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Ge Q, Liu Y, Liu P, Yang Z, Yang L, Liu Z, Li Z. Research on a harmless treatment method for oily sludge in coal chemical wastewater and the pollutant transformation mechanism of oily sludge during the treatment process. JOURNAL OF HAZARDOUS MATERIALS 2024; 478:135568. [PMID: 39178785 DOI: 10.1016/j.jhazmat.2024.135568] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/16/2024] [Revised: 08/15/2024] [Accepted: 08/16/2024] [Indexed: 08/26/2024]
Abstract
This study developed an ultrasound synergistic subcritical hydrothermal treatment method (U-SHT) to address the challenges posed by the high oil and water content, complex composition, and hazardous nature of oily sludge (OS) generated during the pretreatment of coal chemical wastewater. The study investigated the efficiency of this method for the harmless disposal and resource recovery of OS, and the migration-transformation mechanism of hazardous organic pollutants in OS. The findings revealed that U-SHT achieved a removal efficiency of chemical oxygen demand in OS of 91.16 %, an oil resource recovery efficiency of 96.60 %, and a residual oil rate of 0.28 %, meeting API emission standards. Further research indicated that the solubilizing effect of the surfactant on the oil enhanced the demulsifying effect of ultrasonic cavitation on the emulsified structure of OS, enabling ultrasound to efficiently release and disperse pollutants within OS. This promoted the decomposition and transformation of pollutants under subcritical hydrothermal conditions, with synergistic removal efficiencies for typical pollutants such as long-chain alkanes, polycyclic aromatic hydrocarbons, and phenols reaching 96.61 %, 97.63 %, and 97.76 %, respectively. Economic evaluation indicated that the cost of OS treatment was $29.66/m3, significantly lower than existing methods, demonstrating promising practical application prospects.
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Affiliation(s)
- Qian Ge
- School of Environmental and Municipal Engineering, Xi'an University of Architecture and Technology, Yan Ta Road. No.13, Xi'an 710055, China; Key Lab of Northwest Water Resource, Environment and Ecology, Ministry of Education, Xi'an University of Architecture and Technology, Xi'an 710055, China
| | - Yongjun Liu
- School of Environmental and Municipal Engineering, Xi'an University of Architecture and Technology, Yan Ta Road. No.13, Xi'an 710055, China; Key Lab of Northwest Water Resource, Environment and Ecology, Ministry of Education, Xi'an University of Architecture and Technology, Xi'an 710055, China.
| | - Pan Liu
- School of Environmental and Municipal Engineering, Xi'an University of Architecture and Technology, Yan Ta Road. No.13, Xi'an 710055, China; Key Lab of Northwest Water Resource, Environment and Ecology, Ministry of Education, Xi'an University of Architecture and Technology, Xi'an 710055, China
| | - Zhuangzhuang Yang
- School of Environmental and Municipal Engineering, Xi'an University of Architecture and Technology, Yan Ta Road. No.13, Xi'an 710055, China; Key Lab of Northwest Water Resource, Environment and Ecology, Ministry of Education, Xi'an University of Architecture and Technology, Xi'an 710055, China
| | - Lu Yang
- School of Environmental and Municipal Engineering, Xi'an University of Architecture and Technology, Yan Ta Road. No.13, Xi'an 710055, China; Key Lab of Northwest Water Resource, Environment and Ecology, Ministry of Education, Xi'an University of Architecture and Technology, Xi'an 710055, China
| | - Zhe Liu
- School of Environmental and Municipal Engineering, Xi'an University of Architecture and Technology, Yan Ta Road. No.13, Xi'an 710055, China; Key Lab of Northwest Water Resource, Environment and Ecology, Ministry of Education, Xi'an University of Architecture and Technology, Xi'an 710055, China
| | - Zhihua Li
- School of Environmental and Municipal Engineering, Xi'an University of Architecture and Technology, Yan Ta Road. No.13, Xi'an 710055, China; Key Lab of Northwest Water Resource, Environment and Ecology, Ministry of Education, Xi'an University of Architecture and Technology, Xi'an 710055, China
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Zhang W, He Y, Xing X, Wang Y, Li Q, Wang L, Zhu Y. In-depth insight into the effects of intrinsic calcium compounds on the pyrolysis of hazardous petrochemical sludge. JOURNAL OF HAZARDOUS MATERIALS 2023; 455:131593. [PMID: 37172378 DOI: 10.1016/j.jhazmat.2023.131593] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/24/2023] [Revised: 05/01/2023] [Accepted: 05/05/2023] [Indexed: 05/14/2023]
Abstract
To understand the potential effects of intrinsic calcium compounds on sludge pyrolysis, the pyrolysis behavior of petrochemical sludge (PS), calcium carbonate blend PS (CaPS), and decalcified PS (DePS) were investigated using thermogravimetric analysis (TGA) and in-situ Fourier-transform infrared spectroscopy coupled with pyrolysis-gas chromatography and mass spectrometry (Py-GC/MS). The TGA results indicated that decalcification increased and decreased the energy barriers of PS decomposition in ranges 200-350 °C and 350-600 °C, respectively. In contrast, copyrolysis with CaCO3 decreased the activation energy (E) of the pseudoreaction phase 2 (PH2) and altered the mechanism model. Meanwhile, during copyrolysis, char deposition and interaction hindered CaCO3 decomposition. The two-dimensional correlation spectroscopy results, on the other hand, showed that the reaction priority of O-containing groups and CH- vibration of methyl groups were affected by both decalcification and CaCO3 copyrolysis. The Py-GC/MS results indicated that the three sludges mainly released hydrocarbons, N-containing organics, alcohols, aldehydes, and acids. During pyrolysis, CaCO3 also played a neutralization role, which reduced the release of pyrolytic acidic products. In addition, the increase of the pyrolysis temperature increased the hydrocarbon content. This research will guide the industrial application of sludge pyrolysis.
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Affiliation(s)
- Wenqi Zhang
- School of Mechanical and Power Engineering, Nanjing Tech University, Nanjing 211816, Jiangsu, China; Jiangsu Province Engineering Research Center of Organic solid wastes deeply treatment and hydrogen production, Jiangsu, China
| | - Yahui He
- School of Mechanical and Power Engineering, Nanjing Tech University, Nanjing 211816, Jiangsu, China; Jiangsu Province Engineering Research Center of Organic solid wastes deeply treatment and hydrogen production, Jiangsu, China
| | - Xinxin Xing
- School of Mechanical and Power Engineering, Nanjing Tech University, Nanjing 211816, Jiangsu, China; Jiangsu Province Engineering Research Center of Organic solid wastes deeply treatment and hydrogen production, Jiangsu, China
| | - Yinfeng Wang
- School of Energy Science and Engineering, Nanjing Tech University, Nanjing 211816, Jiangsu, China; Jiangsu Province Engineering Research Center of Organic solid wastes deeply treatment and hydrogen production, Jiangsu, China.
| | - Qiyuan Li
- School of Chemical Engineering, The University of New South Wales (UNSW), Kensington, New South Wales 2052, Australia
| | - Lei Wang
- School of Environmental Science and Engineering, Nanjing Tech University, Nanjing 211816, Jiangsu, China
| | - Yuezhao Zhu
- School of Energy Science and Engineering, Nanjing Tech University, Nanjing 211816, Jiangsu, China; Jiangsu Province Engineering Research Center of Organic solid wastes deeply treatment and hydrogen production, Jiangsu, China
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