Comparing conventional and emerging adsorbents for per‐ and polyfluoroalkyl substances: Kinetic, equilibrium, and column experiments

2021 ◽  
Vol 3 (6) ◽  
Author(s):  
Scott A. Grieco ◽  
Joseph Chang ◽  
Elizabeth (Lily) Y. Maio ◽  
Michael Hwang
Keyword(s):  
Column Experiments ◽  
Polyfluoroalkyl Substances ◽  
Kinetic Equilibrium

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

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.

Rates of Aluminum Dissolution in Acid Sandy Soils Observed in Column Experiments

1992 ◽  
Vol 21 (3) ◽  
pp. 439-447 ◽  
Author(s):  
Hans J.M. Grinsven ◽  
Willem H. Riemsdijk ◽  
René Otjes ◽  
Nico Breemen
Keyword(s):  
Sandy Soils ◽  
Column Experiments

Application of iron-coated sand on the treatment of toxic metals

2004 ◽  
Vol 4 (5-6) ◽  
pp. 335-341 ◽  
Author(s):  
Jae-Kyu Yang ◽  
Yoon-Young Chang ◽  
Sung-Il Lee ◽  
Hyung-Jin Choi ◽  
Seung-Mok Lee
Keyword(s):  
Heavy Metals ◽  
Selective Adsorption ◽  
Complete Removal ◽  
Batch Adsorption ◽  
Column Experiments ◽  
Adsorption Behaviour ◽  
Optimum Amount ◽  
Initial Ph ◽  
New Treatment ◽  
Coated Sand

Iron-coated sand (ICS) prepared by using FeCl3 and Joomoonjin sand widely used in Korea was used in this study. In batch adsorption kinetics, As(V) adsorption onto ICS was completed within 20 minutes, while adsorption of Pb(II), Cd(II), and Cu(II) onto ICS was slower than that of As(V) and strongly depended on initial pH. At pH 3.5, ICS showed a selective adsorption of Pb(II) compared to Cd( II) and Cu(II) . However, above pH 4.5, near complete removal of Pb(II), Cd(II), and Cu(II) was observed through adsorption or precipitation depending on pH. As(V) adsorption onto ICS occurred through an anionic-type and followed a Langmuir-type adsorption behaviour. In column experiments, pH was identified as an important parameter in the breakthrough of As(V). As(V) breakthrough at pH 4.5 was much slower than at pH 9 due to a strong chemical bonding between As(V) and ICS as similar with batch adsorption behaviour. With variation of ICS amounts, the optimum amount of ICS at pH 4.5 was identified as 5.0 grams in this research. At this condition, ICS could be used to treat 200 mg of As(V) with 1 kg of ICS until 50 ppb of As(V) appeared in the effluent. In this research, as a new treatment system, ICS can be potentially used to treat As(V) and cationic heavy metals.

Phosphorus transport in saturated slag columns: experiments and mathematical models

1996 ◽  
Vol 34 (1-2) ◽  
pp. 153-160 ◽  
Author(s):  
S. H. Lee ◽  
S. Vigneswaran ◽  
K. Bajracharya
Keyword(s):  
Mathematical Models ◽  
Sorption Capacity ◽  
Algal Blooms ◽  
Sandy Loam ◽  
Dynamic Condition ◽  
Water Environment ◽  
Breakthrough Curves ◽  
Column Experiments ◽  
Phosphorus Transport ◽  
Waste Products

Excessive phosphorus (P as orthophosphate) is one of the major pollutants in natural water that are responsible for algal blooms and eutrophication. P removal by slag is an attractive solution if the P sorption capacity of slag is significant. To design an efficient land treatment facility, basic information on the behaviour of P in the media-water environment is required. In this study, detailed column experiments were conducted to study the P transport under dynamic condition, and mathematical models were developed to describe this process. The column experiments conducted with dust and cake waste products (slag) from a steel industry as adsorbing indicated that they had higher sorption capacity of P than that of a sandy loam soil from North Sydney, Australia. P transport in the dust and cake columns exhibited characteristic S-shaped or curvilinear breakthrough curves. The simulated results from a dynamic physical nonequilibrium sorption model (DPNSM) and Freundlich isotherm constants satisfactorily matched the corresponding experimental breakthrough data. The mobility of P is restricted by the adsorbents and it is proportional to the sorption capacity of them.

Evaluation of Gas Retention in Waste Simulants: Tall Column Experiments

2014 ◽  
Author(s):  
Philip Schonewill ◽  
Phillip Gauglitz ◽  
Rick Shimskey ◽  
Kayte Denslow ◽  
Michael Powell ◽  
...  
Keyword(s):  
Column Experiments

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

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.

Rejection of per- and polyfluoroalkyl substances (PFASs) in aqueous film-forming foam by high-pressure membranes

2021 ◽  
Vol 188 ◽  
pp. 116546
Author(s):  
Charlie J. Liu ◽  
Timothy J. Strathmann ◽  
Christopher Bellona
Keyword(s):  
High Pressure ◽  
Film Forming ◽  
Polyfluoroalkyl Substances

scholarly journals A Chemical Category-Based Prioritization Approach for Selecting 75 Per- and Polyfluoroalkyl Substances (PFAS) for Tiered Toxicity and Toxicokinetic Testing

2019 ◽  
Vol 127 (1) ◽  
pp. 014501 ◽  
Author(s):  
Grace Patlewicz ◽  
Ann M. Richard ◽  
Antony J. Williams ◽  
Christopher M. Grulke ◽  
Reeder Sams ◽  
...  
Keyword(s):  
Polyfluoroalkyl Substances
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