Work

Electrochemical oxidation for the rapid degradation of emerging contaminants: Insights into electrolytes and process parameters for phytotoxicity reduction

Year: 2025

Type: article

Abstract: Atrazine (ATZ), carbamazepine (CBZ), and sulfamethoxazole (SMX) are contaminants of emerging concern (CECs) commonly detected in water sources, posing risk to health, sanitation, and the ecosystems. This study evaluates degradation, mineralization, and phytotoxicity reduction of a solution containing these three CECs using electrochemical advanced oxidation process (EAOP). Key operational parameters – pH, flow rate (Q), current density (j), and type and concentration of supporting electrolytes (NaCl and Na2SO4) – were systematically investigated. The results showed that pH had minimal impact on the process. Higher flow rates (250 L h-1) improved mineralization due to enhanced mass transfer to •OH on the anode surface. However, flow rate had less effect on degradation, as the dominant degradation mechanisms involved chlorine- or sulfate-based oxidants. Current densities of 1 and 10 mA cm-2 produced the most favorable results, leading to efficient degradation and mineralization, along with satisfactory mineralization current efficiency (up to 47%) and energy consumption values (91,76 – 3142,88 kW h kg-1). With NaCl as the supporting electrolyte, degradation of CECs was two times faster compared to Na2SO4, achieving over 88% degradation in 5 min and over 40% mineralization within 60 min. While chlorinated and sulfate species enhance process efficiency, excessive electrolyte concentration should be avoided to prevent scaling and •OH scavenging. Phytotoxicity tests with Allium cepa revealed an unexpected reduction in toxic in samples treated with NaCl, suggesting that Na2SO4 may be more phytotoxic under the tested conditions.

Source: Chemosphere

DOI: 10.1016/j.chemosphere.2025.144363

Authors: Camila F. Zorzo, Louidi L. Albornoz, Andréa M. Bernardes, Valentín Pérez-Herranz, Fernando H. Borba, Salatiel W. da Silva

Institutions: Universidade Federal do Rio Grande do Sul, Universitat Politècnica de València, Universidade Federal da Fronteira Sul

Language: English

Topic: Advanced oxidation water treatment

Subfield: Water Science and Technology

Field: Environmental Science

Domain: Physical Sciences

SDG: Clean water and sanitation

Open Access status: hybrid

Estimated APC paid: $4,010