1
|
Hao L, Ma H, Xing B. Surface characteristics and adsorption properties of polypropylene microplastics by ultraviolet irradiation and natural aging. THE SCIENCE OF THE TOTAL ENVIRONMENT 2024; 944:173962. [PMID: 38876352 DOI: 10.1016/j.scitotenv.2024.173962] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/15/2024] [Revised: 05/23/2024] [Accepted: 06/11/2024] [Indexed: 06/16/2024]
Abstract
The vast application and deep integration of plastic commodity with our human lives raise a great concern about the ubiquitous microplastics (MPs) in nature, yet the environmental behavior of MPs remain unclear. As a main type and candidate of MPs, pristine polypropylene MPs (PP-MP-Pris), as well as the influence of ultraviolet (UV) irradiation on the degree of aging and surface characteristics, were characterized quantitatively by Fourier infrared spectroscopy, scanning electron microscopy, contact angle meter, automatic specific surface area and pore analyzer and laser particle analyzer, with natural aged PP-MPs (PP-MP-Age) as comparison. The carbonyl index (CI) of UV aged PP-MPs (PP-MP-U) was increased with extension of exposure time, while biofilm with abundant functional groups and the maximum CI value were the characteristics of PP-MP-Age. Moreover, the adsorption capacity of PP-MP-U for crystal violet (CV) was increased and reached the maximum after 30 days, while that of PP-MP-Age was weakened, probably due to the enhanced hydrophilicity and the shedding of calcium carbonate (CaCO3) during the natural aging process, which was demonstrated by hydrochloric acid treatment, indicating the vital involvement of CaCO3. Moreover, the better fitting to PSO kinetics and Freundlich isotherm models indicated that the multilayered and non-homogeneous surface adsorption was acted as the rate-controlling step. Furthermore, the positive values of ΔGθ, ΔHθ and ΔSθ indicated that the adsorption was a non-spontaneous, endothermic process with increased degree of the freedom on the interface of PP-MPs and CV solution. The presence of divalent salts inhibited CV adsorption, demonstrating that electrostatic attraction played a major role in CV capture. The hydrophobic interaction, micropore filling, hydrogen bonding, and π - π conjugation were possible involved. This study is of great significance for better understanding the complex pollution of MPs and its potential environmental risks in the future.
Collapse
Affiliation(s)
- Lin Hao
- School of Chemistry and Chemical Engineering, Shaanxi Normal University, Xi'An, Shaanxi 710119, PR China
| | - Hongzhu Ma
- School of Chemistry and Chemical Engineering, Shaanxi Normal University, Xi'An, Shaanxi 710119, PR China.
| | - Baoshan Xing
- Stockbridge School of Agriculture, University of Massachusetts, Amherst, MA 01003, USA
| |
Collapse
|
2
|
Lu C, Hu C, Chen Z, Wang P, Feng F, He G, Wang F, Zhang Y, Liu JZ, Zhang X, Qu J. Dehydration-enhanced ion-pore interactions dominate anion transport and selectivity in nanochannels. SCIENCE ADVANCES 2023; 9:eadf8412. [PMID: 37418527 PMCID: PMC10328398 DOI: 10.1126/sciadv.adf8412] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/16/2022] [Accepted: 06/06/2023] [Indexed: 07/09/2023]
Abstract
State-of-the-art ion-selective membranes with ultrahigh precision are of significance for water desalination and energy conservation, but their development is limited by the lack of understanding of the mechanisms of ion transport at the subnanometer scale. Herein, we investigate transport of three typical anions (F-, Cl-, and Br-) under confinement using in situ liquid time-of-flight secondary ion mass spectrometry in combination with transition-state theory. The operando analysis reveals that dehydration and related ion-pore interactions govern anion-selective transport. For strongly hydrated ions [(H2O)nF- and (H2O)nCl-], dehydration enhances ion effective charge and thus the electrostatic interactions with membrane, observed as an increase in decomposed energy from electrostatics, leading to more hindered transport. Contrarily, weakly hydrated ions [(H2O)nBr-] have greater permeability as they allow an intact hydration structure during transport due to their smaller size and the most right-skewed hydration distribution. Our work demonstrates that precisely regulating ion dehydration to maximize the difference in ion-pore interactions could enable the development of ideal ion-selective membranes.
Collapse
Affiliation(s)
- Chenghai Lu
- State Key Laboratory of Environmental Aquatic Chemistry, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Chengzhi Hu
- State Key Laboratory of Environmental Aquatic Chemistry, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Zhibin Chen
- State Key Laboratory of Environmental Aquatic Chemistry, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Peiyao Wang
- Department of Mechanical Engineering, The University of Melbourne, Parkville, VIC 3010, Australia
| | - Fan Feng
- Department of Mechanical Engineering, The University of Melbourne, Parkville, VIC 3010, Australia
| | - Guangzhi He
- State Key Laboratory of Environmental Aquatic Chemistry, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Fuyi Wang
- University of Chinese Academy of Sciences, Beijing 100049, China
- Beijing National Laboratory for Molecular Sciences, CAS Key Laboratory of Analytical Chemistry for Living Biosystems, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, China
| | - Yanyan Zhang
- University of Chinese Academy of Sciences, Beijing 100049, China
- Beijing National Laboratory for Molecular Sciences, CAS Key Laboratory of Analytical Chemistry for Living Biosystems, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, China
| | - Jefferson Zhe Liu
- Department of Mechanical Engineering, The University of Melbourne, Parkville, VIC 3010, Australia
| | - Xiwang Zhang
- UQ Dow Centre for Sustainable Engineering Innovation, School of Chemical Engineering, The University of Queensland, St. Lucia, QLD 4072, Australia
| | - Jiuhui Qu
- State Key Laboratory of Environmental Aquatic Chemistry, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| |
Collapse
|
3
|
Vernin NS, Gillespie D. Surface charge regulation using classical density functional theory: the effect of divalent potential determining ions. Phys Chem Chem Phys 2023; 25:1023-1031. [PMID: 36533726 DOI: 10.1039/d2cp03644d] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
The charge regulation approach has been used to describe the charge of surfaces susceptible to the presence of protons and other ions. Conventionally, this model is used with the Poisson-Boltzmann equation, which generally neglects the finite size of the ions and the electrostatic correlations. Recently, progress has been made by coupling charge regulation with classical density functional theory (DFT), which explicitly includes these correlations. However, little is known about charge regulation at surfaces with both acid-base equilibria and complexation with multivalent ions. The main purpose of this work is to investigate the role divalent ions play in charge regulation. Using DFT, we show that the size of the divalent ion has significant consequences on the surface charge density and it should not be neglected. For the surface reactions investigated, the larger the size of the divalent cation, the greater the charge on the surface due to higher divalent concentration there. At low divalent concentration, the ion correlations play a second-order but non-negligible role; using Poisson-Boltzmann theory with point ions cannot recover the DFT surface charge. At high concentrations, ion correlations play a dominant role by creating charge inversion.
Collapse
Affiliation(s)
- Nathalia Salles Vernin
- Department of Sanitary and Environmental Engineering, Rio de Janeiro State University, Rio de Janeiro, RJ 20550-900, Brazil.
| | - Dirk Gillespie
- Department of Physiology and Biophysics, Rush University Medical Center, Chicago, IL 60612, USA.
| |
Collapse
|
4
|
Sam S, Krem S, Lee J, Kim D. Recovery of Fatty Acid Monolayers by Salts Investigated by Sum-Frequency Generation Spectroscopy. J Phys Chem B 2022; 126:643-649. [PMID: 35026947 DOI: 10.1021/acs.jpcb.1c08028] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Langmuir monolayers consisting of fatty acids with relatively short alkyl chains (C14H29COOH (pentadecanoic acid), C15H31COOH (palmitic acid), and C16H33COOH (heptadecanoic acid)) are stable at a neutral pH (pH ≈ 6) but become unstable at a high pH (pH ≈ 11). Further addition of a small amount of divalent salt in subphase water was found to recover the monolayer at a high pH because binding of the divalent cations to the carboxylic headgroups renders the molecule more stable against dissolution in subphase water. This revival of the monolayer was observed via a pressure-area isotherm measurement and sum-frequency generation spectrum in the CHx and OH ranges. Fatty acids with longer alkyl chains needed less amount of MgCl2 to recover the monolayer at a high pH. A much lower concentration of Mg2+ as compared to Ca2+ is required to revive fatty acid molecules to the surface. Monovalent and trivalent salts were compared with the above divalent salts on the ability to recover the fatty acid monolayers.
Collapse
Affiliation(s)
- Sokhuoy Sam
- Department of Physics, Sogang University, 35, Baekbeom-ro, Mapo-gu, Seoul 04107, Korea
| | - Sona Krem
- Department of Physics, Sogang University, 35, Baekbeom-ro, Mapo-gu, Seoul 04107, Korea
| | - Jaejin Lee
- Department of Physics, Sogang University, 35, Baekbeom-ro, Mapo-gu, Seoul 04107, Korea
| | - Doseok Kim
- Department of Physics, Sogang University, 35, Baekbeom-ro, Mapo-gu, Seoul 04107, Korea
| |
Collapse
|