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Zhou F, Yu Q, Guo M, Zhang M, Zhao N, Xu Q, Zhang W, Qiu R. The effect of the synergistic thermal treatment and stabilization on the transformation and transportation of arsenic, chromium, and cadmium in soil. THE SCIENCE OF THE TOTAL ENVIRONMENT 2024; 907:167948. [PMID: 37864997 DOI: 10.1016/j.scitotenv.2023.167948] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/13/2023] [Revised: 10/01/2023] [Accepted: 10/18/2023] [Indexed: 10/23/2023]
Abstract
Thermal treatments commonly used to remedy organic-contaminated soils can inadvertently impact the behavior of non-targeted pollutants, notably heavy metal(loid)s in soil. This study introduces an integrated calcination-stabilization remediation strategy employing steel slag as a stabilizing agent, with a focus on elucidating the transformations and remobilization tendencies of As, Cr, and Cd. Thermal treatment alters the mobility of these elements by modifying soil properties, with pH and redox conditions playing pivotal roles. After anaerobic calcination, the leaching concentrations of As reached 163 μg L-1, far surpassed 7.57 μg L-1 after the aerobic calcination. Although Cr and As share oxygen-containing anion forms, they display opposing leaching tendencies after thermal treatment. At 400 °C, Cr leaching from aerobically treated soil reaches 64.5 mg L-1, dropping to 6.63 mg L-1 after anaerobic heating due to pH-induced Cr(OH)3 formation. Thermal treatment significantly amplifies the leaching of Cd cations. In contrast to the leaching concentration of 122 μg L-1 in the untreated soil, aerobic and anaerobic heating (400 °C) resulted in leaching concentrations of 896 μg L-1 and 132 μg L-1, respectively. Noteworthy, the integrated treatment (400 °C anaerobically) decreases leached As and Cd concentrations to 68.3 μg L-1 and 15.4 μg L-1, attributed to stabilizer alkalinity and porosity. Column leaching shows initial rapid release followed by continuous behavior for As and Cd, with the average leaching concentrations of the remediated soil decreasing to 60.5 μg L-1 and 1.32 μg L-1, ensuring safe backfilling. In conclusion, this study contributes to the understanding of the mobility and stabilization of heavy metal(loid)s subsequent to the integrated calcination-stabilization process.
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Affiliation(s)
- Fengping Zhou
- Guangdong Provincial Key Laboratory of Environmental Pollution and Remediation Technology, Guangdong Provincial Engineering Research Center for Heavy Metal Contaminated Soil Remediation, School of Environmental Science and Engineering, Sun Yat-sen University, Guangzhou 510275, PR China; State Key Laboratory of Separation and Comprehensive Utilization of Rare Metals, Institute of Resources Utilization and Rare Earth Development, Guangdong Academy of Sciences, Guangzhou 510275, PR China
| | - Qingxin Yu
- Guangdong Provincial Key Laboratory of Environmental Pollution and Remediation Technology, Guangdong Provincial Engineering Research Center for Heavy Metal Contaminated Soil Remediation, School of Environmental Science and Engineering, Sun Yat-sen University, Guangzhou 510275, PR China
| | - Meina Guo
- Ganjiang Innovation Academy, Chinese Academy of Sciences, Ganzhou 341000, PR China
| | - Miaoyue Zhang
- Guangdong Provincial Key Laboratory of Environmental Pollution and Remediation Technology, Guangdong Provincial Engineering Research Center for Heavy Metal Contaminated Soil Remediation, School of Environmental Science and Engineering, Sun Yat-sen University, Guangzhou 510275, PR China
| | - Nan Zhao
- National-Regional Joint Engineering Research Center for Soil Pollution Control and Remediation in South China, Guangdong Key Laboratory of Integrated Agro-environmental Pollution Control and Management, Institute of Eco-environmental and Soil Sciences, Guangdong Academy of Sciences, Guangzhou 510650, PR China
| | - Qianting Xu
- Guangdong Provincial Key Laboratory of Environmental Pollution and Remediation Technology, Guangdong Provincial Engineering Research Center for Heavy Metal Contaminated Soil Remediation, School of Environmental Science and Engineering, Sun Yat-sen University, Guangzhou 510275, PR China
| | - Weihua Zhang
- Guangdong Provincial Key Laboratory of Environmental Pollution and Remediation Technology, Guangdong Provincial Engineering Research Center for Heavy Metal Contaminated Soil Remediation, School of Environmental Science and Engineering, Sun Yat-sen University, Guangzhou 510275, PR China.
| | - Rongliang Qiu
- Guangdong Provincial Key Laboratory of Environmental Pollution and Remediation Technology, Guangdong Provincial Engineering Research Center for Heavy Metal Contaminated Soil Remediation, School of Environmental Science and Engineering, Sun Yat-sen University, Guangzhou 510275, PR China; Guangdong Provincial Key Laboratory of Agricultural & Rural Pollution Abatement and Environmental Safety, School of Natural Resources and Environment, South China Agricultural University, Guangzhou 510642, PR China
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Distribution of As within Magnetic and Non-Magnetic Fractions of Fluidized-Bed Coal Combustion Ash. MINERALS 2021. [DOI: 10.3390/min11121411] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
Abstract
Separation of coal ash into magnetic and non-magnetic fractions facilitates their utilization when processed separately. Due to desulphurization additives added to coal during the fluidised-bed combustion, non-magnetic fractions often contain elevated CaO levels (while magnetic concentrates are typically rich in Fe2O3). Both CaO and Fe2O3 are known for their ability to bind As during the combustion, whose distribution is a crucial parameter in terms of proper utilization of these fractions. Therefore, the study deals with the As partitioning within magnetic and non-magnetic fractions of fluidized-bed coal combustion ashes. Two different (successive) procedures of dry magnetic separation were used to separate each ash into strongly magnetic, less magnetic, and a non-magnetic fraction. Due to their optimal utilization, the concentrations of As and other target elements in these fractions were evaluated and compared. Magnetic concentrates from the first separation step (in vibrofluidized state) contained 60–70% Fe2O3, magnetic concentrates separated manually out of the residues after the first separation contained 26–41% Fe2O3, and the non-magnetic residues contained 2.4–3.5% Fe2O3. Arsenic levels were the highest in the non-magnetic residues and gradually decreased with the increasing Fe2O3 content in the magnetic fractions. The dominant As association in the studied samples was to CaO (r = +0.909) and with SO3 (r = +0.906) whereas its joint occurrence with Fe2O3 was improbable (r = −0.834).
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Mutuku JK, Lee YY, Huang BW, Chen WH, Hou WC. Assessment of the emission factors for potentially toxic elements from coal-fired boilers and sintering furnaces in a steel production plant. THE SCIENCE OF THE TOTAL ENVIRONMENT 2021; 792:148329. [PMID: 34465047 DOI: 10.1016/j.scitotenv.2021.148329] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/29/2021] [Revised: 05/24/2021] [Accepted: 06/04/2021] [Indexed: 06/13/2023]
Abstract
The emission factor (EF), the weight of potentially toxic elements (PTEs) per unit energy or weight of sinter produced were evaluated for coal-fired boilers and sintering furnaces integrated in a steel plant. From three coal-fired boilers, 15 samples were taken while 22 samples were taken from four sintering furnaces. Investigations were performed on the EF of lead, cadmium, mercury, arsenic and chromium (VI). The coefficient of variance for the first 3 samples from each PTE was used to decide whether 2 more samples were necessary for the investigation. Three samples were sufficient for Cr (VI), however, 5 samples were required for Pb, Cd, Hg, and As, since the variances in concentrations of the first three samples exceeded 20%. The ranges for the ratio of the laboratory-based EF to the default EF applied by the Environment Protection Administration (EPA Taiwan) for Pb, Cd, Hg, and As for the coal-fired boiler were 0.08-0.013, 0.014-0.017, 0.019-0.033, 0.047-0.066 and for the sintering furnaces were 0.059-0.232, 0.05-0.151, 0.05-0.364, and 0.067-0.824. The ratio for Cr (VI)- was constant at 0.005 for all the coal fired boilers while it ranged from 0.057-0.709 for the sintering furnaces. Whilst source identification, enrichment factors, and spatial distributions for PTEs are often studied, laboratory-based investigations on the EFs for PTEs from industrial plants are rarely performed. This study filled the information gap and compared the obtained EFs with the EPA default values. To avoid overcharging industrial plants equipped with the best available technology for emission control, the EPA should apply field investigations and laboratory-based EFs instead of the default EPA EFs to calculate air pollution fees. Insights from this investigation can be applied to promote the adoption of appropriate air pollution control devices to cut down the emission of PTEs.
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Affiliation(s)
- Justus Kavita Mutuku
- Department of Environmental Engineering, National Cheng Kung University, Tainan 70101, Taiwan; Super Micro Mass Research and Technology Center, Cheng Shiu University, Kaohsiung 833, Taiwan; Center for Environmental Toxin and Emerging-Contaminant Research, Cheng Shiu University, Kaohsiung 833, Taiwan
| | - Yen-Yi Lee
- Department of Food and Beverage Management, Cheng Shiu University, Kaohsiung 83347, Taiwan.
| | - Bo-Wun Huang
- Asia-Pacific Cultural Heritage Preservation and Restoration Start-up Technology Research Center, Cheng-Shiu University, Kaohsiung 83347, Taiwan; Department of Mechanical Engineering and Institute of Mechatronic Engineering, Kaohsiung 83347, Taiwan
| | - Wei-Hsin Chen
- Department of Aeronautics and Astronautics, National Cheng Kung University, Tainan 70101, Taiwan; Research Center for Smart Sustainable Circular Economy, Tunghai University, Taichung 407, Taiwan; Department of Mechanical Engineering, National Chin-Yi University of Technology, Taichung 411, Taiwan
| | - Wen-Che Hou
- Department of Environmental Engineering, National Cheng Kung University, Tainan 70101, Taiwan
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