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Metal-organic frameworks (MOFs) as precursors for catalysts has drawn growing attentions. In this study, heterojunction Co 3 O 4 -CuO doped carbon materials (noted as Co 3 O 4 -CuO@CN) were prepared by direct carbonization of CuCo-MOF in air. It was found that the Co 3 O 4 -CuO@CN-2 exhibited excellent catalytic activity with the highest Oxytetracycline (OTC) degradation rate of 0.0902 min -1  at 50 mg/L of Co 3 O 4 -CuO@CN-2 dosage, 2.0 mM of PMS and 20 mg/L of OTC, which was 4.25 and 4.96 times that of CuO@CN and Co 3 O 4 @CN, respectively. Furthermore, Co 3 O 4 -CuO@CN-2 was efficient over a wide pH range (pH 1.9-8.4), and possessed good stability and reusability without OTC degradation decrease after five consecutive uses at pH 7.0. In a comprehensive analysis, the rapid regeneration of Cu(II) and Co(II) is responsible for their excellent catalytic performance, and the p-p heterojunction structure formed between Co 3 O 4 and CuO acts as an intermediary of electron transfer to accelerate PMS decomposition. Moreover, it was interesting to find that Cu rather than Co species played a vital role in the PMS activation. The quenching experiments and electron paramagnetic resonance demonstrated that . OH, SO 4 •- , and 1 O 2 were the reactive species responsible for oxidation of OTC and the non-radical pathway triggered by 1 O 2 was dominant., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 Elsevier Inc. All rights reserved.)

The presence of polycyclic aromatic hydrocarbons (PAHs) in groundwater is making a great threat to human health in the world which has received an increasing environmental concern. Among various Fenton oxidation processes, 97.6%, 92.1% and 89.4% naphthalene (NaP) removals were observed using hydrogen peroxide (H 2 O 2 ), sodium percarbonate (SPC) and calcium peroxide (CP) as oxidants activated by Fe(II) in ultrapure water tests, respectively. While, the inhibitory effect on NaP degradation caused by the weak alkaline solution pH and the presence of HCO 3 - in actual groundwater could be compensated by doubling dosages of oxidants and Fe(II) to different extent. 98.0%, 49.8% and 11.5% of NaP were degraded by using H 2 O 2 , SPC and CP, respectively, strongly suggesting the best H 2 O 2 performance among them. It was observed that 83.3% and 9.6% inhibition on NaP degradation in H 2 O 2 /Fe(II)/NaP system occurred in the presence of isopropyl alcohol and chloroform, confirming that both hydroxyl radical (HO) and superoxide anion radical () contributed to NaP degradation in Fenton process and HO was the prominent radical. The presence of HO was further demonstrated by electro-spin resonance spectrometer analysis. The identification of transformation products of NaP revealed that hydroxylation and ring rupture were the main NaP degradation pathways., (Copyright © 2021 Elsevier Ltd. All rights reserved.)

The waste materials utilization has attained increasing attention due to the generation of a large number of spent materials. In the current study, a practical magnetic adsorbent (Fe 3 O 4 -doped spent Fluid Catalytic Cracking catalysts, abbreviated as FCC x @(Fe) y -O) was prepared, liable to be separated. The batch experiments were employed to investigate the phosphate removal behavior. The findings of this study demonstrated that FCC 4 @(Fe) 1 -O exhibited the best phosphate removal performance among the adsorbents (FCC x @(Fe) y -O), attributed to rough surface layer, i.e., composed of active sites. The various characterizations results revealed that the adsorption behavior of FCC 4 @(Fe) 1 -O followed the inner-sphere adsorption based on ligand exchanges mechanism. Furthermore, OH - played an important role in the adsorption process. Minor effects were showed on the phosphate removal in the experiments of commonly coexisting anions, except CO 3 2- and SiO 3 2- . The above findings affirmed that FCC 4 @(Fe) 1 -O was a suitable adsorbent for phosphate removal in the practical application., (Copyright © 2018. Published by Elsevier Ltd.)