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Production of lactic acid by hydrothermal conversion of glycerol is an option to add value to the large amounts of glycerol that is being generated during the production of biodiesel. This work aimed to separate lactic acid by ion-exchange resins in a fixed-bed column. Adsorption isotherms were obtained from the breakthrough curves using different initial concentrations of lactic acid (60-302 g/l) and temperatures (30, 40 and 60 °C). Maximum adsorption capacities were estimated by the Langmuir model. Adsorption and desorption cycles for a binary and a real mixture were performed. The methodology proposed for the separation of lactic acid in a fixed-bed column presented high values of adsorptive capacity for both Amberlite IRA-96 and Amberlite IRA-67 resins at 30 °C. Lactic acid was more strongly adsorbed by Amberlite IRA-96 than the IRA-67 resin with maximum adsorption capacity of 544 and 341 g/l, respectively. Chromatographic experiments for the singlecomponent solution (lactic acid), binary mixture (lactic acid and glycerol) and real mixture showed high values of recovery (29.2%, 31.3% and 23.5%, respectively) and productivity (3.14, 7.00 and 2.43 kg of lactic acid/kg resin. day).

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The aim of this work was evaluate the adsorption properties of anionic dye Reactive Black 5 (RB5) and cationic dye Methylene Blue (MB) from salted aqueous solution using natural clay, aluminum pillared clay (Al-PILC) and activated carbon. The textural properties of the materials were obtained by N 2 adsorption at 77 K and structural properties of natural and pillared clays were determined by Xray diffraction. The effect of pH, contact time, initial concentration of dye and influence of the addition of NaCl were evaluated by batch adsorption. Adsorption isotherms of Al-PILC, in different salt concentration, were compared with natural clay and activated carbon. The adsorption isotherms were well fitted by Langmuir and Langmuir-Freundlich models. The process of pillaring only improved the adsorption of the anionic dye RB5. Depending on the system adsorbent/adsorbate analyzed, the salt concentration can either help or hinder dye adsorption. We found that a special morphology formed during the process of pillaring greatly increased adsorption of the MB cationic dye in the range of high salt concentrations. This unexpected result may help in developing new pillarization strategies to treat effluents with high salt content.