Ingeniería e Investigación (Jan 2005)
Employing fly ash and FCC catalyser waste in recovering chrome (III) from liquid effluent emitted by tanneries
Abstract
The present work studies the possibility of using two solid industrial wastes TERMOPAIPA's fly ash and ECOPETROL's alkaline hydrothermal treatments for obtaining zeolytic structures having better propierties; waste catalyser was calcined for eliminatin surface coke. Solids were characterised following treatment including DRX, BET area and CEC. A colorimetric method was standardised for determining chrome in solution; a response surface experimental design was implemented for finding optimum removal conditions. The most efficient adsorbent was fly ash treated with increased NaOH concentration; optimum condictions for removing chrome were: 58 minutes at 36ºC, 5.9 pH and 31% w/v solid removal. When reused, it was found that the two batches of treated fly ash became saturated following 6 cycles of use, whilst original ash and FCC Catalyser became saturated the second time they were used. Four de-absorbent agents were used for recovering chrome from adsorbent product H2SO4 0.6M being the best. Field trials showed that removal efficiency became reduced by the effect of other contaminantsm depending on the solution's initial concentration.
