Adsorptive Removal of Aromatic Compounds Present in Wastewater by Using Dealuminated Faujasite Zeolite

International audienceThe adsorption of aromatic compounds (nitrophenols, nitroaniline, chlorophenols, chloroanilines) present in wastewater using dealuminated faujasite zeolite has been investigated. The adsorption capacity of faujasite zeolite depends on the pH, (the neutral form of the pollutants is more easily adsorbed into zeolite than the dissociated form), and on the solubility in water of the aromatic compounds. The adsorption capacity for a family of compounds increases with decreasing water solubility. In this study, we have shown that the pollutant acidic character enhances their adsorption into the zeolite. Thus, the changeover of phenol to aniline decreases the adsorbent-adsorbate interaction, as well as in the substitution of the NO(2) group by a Cl group. The adsorption data was analyzed using the Fowler-Guggenheim isotherm. The sorption mechanism of nitrophenol in faujasite zeolite was investigated using Raman spectroscopy and through a thermodesorption kinetic study. The relative affinity of the phenolic compounds toward the surface of the dealuminated faujasite was related to the electron donor-acceptor complex formed between the basic sites on the zeolite (oxygen) and the hydrogens (acidic site) of the aromatic ring and of the phenols and anilines functions

Bio oil synthesis by coupling biological biomass pretreatment and catalytic hydroliquefaction process

International audienceThe bio-oil synthesis from a mixture of wastes (7 wt.% straw, 38 wt.% wood, and 45 wt.% grass) was carried out by direct liquefaction reaction using Raney Nickel as catalyst and tetralin as solvent. The green wastes were biologically degraded during 3 months. Longer the destructuration time; higher the yield into oil is. Biological pretreatment of green wastes promotes the liquefaction process. Among the components of degraded biomass, Humin, the major fraction (60-80 wt.%) that was favored by the biological treatment, yields to a bio oil extremely energetic with a HHV close to biopetroleum (40 MJ kg−1), contrariwise, Fulvic acids (2-12 wt.%), the minor fraction is refractory to liquefaction reaction

A Short Cost-Effective Methodology for Tracing the Temporal and Spatial Anthropogenic Inputs of Micropollutants into Ecosystems: Verified Mass-Balance Approach Applied to River Confluence and WWTP Release

The aim of this study is to develop a short cost-effective methodology for tracing the temporal and spatial anthropogenic inputs of micropollutants into ecosystems. The method involves a precise identification of the sampling sites based on various constraints: (1) one sampling site at each location to reduce the cost and the sampling time, (2) the sites are at sufficient mixing length from the release of micropollutants, and (3) they are identified with the aim to conduct mass balances. The methodology is applied to the identification, the quantification, and the distribution and transport of 21 emerging micropollutants in the Meurthe and Moselle river systems in the vicinity of the city of Nancy in France. The validity and reliability of the methodology is verified by using a mass-balance method at the confluence of the two rivers, where the mass fluxes upstream and downstream of the confluence compare well for nearly all the micropollutants. The methodology is employed to reveal mass fluxes of micropollutants discharged from the WWTP into the river water and point out the high efficiency of the drinking water treatment plant. The approach provides new insight into the identification of the sources of micropollutants in the rivers and the effects of hydrological and anthropogenic factors. The spatial anthropogenic inputs of micropollutants are highlighted in particular situations where discrepancies in the mass balance take place

Adsorption kinetics and equilibrium of phenol drifts on three zeolites

International audienceIn this study, the sorption of phenol drifts was studied by performing batch kinetic sorption experiments. The equilibrium kinetic data was analyzed using the pseudo-second-order kinetic model. Fowler-Guggenheim model gives a perfect fitting with the isotherm data. The influence of porous structure of a zeolite particle on phenol adsorption from aqueous solutions is analyzed and discussed. The adsorption for phenol drifts on zeolite was proved to be an exothermic process. Thus the solubility of the phenolic compound and the pH of the solution play also an important role in adsorption phenomena. The relative affinity of the phenolic compound toward the zeolite was related to the electron donor-acceptor complexes that were formed between the basic sites on the zeolite (oxygen) and hydrogens (acidic site) of the phenols. Finally zeolite seems to be an efficient adsorbent; it can be easily regenerated by methanol leaching