Utilização de caranguejo e sisal como bioadsorventes na remoção de óleo.

Abstract

Bioadsorbent can be used to minimize environmental damage resulting from discards of effluents from the petrochemical industry, mainly contaminated with oil. It is possible to carry out the oil removal in industrial effluents using biomass of a natural fiber, sisal (Agave sisalana), and the exoskeleton of guajá crab (Calappa ocellata). These materials are cheap and exist in abundance in Brazil; furthermore, they are biodegradable and do not offer environment contamination risk. Chitosan, an active agent present in the crab, has a chemical structure related to cellulose, present in the vegetal fiber, which enables the comparative study between these two different classes materials. Adsorption is a technique potentially used to reduce contaminants, especially when using natural adsorbents. The present work aims to evaluate oil removal percentage content present in synthetic effluents. The adsorption trials were performed through a 23-experimental design with three central points using simulated laboratory effluents, varying the oil concentration in 300, 400 and 500mg / L, pH (3, 5 and 7) and temperature of 28, 34 and 40 ° C in 5 hours of contact. The best conditions were obtained through the treatment of the experimental data in the software STATISTICA 6.0. The materials were characterized by particle size analysis, X-ray diffraction (XRD) and absorption spectroscopy in the infrared region (FT-IR). The removal percentage of sisal was approximately 90% for the highest values of concentration, pH and temperature, and the removal percentage of crab was 70% for the lowest pH value and the highest values of concentration and temperature. The study of the adsorption isotherms was carried out through the treatment of the data, enabling the obtaining of the Freundlich model for the biomasses. The kinetic behavior was also analyzed, obtaining the pseudo-second order model for crustacean and for vegetable fiber. These two bio-adsorbents shows high oil content removal efficiency in synthetic effluents; therefore, they can be considered an alternative because they also present an economical viability.