Effect And Separation Of Inorganic Ions On HPP-SO₂ Adsorption System

In this paper, the enrichment process of various ions in organic amine HPPH+ aqueous solution for SO2 absorption was simulated. And the effects of SO32-, Cl-, NO3-, Fe3+ and Fe2+ on the absorption and desorption of SO2 in HPPH+ aqueous solution were studied.The A222 anion ion resin and 001x7 cation ion resin were selected to remolve the ion in HPPH+ aqueous solution. The maximum exchange capacity of resin for ions exchange was determined through static absorption experiments. The parameters of temperature and resin dosage in both anion resin and cation resin exchange process were optimized.In addition, the ion exchange selectivity for Cl-, NO3-, and SO42- were thus obtained and the mechanism Fe3+ exchange with 001x7 cation exchange resin was analyzed based on kinetics and thermodynamics.The results showed that the enrichment of various ions in HPPH+ aqueous solution hads a great effect on the absorption and desorption process. The enrichment of SO32-was beneficial to the absorption reaction but disadvantageous to the desorption, Cl- and NO3- has an influence on the absorption process, and showed little effect on the desorption process.With the increace of concentration of Fe3+, absorption of SO2 decreased and SO2 oxidation rate increased. SO2 under went chemical absorption and catalytic oxidation under those circumstances, and the intereaction between Fe3+ and SO2 in HPP-SO2 system was mainly the redox reaction. In addition, the enrichment of Fe2+ was unfavorable for the absorption reaction, but showed little effect on desorption.The maximum exchange capacities of A222 anion resin for Cl-, SO42- and NO3-were 0.9494 mmol·g-1,0.8382 mmol·g-1 and 1.2980 mmol·g-1,respectively. The exchange process could be described using Langmuir or Freundlich equations. The exchange capacity of A222 anion resin for Cl-, SO42- and NO3- increases with the increase of temperature. The exchange reaction is an endothermic reaction process. The optimizing condition of resin dosage is 4g/L and temperature is 35 ℃. FT-IR characterizations indicated that there was new chemical bond formation during exchange. The exchange selectivity factor of the resin followed the order of SO42> NO3> Cl-.The maximum exchange capacities of 001x7 cation resin for Fe3+ was 5.32mmol·g-1. The optimizing condition of resin dosage was 4.0 g/L and temperature is 25 ℃. The exchange process could be described using Langmuir or Freundlich equations. The exchange process was unspontaneous, exothermic and entropy decreasing. Pseudo second order kinetic model can describe adsorption process well and the process was found to be controlled by intra-particle diffusion, with apparent activation energy of 6.997KJ-mol-1.