Abstract

HERNANDEZ, ROSÁNGELES; CARRASCO, PEDRO; MUJICA, ROSA  and  ESPINOLA, MARÍA. Evaluación de la capacidad de adsorción de desechos agroindustriales para la remoción de ácido acéticoEvaluation of the adsorption capacity of agro-industrial waste for acetic acid removal. Rev. Fac. Ing. UCV [online]. 2007, vol.22, n.3, pp.31-46. ISSN 0798-4065.

The use of agro-industrial waste was evaluated; namely, rice husks and coffee parchment as alternative adsorbents for acetic acid removal. To this end, material characterization was carried out determining the amount of humidity and ashes, the acid value, and by absorption spectrometry analysis in infrared and x-ray diffraction. Isotherms of acetic acid adsorption on rice husks, coffee parchment and activated charcoal as a reference, were constructed, by means of contact in agitation of different concentrations of solutions of acetic acid. Eight experiments were made in which the factors were varied:adsorbents particle size, adsorbent materials treatment, agitation time and rank of acetic acid concentrations. The rice husk isotherms and coffee parchment adjusted to the Langmuir model within a rank of acetic acid concentration between 0.03 and 0.25 mol/L, 1 hour of agitation and water and 5% sodium bicarbonate washings at 70 ºC. It was concluded that adsorption of acetic acid on rice husks and coffee parchment occurs through hydrogen bond formation between the acid and the surface of these materials because of the presence of cellulose, hemicelluloses, lignin and silicon oxide in its structure, reaching between 40% and 70% of the yields obtained with the activated charcoal.

Keywords : Adsorption; Acetic Acid; Activated Charcoal; Rice Husks; Coffee Parchment.