Candle soot coated polyurethane foam as an adsorbent for removal of organic pollutants from water

Carbon-based materials like graphene and activated-carbon are known for their superior adsorption capabilities in waste-water treatment. Candle soot coated polyurethane foam (CS-foam) was fabricated and studied as an adsorbent for the adsorption of rhodamine B (RB) (dye), ciprofloxacin (a pharmaceutical compound) and detergent from the aqueous solution. CS-foam was hydrophobic and oleophilic in nature and can be used for oil-water separation. A rectangular piece of CS-foam (2x2x2 cm(3)) was able to adsorb 95% of RB and 80% of ciprofloxacin from its 50 ml of an aqueous solution. A significant amount of detergent was also removed efficiently. Kinetic study of adsorption of RB on CS-foam suggests pseudo-second order is the best fit to adsorption kinetic data. Adsorption isotherm study suggests that Langmuir isotherm is a better fit to adsorption equilibrium data for RB. CS-foam was found recyclable as it can desorb the RB in ethanol media after adsorption. It shows 88% of recycling efficiency even after 6 cycles of adsorption. CS-foam can be an effective, low-cost, recyclable adsorbent for removal of various organic contaminants from water.