Research On The Sulfuric Acid Wastewater Treatment And Recycling By Strong Base Ion-exchange Resin SA20

A large amount of wastewater characterized by high concentration ofsulfuric acid is discharged as the production of sulfuric acid oxidizingbath, The ion exchange technology has shown great selectivity and easymanipulation in the separation process.Through the resin selection experiment, SA20 resin showed a bettercapacity for the removal of those substances in the wastewater. Freesulfuric acid removal ratio of sulfuric acid oxidizing bath wastewaterwas over 71.74% at appropriately operating conditions. Effects of time,temperature, pH and the concentration of Al on adsorption and ion exchangebehavior were investigated. The results indicated that the equilibriumtime was about20min. Low temperature and was good for the adsorption. Alin the wastewater was a competitive, leading to a negative effect on thereaction.The results of column dynamic adsorption and regeneration showed itcould be efficiently removed by SA20 resin from sulfuric acid oxidizingbath wastewater. Effects like flow rate, pH, and concentration of Al. Theconcentration of sulfuric acid had also been discussed in severalresearches. The increase of the flow rate led to a worse breakthrough curve,the high concentration of Al could be a negative factor for its competitiveadsorption.In the regenerated experiment, the resin was easily regenerated bywater wash, NaOH stripping, especially with a slow flow rate andhigh concentration of NaOH. The water wash, 1mol/L NaOH, 1. OL/min flowrate and 20-35℃can improve recycling rate. Recycling rate can reach70%-72% in the regenerated experiment.The sulfuric acid was chosen to study the behavior of the resinadsorption and exchange process. Langmuir-Freundlich isotherm was bestto simulate the adsorption among the isotherm models of Langmuir, Freundlich and Langmuir-Freundlich. A second-order adsorption kineticsequation was developed for the process, and three parameters werecalculated. Furthermore, results showed that the process was controlledby the particle diffusion, i.e. PDC.At last, breakthrough curve, product management, the SA20 resinrecycling and regenerated also are been discussed.