Surface modification of heterostructured Bi₈W₄O₂₄/ZrO₂@GO composite via low-pressure cold plasma for boosting photocatalytic potential against Basic fuchsin and Bismarck brown Y dyes

The widely used dyes, Basic fuchsin (BF) and Bismarck brown Y (BBY), pose significant risks to water resources and human health, necessitating efficient removal methods. Semiconductor-based heterogeneous photocatalysis offers an eco-friendly solution. However, improving the photocatalyst’s efficiency remains a challenge. This study aims to fabricate a promising Bi₈W₄O₂₄/ZrO₂@GO (BWOZG) heterojunction via hydrothermal approach, followed by low-pressure cold plasma (LPCP) treatment to improve its properties for environmental remediation of BF and BBY dyes along with industrial wastewater. The prepared composites were analyzed via DLS, UV–visible spectroscopy, SEM–EDX, FTIR, XRD, and EPR. The findings indicated that the LPCP-treated BWOZG has z-average of 225 ± 5 nm, zeta potential of − 38.74 ± 2 mV, band gap of 2.20 eV, a porous morphology, and mixed orthorhombic Bi₈W₄O₂₄ and tetragonal ZrO₂ phases. LPCP-treated BWOZG composite exhibited 5% increase in degradation efficiency of BF (99.7%) at pH = 6, catalyst dose = 20 mg L⁻¹, dye dose and irradiation time = 10 mg L⁻¹/30 min, and 6% for BBY (98%) at pH = 5, catalyst dose = 30 mg L⁻¹, dye dose and irradiation time = 10 mg L⁻¹/30 min, and 80.41% reduction in COD of industrial wastewater. The successful degradation of dyes to nontoxic species was confirmed by FTIR. The formation of ^•OH and O₂^−• radical species during photocatalytic process was confirmed by EPR analysis. Kinetics study showed the best fitness of the pseudo-first-order model on experimental data. LPCPT-BWOZG retained 91 and 89% recyclability after five cycles of BF and BBY degradation, respectively, and good broad-spectrum bactericidal activity for E. coli and S. aureus, demonstrating its potential as antibacterial photocatalytic materials for oxidation of organic pollutants in aqueous media to enhance the environmental safety.