Synthesis of Carbon Quantum Dots from Olive Stones for Efficient Adsorption of Benzene from the Ambient Air

In this research Carbon Quantum Dots (CQDs) made from the olive stones has been revised considering different parameters and factors including temperature, moisture, benzene concentration, the amount of adsorbent and contact time with three different methods and the amount of adsorption of three adsorbents to eliminate the benzene vapor from the ambient air. In the first adsorbent, the primary CQDs activated with nitric acid (CQDs-HNO3), and in the second adsorbent activated with KOH (CQDs-KOH), and in the third one activated with Ionic liquid (CQDs-Ion) were all studied. A pilot was made for the tests which were all equipped with a measurement device of volatile organic compounds with a photoionization detector, and a sensor for indicating the moment concentration of benzene. The most percentage of elimination of benzene in 60 seconds with an adsorption amount of 20 mg/L was calculated. In this study, the most percentage of benzene elimination amounting 70% for CQDs -KOH and the least percentage of elimination for CQDs-HNO3 was 51%. The coefficient correlation R2 for CQDs-KOH adsorbent was 0.990 as the maximum amount. The research results showed that the activated adsorbents with ionized liquid with a specific area of 524 m2/g at the temperature of 35 °C and the moisture of above 50% has more effective reaction compared to CQDs-KOH adsorbent with the specific adsorption area of 550 m2/g. This result is due to the great amount of volume of porosity of the adsorbent CQDs-ion of 1.56 cm3/g compared with the other adsorbents.