Amphiphilic Perfluoropolyether Copolymers for the Effective Removal of Polyfluoroalkyl Substances from Aqueous Environments

Surface active per- and polyfluoroalkyl substances (PFAS) released in the environment generate great concern in the US and worldwide. The sequestration of PFAS amphiphiles from aqueous media can be limited...

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Effective Removal of Nitrogen and Phosphorus from SalineSewage by Dunaliella tertiolecta through Acclimated Cultivation

Modern Environmental Science and Engineering ◽

10.15341/mese(2333-2581)/05.01.2015/003 ◽

2015 ◽

Vol 1 (5) ◽

pp. 225-234 ◽

Cited By ~ 5

Author(s):

Kam-Chau Wu ◽

Kin-Chung Ho ◽

Yiu-Hung Yau

Keyword(s):

Dunaliella Tertiolecta ◽

Nitrogen And Phosphorus ◽

Effective Removal

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The Preparation of p(acrylonitrile-co-acrylamide) hydrogels for uranyl ion recovery from aqueous environments

Hacettepe Journal of Biology and Chemistry ◽

10.15671/hjbc.20144210823 ◽

2014 ◽

Vol 1 (42) ◽

pp. 89-89 ◽

Cited By ~ 4

Author(s):

Duygu Alpaslan ◽

Nahit Aktas ◽

Selehattin Yilmaz ◽

Nurettin Sahiner

Keyword(s):

Uranyl Ion ◽

Aqueous Environments

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Structure-Based Virtual Screening of Perfluoroalkyl and Polyfluoroalkyl Substances (PFASs) as Endocrine Disruptors of Androgen Receptor Activity Using Molecular Docking and Machine Learning

10.26434/chemrxiv.11886702.v1 ◽

2020 ◽

Author(s):

Azhagiya Singam Ettayapuram Ramaprasad ◽

Phum Tachachartvanich ◽

Denis Fourches ◽

Anatoly Soshilov ◽

Jennifer C.Y. Hsieh ◽

...

Keyword(s):

Machine Learning ◽

Molecular Docking ◽

Androgen Receptor ◽

Endocrine Disruptors ◽

Hormone Receptors ◽

Steroid Hormone Receptors ◽

Machine Learning Techniques ◽

Support Vector ◽

Polyfluoroalkyl Substances ◽

Perfluoroalkyl And Polyfluoroalkyl Substances

Perfluoroalkyl and Polyfluoroalkyl Substances (PFASs) pose a substantial threat as endocrine disruptors, and thus early identification of those that may interact with steroid hormone receptors, such as the androgen receptor (AR), is critical. In this study we screened 5,206 PFASs from the CompTox database against the different binding sites on the AR using both molecular docking and machine learning techniques. We developed support vector machine models trained on Tox21 data to classify the active and inactive PFASs for AR using different chemical fingerprints as features. The maximum accuracy was 95.01% and Matthew’s correlation coefficient (MCC) was 0.76 respectively, based on MACCS fingerprints (MACCSFP). The combination of docking-based screening and machine learning models identified 29 PFASs that have strong potential for activity against the AR and should be considered priority chemicals for biological toxicity testing.

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Clay liner materials for land disposal of hazardous non-metal wastes

Water Science & Technology ◽

10.2166/wst.1996.0154 ◽

1996 ◽

Vol 33 (8) ◽

pp. 71-77

Author(s):

I. M.-C. Lo ◽

H. M. Liljestrand ◽

J. Khim ◽

Y. Shimizu

Keyword(s):

Sorption Capacity ◽

Organic Anion ◽

Surface Exchange ◽

Clay Liner ◽

Effective Removal ◽

Exchange Constants ◽

Anionic Species ◽

Surface Ligand ◽

Land Disposal

Simple land disposal systems for hazardous and mixed wastes contain heavy metal cationic species through precipitation and ion exchange mechanisms but typically fail by releasing soluble organic and inorganic anionic species. To enhance the removal of anions from leachate, clays are modified with coatings of iron or aluminium cations to bridge between the anionic surface and the anionic pollutants. A competitive surface ligand exchange model indicates that surface coatings of 10 meq cation/gm montmorillonite under typical leachate conditions increase the inorganic anion sorption capacity by at least a factor of 6 and increase the intrinsic surface exchange constants by more than a factor of 100. Similarly, metal hydroxide coatings on montmorillonite increase the organic anion sorption capacity by a factor of 9 and increase the intrinsic surface exchange constants by a factor of 20. For historical concentrations of non-metal anions in US hazardous and mixed waste leachate, sorption onto natural clay liner materials is dominated by arsenate sorption. With cation coatings, anion exchange provides an effective removal for arsenate, selenate, phenols, cresols, and phthalates. Engineering applications are presented for the use of modified clays as in situ barriers to leachate transport of anionic pollutants as well as for above ground treatment of recovered leachate.

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Electrochemical Oxidation of Perfluorooctanesulfonate by Magnéli Phase Ti4O7 Electrode in the Presence of Trichloroethylene

10.21926/aeer.2004006 ◽

2020 ◽

Vol 1 (4) ◽

Author(s):

Peizeng Yang ◽

Yaye Wang ◽

Junhe Lu ◽

Viktor Tishchenko ◽

Qingguo Huang ◽

...

Keyword(s):

Electrochemical Oxidation ◽

Current Density ◽

First Order ◽

Degradation Rates ◽

Oxidation Technology ◽

Magnéli Phase ◽

Polyfluoroalkyl Substances ◽

Titanium Suboxide ◽

Gas Tight ◽

Magneli Phase

This study examined the degradation of perfluorooctanesulfonate (PFOS) in electrochemical oxidation (EO) processes in the presence of trichloroethylene (TCE). The EO experiment was performed in a gas-tight reactor using Magnéli phase titanium suboxide (Ti4O7) as the anode. The experimental data demonstrated that 75% of PFOS (2 μM) was degraded at 10 mA/cm2 current density in 30 min without TCE present in the solution, while the presence of 76 μM TCE apparently inhibited the degradation of PFOS, reducing its removal down to 53%. Defluorination ratio suggested that PFOS was significantly mineralized upon EO treatment, and it appeared to be not influenced by the presence of TCE. The respective pseudo-first order rate constants (kobs) of PFOS removal were 0.0471 and 0.0254 min-1 in the absence and presence of TCE. The degradation rates of both PFOS and TCE increased with current density rising from 2.5 to 20 mA/cm2. In the presence of TCE, chloride, chlorate, and perchlorate were formed that accounted for 79.7 %, 5.53%, and 1.51% of the total chlorine at 60 min. This work illustrates the promise of the Magnéli phase Ti4O7 electrode based electrochemical oxidation technology for degrading per- and polyfluoroalkyl substances (PFASs) and co-contaminants in groundwaters.

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