Multifunctional diesel exhaust emission soot coated sponge for water treatment.

We demonstrated that a pollutant and waste, diesel exhaust emission soot (DEES) can be used as an absorbent to remove oil and organic pollutants from wastewater. The diesel exhaust emission soot coated sponge (DEES sponge) was prepared using the dip-coating method. Prepared DEES sponge was found hydrophobic in nature as the contact angle between water drop and its surface was recorded to be 147°. The DEES sponge showed high absorption capacity with various oils, without any surface modifications and pretreatments. Highest oil absorption capacity was found to be 39 g/g for engine oil. Excellent separation efficiency was recorded (max. 98.5% for engine oil). It shows promising recyclability having 95% efficiency even after 10 cycles. DEES sponge also demonstrated the capability to be used as an adsorbent due to its ability to absorb pollutants like methylene blue (MB), ciprofloxacin, and detergent from the water. It was able to adsorb 93% of the dye MB from its aqueous solution having concentration of 15 μM.