Ruthenium Nanoparticles Supported on CeO₂ for Catalytic Permanganate Oxidation of Butylparaben

Abstract

This study developed a heterogeneous catalytic permanganate oxidation system with ceria supported ruthenium, Ru/CeO2 (0.8‰ as Ru), as catalyst for the first time. The catalytic performance of Ru/CeO2 toward butylparaben (BP) oxidation by permanganate was strongly dependent on its dosage, pH, permanganate concentration and temperature. The presence of 1.0 g L(-1) Ru/CeO2 increased the oxidation rate of BP by permanganate at pH 4.0-8.0 by 3-96 times. The increase in Ru/CeO2 dosage led to a progressive enhancement in the oxidation rate of BP by permanganate at neutral pH. The XANES analysis revealed that (1) Ru was deposited on the surface of CeO2 as Ru(III); (2) Ru(III) was oxidized by permanganate to its higher oxidation state Ru(VI) and Ru(VII), which acted as the co-oxidants in BP oxidation; (3) Ru(VI) and Ru(VII) were reduced by BP to its initial state of Ru(III). Therefore, Ru/CeO2 acted as an electron shuttle in catalytic permanganate oxidation process. LC-MS/MS analysis implied that BP was initially attacked by permanganate or Ru(VI) and Ru(VII) at the aromatic ring, leading to the formation of various hydroxyl-substituted and ring-opening products. Ru/CeO2 could maintain its catalytic activity during the six successive runs. In conclusion, catalyzing permanganate oxidation with Ru/CeO2 is a promising technology for degrading phenolic pollutants in water treatment.

Catalyzing the oxidation of sulfamethoxazole by permanganate using molecular sieves supported ruthenium nanoparticles

“…Therefore, CeO 2 and TiO 2 supported ruthenium nanoparticles, namely Ru/CeO 2 and Ru/TiO 2 , were synthesized to catalyze permanganate oxidation (Zhang et al, 2013b(Zhang et al, , 2014a. The presence of 1.0 g L À1 Ru/CeO 2 increased the oxidation rate of butylparaben by 3-96 times at pH 4.0-8.0 (Zhang et al, 2013b), while 1.0 g L À1 Ru/TiO 2 increased the reaction rates of bisphenol A, diclofenac, acetaminophen, sulfamethoxazole, benzotriazole, carbamazepine, butylparaben, diclofenac, ciprofloxacin and aniline by 0.3-119 times at pH 7.0 (Zhang et al, 2014a). However, the dependence of the performance of catalysts on the specific area, pore size and diameter of supports and Ru loading has not been clarified.…”

“…The in situ XANES analysis revealed that Ru/CeO 2 acted as an electron shuttle in catalytic permanganate oxidation process (Zhang et al, 2013b). Ru III , deposited on the surface of CeO 2 was oxidized by permanganate to its higher oxidation state Ru VI and Ru VII , which acted as the co-oxidants in organics oxidation.…”

Understanding the molecular basis for the controlled design of ruthenium nanoparticles in microporous aluminophosphates

“…This reveals that the average oxidation-state of the RuAlPO-5-AS species lies between Ru(III) and Ru(IV). [35,36] There is a negligible change in main-edge position before 179 o C, suggesting higher temperatures are required for activation. However, where the phase-transition occurs between 189 and 202 o C the average oxidation-state decreases, as some of the ruthenium ions are reduced to ruthenium metal ( Figure S6).…”

“…[34] These observations confirm that ruthenium species in RuAlPO-5-AS primarily possess characteristics of Ru(IV)O2, with the possibility of some contribution from lower oxidation states. [35,36] This is not uncommon in AlPO chemistry, as the catalytic potential of substituted first row transition metals (Co, Mn, etc.) derives from their ability to exist in multiple oxidation states.…”

Synthetic conditions-regulated catalytic Oxone efficacy of MnO x /SBA-15 towards butyl paraben (BPB) removal under heterogeneous conditions

“…To the best of our knowledge, this is the pioneering work aiming at systematically probing the links between synthetic conditions and physicochemical properties in MS-Oxone reaction system for the removal of PPCPs. Butyl paraben (BPB), as one of the most commonly used parabens in personal care chemicals, was selected as a probe compound to test the catalytic activity and properties of the composites due to its wide presence in aquatic media and physiological risk to organisms [33,34].…”