A New Oil Spill Adsorbent from Sulfuric Acid Modified Wheat Straw D. SIDIRAS, I. KONSTANTINOU Department of Industrial Management and Technology University of Piraeus 80 Karaoli & Dimitriou, GR 18534 Piraeus GREECE sidiras@unipi.gr Abstract: This work deals with the chemical modification of wheat straw, a common lignocellulosic agricultural residue, to obtain low cost adsorbents for diminishing an oil-products spill in seawater. The adsorbent was modified by acid hydrolysis, i.e. 0.045 N sulfuric acid as a chemical catalyst, in a PARR autoclave at 160-220 o C for 0-50 min isothermal time period. The oil adsorbency tests were performed, using diesel and crude oil of predetermined quality specifications. Water adsorbency-values for reaction ending temperature at 160°C were found to increase from 4.89 g/g to a maximum of 9.08 g/g for isothermal reaction time 0 min. At 180°C the maximum was 7.05 g/g for the same isothermal reaction time. At 200 and 220°C the water adsorbency was decreasing as low as 0.93 g/g for extreme hydrolysis conditions. Diesel adsorbency- values for reaction ending temperature at 160°C were found to increase from 2.77 g/g to a maximum of 5.24 g/g for isothermal reaction time 20 min. At 180°C the maximum was 5.14 g/g for isothermal reaction time 30 min. At 200°C the maximum was 4.16 g/g for the same isothermal reaction time. At 220°C the maximum was 4.76 g/g for isothermal reaction time 50 min. Crude oil adsorbency-values for reaction ending temperature at 160°C were found to increase from 2.82 g/g to a maximum of 5.38 g/g for isothermal reaction time the same with that in the case of diesel. At 180°C the maximum was 5.17 g/g for isothermal reaction time 0 min. At 200°C the maximum was 5.16 g/g for isothermal reaction time 50 min. At 220°C the maximum was 4.78 g/g for the same isothermal reaction time. Key-Words: adsorbent, acid hydrolysis, lignocellulosic, oil spill, pretreatment, wheat straw. 1 Introduction The oil spills are usually results of transportation and storage activities. Dispersants, skimmers, oil- water separators, booms and adsorbents are used to remove oil from contaminated marine areas and diminish the impact on the affected ecosystems. Adsorbents can be inorganic or organic, synthetic or natural products. Waste biomass as a lignocellulosic agricultural residue or agro-industrial byproducts is a natural organic adsorbent. The chemical modification by autohydrolysis [1, 2] or acid hydrolysis of this lignocellulosic waste can provide low cost adsorbents with improved qualities for the adsorption of dyes [3-6] and oil products [7-9]. Wheat straw is a renewable source for production of energy chemicals. Wheat straw can be used during containment and cleanup of oil spills in aquatic environment. A thin wax layer covers stalks and leaves of cereals. Therefore wheat straw could favorably adsorb hydrophobic liquids. Waxes are insoluble in water, thus the coating on external surfaces of stems, leaves, flowers, fruits and seeds protects them from excessive water evaporation or outer moisture. Waxes also protect plants from microorganisms and mechanical damage. Wheat straw like the other adsorbing materials is capable of holding oil as the result of adsorption and absorption. The adsorption capacity depends primarily on the chemical structure of straw tissue that has direct contact with oil. The absorption capacity is a function of the structure of the straw stalks in the bundles, distances between them, the diameter and cross-sections of each stalk and leaf. Due to high oil adsorption by wheat straw, oil is mostly held due to capillary of straw tissue and interior part of stalk, as well as to the existence of oil bridges between stalks. Wheat straw adsorption capacity varies for many researches due to different apparent densities of wheat straw and ways of its adsorbent form. The absorption of oil depends on surface properties of wheat straw [10]. According to the technical literature, walnut shell [7], wheat and barley straw [8-10], biomass [11], raw bagasse [12], carbonized pith bagasse [13], acetylated sugarcane bagasse [14], peat [15, 16], fatty acid grafted sawdust [17] and carbonized fir fibers [18] can be used as oil-spill adsorbents. Latest Trends in Environmental and Manufacturing Engineering ISBN: 978-1-61804-135-7 132