Carbon Dots for Improving Water and Oil Absorption of Sponges

Abstract

An oil spill is one of the hazardous problems in the ocean. Cleaning the oil spill requires expensive and specific technologies. Nowadays, advanced techniques such as skimmers, oil dispersion agents, in-situ burning and solar-heated oil-absorbent are frequently used to solve the problem. For oil-absorbent materials, further, development is still required to enhance oil dan water absorption. Carbon dots is one of the promising nanoparticles that can be used to improve oil absorption. In this work, we conjugated carbon dots made of pencil leads into several types of sponges. The purpose of this work was to improve oil and water absorption. Our experiment results showed that 2 to 5 nanometres size of ethanol soluble carbon dots were successfully synthesized using a simple electrochemical process. UV-Vis absorption and FTIR spectra showed clear energy transition and functional groups in carbon dots. We used six different sponges with various mass densities from 9 to 174 mg/cm3. Conjugation of carbon dots into the sponge was simply done by immersing the sponge in carbon dot solution and drying it. The conjugation made the mass of the sponge increase. We examined the water and oil absorption capacity of each sponge. Oil absorption capacities were different for each sponge. In general, the addition of carbon dots in sponges increased the mass density of sponge water twice. Furthermore, one type of sponge decreased oil absorption capacity after carbon dots conjugation. Other types of sponges showed an improvement of oil absorption capacity by 60% after carbon dot conjugation. We believe that this work can be further improved to get higher water and oil absorption.