Se‐catalyzed process of sodium bisulfite disproportionation

Abstract

BACKGROUND: SO 2 is an important gaseous pollutant that seriously affects the environment and human health. The most common method for SO 2 removal is absorption by NaOH solution and then forming HSO 3 − . Since generation of high-value products and reduction of alkali consumption are important for the economy and practical application, selenium-catalyzed HSO 3 − disproportionation was developed in this study.RESULTS: Selenium decreased the reaction temperature of HSO 3 − disproportionation from >433 K to 343 K. The effects of HSO 3 − concentration, temperature, selenium dosage, and stirring intensity were investigated. Selenium could be used at least five times with stable catalytic performance, indicating satisfactory reusability. More importantly, a catalytic mechanism was proposed using dynamic light scattering, differential scanning calorimetry and UV-visible transmittance spectrophotometry. Results showed that selenium-catalyzed HSO 3 − disproportionation experienced a solid-liquid-solid phase transformation process. During this process, SeSO 3 2− and HSe − were identified as the intermediates. Furthermore, products, i.e. sulfur and sodium bisulfate, were characterized to demonstrate their structure and composition. CONCLUSION: Selenium was an efficient catalyst for HSO 3− disproportionation. This catalytic process offered the advantages of less consumption of alkali and production of high-valuable products, and thus was a potential alternative to other technology for SO 2 removal in practical applications. /jctb As shown in the inset graph, standard HSO 3 − had an obvious characteristic absorption peak at 230-350 nm. However, the peak at 235 nm decreased when reaction time was increased from 10 to

Selenium-Assisted Reduction of Sulfur Dioxide by Carbon Monoxide in the Liquid Phase

“…Therefore, the change of the selenium size distribution before and after catalytic reaction will have an insignificant impact on the reduction of SO 2 . This also has been proven by Liu et al and our previous study. , In summary, the above results indicate a good stability of selenium for the catalytic reduction of SO 2 by CO in DMF/H 2 O.…”

“…This also has been proven by Liu et al and our previous study. 22,28 In summary, the above results indicate a good stability of selenium for the catalytic reduction of SO 2 by CO in DMF/H 2 O. adsorption efficiency by providing the carbonyl groups to form DMF/SO 2 complexes. However, no difference is observed in the HATR-FTIR spectra of the solvent before and after desulfurization.…”

“…Notably, CO can not only reduce SO 2 to elemental sulfur but also promote the formation of HSe – from selenium solid under mild conditions . Our previous studies found that HSe – had a strong reductive ability and could reduce SO 2 easily . In this study, inspired by the selenium-catalyzed reduction of organic compounds using CO, − we suggest a new strategy to reduce SO 2 by CO using selenium as the catalyst in the liquid phase.…”

“…21 Our previous studies found that HSe − had a strong reductive ability and could reduce SO 2 easily. 22 In this study, inspired by the selenium-catalyzed reduction of organic compounds using CO, 23−25 we suggest a new strategy to reduce SO 2 by CO using selenium as the catalyst in the liquid phase. A common polar aprotic and nonvolatile solvent DMF and H 2 O mixture solution was used as the solvent.…”

Kinetics and Mechanism of Se-Catalyzed Disproportionation of Bisulfite: The Critical Role of Selenosulfate

“…Recently, we developed a Se-catalyzed method for HSO 3 – disproportionation at a low temperature of 343 K . The results showed that Se-catalyzed HSO 3 – disproportionation was a solid–liquid–solid phase transformation process.…”