Impact of turbine impeller blade inclination on the batch sorption process

Abstract

Batch sorption is a practical process used to remove various species from the wastewater. It is affected by different parameters such as initial concentrations, temperature, pH, surface area, coexisting ions, and mixing that need to be known for batch reactor design. Although reaction mixture in batch processes needs to be well-mixed, and there are many papers regarding sorption, mixing parameters are rather neglected. Therefore, the aim of this work was to analyse the impact of the turbine impeller blades inclination and baffle presence on sorption kinetics in the uncovered batch reactor. This impact was studied using copper (II) ions sorption on zeolite NaX particles. The experiments were conducted in the baffled and unbaffled reactor equipped with the four-blade turbine placed close to the vessel base. To determine the influence of impeller blades inclination on hydrodynamics and sorption kinetics, the blades inclination varied from 30° to 90°. A transient multiphase computational fluid dynamics model was developed to gain valuable insight into complex flow kinetics. The Ritchie model, Mixed surface reaction and diffusion-controlled sorption kinetic model, and Weber-Morris model were used for the kinetic analysis of the experimental kinetic data. According to Ψ and AARD values, the reaction is kinetic controlled regardless of the impeller blades inclination. The process is the fastest if the impeller with a blades inclination of 90° is used and in the baffled reactor. Concurrently, the energy consumption is the lowest for this impeller, regardless of the presence of the baffles.