Degradation of phenol by radical sulfate anion

Author(s)

da Silva, Fabio Barbosa ; Pereira, Anna Karla dos Santos ; Pereira, Douglas Henrique ; De Souza, Nelson Luis Goncalves Dias ; Cavallini, Grasiele Soares

• Document type: Journal article
• Source: JOURNAL OF PHOTOCHEMISTRY AND PHOTOBIOLOGY A-CHEMISTRY; v. 462, p. 7-pg., 2024-12-20.

Abstract

Advanced oxidative processes are a highly efficient technology for removing complex organic pollutants through the generation of radicals, presenting as one of the possibilities the activation of sodium persulfate (SP) to generate sulfate anion radicals. In this work, the activation of SP (10 mmol/L) was evaluated for the degradation of the pollutant phenol using solar radiation, sonication at 40 kHz and heating at 40 degrees C. Assays with solar radiation were evaluated at pH 5 and pH 11. The best degradation efficiency of the phenol test was observed in the activation of SP by exposure to solar radiation over a period of 4 h, with efficiencies of 99.9 % and 60.55 % being achieved for the values pH 5 and 11, respectively. Subsequent test it was observed that after 5 h of testing, acidification occurs mainly at pH 11, making the solution acidic, making its degradation potential equivalent to pH 5, both reaching 99.9 %, due to the formation of compounds that cause a drop in pH, such as acids, generated in the degradation of the pollutant phenol, as well as by products formed by the activation of SP by solar radiation. Regarding the kinetics of phenol degradation by SP activated by solar radiation, the experimental data fit more adequately to the pseudo-first order model (R2 = 0.97). The highest degradation efficiency was obtained at higher doses of solar radiation. The SP activation tests by sonication (40 min) and heating at 40 degrees C (300 min) showed low efficiency rates in phenol degradation, being 11 and 18 %, respectively. The formation of sulfate anion and hydroxyl radicals by the SP process activated by solar radiation was confirmed by the test with the scavenger isopropanol (IPA). (AU)

• FAPESP's process: 23/17727-2 - Application of theoretical methods in studies of adsorptive processes; catalysis; reaction mechanisms, thermodynamic and spectroscopic properties of environmental, (bio)materials and technological interest
• Grantee: Douglas Henrique Pereira
• Support Opportunities: Regular Research Grants
• FAPESP's process: 13/08293-7 - CCES - Center for Computational Engineering and Sciences
• Grantee: Munir Salomao Skaf
• Support Opportunities: Research Grants - Research, Innovation and Dissemination Centers - RIDC
• FAPESP's process: 17/11485-6 - Computational and theoretical developments based on ab initio methods and the Density Functional Theory
• Grantee: Rogério Custodio
• Support Opportunities: Regular Research Grants