Maria Cristina Diez
University of La Frontera, Chile
Title: Kinetic parameters of adsorption of pesticides in an organic matrix with agroindustrial and lignocellulosic residues for a bio-purification system
Biography
Biography: Maria Cristina Diez
Abstract
Bio-purification system is used to adsorb and degrade pesticide spills during handling of products before its application. The PBS has an organic matrix (biomix) composed of soil, commercial peat and wheat straw (1:1:2). We evaluated the adsorption capacity of different agro-industrial and lignocellulosic residues, as components of the biomix of the BPS, to treat water contaminated with pesticides. Sawdust, barley husk, compost and biochar were used in this process. Each biomix and individual components were characterized, and biomixes were formulated with partial replacement of 50% wheat straw or peat, moistened at 60-70% water holding capacity (WHC) and pre-incubated for 30 days at 20-25 °C. For kinetic studies, biomixes were contaminated with atrazine (ATZ), chlorpyrifos (CHL) and iprodione (IPR) at a concentration of 5 mg/L and to attain ionic strength, 0.01 M CaCl2 was added to it. Adsorption at 30, 60, 300, 600, 1080 and 1140 min of incubation at 22 ± 1 °C was evaluated. The adsorption isotherms were carried out with different amounts of biomix and concentration of pesticides for 24 hrs. It was observed that the highest adsorption capacity was achieved in biochar based biomixes, independent of the type of pesticide. CHL presents the highest adsorption rate, ATZ presents a constant and linear saturation for other biomezclas not presenting greater difference, and IPR differs its adsorption for each particular biomix. The Freundlich and Langmuir models were used to describe the kinetics of the adsorption process in the biomixes.