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Zhai X, Li Z, Huang B, Luo N, Huang M, Zhang Q, Zeng G. Remediation of multiple heavy metal-contaminated soil through the combination of soil washing and in situ immobilization. THE SCIENCE OF THE TOTAL ENVIRONMENT 2018; 635:92-99. [PMID: 29660731 DOI: 10.1016/j.scitotenv.2018.04.119] [Citation(s) in RCA: 115] [Impact Index Per Article: 19.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/19/2017] [Revised: 04/08/2018] [Accepted: 04/08/2018] [Indexed: 06/08/2023]
Abstract
The remediation of heavy metal-contaminated soils is a great challenge for global environmental sciences and engineering. To control the ecological risks of heavy metal-contaminated soil more effectively, the present study focused on the combination of soil washing (with FeCl3) and in situ immobilization (with lime, biochar, and black carbon). The results showed that the removal rate of Cd, Pb, Zn, and Cu was 62.9%, 52.1%, 30.0%, and 16.7%, respectively, when washed with FeCl3. After the combined remediation (immobilization with 1% (w/w) lime), the contaminated soils showed 36.5%, 73.6%, 70.9%, and 53.4% reductions in the bioavailability of Cd, Cu, Pb, and Zn (extracted with 0.11M acetic acid), respectively, than those of the soils washed with FeCl3 only. However, the immobilization with 1% (w/w) biochar or 1% (w/w) carbon black after washing exhibited low effects on stabilizing the metals. The differences in effects between the immobilization with lime, biochar, and carbon black indicated that the soil pH had a significant influence on the lability of heavy metals during the combined remediation process. The activity of the soil enzymes (urease, sucrase, and catalase) showed that the addition of all the materials, including lime, biochar, and carbon black, exhibited positive effects on microbial remediation after soil washing. Furthermore, lime was the most effective material, indicating that low soil pH and high acid-soluble metal concentrations might restrain the activity of soil enzymes. Soil pH and nutrition were the major considerations for microbial remediation during the combined remediation. These findings suggest that the combination of soil washing and in situ immobilization is an effective method to amend the soils contaminated with multiple heavy metals.
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Affiliation(s)
- Xiuqing Zhai
- College of Environmental Science and Engineering, Hunan University, Changsha 410082, PR China; Key Laboratory of Environmental Biology and Pollution Control (Hunan University), Ministry of Education, Changsha 410082, PR China
| | - Zhongwu Li
- College of Environmental Science and Engineering, Hunan University, Changsha 410082, PR China; Key Laboratory of Environmental Biology and Pollution Control (Hunan University), Ministry of Education, Changsha 410082, PR China.
| | - Bin Huang
- Guangdong Key Laboratory of Integrated Agro-environmental Pollution Control and Management, Guangdong Institute of Eco-environment Science and Technology, Guangzhou 510650, PR China
| | - Ninglin Luo
- College of Environmental Science and Engineering, Hunan University, Changsha 410082, PR China; Key Laboratory of Environmental Biology and Pollution Control (Hunan University), Ministry of Education, Changsha 410082, PR China
| | - Mei Huang
- College of Environmental Science and Engineering, Hunan University, Changsha 410082, PR China; Key Laboratory of Environmental Biology and Pollution Control (Hunan University), Ministry of Education, Changsha 410082, PR China
| | - Qiu Zhang
- College of Environmental Science and Engineering, Hunan University, Changsha 410082, PR China; Key Laboratory of Environmental Biology and Pollution Control (Hunan University), Ministry of Education, Changsha 410082, PR China
| | - Guangming Zeng
- College of Environmental Science and Engineering, Hunan University, Changsha 410082, PR China; Key Laboratory of Environmental Biology and Pollution Control (Hunan University), Ministry of Education, Changsha 410082, PR China
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Li JS, Wang L, Cui JL, Poon CS, Beiyuan J, Tsang DCW, Li XD. Effects of low-alkalinity binders on stabilization/solidification of geogenic As-containing soils: Spectroscopic investigation and leaching tests. THE SCIENCE OF THE TOTAL ENVIRONMENT 2018; 631-632:1486-1494. [PMID: 29727972 DOI: 10.1016/j.scitotenv.2018.02.247] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/22/2017] [Revised: 02/19/2018] [Accepted: 02/20/2018] [Indexed: 06/08/2023]
Abstract
The low-alkalinity stabilization/solidification (S/S) treatment of the soil containing high concentrations of geogenic As by physical encapsulation is considered as a proper management before land development; however, the choice of an effective binder and the leaching potential of As remain uncertain. In this study, the influence of S/S binders (cement blended with fuel ash (FA), furnace bottom ash (FBA), or ground granulated blast furnace slag (GGBS)) on the speciation and leaching characteristics of geogenic As was studied. The results of X-ray diffractometer (XRD) and X-ray photoelectron spectroscopy (XPS) showed the reduced amount of calcium silicate hydrate phase and the decrease in oxidation state of As(V)-O on the surface of Fe(III) oxides/hydroxides in the low-alkalinity S/S treated soils. This might be due to the binder incorporation and change in pH conditions, which slightly affected the As-Fe interaction and increased the non-specifically sorbed species of As. Therefore, the S/S treatment increased the leachability and bioaccessibility of geogenic As to varying degree but decreased the phyto-extractable As. The S/S treatment by cement incorporating 25% of class C fly ash (O4C1) could achieve comparable or better performance, while reducing the risk assessment code (RAC) to a greater extent compared to that of using cement only. This study illustrates the effectiveness and limitations of low-alkalinity binders (e.g., O4C1) for geogenic As immobilization and encapsulation, which provides a new insight for determining the appropriate S/S binder in soil remediation.
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Affiliation(s)
- Jiang-Shan Li
- Department of Civil and Environmental Engineering, The Hong Kong Polytechnic University, Hung Hom, Kowloon, Hong Kong, China
| | - Lei Wang
- Department of Civil and Environmental Engineering, The Hong Kong Polytechnic University, Hung Hom, Kowloon, Hong Kong, China
| | - Jin-Li Cui
- Department of Civil and Environmental Engineering, The Hong Kong Polytechnic University, Hung Hom, Kowloon, Hong Kong, China
| | - Chi Sun Poon
- Department of Civil and Environmental Engineering, The Hong Kong Polytechnic University, Hung Hom, Kowloon, Hong Kong, China.
| | - Jingzi Beiyuan
- Department of Civil and Environmental Engineering, The Hong Kong Polytechnic University, Hung Hom, Kowloon, Hong Kong, China
| | - Daniel C W Tsang
- Department of Civil and Environmental Engineering, The Hong Kong Polytechnic University, Hung Hom, Kowloon, Hong Kong, China.
| | - Xiang-Dong Li
- Department of Civil and Environmental Engineering, The Hong Kong Polytechnic University, Hung Hom, Kowloon, Hong Kong, China
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53
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Beiyuan J, Tsang DCW, Valix M, Baek K, Ok YS, Zhang W, Bolan NS, Rinklebe J, Li XD. Combined application of EDDS and EDTA for removal of potentially toxic elements under multiple soil washing schemes. CHEMOSPHERE 2018; 205:178-187. [PMID: 29698828 DOI: 10.1016/j.chemosphere.2018.04.081] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/19/2017] [Revised: 02/11/2018] [Accepted: 04/14/2018] [Indexed: 06/08/2023]
Abstract
Chelant-enhanced soil washing, such as EDTA (ethylenediaminetetraacetic acid) and biodegradable EDDS ([S,S]-ethylene-diamine-disuccinic acid), has been widely studied, however, EDTA is persistent under natural conditions while EDDS has a low efficiency for Pb extraction. Therefore, we investigated the efficacy of mixed chelants (EDDS and EDTA mixture at 1:1 M ratio) for the removal of Cu, Zn, and Pb from a field-contaminated soil using various washing schemes (multi-pulse, step-gradient chelant, and continuous washing schemes). Speciation modelling of the target metals, mineral elements, and EDDS/EDTA was performed, while the leachability and bioaccessibility of residual metals in the treated soils were also assessed. Our results suggested that the combined use of EDDS and EDTA reached equivalent extraction efficiency of the target metals as EDTA, i.e., 50% reduction in the dosage of EDTA was made possible. This was accomplished by selective extraction of Cu by EDDS and Pb by EDTA, which was supported by the results of speciation calculation. Multi-pulse washing scheme with intermittent water rinsing steps removed entrapped metal-chelant complexes and free chelants, therefore reducing the leachability and bioaccessibility of residual metals in the treated soils. Step-gradient chelant washing with the maximum dosage of chelants in the first washing step only achieved marginal improvement but undesirably promoted Pb bioaccessibility. Continuous washing for 24 h enhanced metal extraction but promoted mineral dissolution, together with a large amount of uncomplexed chelants and increase in Cu leachability. Thus the combined use of EDDS and EDTA in multi-pulse washing is recommended for further studies.
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Affiliation(s)
- Jingzi Beiyuan
- Department of Civil and Environmental Engineering, The Hong Kong Polytechnic University, Hung Hom, Kowloon, Hong Kong, China; Centre for Sustainable Design and Environment, Faculty of Design and Environment, Technological and Higher Education Institute of Hong Kong, Hong Kong, China
| | - Daniel C W Tsang
- Department of Civil and Environmental Engineering, The Hong Kong Polytechnic University, Hung Hom, Kowloon, Hong Kong, China.
| | - Marjorie Valix
- School of Chemical and Biomolecular Engineering, The University of Sydney, NSW 2006, Australia
| | - Kitae Baek
- Department of Environmental Engineering and Soil Environment Research Center, Chonbuk National University, 567 Baekje-daero, Deokjin-gu, Jeonju, Jeollabuk-do, 54896, Republic of Korea
| | - Yong Sik Ok
- O-Jeong Eco-Resilience Institute (OJERI) & Division of Environmental Science and Ecological Engineering, Korea University, Seoul 02841, Republic of Korea
| | - Weihua Zhang
- School of Environmental Science and Engineering, Sun Yat-sen University, Guangzhou 510275, China
| | - Nanthi S Bolan
- Global Centre for Environmental Remediation (GCER), Faculty of Science and Information Technology, The University of Newcastle, Callaghan NSW 2308, Australia
| | - Jörg Rinklebe
- University of Wuppertal, School of Architecture and Civil Engineering, Institute of Foundation Engineering, Water- and Waste-Management, Soil- and Groundwater-Management, Pauluskirchstraße 7, 42285 Wuppertal, Germany; Department of Environment and Energy, Sejong University, Seoul 05006, Republic of Korea
| | - Xiang-Dong Li
- Department of Civil and Environmental Engineering, The Hong Kong Polytechnic University, Hung Hom, Kowloon, Hong Kong, China
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54
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Chen SC, Lin WH, Chien CC, Tsang DCW, Kao CM. Development of a two-stage biotransformation system for mercury-contaminated soil remediation. CHEMOSPHERE 2018; 200:266-273. [PMID: 29494907 DOI: 10.1016/j.chemosphere.2018.02.085] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/31/2017] [Revised: 02/13/2018] [Accepted: 02/14/2018] [Indexed: 06/08/2023]
Abstract
Utilization of bacterial volatilization can be problematic to remediate mercury (Hg)-contaminated soils because most of the Hg in soils is bound to soil particles. The objective of this study was to develop a two-stage system (chemical extraction followed by microbial reduction) for Hg-contaminated soil remediation. The tasks were to (1) select the extraction reagents for Hg extraction, (2) assess the effects of extraction reagents on the growth of Hg-reducing bacterial strains, and (3) evaluate the effectiveness of Ca2+ and Mg2+ addition on merA gene (Hg reductase) induction. Bacterial inhibition was observed with the addition of 0.1 M ethylenediaminetetraacetic acid or citric acid. Up to 65% of Hg was biotransformed (Hg concentration = 69 mg/kg) from the soils after a 24 h extraction using 0.5 M ammonium thiosulfate. Ca2+ and Mg2+ were selected because they have the same electric charge as Hg and the studied groundwater contained high concentrations of Ca2+ and Mg2+. Results showed that the addition of 200 mg/L Ca2+ or 650 mg/L Mg2+ could reach effective merA induction. In the two-stage experiment, 120 mg/kg Hg-contaminated soils were extracted with 2 rounds of extraction processes for 10 h using 0.5 M ammonium thiosulfate. Approximately 77% of Hg was extracted from the soils after the first-step extraction process. Up to 81% of Hg2+ was transformed from the washing solution via the biotransformation processes with Enterobacter cloacae addition and Ca2+ and Mg2+ supplementation. The two-stage remedial system has the potential to be developed into a practical technology to remediate Hg-contaminated sites.
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Affiliation(s)
- S C Chen
- Department of Life Sciences, National Central University, Chung-Li, Taiwan
| | - W H Lin
- Institute of Environmental Engineering, National Sun Yat-Sen University, Kaohsiung, Taiwan
| | - C C Chien
- Graduate School of Biotechnology & Bioengineering, Yuan Ze University, Taoyuan City, Taiwan
| | - D C W Tsang
- Department of Civil and Environmental Engr., Hong Kong Polytechnic University, Hung Hom, Hong Kong
| | - C M Kao
- Institute of Environmental Engineering, National Sun Yat-Sen University, Kaohsiung, Taiwan.
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55
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Wang G, Zhang S, Zhong Q, Xu X, Li T, Jia Y, Zhang Y, Peijnenburg WJGM, Vijver MG. Effect of soil washing with biodegradable chelators on the toxicity of residual metals and soil biological properties. THE SCIENCE OF THE TOTAL ENVIRONMENT 2018; 625:1021-1029. [PMID: 29996399 DOI: 10.1016/j.scitotenv.2018.01.019] [Citation(s) in RCA: 74] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/20/2017] [Revised: 01/02/2018] [Accepted: 01/03/2018] [Indexed: 06/08/2023]
Abstract
Soil washing with chelators is a promising and efficient method of remediating metals-contaminated soils. However, the toxicity of residual metals and the effects on soil microbial properties have remained largely unknown after washing. In this study, we employed four biodegradable chelators for removal of metals from contaminated soils: iminodisuccinic acid (ISA), glutamate-N,N-diacetic acid (GLDA), glucomonocarbonic acid (GCA), and polyaspartic acid (PASP). The maximum removal efficiencies for Cd, Pb, and Zn of 85, 55, and 64% and 45, 53, and 32% were achieved from farmland soil and mine soil using biodegradable chelators, respectively. It was found that the capacity of ISA and GLDA to reduce the labile fraction of Cd, Pb, and Zn was similar to that of the conventional non-biodegradable chelator ethylenediaminetetraacetic acid (EDTA). The leachability, mobility, and bioaccessibility of residual metals after washing decreased notably in comparison to the original soils, thus mitigating the estimated environmental and human health risks. Soil β-glucosidase activity, urease activity, acid phosphatase activity, microbial biomass nitrogen, and microbial biomass phosphorus decreased in the treated soils. However, compared with EDTA treatment, soil enzyme activities distinctly increased by 5-94% and overall microbial biomass slightly improved in the remediated soils, which would facilitate reuse of the washed soils. Based on soil toxicity tests that employed wheat seed germination as the endpoint of assessment, the washed soils exhibited only slight effects especially after ISA and GLDA treatments, following high-efficiency metal removal. Hence, ISA and GLDA appear to possess the greatest potential to rehabilitate polluted soils with limited toxicity remaining.
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Affiliation(s)
- Guiyin Wang
- College of Environmental Science, Sichuan Agricultural University, Wenjiang 611130, China; Institute of Environmental Sciences (CML), Leiden University, P. O. Box 9518, 2300 RA Leiden, The Netherlands
| | - Shirong Zhang
- College of Environmental Science, Sichuan Agricultural University, Wenjiang 611130, China.
| | - Qinmei Zhong
- College of Environmental Science, Sichuan Agricultural University, Wenjiang 611130, China
| | - Xiaoxun Xu
- College of Environmental Science, Sichuan Agricultural University, Wenjiang 611130, China
| | - Ting Li
- College of Resources, Sichuan Agricultural University, Wenjiang 611130, China
| | - Yongxia Jia
- College of Resources, Sichuan Agricultural University, Wenjiang 611130, China
| | - Yanzong Zhang
- College of Environmental Science, Sichuan Agricultural University, Wenjiang 611130, China
| | - Willie J G M Peijnenburg
- Institute of Environmental Sciences (CML), Leiden University, P. O. Box 9518, 2300 RA Leiden, The Netherlands; National Institute of Public Health and the Environment (RIVM), P.O. Box 1, 3720 BA Bilthoven, The Netherlands
| | - Martina G Vijver
- Institute of Environmental Sciences (CML), Leiden University, P. O. Box 9518, 2300 RA Leiden, The Netherlands
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56
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Zhou LY, Chen S, Li H, Guo S, Liu YD, Yang J. EDDS enhanced Shewanella putrefaciens CN32 and α-FeOOH reductive dechlorination of carbon tetrachloride. CHEMOSPHERE 2018; 198:556-564. [PMID: 29422245 DOI: 10.1016/j.chemosphere.2018.01.083] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/28/2017] [Revised: 01/10/2018] [Accepted: 01/16/2018] [Indexed: 06/08/2023]
Abstract
S,S-ethylenediamine-N,N-disuccinic acid (EDDS) enhanced reductive dissolution of α-FeOOH by Shewanella putrefaciens CN32 (CN32), resulting in formation of surface-bound Fe(II) species (FeIIEDDS) to improve reductive dechlorination of carbon tetrachloride (CT). The pseudo-first-order rate constants for bio-reduction extents of α-FeOOH by CN32 in the presence of 1.36 mM EDDS was 0.023 ± 0.0003 d-1 which was higher than without EDDS. The enhancement mechanism of bio-reduction was attributed to the strong complexation ability of EDDS to formed FeIIIEDDS, which could be better utilized by CN32. The dechlorination kinetic of CT by FeIIEDDS (2.016 h-1) in the presence of 1.36 mM EDDS was 24 times faster than without EDDS. Chloroform were detected as main products for the degradation of CT. The chemical analyses and morphological observation showed that combination between EDDS and Fe2+ produced FeIIEDDS complex, which had a reductive potential of -0.375 V and significantly enhanced CT dechlorination. The results showed that EDDS played an important role in enhancing the bio-reduction of α-FeOOH to accelerate reductive dechlorination of CT.
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Affiliation(s)
- Li Yang Zhou
- State Environmental Protection Key Laboratory of Environmental Risk Assessment and Control on Chemical Process, School of Resources and Environmental Engineering, East China University of Science and Technology, Shanghai 200237, PR China
| | - Shuai Chen
- State Environmental Protection Key Laboratory of Environmental Risk Assessment and Control on Chemical Process, School of Resources and Environmental Engineering, East China University of Science and Technology, Shanghai 200237, PR China
| | - Hui Li
- State Environmental Protection Key Laboratory of Environmental Risk Assessment and Control on Chemical Process, School of Resources and Environmental Engineering, East China University of Science and Technology, Shanghai 200237, PR China; Shanghai Key Lab for Urban Ecological Processes and Eco-Restoration, East China Normal University, Shanghai 200239, PR China.
| | - Shu Guo
- Center for Environmental Health Research, South China Institute of Environmental Sciences, MEP, Guangzhou 510535, PR China
| | - Yong Di Liu
- State Environmental Protection Key Laboratory of Environmental Risk Assessment and Control on Chemical Process, School of Resources and Environmental Engineering, East China University of Science and Technology, Shanghai 200237, PR China
| | - Jie Yang
- Research Institute of Wastes and Soil Remediation, Shanghai Academy of Environmental Sciences, Shanghai 200233, PR China.
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57
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O'Connor D, Peng T, Zhang J, Tsang DCW, Alessi DS, Shen Z, Bolan NS, Hou D. Biochar application for the remediation of heavy metal polluted land: A review of in situ field trials. THE SCIENCE OF THE TOTAL ENVIRONMENT 2018; 619-620:815-826. [PMID: 29166628 DOI: 10.1016/j.scitotenv.2017.11.132] [Citation(s) in RCA: 257] [Impact Index Per Article: 42.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/20/2017] [Revised: 10/19/2017] [Accepted: 11/12/2017] [Indexed: 05/12/2023]
Abstract
Polluted land is a global issue, especially for developing countries. It has been reported that soil amendment with biochar may reduce the bioavailability of a wide range of contaminants, including heavy metal(loids), potentially reclaiming contaminated soils for agricultural use. However, there have been only limited reports on the in situ application of biochar at the field scale. This review was devoted to providing preliminary scientific evidence from these field trials, based on a review of 29 publications involving field applications of biochar in 8 different countries. The data show that biochar's effectiveness in reducing the impacts of pollution depends on a myriad of factors in the field, including the application time period, site-specific factors (e.g. climate, biochar dosage rate, and mixing depth), biochar feedstock type, and biochar properties. The results of this review indicate that biochar application can potentially reduce contaminant bioavailability in the field; for instance, a significant decrease (control normalized mean value=0.55) in the Cd enrichment of rice crops was observed. It was found that the use of biochar may help increase crop yields on polluted land, and thus reduce the amount of mineral fertilizer used in the field. However, in order to maximize the benefits of biochar addition, farmers need to accept that the dosage rates of mineral fertilizers should be reduced. This review also revealed that the effectiveness of biochar in mitigating pollution may decrease with time due to ageing factors, such as leaching of biochar alkalinity.
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Affiliation(s)
- David O'Connor
- School of Environment, Tsinghua University, Beijing 100084, China
| | - Tianyue Peng
- School of Environment, Tsinghua University, Beijing 100084, China
| | - Junli Zhang
- Solid Waste and Chemical Management Center, Ministry of Environmental Protection, Beijing 100029, China
| | - Daniel C W Tsang
- Department of Civil and Environmental Engineering, Hong Kong Polytechnic University, Hung Hom, Kowloon, Hong Kong, China
| | - Daniel S Alessi
- Department of Earth and Atmospheric Sciences, University of Alberta, Edmonton, AB T6G 2E3, Canada
| | - Zhengtao Shen
- School of Environment, Tsinghua University, Beijing 100084, China; Department of Earth and Atmospheric Sciences, University of Alberta, Edmonton, AB T6G 2E3, Canada
| | - Nanthi S Bolan
- Global Centre for Environmental Remediation, Faculty of Science, University of Newcastle, Callaghan NSW2308, Australia
| | - Deyi Hou
- School of Environment, Tsinghua University, Beijing 100084, China.
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58
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Zhu X, Beiyuan J, Lau AYT, Chen SS, Tsang DCW, Graham NJD, Lin D, Sun J, Pan Y, Yang X, Li XD. Sorption, mobility, and bioavailability of PBDEs in the agricultural soils: Roles of co-existing metals, dissolved organic matter, and fertilizers. THE SCIENCE OF THE TOTAL ENVIRONMENT 2018; 619-620:1153-1162. [PMID: 29734594 DOI: 10.1016/j.scitotenv.2017.11.159] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/16/2017] [Revised: 11/08/2017] [Accepted: 11/14/2017] [Indexed: 06/08/2023]
Abstract
Polybrominated diphenyl ethers (PBDEs) are common pollutants released from electronic waste (e-waste) dismantling and recycling activities. Our city-wide survey of agricultural soils in Qingyuan (40 sampling sites), where e-waste recycling has been active, observed exceedance of PBDEs above background levels (average of 251.9ngg-1, 87 times the regional baseline concentration) together with elevated levels of metals/metalloids at the contamination hotspots, such as As (180.4mgkg-1), Cu (100.7mgkg-1), Zn (93.4mgkg-1), Pb (37.8mgkg-1), Cr (15.1mgkg-1), and Cd (0.3mgkg-1). Hence, a twenty-cycle batch sorption test on composite soil samples from the e-waste site was conducted to study the fate of BDE-28 (2,4,4'-tribromodiphenyl ether) and BDE-99 (2,2',4,4',5-pentabromodiphenyl ether) under the influence of co-existing trace elements (TEs) (Cu, Pb, Zn, and Cd, which exceeded Chinese Environmental Quality Standard for Soils), dissolved organic matter (extracted from local peat), and locally available commercial fertilizer. The results showed that the presence of TEs barely affected the sorption of BDEs, probably because the low concentration of BDEs in the environment resulted in nearly complete sorption onto the soil. In contrast, metals sorption onto soil was promoted by the presence of BDEs. The mobility of BDE-28 was higher than BDE-99 in water leaching tests, while the leaching concentration of BDE-99 was further reduced in simulated acid rain possibly due to protonation of π-accepting sites in soil organic matter. In the freshly spiked soil, BDEs of greater hydrophobicity and larger molecular size exhibited higher bioavailability (due to greater affinity to Tenax extraction), which was contrary to the field contaminated soil. Similarly, the co-occurrence of metals and fertilizer increased the bioavailability of newly sorbed BDE-99 more than BDE-28 in the soil. These results illustrate the need to holistically assess the fate and interactions of co-existing organic and inorganic pollutants in the agricultural soils.
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Affiliation(s)
- Xuan Zhu
- School of Environmental Science and Engineering, Sun Yat-sen University, Guangzhou 510275, China; Department of Civil and Environmental Engineering, The Hong Kong Polytechnic University, Hung Hom, Kowloon, Hong Kong, China
| | - Jingzi Beiyuan
- Department of Civil and Environmental Engineering, The Hong Kong Polytechnic University, Hung Hom, Kowloon, Hong Kong, China; Centre of Sustainable Design and Environment, Faculty of Design and Environment, Technological and Higher Education Institute of Hong Kong, Tsing Yi Road, Hong Kong, China
| | - Abbe Y T Lau
- Department of Civil and Environmental Engineering, The Hong Kong Polytechnic University, Hung Hom, Kowloon, Hong Kong, China
| | - Season S Chen
- Department of Civil and Environmental Engineering, The Hong Kong Polytechnic University, Hung Hom, Kowloon, Hong Kong, China
| | - Daniel C W Tsang
- Department of Civil and Environmental Engineering, The Hong Kong Polytechnic University, Hung Hom, Kowloon, Hong Kong, China.
| | - Nigel J D Graham
- Environmental and Water Resources Engineering, Department of Civil and Environmental Engineering, Imperial College London, South Kensington, London SW7 2AZ, UK
| | - Daohui Lin
- College of Environmental and Resources Sciences, Zhejiang University, Hangzhou 310058, China
| | - Jianteng Sun
- College of Environmental and Resources Sciences, Zhejiang University, Hangzhou 310058, China
| | - Yanheng Pan
- School of Environmental Science and Engineering, Sun Yat-sen University, Guangzhou 510275, China
| | - Xin Yang
- School of Environmental Science and Engineering, Sun Yat-sen University, Guangzhou 510275, China.
| | - Xiang-Dong Li
- Department of Civil and Environmental Engineering, The Hong Kong Polytechnic University, Hung Hom, Kowloon, Hong Kong, China
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59
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Li JS, Chen Z, Wang QM, Fang L, Xue Q, Cheeseman CR, Donatello S, Liu L, Poon CS. Change in re-use value of incinerated sewage sludge ash due to chemical extraction of phosphorus. WASTE MANAGEMENT (NEW YORK, N.Y.) 2018; 74:404-412. [PMID: 29311013 DOI: 10.1016/j.wasman.2018.01.007] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/23/2017] [Revised: 11/27/2017] [Accepted: 01/03/2018] [Indexed: 05/26/2023]
Abstract
The potential of six different extractants to recover phosphorus (P) from incinerated sewage sludge ash (ISSA) was evaluated. Secondary effects such as the co-dissolution of Zn and Cu were also considered. The residual ISSA from each study was assessed in particular detail, focusing on the leachability of remaining Zn and Cu, major element composition, crystalline phases and overall degree of crystallinity and particle size distribution. The residual ISSA was also evaluated as a pozzolanic material using a Strength Activity Index (SAI) test with mortars containing Portland cement with a 20% substitution by ISSA. All results were compared to tests with untreated ISSA. Overall, the use of 3 of the 6 extractants could be ruled out due to poor P recovery potential and/or a serious compromise of the potential reuse of residual ISSA in Portland cement-based materials. The results highlight the added value of considering the potential reuse of residual ISSA when trying to optimize P recovery from ISSA by wet methods.
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Affiliation(s)
- Jiang-Shan Li
- Department of Civil and Environmental Engineering, The Hong Kong Polytechnic University, Hung Hom, Kowloon, Hong Kong; State Key Laboratory of Geomechanics and Geotechnical Engineering, Institute of Rock and Soil Mechanics, Chinese Academy of Sciences, Wuhan 430071, China
| | - Zhen Chen
- Department of Civil and Environmental Engineering, The Hong Kong Polytechnic University, Hung Hom, Kowloon, Hong Kong
| | - Qi-Ming Wang
- Department of Civil and Environmental Engineering, The Hong Kong Polytechnic University, Hung Hom, Kowloon, Hong Kong
| | - Le Fang
- Department of Civil and Environmental Engineering, The Hong Kong Polytechnic University, Hung Hom, Kowloon, Hong Kong
| | - Qiang Xue
- State Key Laboratory of Geomechanics and Geotechnical Engineering, Institute of Rock and Soil Mechanics, Chinese Academy of Sciences, Wuhan 430071, China
| | - C R Cheeseman
- Department of Civil and Environmental Engineering, Imperial College London, London, United Kingdom
| | - Shane Donatello
- Cements and Materials Recycling Department, Eduardo Torroja Institute of Construction Sciences, Consejo Superior de Investigaciones Cientificas (CSIC), c/ Serrano Galvache, 4, Madrid, Spain
| | - Lei Liu
- State Key Laboratory of Geomechanics and Geotechnical Engineering, Institute of Rock and Soil Mechanics, Chinese Academy of Sciences, Wuhan 430071, China
| | - Chi Sun Poon
- Department of Civil and Environmental Engineering, The Hong Kong Polytechnic University, Hung Hom, Kowloon, Hong Kong.
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Yoo JC, Beiyuan J, Wang L, Tsang DCW, Baek K, Bolan NS, Ok YS, Li XD. A combination of ferric nitrate/EDDS-enhanced washing and sludge-derived biochar stabilization of metal-contaminated soils. THE SCIENCE OF THE TOTAL ENVIRONMENT 2018; 616-617:572-582. [PMID: 29128124 DOI: 10.1016/j.scitotenv.2017.10.310] [Citation(s) in RCA: 98] [Impact Index Per Article: 16.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/28/2017] [Revised: 10/10/2017] [Accepted: 10/30/2017] [Indexed: 06/07/2023]
Abstract
In this study, soil washing and stabilization as a two-step soil remediation strategy was performed to remediate Pb- and Cu-contaminated soils from shooting range and railway sites. Ferric nitrate (Fe(NO3)3) and [S,S]-ethylenediamine disuccinate (EDDS) were used as washing agents, whereas three types of sludge-derived biochars and phosphogypsum were employed as soil stabilizers. While Fe(NO3)3 extracted larger amounts of metals compared to EDDS (84% Pb and 64% Cu from shooting range soil; 30% Pb and 40% Cu from railway site soil), it caused severe soil acidification. Both Fe(NO3)3 and EDDS washing enhanced the mobility of residual metals in the two soils, which in most cases could be mitigated by subsequent 2-month stabilization by sludge-derived biochars or phosphogypsum. By contrast, the metal bioaccessibility could only be reduced by soil washing. Nutrient-rich sludge-derived biochar replenished available P and K in both soils, whereas Fe(NO3)3 washing provided available nitrogen (N). Soil amendment enhanced acid phosphatase activity but marginally improved soil dehydrogenase and urease activity in the treated soils, possibly due to the influence of residual metals. This study supported the integration of soil washing (by Fe(NO3)3 or EDDS) with soil stabilization (by sludge-derived biochars or phosphogypsum) for accomplishing the reduction of metal mobility and bioaccessibility, while restoring the environmental quality of the treated soils.
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Affiliation(s)
- Jong-Chan Yoo
- Mineral Processing Division, Korea Institute of Geoscience and Mineral Resources (KIGAM), 124, Gwahak-ro, Yuseong-gu, Daejeon 34132, Republic of Korea; Department of Civil and Environmental Engineering, The Hong Kong Polytechnic University, Hung Hom, Kowloon, Hong Kong, China
| | - Jingzi Beiyuan
- Department of Civil and Environmental Engineering, The Hong Kong Polytechnic University, Hung Hom, Kowloon, Hong Kong, China; Centre of Sustainable Design and Environment, Faculty of Design and Environment, Technological and Higher Education Institute of Hong Kong, Hong Kong, China
| | - Lei Wang
- Department of Civil and Environmental Engineering, The Hong Kong Polytechnic University, Hung Hom, Kowloon, Hong Kong, China
| | - Daniel C W Tsang
- Department of Civil and Environmental Engineering, The Hong Kong Polytechnic University, Hung Hom, Kowloon, Hong Kong, China.
| | - Kitae Baek
- Department of Environmental Engineering and Soil Environment Research Center, Chonbuk National University, Baekje-daero, Deokjin-gu, Jeonju, Jeollabuk-do 54896, Republic of Korea; Department of Bioactive Material Sciences, Chonbuk National University, 567 Baekje-daero, Deokjin-gu, Jeonju, Jeollabuk-do 54896, Republic of Korea.
| | - Nanthi S Bolan
- Global Centre for Environmental Remediation (GCER), Faculty of Science and Information Technology, The University of Newcastle, Callaghan, NSW 2308, Australia
| | - Yong Sik Ok
- O-Jeong Eco-Resilience Institute (OJERI) & Division of Environmental Science and Ecological Engineering, Korea University, Seoul 02841, Republic of Korea
| | - Xiang-Dong Li
- Department of Civil and Environmental Engineering, The Hong Kong Polytechnic University, Hung Hom, Kowloon, Hong Kong, China
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Fang L, Li JS, Guo MZ, Cheeseman CR, Tsang DCW, Donatello S, Poon CS. Phosphorus recovery and leaching of trace elements from incinerated sewage sludge ash (ISSA). CHEMOSPHERE 2018; 193:278-287. [PMID: 29145088 DOI: 10.1016/j.chemosphere.2017.11.023] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/28/2017] [Revised: 10/20/2017] [Accepted: 11/06/2017] [Indexed: 06/07/2023]
Abstract
Chemical extraction of phosphorus (P) from incinerated sewage sludge ash (ISSA) is adversely influenced by co-dissolution of metals and metalloids. This study investigated P recovery and leaching of Zn, Cu, Pb, As and Ni from ISSA using inorganic acids (sulphuric acid and nitric acid), organic acids (oxalic acid and citric acid), and chelating agents (ethylenediaminetetraacetic acid (EDTA) and ethylene diamine tetramethylene phosphonate (EDTMP)). The aim of this study was to optimize a leaching process to recover P-leachate with high purity for P fertilizer production. The results show that both organic and inorganic acids extract P-containing phases but organic acids leach more trace elements, particularly Cu, Zn, Pb and As. Sulphuric acid was the most efficient for P recovery and achieved 94% of total extraction under the optimal conditions, which were 2-h reaction with 0.2 mol/L H2SO4 at a liquid-to-solid ratio of 20:1. EDTA extracted only 20% of the available P, but the leachates were contaminated with high levels of trace elements under optimum conditions (3-h reaction with EDTA at 0.02 mol/L, pH 2, and liquid-to-solid ratio of 20:1). Therefore, EDTA was considered an appropriate pre-treatment agent for reducing the total metal/metalloid content in ISSA, which produced negligible changes in the structure of ISSA and reduced contamination during subsequent P extraction using sulphuric acid.
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Affiliation(s)
- Le Fang
- Department of Civil and Environmental Engineering, The Hong Kong Polytechnic University, Hung Hom, Kowloon, Hong Kong
| | - Jiang-Shan Li
- Department of Civil and Environmental Engineering, The Hong Kong Polytechnic University, Hung Hom, Kowloon, Hong Kong
| | - Ming Zhi Guo
- College of Mechanics and Materials, Hohai University, Nanjing 210098, PR China
| | - C R Cheeseman
- Department of Civil and Environmental Engineering, Imperial College London, London, United Kingdom
| | - Daniel C W Tsang
- Department of Civil and Environmental Engineering, The Hong Kong Polytechnic University, Hung Hom, Kowloon, Hong Kong
| | - Shane Donatello
- Brussels Joint Research Centre, European Commission, Brussels, Belgium
| | - Chi Sun Poon
- Department of Civil and Environmental Engineering, The Hong Kong Polytechnic University, Hung Hom, Kowloon, Hong Kong.
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62
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Beiyuan J, Lau AYT, Tsang DCW, Zhang W, Kao CM, Baek K, Ok YS, Li XD. Chelant-enhanced washing of CCA-contaminated soil: Coupled with selective dissolution or soil stabilization. THE SCIENCE OF THE TOTAL ENVIRONMENT 2018; 612:1463-1472. [PMID: 28903175 DOI: 10.1016/j.scitotenv.2017.09.015] [Citation(s) in RCA: 41] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/09/2017] [Revised: 08/19/2017] [Accepted: 09/02/2017] [Indexed: 06/07/2023]
Abstract
Remediation of CCA-contaminated soil (Cr, Cu, and As) by biodegradable chelant-enhanced washing (EDDS, S,S-ethylene-diamine-disuccinic-acid) needs further enhancement. This study investigated the effectiveness of coupling with pre-treatment by selective dissolution and post-treatment by soil amendments, respectively. Three groups of reagents (reductants, alkaline solvents, and organic ligands) were adopted in the pre-treatment to dissolve the oxide minerals before EDDS extraction. In the post-treatment, soil amendments (coal fly ash (CFA), acid mine drainage sludge (AMDS), green waste compost (GWC)), and their mixtures) were used for a 2-month stabilization after 2-h EDDS washing. Multi-endpoint evaluation was performed by assessing the chemical state, leachability, mobility, bioaccessibility, and plant-availability of residual metal(loid)s as well as the cytotoxicity, enzyme activities, and available nutrients of the treated soils. Pre-treatment by dithionite-citrate-bicarbonate significantly enhanced extraction efficiency, but also increased the leachability of As and Cr and bioaccessibility of Cr in the treated soils. While sodium hydroxide removed the majority of As without increasing its leachability and bioaccessibility, it increased the cytotoxicity and inhibited the acid phosphatase activity. Post-treatment with AMDS and CFA effectively controlled the mobility and leachability of residual As and Cr after EDDS washing. However, destabilized Cu was only marginally immobilized by GWC due to strong Cu-EDDS complexation. The bioaccessibility and phytoavailability of Cu was primarily reduced by EDDS washing, while those of As and Cr could be attenuated by AMDS and CFA. This study indicates that coupling chemical extraction with subsequent soil amendment plays complementary roles in mitigating effects of residual metal(loid)s and improving environmental quality.
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Affiliation(s)
- Jingzi Beiyuan
- Department of Civil and Environmental Engineering, The Hong Kong Polytechnic University, Hung Hom, Kowloon, Hong Kong, China
| | - Abbe Y T Lau
- Department of Civil and Environmental Engineering, The Hong Kong Polytechnic University, Hung Hom, Kowloon, Hong Kong, China
| | - Daniel C W Tsang
- Department of Civil and Environmental Engineering, The Hong Kong Polytechnic University, Hung Hom, Kowloon, Hong Kong, China.
| | - Weihua Zhang
- School of Environmental Science and Engineering, Sun Yat-sen University, Guangzhou 510275, China
| | - Chih-Ming Kao
- Institute of Environmental Engineering, National Sun Yat-Sen University, Kaohsiung 804, Taiwan
| | - Kitae Baek
- Department of Environmental Engineering, Chonbuk National University, Jeollabuk-do 561-756, Republic of Korea
| | - Yong Sik Ok
- O-Jeong Eco-Resilience Institute (OJERI), Division of Environmental Science and Ecological Engineering, Korea University, Seoul, Republic of Korea
| | - Xiang-Dong Li
- Department of Civil and Environmental Engineering, The Hong Kong Polytechnic University, Hung Hom, Kowloon, Hong Kong, China
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63
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Wang YS, Dai JG, Wang L, Tsang DCW, Poon CS. Influence of lead on stabilization/solidification by ordinary Portland cement and magnesium phosphate cement. CHEMOSPHERE 2018; 190:90-96. [PMID: 28985540 DOI: 10.1016/j.chemosphere.2017.09.114] [Citation(s) in RCA: 73] [Impact Index Per Article: 12.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/09/2017] [Revised: 09/14/2017] [Accepted: 09/25/2017] [Indexed: 05/25/2023]
Abstract
Inorganic binder-based stabilization/solidification (S/S) of Pb-contaminated soil is a commonly used remediation approach. This paper investigates the influences of soluble Pb species on the hydration process of two types of inorganic binders: ordinary Portland cement (OPC) and magnesium potassium phosphate cement (MKPC). The environmental leachability, compressive strength, and setting time of the cement products are assessed as the primary performance indicators. The mechanisms of Pb involved in the hydration process are analyzed through X-ray diffraction (XRD), hydration heat evolution, and thermogravimetric analyses. Results show that the presence of Pb imposes adverse impact on the compressive strength (decreased by 30.4%) and the final setting time (prolonged by 334.7%) of OPC, but it exerts much less influence on those of MKPC. The reduced strength and delayed setting are attributed to the retarded hydration reaction rate of OPC during the induction period. These results suggest that the OPC-based S/S of soluble Pb mainly depends on physical encapsulation by calcium-silicate-hydrate (CSH) gels. In contrast, in case of MKPC-based S/S process, chemical stabilization with residual phosphate (pyromorphite and lead phosphate precipitation) and physical fixation of cementitious struvite-K are the major mechanisms. Therefore, MKPC is a more efficient and chemically stable inorganic binder for the Pb S/S process.
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Affiliation(s)
- Yan-Shuai Wang
- Department of Civil and Environmental Engineering, The Hong Kong Polytechnic University, Hong Kong, China
| | - Jian-Guo Dai
- Department of Civil and Environmental Engineering, The Hong Kong Polytechnic University, Hong Kong, China.
| | - Lei Wang
- Department of Civil and Environmental Engineering, The Hong Kong Polytechnic University, Hong Kong, China
| | - Daniel C W Tsang
- Department of Civil and Environmental Engineering, The Hong Kong Polytechnic University, Hong Kong, China.
| | - Chi Sun Poon
- Department of Civil and Environmental Engineering, The Hong Kong Polytechnic University, Hong Kong, China
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64
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Li JS, Wang L, Tsang DCW, Beiyuan J, Poon CS. Dynamic leaching behavior of geogenic As in soils after cement-based stabilization/solidification. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2017; 24:27822-27832. [PMID: 28986736 DOI: 10.1007/s11356-017-0266-x] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/07/2017] [Accepted: 09/19/2017] [Indexed: 06/07/2023]
Abstract
Cement-based stabilization/solidification (S/S) is a practical treatment approach for hazardous waste with anthropogenic As sources; however, its applicability for geogenic As-containing soil and the long-term leaching potential remain uncertain. In this study, semi-dynamic leaching test was performed to investigate the influence of S/S binders (cement blended with fuel ash (FA), furnace bottom ash (FBA), or ground granulated blast furnace slag (GGBS)) on the long-term leaching characteristics of geogenic As. The results showed that mineral admixtures with higher Ca content and pozzolanic activity were more effective in reducing the leached As concentrations. Thus, cement blended with FBA was inferior to other binders in suppressing the As leaching, while 20% replacement of ordinary Portland cement by GGBS was considered most feasible for the S/S treatment of As-containing soils. The leachability of geogenic As was suppressed by the encapsulation effect of solidified matrix and interlocking network of hydration products that were supported by scanning electron microscopy (SEM), X-ray diffraction (XRD), and X-ray photoelectron spectroscopy (XPS) results. The long-term leaching of geogenic As from the monolithic samples was diffusion-controlled. Increasing the Ca content in the samples led to a decrease in diffusion coefficient and an increase in feasibility for "controlled utilization" of the S/S-treated soils.
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Affiliation(s)
- Jiang-Shan Li
- Department of Civil and Environmental Engineering, The Hong Kong Polytechnic University, Hung Hom, Kowloon, Hong Kong, China
| | - Lei Wang
- Department of Civil and Environmental Engineering, The Hong Kong Polytechnic University, Hung Hom, Kowloon, Hong Kong, China
| | - Daniel C W Tsang
- Department of Civil and Environmental Engineering, The Hong Kong Polytechnic University, Hung Hom, Kowloon, Hong Kong, China.
| | - Jingzi Beiyuan
- Department of Civil and Environmental Engineering, The Hong Kong Polytechnic University, Hung Hom, Kowloon, Hong Kong, China
| | - Chi Sun Poon
- Department of Civil and Environmental Engineering, The Hong Kong Polytechnic University, Hung Hom, Kowloon, Hong Kong, China.
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65
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Beiyuan J, Li JS, Tsang DCW, Wang L, Poon CS, Li XD, Fendorf S. Fate of arsenic before and after chemical-enhanced washing of an arsenic-containing soil in Hong Kong. THE SCIENCE OF THE TOTAL ENVIRONMENT 2017; 599-600:679-688. [PMID: 28494293 DOI: 10.1016/j.scitotenv.2017.04.208] [Citation(s) in RCA: 71] [Impact Index Per Article: 10.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/14/2017] [Revised: 04/25/2017] [Accepted: 04/27/2017] [Indexed: 06/07/2023]
Abstract
This study evaluated the feasibility of 2-h chemical-enhanced washing of As-containing soil resulting from geogenic sources in Hong Kong and the fate of As before and after remediation. The soil morphology and As speciation in soil was elucidated by scanning electron microscopy with energy dispersive X-ray spectroscopy, X-ray diffractometer, X-ray photoelectron spectroscopy, and X-ray absorption spectroscopy. Integrated analysis of the results suggests that the As (>90%) resides predominantly as arsenate bound to ferric iron oxides, with a minor contribution (<10%) from an AsIII-sulphide phase. This accounts for the marginal leachability, mobility, and bioaccessibility of geogenic As in the untreated soil despite its high concentration. Among the five types of reagents (organic ligands, reductants, alkaline solvents, inorganic acids, and chelants), only dithionite-citrate-bicarbonate method and alkaline solvents (NaOH and Na2CO3) extracted 37-78% and 26-42% of the As by mineral dissolution. However, these extraction methods notably increased the leachability, mobility, and bioaccessibility of remaining As after soil washing, suggesting that a significant proportion of newly released As is prone to re-adsorption onto the soil surface and becomes highly mobile and bioaccessible. While inorganic acids and chelating agents had marginal effects on the fate of remaining As, organic ligands (citrate, oxalate, or pyrophosphate) probably destabilized the bonding of geogenic As and increased its mobility/bioaccessibility despite marginal extraction. The applicability of chemical extraction of geogenic As is questionable regardless of chemical agents, thus proper management of the As-containing soil by containment or physical encapsulation may be considered before land development.
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Affiliation(s)
- Jingzi Beiyuan
- Department of Civil and Environmental Engineering, The Hong Kong Polytechnic University, Hung Hom, Kowloon, Hong Kong, China
| | - Jiang-Shan Li
- Department of Civil and Environmental Engineering, The Hong Kong Polytechnic University, Hung Hom, Kowloon, Hong Kong, China
| | - Daniel C W Tsang
- Department of Civil and Environmental Engineering, The Hong Kong Polytechnic University, Hung Hom, Kowloon, Hong Kong, China.
| | - Lei Wang
- Department of Civil and Environmental Engineering, The Hong Kong Polytechnic University, Hung Hom, Kowloon, Hong Kong, China
| | - Chi Sun Poon
- Department of Civil and Environmental Engineering, The Hong Kong Polytechnic University, Hung Hom, Kowloon, Hong Kong, China
| | - Xiang-Dong Li
- Department of Civil and Environmental Engineering, The Hong Kong Polytechnic University, Hung Hom, Kowloon, Hong Kong, China
| | - Scott Fendorf
- Earth System Science Department, Stanford University, Stanford, California 94305, United States
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66
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Li JS, Tsang DCW, Wang QM, Fang L, Xue Q, Poon CS. Fate of metals before and after chemical extraction of incinerated sewage sludge ash. CHEMOSPHERE 2017; 186:350-359. [PMID: 28800536 DOI: 10.1016/j.chemosphere.2017.08.012] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/14/2017] [Revised: 08/04/2017] [Accepted: 08/04/2017] [Indexed: 06/07/2023]
Abstract
Chemical extraction of incinerated sewage sludge ash (ISSA) can effectively recycle P, but it may change the speciation and mobility of the remaining metals. This study investigated the changes of the leaching potential and distribution of metals in the chemically extracted ISSA. Batch extraction experiments with different extractants, including inorganic acids, organic acids, and chelating agents, were conducted on the ISSA collected from a local sewage sludge incinerator. The extraction of Zn, Cu, Pb, Ni, Cd, Ba, Cr and As from the ISSA and the corresponding changes of the mobility and speciation were examined. The results showed that the metals in ISSA were naturally stable because large portions of metals were associated with the residual fraction. The inorganic (HNO3 and H2SO4) and organic acids (citric acid and oxalic acid) significantly co-dissolved the metals through acid dissolution, but the reduction in the total concentrations did not tally the leaching potential of the residual metals. The increase in the exchangeable fraction due to destabilization by the extractants significantly enhanced the mobility and leachability of the metals in the residual ISSA. Chelating agents (EDTA and EDTMP) only extracted a small quantity of metals and had a marginal effect on the fate of the residual metals, but they significantly reduced the Fe/Mn oxide-bound fraction. In comparison, the bioaccessibility of residual metals were reduced to varying extent. Therefore, the disposal or reuse of chemically extracted ISSA should be carefully evaluated in view of possible increase in mobility of residual metals in the environment.
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Affiliation(s)
- Jiang-Shan Li
- Department of Civil and Environmental Engineering, The Hong Kong Polytechnic University, Hung Hom, Kowloon, Hong Kong; State Key Laboratory of Geomechanics and Geotechnical Engineering, Institute of Rock and Soil Mechanics, Chinese Academy of Sciences, Wuhan 430071, China
| | - Daniel C W Tsang
- Department of Civil and Environmental Engineering, The Hong Kong Polytechnic University, Hung Hom, Kowloon, Hong Kong
| | - Qi-Ming Wang
- Department of Civil and Environmental Engineering, The Hong Kong Polytechnic University, Hung Hom, Kowloon, Hong Kong
| | - Le Fang
- Department of Civil and Environmental Engineering, The Hong Kong Polytechnic University, Hung Hom, Kowloon, Hong Kong
| | - Qiang Xue
- State Key Laboratory of Geomechanics and Geotechnical Engineering, Institute of Rock and Soil Mechanics, Chinese Academy of Sciences, Wuhan 430071, China
| | - Chi Sun Poon
- Department of Civil and Environmental Engineering, The Hong Kong Polytechnic University, Hung Hom, Kowloon, Hong Kong.
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67
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Bretti C, Cigala RM, De Stefano C, Lando G, Sammartano S. Understanding the bioavailability and sequestration of different metal cations in the presence of a biodegradable chelant MGDA in biological fluids and natural waters. CHEMOSPHERE 2017; 183:107-118. [PMID: 28538167 DOI: 10.1016/j.chemosphere.2017.05.099] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/23/2017] [Revised: 04/11/2017] [Accepted: 05/16/2017] [Indexed: 06/07/2023]
Abstract
Thermodynamic information about the metal-ligand interaction between Fe3+, Zn2+, Cu2+ and Sn2+, and a biodegradable ligand as MGDA is reported. The speciation scheme was obtained by means of potentiometric measurements and isothermal titration calorimetry (to determine enthalpy changes) in NaCl medium. The formation of the ML and MLOH species was evidenced for all the metal cations, and for Fe3+ also the ML2 and ML(OH)2 were found. The relative stability, for the ML species, follows the order: Sn2+ > Fe3+ > Cu2+ > Zn2+. Stability constants and enthalpy changes were obtained at different ionic strengths, and data were modeled using the Debye-Hückel and SIT approaches to obtain data in a standard state. At infinite dilution, the enthalpy changes are largely negative for Cu2+ (-34.1 kJ mol-1) and Sn2+ (-16.6 kJ mol-1), slightly negative for Fe3+ (-3.3 kJ mol-1) and positive for Zn2+ (8.7 kJ mol-1). In all cases, the entropic contribution to the stability is predominant. The sequestering ability of MGDA was evaluated determining the pL0.5 values in different conditions. Comparing the data reported in this work and literature ones, some empirical relationships were obtained with predictive purpose. For example, using 11 data in the test set we have: log K (M/MGDA) ± 0.1 = 1.13 + 0.84·log K (M/NTA) Case studies were built up in the conditions of seawater, fresh water and urine to study the possible use of MGDA towards the metal cations here studied. Some considerations were also done in the light of the ocean acidification.
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Affiliation(s)
- Clemente Bretti
- Dipartimento di Scienze Chimiche, Biologiche, Farmaceutiche ed Ambientali, Università degli Studi di Messina, Viale Ferdinando Stagno d'Alcontres, 31, I-98166 Messina (Vill. S. Agata), Italy.
| | - Rosalia Maria Cigala
- Dipartimento di Scienze Chimiche, Biologiche, Farmaceutiche ed Ambientali, Università degli Studi di Messina, Viale Ferdinando Stagno d'Alcontres, 31, I-98166 Messina (Vill. S. Agata), Italy.
| | - Concetta De Stefano
- Dipartimento di Scienze Chimiche, Biologiche, Farmaceutiche ed Ambientali, Università degli Studi di Messina, Viale Ferdinando Stagno d'Alcontres, 31, I-98166 Messina (Vill. S. Agata), Italy.
| | - Gabriele Lando
- Dipartimento di Scienze Chimiche, Biologiche, Farmaceutiche ed Ambientali, Università degli Studi di Messina, Viale Ferdinando Stagno d'Alcontres, 31, I-98166 Messina (Vill. S. Agata), Italy.
| | - Silvio Sammartano
- Dipartimento di Scienze Chimiche, Biologiche, Farmaceutiche ed Ambientali, Università degli Studi di Messina, Viale Ferdinando Stagno d'Alcontres, 31, I-98166 Messina (Vill. S. Agata), Italy.
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68
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Li JS, Beiyuan J, Tsang DCW, Wang L, Poon CS, Li XD, Fendorf S. Arsenic-containing soil from geogenic source in Hong Kong: Leaching characteristics and stabilization/solidification. CHEMOSPHERE 2017; 182:31-39. [PMID: 28486153 DOI: 10.1016/j.chemosphere.2017.05.019] [Citation(s) in RCA: 67] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/23/2017] [Revised: 04/25/2017] [Accepted: 05/03/2017] [Indexed: 06/07/2023]
Abstract
Geogenic sources of arsenic (As) have aroused extensive environmental concerns in many countries. This study evaluated the vertical profiles, leaching characteristics, and surface characteristics of As-containing soils in Hong Kong. The results indicated that elevated levels of As (486-1985 mg kg-1) were mostly encountered in deeper layer (15-20 m below ground). Despite high concentrations, geogenic As displayed a high degree of chemical stability in the natural geochemical conditions, and there was minimal leaching of As in various leaching tests representing leachability, mobility, phytoavailability, and bioaccessibility. Microscopic/spectroscopic investigations suggested that As in the soils was predominantly present as As(V) in a coordination environment with Fe oxides. Sequential extraction indicated that the majority of As were strongly bound with crystalline Fe/Al oxides and residual phase. Yet, uncertainties may remain with potential As exposure through accidental ingestion and abiotic/biotic transformation due to changes in geochemical conditions. Hence, the effectiveness of stabilization/solidification (S/S) treatment was evaluated. Although the leached concentrations of As from the S/S treated soils increased to varying extent in different batch leaching tests due to the increase in alkalinity, the mobility of As was considered very low based on semi-dynamic leaching test. This suggested that As immobilization in the S/S treated soils was predominantly dependent on physical encapsulation by interlocking framework of hydration products, which could also prevent potential exposure and allow controlled utilization of S/S treated soils as monolithic materials. These results illustrate the importance of holistic assessment and treatment/management of As-containing soils for enabling flexible future land use.
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Affiliation(s)
- Jiang-Shan Li
- Department of Civil and Environmental Engineering, The Hong Kong Polytechnic University, Hung Hom, Kowloon, Hong Kong, China
| | - Jingzi Beiyuan
- Department of Civil and Environmental Engineering, The Hong Kong Polytechnic University, Hung Hom, Kowloon, Hong Kong, China
| | - Daniel C W Tsang
- Department of Civil and Environmental Engineering, The Hong Kong Polytechnic University, Hung Hom, Kowloon, Hong Kong, China.
| | - Lei Wang
- Department of Civil and Environmental Engineering, The Hong Kong Polytechnic University, Hung Hom, Kowloon, Hong Kong, China
| | - Chi Sun Poon
- Department of Civil and Environmental Engineering, The Hong Kong Polytechnic University, Hung Hom, Kowloon, Hong Kong, China.
| | - Xiang-Dong Li
- Department of Civil and Environmental Engineering, The Hong Kong Polytechnic University, Hung Hom, Kowloon, Hong Kong, China
| | - Scott Fendorf
- Earth System Science Department, Stanford University, Stanford, CA 94305, United States
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69
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Chen SS, Sun Y, Tsang DCW, Graham NJD, Ok YS, Feng Y, Li XD. Potential impact of flowback water from hydraulic fracturing on agricultural soil quality: Metal/metalloid bioaccessibility, Microtox bioassay, and enzyme activities. THE SCIENCE OF THE TOTAL ENVIRONMENT 2017; 579:1419-1426. [PMID: 27913018 DOI: 10.1016/j.scitotenv.2016.11.141] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/09/2016] [Revised: 11/16/2016] [Accepted: 11/20/2016] [Indexed: 06/06/2023]
Abstract
Hydraulic fracturing has advanced the development of shale gas extraction, while inadvertent spills of flowback water may pose a risk to the surrounding environment due to its high salt content, metals/metalloids (As, Se, Fe and Sr), and organic additives. This study investigated the potential impact of flowback water on four representative soils from shale gas regions in Northeast China using synthetic flowback solutions. The compositions of the solutions were representative of flowback water arising at different stages after fracturing well establishment. The effects of solution composition of flowback water on soil ecosystem were assessed in terms of metal mobility and bioaccessibility, as well as biological endpoints using Microtox bioassay (Vibrio fischeri) and enzyme activity tests. After one-month artificial aging of the soils with various flowback solutions, the mobility and bioaccessibility of As(V) and Se(VI) decreased as the ionic strength of the flowback solutions increased. The results inferred a stronger binding affinity of As(V) and Se(VI) with the soils. Nevertheless, the soil toxicity to Vibrio fischeri only presented a moderate increase after aging, while dehydrogenase and phosphomonoesterase activities were significantly suppressed with increasing ionic strength of flowback solutions. On the contrary, polyacrylamide in the flowback solutions led to higher dehydrogenase activity. These results indicated that soil enzyme activities were sensitive to the composition of flowback solutions. A preliminary human health risk assessment related to As(V) suggested a low level of cancer risk through exposure via ingestion, while holistic assessment of environmental implications is required.
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Affiliation(s)
- Season S Chen
- Department of Civil and Environmental Engineering, Hong Kong Polytechnic University, Hung Hom, Kowloon, Hong Kong, China
| | - Yuqing Sun
- Department of Civil and Environmental Engineering, Hong Kong Polytechnic University, Hung Hom, Kowloon, Hong Kong, China; State Key Laboratory of Urban Water Resource and Environment, Harbin Institute of Technology, Harbin 150090, China
| | - Daniel C W Tsang
- Department of Civil and Environmental Engineering, Hong Kong Polytechnic University, Hung Hom, Kowloon, Hong Kong, China.
| | - Nigel J D Graham
- Environmental and Water Resources Engineering, Department of Civil and Environmental Engineering, Imperial College London, South Kensington, London SW7 2AZ, UK
| | - Yong Sik Ok
- School of Natural Resources and Environmental Science, Korea Biochar Research Center, Kangwon National University, Chuncheon 24341, Republic of Korea
| | - Yujie Feng
- State Key Laboratory of Urban Water Resource and Environment, Harbin Institute of Technology, Harbin 150090, China.
| | - Xiang-Dong Li
- Department of Civil and Environmental Engineering, Hong Kong Polytechnic University, Hung Hom, Kowloon, Hong Kong, China
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