Adsorption Behavior of Rifampicin from Aqueous Solution onto Locally Available Mud: Equilibrium, Kinetics, and Thermodynamic Study

Several methods have been implemented to eliminate antibiotics from wastewater. Serious issues are associated with the disposal of antibiotics into the aqua resources, resulting in the contamination of these systems. The utilization of natural adsorbents, like clays and naturally derived adsorbents, has been tried to solve this problem. Red mud was examined as an adsorbent for multiple pollutants in this regard. This work reports the utilization of the Iraqi red mud as a priceless and effective adsorbent for eliminating the Rifampicin antibiotic from its aqueous solution after being activated with 10 % HCl to enhance its surface area. BET surface area, Field Emission Scanning Electron Microscope, Fourier infrared spectroscopy, Energy Dispersive X-ray, and X-ray diffraction of both the raw mud and its activated sample were determined. The BET surface area of the Iraqi red mud rose from 30.99 m2/g to 60.96 m2/g because of the acid treatment. The influence of the adsorption operative factors, including the solution pH, Rifampicin initial concentration, adsorbent dosage, temperature, and contact time, on Rifampicin elimination by the activated red mud, was inspected. The typical adsorption capacity of Rifampicin by the activated red mud was 217.93 mg/g utilizing 0.20 g of the activated red mud at 328 K for 180 minutes contact time in an acidic medium (pH = 4.0). The Langmuir model best described the adsorption behavior of Rifampicin over the activated red mud due to its higher correlation coefficient value (R2 = 0.9928) than that of the Freundlich model (R2 = 0.9117). Rifampicin adsorption by the activated red mud followed the pseudo-second-order kinetic model. Thermodynamic analysis revealed that the adsorption of Rifampicin favored high temperatures, suggesting that the adsorption is endothermic in nature and spontaneous. Finally, the activated red mud is an eco-friendly and reusable adsorbent to remove antibiotic pollutants.