PREFORMED FERRIC HYDROXIDE FLOCS AS ADSORBENTS OF HUMIC SUBSTANCES

The purpose of this study is to show that previously built flocs obtained by the coagulation-flocculation of kaolinite suspension with ferric chloride are a potential adsorbent of humic substances. Flocs are prepared from kaolinite (< 50 mum) and FeCl3 according to the jar-test technique:after 3 minutes of rapid mixing at pH = 5.4 +/- 0.1, 30 minutes of slow mixing, humic acids are added for a contact time of 6 hours ; the effects of calcium, sodium salts (chloride, sulphate) on the adsorptive capacity of preformed flocs are also studied. The results indicate that the preformed flocs are good adsorbent materials. Langmuir equation is used to determine adsorption capacities.