PARAMETRIC OPTIMIZATION OF CADMIUM AND CHROMIUM ADSORPTION ON THE MEDITERRANEAN SEAGRASS POSIDONIA OCEANICA BY SURFACE RESPONSE ANALYSIS
Special Symposium - Environmental Protection & Sustainability
Environmental Protection & Sustainability (EPS - Poster)
Keywords: Cadmium, chromium, adsorption, experimental design
Heavy metal pollution has gained considerable public attention as a corollary of the damages in aquatic environment and severe physiological and health effects in humans. These metals are introduced to the environment by many industrial activities such as metal plating, mining operations, and fertilizer and textile industries. Conventional methods for the removal of heavy metal ions are chemical precipitation, membrane filtration, ion exchange, and adsorption. The selection of the method is based on the concentration of the metal ions, efficiency/cost ratio and the adsorption capacity of the adsorbent. Although adsorption appears to be the most widely used method for the removal of heavy metals, high expense of conventional adsorbents creates a drawback. As a result, most of the research on heavy metal adsorption has been redirected to utilization of alternative adsorbents which are cost effective and abundant in nature. Recently, the heavy metal adsorption potential for many low cost adsorbents including bark/tannin-rich materials, lignin, pectin, chitin/chitosan, dead biomass, barks and husks of several materials have been investigated. The adsorption capacity of an adsorbent is dependent upon its properties such as the type, surface potential, particle size, shape, and the extent of adsorption is significantly influenced by the process parameters such as adsorbent dosage, pollutant concentration, rate of agitation etc.
This study aimed to determine the potential of Mediterranean sea grass posidonia oceanica to remove heavy metals, namely, Cd2+, Cr6+. The influences of pH, initial metal ion concentration, and adsorbate dosage on Cd2+ and Cr6+adsorption upon Mediterranean sea grass posidonia oceanica were investigated in ranges 2-12, 1-10 g/L and 2-50 mg/L, respectively, by application of surface response experimental design technique. In the case of Cr6+ adsorption, the extent of adsorption was calculated as 92.48% at pH 2.0 with 8 g/L adsorbent dosage while, 91.88% Cd2+ removal was detected at pH 4.5 with 6g/L adsorbent dosage. Adsorption data was characterized in terms of isotherms, and it was found that the data fitted well to Freundlich isotherm. Spent adsorbent was regenerated for 0.5-2 hours in 0.1M HCl. Despite the weight loss caused by the strong acidic media, regenerated posidonia oceanica performed quite well, retaining 67%, 82% of its Cd2+ and Cr6+ adsorption capacity respectively. The outcomes proved that the chromium adsorption capacity of posidonia oceanica was comparable to that of other low cost adsorbents.
Presented Monday 17, 13:30 to 15:00, in session Environmental Protection & Sustainability (EPS - Poster) S-7P.
