Estudo comparativo da eficiência adsortiva da vagem de algaroba (Prosopis juliflora) com e sem semente na remoção de gasolina em corpos d'água, utilizando adsorção em leito diferencial.

Abstract

A major concern today has been contamination of soils and groundwater by toxic organic compounds. Contaminants such as gasoline, diesel and other chemicals can be potential pollutants for environment, which can affect ecosystems, water quality and public health. As an alternative to the problem, adsorption is a method of separation and purification, which has several applications, among them in treatment of effluents. Use of biomass in this process has become common, as it is an alternative that is easy to obtain, low cost and high efficiency in treatment. Therefore, objective of this work was to analyze and compare adsorptive efficiency of mesquite pods (Prosopis juliflora) with and without seed, when used in removal of gasoline present in water bodies, using differential bed adsorption system. Methodology used was proposed by Lima et al. (2014). Initially, biomass was prepared in particulate form using Tyler Series sieves. Subsequently, experiments were carried out to study adsorption kinetics, in which times from 5 to 60 minutes (with intervals of 5 minutes) and adsorption equilibrium were evaluated, whose concentrations of contaminants varied from 5 to 60% (with rate of 5%). To differential bed system, concentrations of 5%, 7.5% and 10% of pollutant were used. Results confirmed that gasoline adsorption kinetics was fast for 5% concentration, in which total removal of contaminant occurred after 25 minutes of contact between biomass and contaminant. In.5% concentration, there was a residual volume of 3.5 mL at 40 minutes of contact with biomass and, for 10% concentration, there was no residual volume at 45 minutes of contact. Equilibrium isotherms showed maximum adsorption capacity values of 8.67 g.g-1 and 14.81 g.g-1 for seed and seedless biomass, respectively. In differential bed system for biomass with seed, at concentrations of 5% and 10%, total removal of contaminant occurred. In concentration of 7.5%, there was a residual volume of 3.5 mL after 40 minutes of contact with biomass. In differential bed system for seedless biomass, in concentrations of 5, 7.5 and 10%, there was a total removal of contaminants. Therefore, it can be said that mesquite pod without seed proved to be more efficient than mesquite pod with seed in removal of gasoline present in water.