Removal of Nitric Acid From Liquid Effluent by the Solvent Extraction Method: Effect of Different Operating Parameters, Kinetic and Thermodynamic Study

ABSTRACT This investigation focuses on the liquid‐liquid extraction of nitric acid utilizing various organic solvents, specifically dichloroethane, dichloromethane, and trichloroethylene. The study comprehensively evaluated the impact of several operational parameters, such as solvent concentration, contact time, nitric acid concentration, settling time, the ratio of the organic to aqueous phase (V O /V a ), stirring speed, and temperature on the extraction efficiency. Additionally, thermodynamic and kinetic studies were conducted to gain a deeper insight into the processes involved. The thermodynamic results indicate static system stability, characterized by low, negative ΔS values, suggesting that the organic phase system has achieved equilibrium. Kinetic findings reveal that the extraction rate is predominantly controlled by diffusion through the liquid film. (ΔS° ranging from approximately −12 to −45 J.mol 1− .K 1− depending on the solvent)