Use of Modified Bentonite for Phenolic Adsorption in Treatment of Olive Oil Mill Wastewater

Natural and modified clays were applied as adsorbents for the removal of organic contaminants from wastewater. This study presents an investigation on the technical feasibility of using modified minerals that are named organoclay for treatment of dissolved substances, mainly polyphenols in olive mill wastewater. The different parameters such as applied cation dosage were effective on the removal of contaminants by these adsorbents (%CEC), pollutant concentration, pH and particle size of minerals. In this investigation bentonite particles were modified by stirring the clay with a long chain quaternary ammonium cation. Doses of the applied cation varied from zero to 1.5 times the clay CEC. Results from tests using 40 g/L of natural minerals with CEC=90 miliequivalent/100g, ground clay with less than 0.2 mm size in solution, and pH=3, showed that the removal of polyphenols from olive mill wastewater and orthodiphenol from synthetic wastewater were 22% and 30% respectively. By using 40 g/L organo-bentonite modified with benzyl dimethyl hexadecyl ammonium bromide (BDHDA) and an applied cation dosage equal to 50% CEC for the removal of total polyphenols and orthodiphenol from industrial and synthetic wastewater, with particles less than 0.2 mm, after the mixture was shaken for about 24 h at room temperature and pH=3 using a rotary shaker resulted in 80% and 88% maximum reduction of contaminants from industrial and synthetic wastewater respectively.