Rust-Based Catalysts under Thermal Influence in Heterogenous Photo-Fenton Process for Improving Removal of Linear Alkylbenzene Sulfonate from Laundry Effluent at Near Neutral pH

Water pollution caused by linear alkylbenzene sulfonate (LAS) from laundry effluent has been increasingly detected, posing serious threats to both the environment and human health. Preventing this pollution requires a method that not only effectively reduces LAS concentration but also transforms it into smaller, safer molecules. This research aims to enhance the effectiveness of the photo-Fenton process at near-neutral pH for the removal of LAS from laundry effluent by introducing rusted iron waste as a heterogeneous catalyst thermally treated at 100 °C and 450 °C. LAS photodegradation was conducted using a batch technique along with optimization of several process variables. The systematic characterization using XRD, DR-UV/Visible, SEM, and surface area analyzer techniques confirmed that increasing the calcination temperature of rusty waste results in the formation of more crystalline and purer iron oxide (Fe2O3) exhibiting larger surface areas, wider pore diameters, and smaller band gap energies. Consistent with these properties, the iron oxide catalyst was able to remove LAS from laundry wastewater at an initial concentration of 119.18mg/L, achieving up to 95% degradation efficiency, significantly higher than catalysts prepared at lower temperatures. The optimal degradation condition for 50 mL of wastewater was obtained by applying 6 g L^−1 catalyst dose and 250 mmolL^−1 of H2O2 at pH 6, resulting in a 95% reduction of LAS within 60 minutes. These findings demonstrate that the heterogeneous photo-Fenton process, employing low-cost rust-derived iron oxide catalysts under near-neutral pH conditions, provides an effective and environmentally sustainable approach for treating laundry wastewater. Consequently, this method holds great potential in mitigating environmental pollution.