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Enhanced Degradation of 4-Nitrophenol via a Two-Stage Co-Catalytic Fenton Packed-Bed Reactor with External Circulation

by Yan Liu, Jingyu Liu, Yongyou Hu, Yueyue Shi, Chaoyang Tang, Jianhua Cheng, Xiaoqiang Zhu, Guobin Wang and Jieyun Xie

Environments 2025, 12(8), 280; https://doi.org/10.3390/environments12080280 - 14 Aug 2025

Cited by 1 | Viewed by 1070

Abstract

To mitigate the consumption of active sites on co-catalysts by H₂O₂ and to enhance the efficiency and stability of co-catalytic Fenton reactions, an external circulation two-stage packed-bed reactor (ECTPBR) was developed using DPW (diatomite plate@polydopamine@WC) as a co-catalyst to degrade 4-nitrophenol (4-NP). Under suitable conditions, the ECTPBR could achieve over 91.97% 4-NP degradation, with low iron sludge production (11.97 mg/L) and minimal tungsten leaching (3.6363 mg/L). The two-stage strategy enabled spatial separation of Fe³⁺ reduction and Fenton reactions, minimizing the loss of active sites on DPW, ensuring long-term system stability, and reducing the toxicity of 4-NPdegradation products. In addition, external circulation enhanced mass transfer and improved resistance to shock loads. These advantages suggest that the ECTPBR may serve as an effective strategy for applying co-catalytic Fenton reactions in the treatment of toxic and refractory organic wastewater. Full article

(This article belongs to the Special Issue Advances in Heavy Metal Remediation Technologies)

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11 pages, 1214 KB

Open AccessArticle

Catalytic Behavior of Cobalt Complexes Bearing Pyridine–Oxime Ligands in Isoprene Polymerization

by Yuanxu Du, Shuo Gao, Hui Ma, Siqi Lu, Zhenhua Zhang and Mengmeng Zhao

Polymers 2023, 15(24), 4660; https://doi.org/10.3390/polym15244660 - 10 Dec 2023

Cited by 3 | Viewed by 2334

Abstract

Several cobalt(II) complexes Co1–Co3 bearing pyridine–oxime ligands (L1 = pyridine-2-aldoxime for Co1; L2 = 6-methylpyridine-2-aldoxime for Co2; L3 = phenyl-2-pyridylketoxime for Co3) and picolinaldehyde O-methyl oxime (L4)-supported Co4 were synthesized and well characterized by FT-IR, mass spectrum and elemental analysis. The single-crystal X-ray diffraction of complex Co2 reveals that the cobalt center of CoCl₂ is coordinated with two 6-methylpyridine-2-aldoxime ligands binding with N_pyridine and N_oxime atoms, which feature a distorted octahedral structure. These Co complexes Co1–Co4 displayed extremely high activity toward isoprene polymerization upon activation with small amount of AlClEt₂ in toluene, giving polyisoprene with high activity up to 16.3 × 10⁵ (mol of Co)⁻¹(h)⁻¹. And, the generated polyisoprene displayed high molecular weights and narrow molecular distribution with a cis-1,4-enriched selectivity. The type of cobalt complexes, cocatalyst and reaction temperature all have effects on the polymerization activity but not on the microstructure of polymer. Full article

(This article belongs to the Special Issue Catalytic Olefin Polymerization and Polyolefin Materials)

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