Polar organic chemical integrative sampler (POCIS) contains sorbent, which is typically enclosed between two polyethersulfones (PES) membranes. A significant PES uptake is reported for many ...contaminants, yet, aqueous concentration is mainly correlated with the sorbent uptake using first-order kinetics. Under high PES sorption, the first-order kinetics often provide erroneous sampling rate for the sorbent phase due to increased membrane resistance. This work evaluated the uptake of four high PES sorbing chemicals, i.e., three Cl- and CH3-substituted nitrobenzenes and one chlorinated aniline using POCIS and the potential of a single-phase PES sampler using laboratory experiments. POCIS calibration results demonstrated that both sorbent and membrane had similar affinity for the target compounds. A rapid PES sorption occurred in the earlier days (<7 days) followed by a gradual increase in the PES phase concentration (equilibrium not achieved after 60 days). Especially, the membrane was the primary sink for 3,4-dichloroaniline and 3,4-dichloronitrobenzene for up to 14 and 31 days, respectively. On the other hand, the single-phase PES sampler showed similar mass uptake as POCIS and reached equilibrium within 19 days under static condition, indicating its potential suitability in the equilibrium regime. PES-water partition coefficient of the target compounds was between 1.2 and 6.5 L/g. Finally, we present a poly-parameter linear-free energy relationship (pp-LFER) using published data to predict the PES-water partition coefficients. The pp-LFER models showed moderate predictability as indicated by R2adj values between 0.7 and 0.9 for both internal and external data set consisting of a wide range of hydrophobic and hydrophilic compounds (−0.1 ≤ logKOW ≤ 7.4). The proposed pp-LFER model can be used to screen high PES-sorbing chemicals to increase the reliability and accuracy of aqueous concentration prediction from POCIS sampling and to select the most appropriate sampling approach for new compounds.
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•Significant PES sorption in POCIS affects Rs calculation using first-order models.•Comparable mass uptake by single-phase PES and POCIS for substituted chlorobenzenes•PES-water partition can be calculated using developed pp-LFER model.•Model shows PES sampler can be used for both hydrophilic and hydrophobic chemicals.•Developed pp-LFER model can screen suitable compounds for PES and POCIS samplers.
The rapid development of industrial activities has led to the release of particulate matter and volatile organic compounds, the two major anthropogenic pollutants in the atmosphere. To degrade those ...air pollutants, photocatalysts are commonly used; a high photocatalytic activity is beneficial for enhanced degradation of air pollutants. In this study, electrospinning technology was used to combine the QD/TiO2 with both polyimide (PI) and polyethersulfone (PES) to form a PI/PES nano-fiber membrane. The Taguchi method was applied to calculate four operational parameters (PI/PES content, QD/TiO2 content, operational voltage, and electrospinning time) with three levels for nine combinations of experimental conditions. The optimal electrospinning conditions of the QD/TiO2@PI/PES module comprised 40 wt% PI/PES and 5 wt% QD/TiO2 in the electrospinning solution, and the operational voltage of 20 kV and electrospinning time of 2 h was applied to obtain filtration efficiency and quality of 99.60 % and 0.151. The degradation rates of methylene blue and acetone were 45.5% and 87% with photocatalysis reaction via QD/TiO2@PI/PES. In the antibacterial test, QD/TiO2 was highly efficient in inactivating Staphylococcus aureus (100%) under ultraviolet (UV) irradiation of 4 h. Therefore, QD/TiO2@PI/PES membrane showed great potential in medical and industrial applications for the elimination of both particulate matter and volatile organic compounds.
•The photocatalytic activity is beneficial for enhanced degradation of air pollutants.•QD/TiO2 with polyimide (PI) and polyethersulfone (PES) to form a nano-fiber membrane.•QD/TiO2@PI/PES shows the best filtration efficiency and quality of 99.60 % and 0.151.•The nano-fiber membrane shows great antibacterial efficiency of 100% against E. coli.
The rapid emergence of payments for ecosystem services (PES) schemes in China has been reported widely. However, it seems that the relevant policies and PES practices have not been fully documented. ...In this study, we provide insights into the overall status of PES schemes in China. We start by introducing the concept of eco-compensation, the equivalent of PES in China, and we describe its initiation and development. We then explore the institutional context upon which PES schemes are based on and we develop a classification system to interpret the different schemes. We employ the concept of PES-like scheme to reconcile divergent views on the scope of PES among researchers and decision makers. Subsequently, we describe the objectives, relevant policies from national to local level, implementation characteristics, funding sources, coverage, payment criteria, and primary effects of the major PES schemes. Broad institutional gaps, scheme overlaps, sole funding source, and the lack of effective tools in monitoring ecological outcomes are identified as major challenges for existing PES schemes. We conclude by proposing to reshape China’s PES frameworks and strengthen the market-based PES schemes, as well as scaling scale piloting PES schemes up to address pressing ecological issues in broader ecosystems and areas.
•We develop a classification system to clarify Chinese PES schemes.•We present recent data regarding the main PES schemes in China.•We report institutional, scheme overlapping, and monitoring issues in PES practice.
Payments for Ecosystem Services (PES) are defined in different ways and a variety of approaches is currently summarized under the PES label. This paper introduces a system for the ...multi-classification of PES schemes. The classification is based on different PES characteristics and their specifications. Analyzed characteristics include, amongst others: PES type, ecosystem service paid for (e.g. types of services, if the PES tries to improve the quality of the service vs. the quantity); payments specifics (e.g. funding sources, input- vs. output-based payments, etc.); involved actors (e.g. actors from the market, government or civil society sector); duration (short or long-term), and spatial scale (local to global). The classification system is then applied to 22 PES cases from Germany and the United States (US) that were assessed as successful by expert judgment. A comparative analysis (CA) is used to investigate how certain PES characteristics relate to PES success. Results of the CA indicate that characteristics such as intermediary involvement, involvement of governmental actors, contract length, co-benefits, voluntariness in entering the PES agreement, and design of PES as output-based schemes are of particular importance for the success of PES schemes.
•A system for the multi-classification of payments for ecosystem services is presented.•Classification is based on PES characteristics, such as ecosystem service addressed, payments specifics, involved actors, etc.•Classification is applied to PES cases from Germany and the United States, that were assessed as successful through expert judgment.•Relation of certain PES characteristics to overall PES success is examined through comparative analysis.
Abstract
The degradation reaction of CH
2
CN radical with O(
3
P) was firstly studied using quantum chemical methods. The energetics were calculated at CCSD(T)/cc‐pVTZ//B3LYP/6‐311++G(d,p). The ...formation of the intermediate C‐IM1 (CH
2
C(O)N) is the dominant channel by addition between O(
3
P) and the central‐C atom of CH
2
CN. Due to higher barriers, the terminal‐C‐addition/elimination, N‐addition/elimination, substitution and hydrogen abstraction channels are negligible. The rate constants were calculated by means of the RRKM‐TST theory. The total rate constants revealed positive temperature dependence and pressure independence. The calculated results were in good agreement with the experimental values.
This study aims to determine the effect of ammonium chloride (NH4Cl) on the characteristics and performance of polyethersulfone (PES)/Chitosan (CS)-based ultrafiltration composite membranes. The PES ...membranes were synthesized using phase inversion technique in dimethylacetamide (DMAc) solvent. A mixture of chitosan solution (fixed concentration) and NH4Cl (concentration 100–400 ppm) with ratio 2:1 (v/v) were coated into the PES membrane. The synthesized membranes morphology and properties were characterized by FTIR, SEM, contact angle, mechanical properties, and porosity tests. The membrane performance parameters including water permeability, rejection, and antifouling properties were studied. Incorporation of NH4Cl modified the membrane morphology and improved membrane porosity (49.64–71.5 %). The decrease in the water contact angle (80.21° to 63.53°) has confirmed the improvement of membrane hydrophilicity. Moreover, improved mechanical properties (11–16 MPa) were observed due to NH4Cl addition. The incorporation of NH4Cl improved water flux and specific flux membranes in dead-end cell from 51.34 to 159.18 L/m2∙h and 22–26.53 L/m2∙h∙bar, respectively, and in the cross-flow cell from 82.38 to 182.53 L/m2∙h and from 16.47 to 36.51 L/m2∙h∙bar, respectively. The addition of NH4Cl into membrane remarkably improved the rejection of bovine serum albumine (75.90 %, to 96.79 %), methyl orange (47.18–89.29 %), and methylene blue (60.14–97.34 %) Composite membranes have good fouling resistance as indicated by an increase in the flux recovery ratio (53.58–70.67 %). It is inferred that the addition of NH4Cl improved the performance of PES/chitosan composite membranes in ultrafiltration.
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•NH4Cl incorporated in PES/CS composite membrane via electrostatic interaction.•The NH4Cl/ PES/CS composite membrane has improved antifouling capability.•The permeability and permselectivity of the membrane were significantly enhanced.•Both structural modification and electrostatic interaction play a combinatorial role in contaminant rejection.
Short foot exercise (SFE) can be combined with dynamic functional tasks such as squats; however, it is unclear whether this combination increases intrinsic foot muscle activity.
This study aimed to ...investigate and compare the abductor hallucis muscle (AbdH) activity during SFE in static and dynamic functional tasks.
The AbdH electromyography data of 17 healthy participants with and without SFE were analyzed during static tasks (sitting, double-leg standing, and single-leg standing) and dynamic tasks (double-leg squat, single-leg squat, split squat, and heel-raise). The static tasks were performed with SFE for 5 seconds, and the dynamic tasks were performed while performing SFE. AbdH activity with or without SFE during the task was compared using the Friedman and Wilcoxon signed-rank tests.
AbdH activity was significantly greater in conditions with SFE than in those without SFE for all tasks (P < 0.01) except for heel-raise (P = 0.163). AbdH activity during SFE in single-leg standing was significantly higher than that in sitting, double-leg standing, and double-leg squats (P < 0.05). AbdH activity during SFE in the single-leg squat was also significantly greater than that in the sitting position (P = 0.024). No significant differences were found in any other between-task comparisons of AbdH activity during SFE. AbdH activity during tasks without SFE revealed significantly lower levels for sitting and double-leg standing compared to single-leg squat, split squat, and heel-raise (P < 0.001). Additionally, the activity in double-leg squat was significantly lower than in both single-leg squat and heel-raise (P < 0.05).
Combining dynamic tasks, except for the heel-raise task, with SFE can increase AbdH activity more than dynamic tasks without SFE. However, clinicians should note that combining dynamic tasks with the SFE may not increase AbdH activity compared to combining static tasks with the SFE.
•AbdH EMG was examined during SFE combined with static and dynamic tasks.•Dynamic tasks: double-leg (DL), single-leg (SL), and split squats and heel raise.•Performing SFE during the tasks increased AbdH EMG in all tasks except heel raise.•AbdH EMG during SFE was higher in SL stance than in sitting, DL stance and squat.•SFE during dynamic tasks did not show greater EMG than SFE during static tasks.
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•A novel tanning-inspired coating is suggested to surface modification of boehmite.•Hydrophilicity and surface softness was improved in novel embedded membranes.•The significant ...increment of permeability was observed in TA-BM/PES membranes.•The novel membranes show antifouling performance toward licorice and Direct Red.
We present a novel procedure for surface modification of boehmite nanoparticles via tanning-inspired coating. The impact of tannic acid coated boehmite (TA-BM) as a nanofiller on preparation of nanocomposite membranes were evaluated in terms of wettability, permeability, membrane morphology and fouling resistance capability. The surface morphology and chemical structure of TA-BM/PES blend membranes were investigated by SEM, AFM, measurement of contact angle and pore structure, FTIR and XRD analysis. Both of surface hydrophilicity and permeation flux of pure water improved significantly with incorporating of TA-BM nanofiller. The SEM image exhibited the wider finger-like pore of TA-BM/PES embedded membranes compared to bare PES membrane. The AFM image analysis indicated that, the roughness parameters of membranes reduced remarkably in presence of TA-BM nanostructures. In order to assessment of nanofiltration performance, the removal capability of Direct Red 16 and licorice dye was studied. The results revealed that, the TA-BM embedded membranes possessed superior dye removal capability (more than 96%) in comparison of bare membrane (90%). The antifouling performance tests of membranes studied by protein rejection. It was shown that, the best antifouling performance was belonged to 0.5 wt% TA-BM/PES blend membrane (FRR = 96.4%, Rir = 3.604). The TA-BM nanostructures had a great potential for surface treatment of hydrophobic membranes.
In this work, the
code, developed previously by the authors to find "holes" as well as legitimate transition states in existing potential energy surface (PES) functions JPC Lett. 11, 6468 (2020), is ...retooled to perform on-the-fly "direct dynamics"-type PES explorations, as well as automatic construction of new PES functions. In all of these contexts, the chief advantage of
over other methods is its ability to globally map the PES, thereby determining the most relevant regions of configuration space quickly and reliably-even when the dimensionality is rather large. Here,
is used to generate a uniformly spaced grid of density functional theory (DFT) or ab initio points, truncated over the relevant regions, which can then be used to either: (a) hone in precisely on PES features such as minima and transition states, or; (b) create a new PES function automatically, via interpolation. Proof of concept is demonstrated via application to three molecular systems: water (H
O), (reduced-dimensional) methane (CH
), and methylene imine (CH
NH).
In this paper the characteristics and functioning of PES is analyzed from an institutional perspective. While in theory PES is seen as a market solution to environmental problems — as an alternative ...to state (hierarchical) and community governance — a review of a large amount of case studies shows that PES in practice depends rather fundamentally on state and/or community engagement. Hence PES are foremost a reconfiguration of the roles of public bodies and communities becoming core intermediaries or ‘buyers’. First, to establish PES, rights to the land that delivers the environmental service must be clarified. This demands public action. Second, transacting over environmental amenities is very costly. Creating ‘markets’ for environmental services depends therefore crucially on state and community facilitation. Hence ‘buyers’ are often public agencies. High transaction costs also influence price setting. Payments do not follow the market format as intermediaries frequently are setting the price, with users often being unaware even of the fact that they pay. Finally, the distinction between payments as incentives and as fair compensations is emphasized. While payments may strengthen community relations and simplify action for environmental care, they may also introduce a purely instrumental logic and in some cases worsen the environmental status by crowding out environmental virtues. For the future, greater awareness of these dynamics is warranted.
