Application of waste iron in wet flue gas desulfurization (WFGD) wastewater treatment

Environ Sci Pollut Res Int. 2024 Nov 30. doi: 10.1007/s11356-024-35646-z. Online ahead of print.

Abstract

The wet flue gas desulfurization (WFGD) procedure results in wastewater containing a complex mixture of pollutants, including heavy metals and organic compounds, which are hardly degradable and pose significant environmental challenges. Addressing this issue, the proposed approach, incorporating waste iron shavings as a heterocatalyst within a modified Fenton process, represents a sustainable and effective solution for contaminants degrading in WFGD wastewater. Furthermore, this study aligns with the Best Available Techniques (BAT) regulations by meeting the requirement for compound oxidation-replacing the chlorine utilization with the generation of highly reactive radicals-and coagulation, which completes the treatment process. This method introduces an innovative use of waste-derived iron shavings in a BAT-compliant technology, providing a sustainable and cost-effective alternative to conventional treatments. The study focuses on process kinetics and optimization parameters, achieving approximately 48% total organic carbon (TOC) removal in 90 min at an optimal pH 3, using 1998 mgL-1 H2O2 under UV light. Analysis of variance revealed that the process efficiency depended more significantly on pH than time duration or the H2O2 dose. Catalyst's characterization, including the use of microscopic techniques, including electron microscopy, laser diffraction, X-ray fluorescence, Raman spectroscopy, and UV spectroscopy, indicates its stability and great reusability with consistent TOC decrease across three process cycles. This research demonstrates a cost-effective, environmentally friendly approach to wastewater treatment, advancing sustainable methodologies through the repurposing of waste materials and underscoring the catalyst's reuse potential.

Keywords: Flue gas desulfurization; Modified Fenton process; Wastewater treatment; Zero-valent iron.