biphasic medium using response-surface methodology

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Adaptation of a <i>Mycobacterium</i> stain to phenanthrene degradation in a biphasic culture system: influence on interfacial area and droplet size

International audienceA phenanthrene-degrading Mycobacterium sp. strain 6PY1 was grown in an aqueous/organic biphasic culture system with phenanthrene as sole carbon source. Its capacity of degradation was studied during sequential inoculum enrichments, reaching complete phenanthrene degradation at a maximim rate of 7 mg l−1 h−1. Water–oil emulsions and biofilm formation were observed in biphasic cultures after four successive enrichments. The factors influencing interfacial area in the emulsions were: the initial phenanthrene concentration, the initial inoculum size, and the silicone oil volume fraction. The results showed that the interfacial area was mainly dependent on the silicone oil/mineral salts medium ratio and the inoculum size