Remediation of PAHs contaminated soil by extraction using subcritical water

Islam, Mohammad Nazrul; Jo, Young-Tae

doi:10.1016/j.jiec.2012.03.013

Cited by 56 publications

(16 citation statements)

References 35 publications

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“…As shown in Table 1, one of the most dramatic changes for liquid water at saturation pressure is the ε r , going from 78 at 25°C to 14 at 350°C [13]. Water at near critical conditions (P and T just below the critical point) dissolves hydrophobic compounds such as PAHs and PCBs [2,14]. Salt is no longer soluble in the water (i.e., it precipitates).…”

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confidence: 99%

Pressurized hot water extraction of bioactives

Plaza

Turner

2015

TrAC Trends in Analytical Chemistry

454

224

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HIGHLIGHTS  Review of pressurized hot water extraction of bioactive compounds, 2009-14  Chemical and physical properties of pressurized hot liquid water  Equipment, method optimization, applications, coupling and future prospects  Challenges with degradation and other chemical reactions during extraction ABSTRACT The purpose of this review is to give the reader a thorough background to the fundamentals and applications of pressurized hot water extraction (PHWE) for the analysis of bioactive compounds. We summarize the field in the period 2009-14, and include fundamentals of water as a solvent: equipment; method optimization; applications; coupling; and, future prospects. We highlight that solvent properties of water are tunable by changing the temperature, particularly self-ionization, dielectric constant, viscosity, diffusivity, density and surface tension. Furthermore, important aspects to consider are the risk of degradation of the analytes and other potential reactions, such as hydrolysis, caramelization and Maillard reactions that may lead to erroneous results. For the extraction of bioactive compounds, we report PHWE methods based on using water of 80-175°C and short extraction times. In conclusion, PHWE provides advantages over conventional extraction methods, such as being "greener", faster and more efficient. Why another review article on pressurized hot water extraction?Pressurized hot water extraction (PHWE) is an extraction technique that uses liquid water as extractant (extraction solvent) at temperatures above the atmospheric boiling point of water (100°C/273 K, 0.1 MPa), but below the critical point of water (374°C/647 K, 22.1 MPa) (Fig. 1). The use of PHWE in analytical chemistry started with the work in environmental analysis by Hawthorne and colleagues in the mid-1990s [1,2], and can also be referred to as subcritical water extraction (SWE), superheated water extraction and pressurized liquid extraction or accelerated solvent extraction with water as a solvent. There are a few relatively recent review articles on analytical PHWE, which the reader is recommended to read [3][4][5][6][7].The aim of this review article is to give a thorough background on the fundamental properties of water -an aspect that has been virtually overlooked in most review articles written so far about analytical PHWE. Hence, the first part of this review article concerns the fundamentals of chemical/physical properties of water and how these change with the increase in temperature, as well as how these affect the extraction performance both positively and negatively in different analytical applications.The second part deals with technical solutions of PHWE and how to conduct the experiment in practice. This technical part includes discussions on using commercially available and home-built equipment. The third part includes aspects on method optimization in PHWE. The fourth part summarizes some of the key applications and related publications mainly in the field of extraction of bioactive compounds from plants, food, ...

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confidence: 99%

Pressurized hot water extraction of bioactives

Plaza

Turner

2015

TrAC Trends in Analytical Chemistry

454

224

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“…Anekpankul et al [21] suggested that extraction is controlled by intra-particle diffusion which is also related to water flow rate. Therefore, the temperature and flow rate effects on extraction efficiency were examined and the results were described in our previous study [14]. Figs.…”

Section: Extraction Efficiencies Of Pahsmentioning

confidence: 99%

“…The lab-scale subcritical water extractor and the PAHs extraction process was described in our previous work [14]. The extraction process is briefly described herein.…”

Section: Extraction Processmentioning

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Thermodynamic and kinetic study for subcritical water extraction of PAHs

Islam

Jung³

2013

Journal of Industrial and Engineering Chemistry

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“…3). 다른 연구 결과들에서도 추출시간 이 제거율에 영향을 미쳤으며, 시간이 길어질수록 제거율 이 증가하는 것으로 보고하였다 (Hawthorne et al, 1994;Islam et al, 2012a;Saeed et al, 2009;Yang and Li, 1999). 또한 추출시간에 의한 영향은 온도가 낮아질수록 더 커지는 것으로 알려져 있다 (Saeed et al, 2009) …”

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Influence Factor on Remediation of PAHs-Contaminated Soil by Using Flowing Subcritical Water

Jo¹,

Islam²,

Park

2013

Journal of Soil and Groundwater Environment

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Subcritical water which acts as organic solvent with increasing temperature and pressure because dielectric constant and viscosity decrease can be used to remediate PAHs-contaminated soil. Factors influencing on extraction were studied with varying the water temperature 200~275 o C, extraction time 0~90 min, flow rate 10~100 mL/min and pressure 3.9~10 MPa. 300 g of soil sample which was contaminated with PAHs(naphthalene, phenanthrene, fluoranthene and pyrene; 423, 420, 539 and 428 mg/kg of initial concentration) was packed into the cell and placed to reactor and then the subcritical water was pumped through the cell for PAHs extraction. Naphthalene was removed almost 100% at relatively low temperature (200 o C). The removal rate of phenanthrene, fluoranthene, and pyrene increased by 8, 26, and 23% when the temperature increased from 200 to 275 o C; and it was gradually increased as extraction time increased from 0 to 90 min. Decreasing removal rate when water flow rate increased from 10 to 30 mL/min, but there was no significant change after 30 mL/min. This is supposed due to channeling phenomenon. The pressure was not an effective factor for extraction of PAHs in this study. Based on the results, the importance of effective factor was in following sequence: temperature >> time > flow rate.

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Remediation of PAHs contaminated soil by extraction using subcritical water

Cited by 56 publications

References 35 publications

Pressurized hot water extraction of bioactives

Pressurized hot water extraction of bioactives

Thermodynamic and kinetic study for subcritical water extraction of PAHs

Influence Factor on Remediation of PAHs-Contaminated Soil by Using Flowing Subcritical Water

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