(215p) Removal of Oil From Oily Waters By Chitosan Microspheres: Batch Studies

One of the mayor problems of the petrochemical industry is the great amount of wastewater produced. The purification of the wastewater is an important global problem, mainly due to the restricted quantities of water that can be safely used directly and the high cost of purification installations. In recent years suitable technologies for treatment of wastewaters and other effluents has attracted great interest, due to more rigorous laws and regulations. Some of the common pollutants are phenols, dyes, detergents, insecticides and heavy metals. The nature of pollutants depends on the source of generation and varies from place to place. These pollutants are often toxic and cause adverse affects on human and animal life if presente above certain concentration levels.  Unlike free or floating oil spilled in the sea, lakes or rivers, most of industrial wastewaters contain oil-in-water emulsions among their basic contaminants. Among several chemical and physical methods, adsorption process is one of the effective methods widely used in wastewater systems. Chitosan is a natural polymer that has been used in a variety of practical fields including wastewater management.  Chitosan among its various properties, presents adsorptive capacity. Crosslinked chitosans have been used to adsorb mainly reactive dyes, some cations and anions, and other contaminants, but apparently no mayor studies have been done to adsorb oil from wastewater using chitosan.

In this presentation we will discuss the efficience of chitosan microspheres as adsorbents in the removal of crude oil from synthetic oily waters. For this, bacth studies were done.

First of all, we synthesized the chitin from residues of shrimp in order to obtain chitosan. Chitosan is produced by the deacetilation of chitin. The molar mass and acetylation degree of the chitosan obtained were determined by rheology and NMR H¹,respectively. We prepared chitosan microspheres crosslinked with sodium tripolyphasphate. For this, chitosan was dissolved in a acid acetic solution and the solution was slowly dropped into a tripolyphosphate solution The microspheres were analised by optical microscopy, scanning electron microscopy and ASAP. We also prepared the synthetic oily water from the dispersion of oil in water under high shear rates. After that, we made some batch adsorption studies. We studied the effect of adsorbent mass, pH, oil concentration, temperature and time. The amount of oil in these experiments was measurement by a fluorimeter, with n-hexane being used as the oil-extraction solvent. These studies were realized in a shaker with a constant stirring of 100 cicles/minutes.

With the results obtained we could observe the capacity and efficiency of the material, as well as the best conditions in which it should be used.