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Muñoz-Vega E, Horovitz M, Dönges L, Schiedek T, Schulz S, Schüth C. Competitive sorption experiments reveal new regression models to predict PhACs sorption on carbonaceous materials. JOURNAL OF HAZARDOUS MATERIALS 2024; 471:134239. [PMID: 38640667 DOI: 10.1016/j.jhazmat.2024.134239] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/04/2024] [Revised: 04/03/2024] [Accepted: 04/07/2024] [Indexed: 04/21/2024]
Abstract
Sorption of hydrophobic organic contaminants onto thermally altered carbonaceous materials (TACM) constitutes a widely used technology for remediation of polluted waters. This process is typically described by sorption isotherms, with one of the most used models, the Polanyi-Dubinin-Manes (PDM) equation, including water solubility (Sw) as a normalizing factor. In case of pharmaceutical active compounds (PhACs), Sw depends on the pH of the environment due to the ionic/ionizable behavior of these chemicals, a fact frequently ignored in sorption studies of PhACs. In this work, we set the theoretical framework to include the variation of Sw with pH in the definition of the PDM model, and we applied this approach to describe the effect of ambient pH in the competitive sorption of three commonly detected PhACs (carbamazepine, ibuprofen, and sulfamethoxazole) onto three carbonaceous sorbents (biochar, powder activated carbon, and colloidal activated carbon). Changes in the ambient pH and hence in the hydrophobicity of the compounds could explain the strong variations observed in single-solute sorption and also in competitive sorption. Furthermore, Sw was used as a parameter for the linear regression model of sorption coefficients of our experiments, suggesting the incorporation of this variable as an improvement to existing approaches for prediction of PhACs sorption onto TACM.
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Affiliation(s)
- Edinsson Muñoz-Vega
- Technical University of Darmstadt, Institute of Applied Geosciences, Schnittspahnstraße 9, Darmstadt D-64287, Germany.
| | - Marcel Horovitz
- Technical University of Darmstadt, Institute of Applied Geosciences, Schnittspahnstraße 9, Darmstadt D-64287, Germany; Laboratório Nacional de Engenharia Civil, Avenida do Brasil 101, Lisbon 1700-066, Portugal
| | - Lisa Dönges
- Technical University of Darmstadt, Institute of Applied Geosciences, Schnittspahnstraße 9, Darmstadt D-64287, Germany
| | - Thomas Schiedek
- Technical University of Darmstadt, Institute of Applied Geosciences, Schnittspahnstraße 9, Darmstadt D-64287, Germany
| | - Stephan Schulz
- Technical University of Darmstadt, Institute of Applied Geosciences, Schnittspahnstraße 9, Darmstadt D-64287, Germany
| | - Christoph Schüth
- Technical University of Darmstadt, Institute of Applied Geosciences, Schnittspahnstraße 9, Darmstadt D-64287, Germany; Water Resources Management Division, IWW Water Centre, Moritzstraße 26, Mülheim an der Ruhr D-45476, Germany
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Wu Z, Lin T, Hu L, Guo T, Guo Z. Polycyclic aromatic hydrocarbons in sediment-porewater system from the East China Sea: Occurrence, partitioning, and diffusion. ENVIRONMENTAL RESEARCH 2022; 209:112755. [PMID: 35134381 DOI: 10.1016/j.envres.2022.112755] [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: 10/23/2021] [Revised: 12/13/2021] [Accepted: 01/14/2022] [Indexed: 06/14/2023]
Abstract
The distribution, partitioning behavior, and diffusion of polycyclic aromatic hydrocarbons (PAHs) within sediment-porewater system were determined in two cores obtained from the Min-Zhe coastal mud of the East China Sea (ECS). Depth profiles of apparently dissolved PAH levels exhibited greater variabilities, with their elevated levels at depth and a high abundance of two-to three-ring PAHs observed. These distribution and composition patterns were inconsistent with the corresponding sediment PAHs, indicating differences in controlling factors for PAHs present in the system. In addition to compound's hydrophobicity, low detection of heavier PAHs in porewater was possibly correlated with the sediment transport process, as indicated by a relatively high weathering ratio in southern Min-Zhe coastal mud. PAH sorption affinity to the collected core sediments exhibited a generally decreasing trend downcore, as expressed by sediment-porewater partition coefficients. This was consistent with the higher content of porewater PAHs in deep core sediment. The established sediment total organic carbon (TOC)-porewater partitioning profiles in cores were predicted with amorphous organic carbon (AOC)-, coal tar-, and TOC-based distribution models, suggesting a dominant nonlinear sorption of PAHs to AOC. Through activity determinations, PAH diffusion within porewater was elucidated, with significant upward and downward mass transfer for PAHs occurring in both cores. The upward diffusion in the core collected from northern Min-Zhe coastal mud was in significant association with sediment TOC. This suggests that sediment TOC (especially AOC)-desorption of lighter PAHs into porewater, and therefore the possibility of their participation in environmental cycling. Baseline toxicity potential and toxic unit calculations indicated a relatively low exposure risk for benthic organisms to porewater PAHs.
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Affiliation(s)
- Zilan Wu
- State Environmental Protection Key Laboratory of Coastal Ecosystem, National Marine Environmental Monitoring Center, Dalian, 116023, China; Shanghai Key Laboratory of Atmospheric Particle Pollution and Prevention, Institute of Atmospheric Sciences, Department of Environmental Science and Engineering, Fudan University, Shanghai, 200433, China
| | - Tian Lin
- College of Marine Ecology and Environment, Shanghai Ocean University, Shanghai, 201306, China.
| | - Limin Hu
- College of Marine Geosciences, Key Laboratory of Submarine Geosciences and Prospecting Technology, Ocean University of China, Qingdao, 266100, China
| | - Tianfeng Guo
- Shanghai Key Laboratory of Atmospheric Particle Pollution and Prevention, Institute of Atmospheric Sciences, Department of Environmental Science and Engineering, Fudan University, Shanghai, 200433, China
| | - Zhigang Guo
- Shanghai Key Laboratory of Atmospheric Particle Pollution and Prevention, Institute of Atmospheric Sciences, Department of Environmental Science and Engineering, Fudan University, Shanghai, 200433, China
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Rahman MM, Worch E. Nonequilibrium sorption of phenols onto geosorbents: the impact of pH on intraparticle mass transfer. CHEMOSPHERE 2005; 61:1419-26. [PMID: 15982712 DOI: 10.1016/j.chemosphere.2005.04.085] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/11/2003] [Revised: 04/19/2005] [Accepted: 04/29/2005] [Indexed: 05/03/2023]
Abstract
While the pH effect on sorption equilibrium of weak acids on natural sorbents was investigated in a number of studies, less is known about the pH dependence of sorption kinetics. This paper investigates the impact of pH on sorption kinetics during the transport of some selected phenols through a sandy aquifer material. Breakthrough curves measured in column experiments were analyzed using a mass transfer based nonequilibrium model designated as dispersed flow, film and particle diffusion model (DF-FPDM). In this model, the rate limiting intraparticle diffusion is characterized by the mass transfer coefficient, kSaV, which can be determined from breakthrough curves by curve fitting. The experimental results indicate that the kSaV is pH-dependent and inversely correlated with the pH-dependent distribution coefficient, K(d,app). Regression equations are presented that may be used to estimate approximate values of intraparticle mass transfer coefficients on the basis of experimentally determined or LFER predicted distribution coefficients.
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Affiliation(s)
- Md Mokhlesur Rahman
- Institute of Waste Management and Contaminated Site Remediation, Dresden University of Technology, D-01062 Dresden, Germany
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Sander M, Pignatello JJ. Characterization of charcoal adsorption sites for aromatic compounds: insights drawn from single-solute and bi-solute competitive experiments. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2005; 39:1606-1615. [PMID: 15819216 DOI: 10.1021/es049135l] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
Charcoal, the residue of incomplete biomass burning that is found in many soils and sediments, is considered a high affinity sorbent for organic pollutants. However, little is known about the microscopic processes controlling sorption. The purpose of this study was to gain molecular-scale insight into the sorption on a charcoal of three weakly soluble aromatic compounds [benzene (BEN), toluene (TOL), and nitrobenzene (NBZ)] by conducting both single-solute and bi-solute experiments. The charcoal (420 m2 g(-1)) was produced from maple wood shavings by oxygen-limited pyrolysis at 673 K. Solute affinity for charcoal followed the order NBZ > TOL > BEN. Commonly employed sorption models did not adequately describe the single-solute isotherms. Competition in both TOL-BEN and the TOL-NBZ bi-solute systems was strong. Normalization of the isotherms for the hydrophobic driving force by using an existing free energy correlation between sorption and partitioning to an inert solvent (benzene or n-hexadecane) with a nonpolar aromatic compound calibration set resulted in a finding of enhanced sorption of NBZ relative to the coalesced BEN and TOL isotherms, indicating some specificity in the interaction of NBZ. The competitive data indicated 1:1 molar competition between BEN and TOL and between NBZ and TOL, showing conclusively that this specificity was not due to a subpopulation of sorption sites unique to NBZ. H-bonding was ruled out, as the relative affinity for the sorbent among the solutes did not change at all when increasing the solution pH from 6.5 to 11. 1H NMR experiments showed molecular complexation in chloroform between NBZ and model graphene polycyclic aromatic units (naphthalene, phenanthrene, and pyrene) which was absentfor BEN and TOL. This result, in combination with the results of a companion study (Zhu and Pignatello, Environ. Sci. Technol. (in press)), is used to support the existence of pi-pi electron donor-acceptor interactions between NBZ (electron acceptor) and the polycyclic aromatic charcoal surface (electron donor) as the cause of enhanced NBZ sorption.
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Affiliation(s)
- Michael Sander
- Department of Chemical Engineering, Environmental Engineering Program, Yale University, New Haven, Connecticut 06511, USA
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Sorption Behaviour of Phenols on Natural Sandy Aquifer Material during Flow-through Column Experiments: The Effect of pH. ACTA ACUST UNITED AC 2004. [DOI: 10.1002/aheh.200300531] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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Ran Y, Xiao B, Fu J, Sheng G. Sorption and desorption hysteresis of organic contaminants by kerogen in a sandy aquifer material. CHEMOSPHERE 2003; 50:1365-1376. [PMID: 12586168 DOI: 10.1016/s0045-6535(02)00762-2] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
Sorption and desorption hysteresis of 1,2-dichlorobenzene, 1,3,5-trichlorobenzene, naphthalene, and phenanthrene were investigated for the Borden aquifer material with total organic carbon of 0.021% and the isolated natural organic matter (NOM). The isolated NOM is a kerogen type of organic matter with relatively low maturation degree and contained many different types of organic matters including vitrinite particles. The modified Freundlich sorption capacities (logK(')(f) and logK(')(foc)) are very close for the sorption of the four solutes by the isolated NOM and the original sand, respectively. Isotherm non-linearity (n value) and hysteric behaviors are related to solute molecular properties (e.g. K(ow) and molecular size). Kerogen encapsulated by inorganic matrices in the original aquifer may not be accessed fully by solutes. The larger the hydrophobic organic chemical (HOC) (hydrophobic organic contaminant) molecule is, the lower accessibility of the HOC to kerogen. This study disputes widely held hypothesis that sorption to mineral surfaces may play a major role in the overall sorption by low TOC (e.g. 0.1% by mass) geomaterials such as Borden sand. It also demonstrates the importance of the condensed NOM domain, even at very low contents, in the sorption and desorption hysteresis of HOCs in groundwater systems.
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Affiliation(s)
- Yong Ran
- State Key Laboratory of Organic Geochemistry, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Wushan, People's Republic of China.
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