Ingenious integration of Fe0 and multiphased MoS2 to activate peroxymonosulfate for carbamazepine removal at high salinity condition

Abstract

To tackle high salinity challenge, differently from singlet oxygen-governed systems, extremely abundant and highly reactive sulfate radicals (SO4•─)-dominated systems might be also feasible. Ingenious integration of two active popular catalysts, and optimal selection of reaction parameters could sufficiently activate the added peroxymonosulfate (PMS) to efficiently degrade complicated pollutants within a short time so as to overlook the negative effects of inorganic anions. Herein, zero-valent iron decorated metallic 1T/semiconducting 2H hybrid phased molybdenum disulfide with different Mo/S feeding ratio (Fe0/Nx-MoS2) were constructed and compared to activate PMS for carbamazepine (CBZ) removal, where Fe0/N2-MoS2 (M(Mo):M(S) = 7:30) with ultrathin sheet morphology presented most charming decontamination performance. Optimal Fe0/N2-MoS2 dosage and PMS amount was respectively selected as 75 and 50 mg·L-1 in treating 10 mg·L-1 CBZ at pH = 3.00 via tailoring reaction parameters. CBZ could be completely removed in a short time of 10 min with a high pseudo-first-order kinetic rate constant of 0.939 ± 0.016 min−1. The system exhibits the promising anti-interference capacity toward Cl─, NO3─ and SO42─ of high concentration (even up to 3000 mg·L-1). Electron paramagnetic resonance and scavenging experiments of reactive species suggested that SO4•─ played a dominant function. Furthermore, Mo and Fe bimetallic cycles could efficiently promote PMS activation to produce rich reactive radicals. Degradation pathways and toxicity evolutions for CBZ in the (Fe0/N2-MoS2 + PMS) system were proposed via liquid chromatography time-of-flight mass spectrometer and Toxicity Estimation Software Tool, and we hope that the system would be applied in high salinity wastewater treatment in future.