USE OF KAOLIN WASTE IN THE ADSORPTION OF FOOD DYES
Kaolin waste. Food dyes. Adsorption.
Waste is present in industrial processes; therefore, using this waste for a purpose other than disposal creates a new avenue for disposal and sustainable development in the processes. In this way, this study aims to assess the potential use of kaolin waste as an adsorbent for the removal of food dyes present in effluents. To achieve this, the kaolin waste was obtained from an industry in Equador/RN. Subsequently, the waste was characterized through particle size, XRF, XRD, and SEM analyses. Next, pellets were manufactured in the ratio of 10 g of kaolin waste to 3 ml of water, which were then calcined at 800°C for 2 hours with a heating rate of 10°C/min. This material was tested using an adsorption system constructed with easily obtainable laboratory materials such as a graduated cylinder, PET bottle, and faucets. It was verified in the characterization that the main mineral in the waste is kaolinite. In batch tests, the assay that showed the best adsorption capacity was with calcined kaolin powder and Tartrazine Yellow, which was 0.3658 mg/g. However, for a column test, it was observed that the use of calcined pellets was necessary due to their resilience for this operation. Thus, in batch tests with pellets, the one that exhibited the best adsorption capacity was with Tartrazine Yellow and kaolin waste in pellet form, which was 0.2023 mg/g. In comparison to the dyes, it was observed that Tartrazine Yellow exhibited a higher affinity for removal with the kaolin waste. During the column adsorption tests, it was noted that the effluent flow rate is an important factor in the process, as well as the resistance of the pellets. Finally, it is considered that each process has its advantages, and conducting further column tests with constant flow and recycling may yield additional complementary results.