An efficient catalyst for carbamazepine degradation that alkali-etched silicon carbide synergy effect with ZIF-67 (ZIF-67/AE-SiC) in peroxymonosulfate system

Abstract

• ZIF-67/AE-SiC was synthesized via co-precipitation to enhance PMS activation. • The optimized ZIF-67/AE-SiC(0.08) + PMS system degraded 80 mg/L CBZ over 95 % in 8 min. • SO 4 ·− , O 2 ·− , and 1 O 2 are key reactive species in the ZIF-67/AE-SiC + PMS system. • PMS enters ZIF-67 via AE-SiC faster than onto its surface directly, per Murray’s Law. Addressing the agglomeration issue of ZIF-67 is of great significance for its application in advanced oxidation processes (AOPs) targeting organic macromolecule pollutants. In this study, we etched commercially available silicon carbide (C-SiC) in an alkaline solution to obtain alkali-etched silicon carbide (AE-SiC). Using a co-precipitation method, we synthesized a composite material where ZIF-67 is surface-modified by AE-SiC (ZIF-67/AE-SiC). After alkali etching, AE-SiC particles become smaller, with increased porosity and larger pore size. These modifications allow AE-SiC to chemically bond to the surface of ZIF-67, effectively reducing its surface energy and thus resolving the issue of self-agglomeration. Meanwhile, the introduction of AE-SiC allows peroxymonosulfate (PMS) to enter ZIF-67 more rapidly, facilitating dynamic redox cycling in ZIF-67. This enhances the forming of reactive species like SO 4 ·− , O 2 ·− , and 1 O 2 , leading to the production of additional free radicals that effectively degrade organic macromolecular pollutants. The optimized ZIF-67/AE-SiC(0.08) composite exhibited excellent catalytic activity in PMS-mediated carbamazepine (CBZ) degradation, achieving over 95% degradation within 8 min. A comprehensive investigation into the degradation pathways of CBZ was conducted, concurrently with an evaluation of the toxicity of itself and its degradation intermediates. This study expands the potential applications of silicon carbide and ZIF-67 materials in the development of PMS-based advanced oxidation processes.