A method is tested to reduce the pollution of effluents produced in the hide transformation process. Adsorption processes with clays could constitute a simple, selective and economical alternative to conventional physical-chemical treatments.The adsorption capacity of natural and acid-activated bentonite and sepiolite for anionic dyes normally used in the tannery was compared with that of a conventional adsorbent such as activated carbon. Natural bentonite with a different level of acid activation was used to adsorb a non-ionic surfactant such as nonylphenol ethoxylated with 8 moles of ethylene oxide.The capacity of sepiolite and acid-activated bentonite to adsorb anionic dyes normally used in the tannery was much greater than that of conventional adsorbents. A surfactant removal of 90 % was achieved in approximately 10 minutes because of the high affinity between surfactant and adsorbent. Natural bentonite activated with 0.5 M H 2 SO 4 was the most effective adsorbent for ethoxylated nonylphenol.

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ZrO 2 :Mn , Cl luminescent powders have been synthesized at temperatures ranging from 250 to 500 °C. X-ray diffraction measurements indicate changes in the crystallinity of the material as a function of the processing temperature. The photoluminescence spectra show bands associated with transitions from the 4T1 level to the 6A1 levels of the Mn2+ ions. An impurity concentration quenching is observed with the Mn contents. In addition, the presence of Cl in the synthesized material has been found to have an important role on the photoluminescence intensity emission. Preliminary results on cathodoluminescent emission are also reported.

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