Abstract

The development of most effective reduction catalysts is an essential for promoting the sustainability by minimizing the waste and safeguard the environment. Herein, we prepared palladium-cobalt bimetallic nanoparticles modified on goethite nanorods (PdCo/alpha-FeOOH) as a catalyst for the catalytic degradation of various organic pollutants under mild reaction conditions. The structure and morphology of synthesized catalysts were tested by XRD, FT-IR, BET, SEM, TEM, HR-TEM and XPS techniques. The ultra-small PdCo bimetallic NPs (2.95 +/- 0.5 nm) synthesized onto the surface of alpha-FeOOH nanorod were confirmed by HR-TEM analysis. The prepared catalysts were played an important role in the reduction of toxic nitrocompounds such as (4-nitrophenol (4-NP), 4-nitroaniline (4-NA), 4-(4-nitrophenyl)morpholine (4-NM) and 4-(2-fluoro-4-nitrophenyl)morpholine (4-FNM)) and rhodamine B (RhB) dye. The PdCo/alpha-FeOOH nanocatalyst displayed a greater rate constant (similar to 1.5 min and k(app) = 2.631 min(-1)) compared to their respective mono-metallic counterparts (Pd/alpha-FeOOH and Co/alpha-FeOOH). The reusability results indicated that >97 % of conversion for 4-NP, and RhB dye over 10 consecutive reaction cycles in the batch method. Furthermore, the continuous flow reactor with PdCo/alpha-FeOOH catalyst was constructed, and it showed the ability to eliminate > 99 % of both 4-NP and RhB dye and maintained a degradation rate of >98 % for 20 consecutive recycles. The superior catalytic activity of the PdCo/alpha-FeOOH catalyst compared to other mono-metallic catalysts could be attributed to their particle size and synergistic effect. This study has the potential to facilitate the utilization of the synthesized bimetallic nanostructure in a wider range of other wastewater treatments.