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Olasupo A, Corbin DR, Shiflett MB. Trends in low temperature and non-thermal technologies for the degradation of persistent organic pollutants. JOURNAL OF HAZARDOUS MATERIALS 2024; 468:133830. [PMID: 38387180 DOI: 10.1016/j.jhazmat.2024.133830] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/01/2023] [Revised: 02/07/2024] [Accepted: 02/16/2024] [Indexed: 02/24/2024]
Abstract
The daunting effects of persistent organic pollutants on humans, animals, and the environment cannot be overemphasized. Their fate, persistence, long-range transport, and bioavailability have made them an environmental stressor of concern which has attracted the interest of the research community. Concerted efforts have been made by relevant organizations utilizing legislative laws to ban their production and get rid of them completely for the sake of public health. However, they have remained refractive in different compartments of the environment. Their bioavailability is majorly a function of different anthropogenic activities. Landfilling and incineration are among the earliest classical means of environmental remediation of waste; however, they are not sustainable due to the seepage of contaminants in landfills, the release of toxic gases into the atmosphere and energy requirements during incineration. Other advanced waste destruction technologies have been explored for the degradation of these recalcitrant pollutants; although, some are efficient, but are limited by high amounts of energy consumption, the use of organic solvents and hazardous chemicals, high capital and operational cost, and lack of public trust. Thus, this study has systematically reviewed different contaminant degradation technologies, their efficiency, and feasibility. Finally, based on techno-economic feasibility, non-invasiveness, efficiency, and environmental friendliness; radiation technology can be considered a viable alternative for the environmental remediation of contaminants in all environmental matrices at bench-, pilot-, and industrial-scale.
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Affiliation(s)
- Ayo Olasupo
- Institute for Sustainable Engineering, 1536 W. 15th Street, Lawrence, Kansas 66045, United States; Department of Chemical and Petroleum Engineering, University of Kansas, 1530 W. 15th Street, Lawrence, Kansas, 66045, United States
| | - David R Corbin
- Institute for Sustainable Engineering, 1536 W. 15th Street, Lawrence, Kansas 66045, United States; Department of Chemical and Petroleum Engineering, University of Kansas, 1530 W. 15th Street, Lawrence, Kansas, 66045, United States
| | - Mark B Shiflett
- Institute for Sustainable Engineering, 1536 W. 15th Street, Lawrence, Kansas 66045, United States; Department of Chemical and Petroleum Engineering, University of Kansas, 1530 W. 15th Street, Lawrence, Kansas, 66045, United States.
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Dai S, Zheng Y, Zhao Y, Chen Y, Niu D. Molten hydroxide for detoxification of chlorine-containing waste: Unraveling chlorine retention efficiency and chlorine salt enrichment. J Environ Sci (China) 2019; 82:192-202. [PMID: 31133264 DOI: 10.1016/j.jes.2019.03.007] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2018] [Revised: 03/08/2019] [Accepted: 03/11/2019] [Indexed: 06/09/2023]
Abstract
Hazardous waste dechlorination reduces the potential of creating dioxins during the incineration process. To investigate the salt effect on waste dechlorination, molten hydroxides with a low melting temperature were utilized for the pre-dechlorination and decomposition of chlorine-containing organic wastes (COWs) including trichlorobenzene (TCB), perchloroethylene, hexachlorobenzene and chlordane. The results showed that a eutectic mixture of caustic sodium and potassium hydroxides (41 wt.% NaOH and 59 wt.% KOH) led to a low melting point below 300°C and a relatively high chlorine retention efficiency (CRE) with TCB as a representative COWs. The amounts of hydroxides, reaction time, and temperature all had notable influence on CRE. When the mass ratio of hydroxides to TCB reached 30:1, approximately 98.1% of the TCB was destroyed within 2.5 hr at 300°C with CRE of 71.6%. According to the residue analysis, the shapes of reaction residues were irregular with particles becoming swollen and porous. The benzene ring and C-Cl bonds disappeared, while carboxyl groups formed in the residues. The stripped chlorine was retained and condensed to form chloride salts, and the relative abundance of the chloride ions associated with the mass of TCB in residues increased from 0 to 75.0% within the 2.5 hr reaction time. The observed concentration of dioxins in residues was 5.6 ngTEQ/kg. A reaction pathway and possible additional reactions that occur in this dechlorination system were proposed. Oxidizing agents may attack TCB and facilitate hydrogenation/dechlorination reactions, making this process a promising and environmentally friendly approach for chlorine-containing organic waste treatment.
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Affiliation(s)
- Shijin Dai
- College of Environmental Science and Engineering, Tongji University, Shanghai 200092, China.
| | - Yilin Zheng
- College of Environmental Science and Engineering, Tongji University, Shanghai 200092, China
| | - Youcai Zhao
- College of Environmental Science and Engineering, Tongji University, Shanghai 200092, China; Shanghai Institute of Pollution Control and Ecological Security, Shanghai 200092, China
| | - Yu Chen
- College of Environmental Science and Engineering, Tongji University, Shanghai 200092, China
| | - Dongjie Niu
- College of Environmental Science and Engineering, Tongji University, Shanghai 200092, China; Shanghai Institute of Pollution Control and Ecological Security, Shanghai 200092, China.
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Garbou AM, Liu M, Zou S, Yestrebsky CL. Degradation kinetics of hexachlorobenzene over zero-valent magnesium/graphite in protic solvent system and modeling of degradation pathways using density functional theory. CHEMOSPHERE 2019; 222:195-204. [PMID: 30708153 DOI: 10.1016/j.chemosphere.2019.01.134] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/23/2018] [Revised: 12/23/2018] [Accepted: 01/23/2019] [Indexed: 06/09/2023]
Abstract
Hexachlorobenzene (HCB), like many chlorinated organic compounds, has accumulated in the environment from agricultural and industrial activity. Because of its health risks and adverse impact on various ecosystems, remediation of this contaminant is of vital concern. The objective of this study is to evaluate the proficiency of activated magnesium metal in a protic solvent system to accomplish reductive dechlorination of HCB. Experimental results were compared with those predicted by quantum chemical calculations based on Density Functional Theory (DFT). Multivariate analysis detected complete degradation of HCB within 30 min at room temperature, the reaction having a rate constant of 0.222 min-1. Dechlorination was hypothesized to proceed via an ionic mechanism; the main dechlorination pathways of HCB in 1:1 ethanol:ethyl lactate were HCB → PCBz → 1,2,4,5-TCB; 1,2,3,5-TCB → 1,2,4-TriCB; 1,3,5-TriCB → 1,4-DiCB; 1,3-DiCB. The direct relationship between the decreasing number of Cl substituents and dechlorination reaction kinetics agrees with the ΔG values predicted by the computational model. This methodology shows promise for the development of a practical and sustainable field application for the remediation of other chlorinated aromatic compounds.
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Affiliation(s)
- Amel M Garbou
- Environmental Chemistry Laboratory, University of Central Florida, 4000 Central Florida Blvd., Orlando, FL 32816, United States
| | - Muqiong Liu
- Department of Chemistry, University of Central Florida, 4000 Central Florida Blvd., Orlando, FL 32816, United States
| | - Shengli Zou
- Department of Chemistry, University of Central Florida, 4000 Central Florida Blvd., Orlando, FL 32816, United States
| | - Cherie L Yestrebsky
- Environmental Chemistry Laboratory, University of Central Florida, 4000 Central Florida Blvd., Orlando, FL 32816, United States.
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Liu J, Zhang H, Yao Z, Li X, Tang J. Thermal desorption of PCBs contaminated soil with calcium hydroxide in a rotary kiln. CHEMOSPHERE 2019; 220:1041-1046. [PMID: 33395790 DOI: 10.1016/j.chemosphere.2019.01.031] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/03/2018] [Revised: 12/31/2018] [Accepted: 01/05/2019] [Indexed: 06/12/2023]
Abstract
In this study, thermal desorption was combined with the addition of calcium hydroxide to remediate polychlorinated biphenyls (PCBs) contaminated soil, collected from a storage point for PCB-contaminated capacitors and transformers. The thermal desorption test conditions were varied from 300 to 600 °C, both with blank soil and with 1% Ca(OH)2 added. The results showed that the synergistic thermal desorption was effective to removal most of PCBs. At 600 °C, the removal efficiency (RE) reached 94.0% in presence of Ca(OH)2, higher than that of 90.9% in blank soil. The dechlorination was significant when compared with blank soil. Ca(OH)2 effectively decreased both the sum and the toxic equivalence quantity (TEQ) value of the 12 dioxin-like PCBs, with the RE based on TEQ of 90.0%. Ca(OH)2 strengthened the removal, dechlorination and detoxication of PCBs. The synergistic effect factor proved the promotion did exist in the presence of Ca(OH)2.
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Affiliation(s)
- Jie Liu
- College of Materials and Environmental Engineering, Hangzhou Dianzi University, Hangzhou, 310018, China.
| | - Hao Zhang
- State Key Laboratory of Clean Energy Utilization, Institute for Thermal Power Engineering, Zhejiang University, Hangzhou, 310027, China
| | - Zhitong Yao
- College of Materials and Environmental Engineering, Hangzhou Dianzi University, Hangzhou, 310018, China
| | - Xiaodong Li
- State Key Laboratory of Clean Energy Utilization, Institute for Thermal Power Engineering, Zhejiang University, Hangzhou, 310027, China
| | - Junhong Tang
- College of Materials and Environmental Engineering, Hangzhou Dianzi University, Hangzhou, 310018, China.
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Dai S, Zheng Y, Zhao Y, Li Q, Niu D. Dechlorination and conversion mechanism of trichlorobenzene as a model compound of chlorine-containing wastes by different base-catalyzed combinations. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2019; 26:9480-9489. [PMID: 30726536 DOI: 10.1007/s11356-019-04221-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/26/2018] [Accepted: 01/10/2019] [Indexed: 06/09/2023]
Abstract
Chlorine-containing organic waste (COWs) is a big threat for the waste incineration because of the dioxin generation and equipment corrosion. Recently, dechlorination and detoxification of COWs is emergent in order to lower the environmental risk and treatment costs. In this study, base-catalyzed decomposition processes with different hydroxides, hydrogen donors, and catalysts were conducted for pre-treatment of COWs to reduce organic chlorine content, with the TCB as a model compound and industrial rectification residues for verification. Results showed that maximum chlorine retention efficiency (CRE) of four alkalis followed the order of KOH > NaOH-KOH > NaOH > Mg(OH)2, which were 98.3%, 93.4%, 97.2%, and 1.5%, respectively, and could be expressed as an apparent first-order reaction. The differences were resulted from the varying ionic potentials of the metal cations. Hydrogen donors (glycol, glycerol, paraffin oil, and PEG 200) acted as effective dechlorination regents follow the order of PEG > glycol > paraffin oil > glycerol. In addition, Fe, Ni, Cu, and activated carbon catalysts increased the CRE by 68.9% to 92.4%, 91.9%, 89.2%, and 73.3%, respectively. Residue analysis through X-ray diffraction and Fourier transform infrared spectroscopy revealed that KCl, sodium oxalate, and phenol were the main products and a plausible stepwise dechlorination pathway was proposed. The effectiveness of three optimized combinations including NaOH/PEG, KOH/PEG, and NaOH-KOH/PEG (with the Fe catalyst) was confirmed by using them for dechlorinating rectification residues, and they restrained 98.2%, 91.2%, and 94.6% of the chlorine, respectively. The organochlorine content decreased from 19.2 to 1.8% within 180 min, while inorganic chorine content increased from 1.5 to 18.9%, indicating the potential for COWs dechlorination.
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Affiliation(s)
- Shijin Dai
- College of Environmental Science and Engineering, Tongji University, Siping Rd. 1239, Shanghai, 200092, China
| | - Yilin Zheng
- College of Environmental Science and Engineering, Tongji University, Siping Rd. 1239, Shanghai, 200092, China
| | - Youcai Zhao
- College of Environmental Science and Engineering, Tongji University, Siping Rd. 1239, Shanghai, 200092, China
- Shanghai Institute of Pollution Control and Ecological Security, 1515 North Zhongshan Rd. (No. 2), Shanghai, 200092, China
| | - Qiang Li
- China Everbright Greentech Limited, Shenzhen, 518040, China
| | - Dongjie Niu
- College of Environmental Science and Engineering, Tongji University, Siping Rd. 1239, Shanghai, 200092, China.
- Shanghai Institute of Pollution Control and Ecological Security, 1515 North Zhongshan Rd. (No. 2), Shanghai, 200092, China.
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Zhao Z, Ni M, Li X, Buekens A, Yan J. Suppression of PCDD/Fs during thermal desorption of PCBs-contaminated soil. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2016; 23:25335-25342. [PMID: 27696164 DOI: 10.1007/s11356-016-7732-8] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/13/2016] [Accepted: 09/15/2016] [Indexed: 06/06/2023]
Abstract
Thermal treatment of polychlorinated biphenyls (PCBs) contaminated soil was shown in earlier work to generate new PCBs, as well as polychlorinated dibenzo-p-dioxins (PCDDs) and polychlorinated dibenzofurans (PCDFs). In this study, this thermal desorption was conducted with addition of three distinct inhibitors, including ammonium sulphate, urea and calcium oxide, to inhibit the formation of PCDDs and PCDFs when remediating PCBs-contaminated soil. Experiments were conducted for 40 min at 400 °C after adding 1 wt.% of inhibitor. Both the total PCDD/Fs and international toxic equivalent quantity (I-TEQ) reduced when inhibitors were introduced. Of the three compounds tested, CaO shows the highest inhibition efficiency, 92.2 % for total PCDD/Fs and 95.6 % for I-TEQ. The amount of CaO added also influences the suppression efficiency of PCDD/Fs. These results suggest that promoting desorption and destruction of precursors is probably the mechanism of suppression.
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Affiliation(s)
- Zhonghua Zhao
- State Key Laboratory of Clean Energy Utilization, Institute for Thermal Power Engineering, Zhejiang University, Hangzhou, 310027, China
| | - Mingjiang Ni
- State Key Laboratory of Clean Energy Utilization, Institute for Thermal Power Engineering, Zhejiang University, Hangzhou, 310027, China
| | - Xiaodong Li
- State Key Laboratory of Clean Energy Utilization, Institute for Thermal Power Engineering, Zhejiang University, Hangzhou, 310027, China.
| | - Alfons Buekens
- State Key Laboratory of Clean Energy Utilization, Institute for Thermal Power Engineering, Zhejiang University, Hangzhou, 310027, China
| | - Jianhua Yan
- State Key Laboratory of Clean Energy Utilization, Institute for Thermal Power Engineering, Zhejiang University, Hangzhou, 310027, China
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Liu J, Qi Z, Zhao Z, Li X, Buekens A, Yan J, Ni M. Thermal desorption of PCB-contaminated soil with sodium hydroxide. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2015; 22:19538-19545. [PMID: 26263886 DOI: 10.1007/s11356-015-5136-9] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/07/2015] [Accepted: 07/29/2015] [Indexed: 06/04/2023]
Abstract
The thermal desorption was combined with sodium hydroxide to remediate polychlorinated biphenyl (PCB)-contaminated soil. The experiments were conducted at different temperatures ranging from 300 to 600 °C with three NaOH contents of 0.1, 0.5, and 1 %. The results showed that thermal desorption was effective for PCB removal, destruction, and detoxication, and the presence of NaOH enhanced the process by significant dechlorination. After treatment with 0.1 % NaOH, the removal efficiency (RE) increased from 84.8 % at 300 °C to 98.0 % at 600 °C, corresponding to 72.7 and 91.7 % of destruction efficiency (DE). With 1 % NaOH content treated at 600 °C, the RE and DE were 99.0 and 93.6 %, respectively. The effect of NaOH content on PCB removal was significant, especially at lower temperature, yet it weakened under higher temperature. The interaction between NaOH content and temperature influenced the PCB composition. The higher temperature with the help of NaOH effectively increased the RE and DE of 12 dioxin-like PCBs (based on WHO-TEQ).
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Affiliation(s)
- Jie Liu
- State Key Laboratory of Clean Energy Utilization, Institute for Thermal Power Engineering, Zhejiang University, Hangzhou, 310027, China
| | - Zhifu Qi
- State Key Laboratory of Clean Energy Utilization, Institute for Thermal Power Engineering, Zhejiang University, Hangzhou, 310027, China
| | - Zhonghua Zhao
- State Key Laboratory of Clean Energy Utilization, Institute for Thermal Power Engineering, Zhejiang University, Hangzhou, 310027, China
| | - Xiaodong Li
- State Key Laboratory of Clean Energy Utilization, Institute for Thermal Power Engineering, Zhejiang University, Hangzhou, 310027, China.
| | - Alfons Buekens
- State Key Laboratory of Clean Energy Utilization, Institute for Thermal Power Engineering, Zhejiang University, Hangzhou, 310027, China
| | - Jianhua Yan
- State Key Laboratory of Clean Energy Utilization, Institute for Thermal Power Engineering, Zhejiang University, Hangzhou, 310027, China
| | - Mingjiang Ni
- State Key Laboratory of Clean Energy Utilization, Institute for Thermal Power Engineering, Zhejiang University, Hangzhou, 310027, China
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Chemical dechlorination of hexachlorobenzene with polyethylene glycol and hydroxide: dominant effect of temperature and ionic potential. Sci Rep 2014; 4:6305. [PMID: 25200551 PMCID: PMC4158325 DOI: 10.1038/srep06305] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2014] [Accepted: 08/15/2014] [Indexed: 01/28/2023] Open
Abstract
Persistent organic pollutants (POPs) originating from POP waste are playing an increasingly important role in the elevation of regional POP levels. In this study we realized the complete dechlorination of high concentration hexachlorobenzene (HCB) waste in the presence of polyethylene glycol and hydroxide, rather than using conventional high temperature incineration. Here, we demonstrate the dominant effect of temperature and hydroxide on HCB dechlorination in this process. Complete dechlorination of HCB was only observed at temperature about 200°C or above within 4 h reaction, and the apparent activation energy of this process was 43.1 kJ/mol. The alkalinity of hydroxides had notable effects on HCB dechlorination, and there was a considerable linear relationship between the natural logarithm of the HCB dechlorination rate constant and square root of the ionic potential of metal cation (R2 = 0.9997, p = 0.0081, n = 3). This study highlights a promising technology to realize complete dechlorination of POP waste, especially at high concentrations, in the presence of PEG in conjunction with hydroxide.
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