A Feasible Strategy for Calculating the Required Mass Transfer Height of a New Bubbling Organic Liquid Membrane Extraction Tower Directly Based upon the Experimental Kinetic Data

Abstract

Extraction and recovery of gold(I) with extremely low concentration in cyanide wastewater were conducted as an example aimed to develop a feasible method based upon the experimental kinetic data for calculating the required mass transfer height of a new bubbling organic liquid membrane extraction tower. The kinetic extraction equation based on curve fitting the experimental c(t) ∼ t data from single column extraction could be established to describe the quantitative relationship of the concentration change of gold(I) in flowing-out aqueous solution from the tower with the reaction time in the tower, so that the required tower height involved in the axial gas mixing effect could be calculated from the residence time of the aqueous solution passing through the tower to achieve a target equilibrating concentration. The influence of organic phase recycling on the calculation was discussed. Double column extraction experiments confirmed that the suggested calculation method obtained from single column extraction is reasonable. The present work is in favor of understanding the mass transferring kinetic behaviors of target components in that suggested bubbling extraction tower, and it highlights a feasible strategy directly from the experimental kinetic data to calculate the required mass transferring height of the tower for its structure design, optimization, and scale-up, and provides fundamental data for future industrial application of the tower to extract and recover other heavy metal ions from wastewater.