Publications (2)8.15 Total impact
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Article: Ultrafiltration/nanofiltration for the tertiary treatment of leather industry effluents.
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ABSTRACT: Biologically treated effluents from the leather industry pose severe problems for the environment due in part to both the inorganic charge and the high nitrogen content associated with the organic charge. Pressure-driven membrane processes, namely ultrafiltration/nanofiltration (UF/NF) technology, were investigated for their selective retention of the organics and permeation of the inorganic fraction. Permeation experiments were carried out with two model solutions representative of a treated tannery effluent. UF and NF of these model solutions were assessed in terms of both their inorganic/organic fractionation capability and their permeation productivity. The UF membranes with MWCOs ranging from 10,000 to 1000 Da yield retentate streams enriched in organic compounds and permeate streams enriched in salts. Despite their high capacity for pure water permeation, they displayed low permeation fluxes, as the result of concentration polarization and fouling phenomena. NF 200 and NF 270 membranes associated fractionation capability with high permeation rates. Furthermore, these membranes demonstrated the highest permeate fluxes -30 kg/h/m(2) and 16 kg/h/m(2) for different model solutions, at the transmembrane pressure of 8 bar. Although these membranes had lower hydraulic permeabilities relative to the other membranes tested, they exhibited the best characteristics in terms of minimization of colloidal fouling.Environmental Science and Technology 12/2009; 43(24):9130-5. · 5.23 Impact Factor -
Article: Nanofiltration for the treatment of coke plant ammoniacal wastewaters
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ABSTRACT: This work addresses the treatment by nanofiltration (NF) of solutions containing NaCN and NH4Cl at various pH values. The NF experiments are carried out in a Lab-Unit equipped with NF-270 membranes for model solutions that are surrogates of industrial ammoniacal wastewaters generated in the coke-making processes. The applied pressure is 30 bar. The main objective is the separation of the compounds NaCN and NH4Cl and the optimization of this separation as a function of the pH. Membrane performance is highly dependent on solution composition and characteristics, namely on the pH. In fact, the rejection coefficients for the binary model solution containing sodium cyanide are always higher than the rejections coefficients for the ammonium chloride model solution. For ternary solutions (cyanide/ammonium/water) it was observed that for pH values lower than 9 the rejection coefficients to ammonium are well above the ones observed for the cyanides, but for pH values higher than 9.5 there is a drastic decrease in the ammonium rejection coefficients with the increase of the pH. These results take into account the changes that occur in solution, namely, the solute species that are predominant, with the increase of the pH. The fluxes of the model solutions decreased with increased pH.Research highlights▶ Ammoniacal wastewaters fractionation is highly dependent on feed solution chemistry. ▶ pH dominates selective mass transport and nanofiltration rejection coefficients. ▶ For pH lower than 9.5, there is a concentration of ammonium in the concentrate. ▶ For pH higher than 9.5, the ammonium rejection coefficients drop to 10%.Separation and Purification Technology 76(3):303-307. · 2.92 Impact Factor
