Innovative sustained-release Ferrate(VI) composites for controlling algal derived disinfection by-products in waters

The study presents a novel approach to tackling algal-induced disinfection byproducts (DBPs) in water treatment using potassium ferrate (K₂FeO₄) composites coated with paraffin or β-cyclodextrin. The encapsulation technology significantly enhances Fe(VI) stability and enables controlled release, mitigating rapid self-decomposition and oxidative overreaction. Composite materials were synthesized via melt suspension and host-guest encapsulation, achieving encapsulation efficiencies >90 % for paraffin (mass ratio 7:1) and 70 % for β-cyclodextrin. Sustained-release kinetics followed non-Fickian diffusion models (R² > 0.98), with optimized 3:1 coating ratios yielding 46–53 % cumulative release over 120 min. Pre-oxidation using coated Fe(VI) reduced total DBPs by 60 %, outperforming uncoated Fe(VI) in controlling brominated species (Tribromomethane reduction: 67.15 % for intracellular organics). Three-dimensional fluorescence and UV spectroscopy analysis confirmed effective degradation of algal-derived aromatic proteins, fulvic acids, and humic substances. β-Cyclodextrin composites demonstrated superior pH adaptability (6–9) and toxicity reduction, lowering mutagenicity and bioconcentration factors by 48–53 % via controlled precursor degradation. Coating-mediated release minimized algal cell lysis, reducing intracellular organic release by 49 % compared to uncoated systems. The study establishes ferrate-coated composites as a dual-functional solution combining oxidation and coagulation, offering enhanced DBPs control in algae-impacted waters while addressing Fe(VI) instability limitations.