Magnetically separable NiFe2O4/Sepiolite catalyst for enhanced ozonation treatment of quinoline and bio-treated coking wastewater in a catalytic ozonation system

In this work, the treatment of bio-treated coking wastewater (BCW) by catalytic ozonation was conducted in semi-batch and continuous flow reactors. The kinetics of chemical oxygen demand (COD) removal were analyzed using BCWs from five coking plants. An integral reactor with catalytic ozonation stacked by ozone absorption (IR) was developed, and its efficiency was studied. The catalyst of MnxCe1-xO2/γ-Al2O3 was efficient in the catalytic ozonation process for the treatment of various BCWs. The chemical oxygen demand (COD) removal efficiencies after 120 min reaction were 64–74%. The overall apparent reaction rate constants were 0.0101–0.0117 min−1, which has no obvious relationship with the initial COD of BCW and pre-treatment biological process. The IR demonstrated the highest efficiency due to the enhancement of mass transfer and the utilization efficiency of ozone. Bypass internal circulation can further improve the reactor efficiency. The optimal results were obtained with the ozone absorption section accounting for 19% of the valid water depth in the reactor and 250% of circulation flow ratio. The long-term and full-scale application of the novel reactor in a continuous mode indicated stable removal of COD and polycyclic aromatic hydrocarbons (PAHs). The results showed that the system of IR is a promising reactor type for tertiary treatment of coking wastewater by catalytic ozonation.

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Catalytic ozonation of bio-treated coking wastewater in continuous pilot- and full-scale system: Efficiency, catalyst deactivation and in-situ regeneration

Water Research ◽

10.1016/j.watres.2020.116090 ◽

2020 ◽

Vol 183 ◽

pp. 116090 ◽

Cited By ~ 2

Author(s):

Can He ◽

Jianbing Wang ◽

Chunrong Wang ◽

Chunhui Zhang ◽

Pin Hou ◽

...

Keyword(s):

Catalyst Deactivation ◽

Catalytic Ozonation ◽

Full Scale ◽

Coking Wastewater ◽

System Efficiency ◽

In Situ Regeneration

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Removal efficiency and mechanism of bio-treated coking wastewater by catalytic ozonation using MnO2 modified with anionic precursors

Environmental Engineering Research ◽

10.4491/eer.2020.394 ◽

2020 ◽

Vol 26 (5) ◽

pp. 200394-0

Author(s):

Jie Zhang ◽

Ben Dong ◽

Ding Ding ◽

Shilong He ◽

Sijie Ge

Keyword(s):

Specific Surface ◽

Surface Area ◽

Specific Surface Area ◽

Catalytic Performance ◽

Catalytic Ozonation ◽

Relative Content ◽

Precipitation Method ◽

Coking Wastewater ◽

Physiochemical Properties ◽

Removal Efficiencies

In this paper, MnO2 catalyst were firstly prepared and modified by four kinds of anionic precursors (i.e., NO3-, AC-, SO42- and Cl-) through redox precipitation method. After that, bio-treated coking wastewater (BTCW) was prepared and employed as targeted pollutants to investigate the catalytic ozonation performance of prepared-MnO2 catalyst was investigated and characterized by the removal efficiencies and mechanism of the prepared bio-treated coking wastewater (BTCW), which was employed as the targeted pollutants. Specifically, the effects of specific surface area, crystal structure, valence state of Mn element and lattice oxygen content on catalytic activity of MnO2 materials were characterized by BET, XRD and XPS, respectively. Results showed that COD of BTCW could be removed 47.39% under MnO2-NO3- catalyst with 2 h reaction time, which was much higher than that of MnO2-AC- (3.94%), MnO2-SO42- (12.42%), MnO2-Cl- (12.94%) and pure O3 without catalyst (21.51%), respectively. So, MnO2-NO3- presented the highest catalytic performance among these catalysts. The reason may be attributed to a series of better physiochemical properties including the smaller average grain, the larger specific surface area and active groups, more crystal defect and oxygen vacancy, higher relative content of Mn3+ and adsorbed oxygen (Oads) than that of another three catalysts.

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