Abstract

The development of highly efficient and recyclable heterogeneous catalysts for the reduction of hazardous organic pollutants continues to be a significant problem in environmental remediation. In this regard, three-dimensional framework carbon (3DFC) as support material was prepared using calcination of sodium citrate for the immobilization of palladium nanoparticles (3.90 ± 0.80 nm) (PdNPs-3DFC). The PdNPs-3DFC catalyst was characterized with various advanced characterization techniques. Consequently, the PdNPs-3DFC catalyst exhibited excellent catalytic activity toward the reduction of various nitrophenols, and organic dyes including 4-nitrophenol (4-NP), 3-nitrophenol (3-NP), 2-nitrophenol (2-NP), 2,4-dinitrophenol (2,4-DNP), 2-chloro-4-nitrophenol (2-CNP), methyl orange (MO) and rhodamine B (RhB). The catalytic activity was eventually retained after five recycles for the reduction of pollutants (4-NP, RhB and MO), confirming the excellent stability of the PdNPs-3DFC catalyst. The proposed catalyst revealed the excellent catalytic efficiency for the simultaneous removal of multiple pollutants (4-NP, RhB, and MO) system with conversion rate of > 98 % within 12 min. The catalyst was loaded into the fixed bed system for 4-NP removal in a continuous flow system with the retention of efficiency more than 99% and its long-term stability. These results demonstrate that the integration of PdNPs with 3DFC support creates a beneficial structure-property relationship that improves the catalytic performance and stability, underscoring the potential of PdNPs-3DFC as an effective catalyst for continuous wastewater remediation.