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Abstract This study aims to optimize ammonium removal from NH4Cl‐enriched groundwater at different concentrations using an electrodialysis (ED) process. A customized design (CD) based on response surface methodology (RSM) was employed to develop predictive models and improve the performance of the demineralization system. Ion removal efficiency was evaluated in 32 unique experimental configurations, taking into account variations in three input parameters: voltage (A), initial ammonium concentration (B) and demineralization rate (C). These parameters were selected for their impact on two response variables: electric conductivity (Y1) and final ammonium concentration (Y2). An in‐depth analysis of variance (ANOVA) was performed to examine the variables and their interactions. The results indicated that Y1 was significantly influenced by C, while Y2 was influenced by B. In addition, the predictive models demonstrated strong correlations, with a coefficient of determination (R2) greater than 0.88 for both response variables. The RSM approach applied to optimize the parameters studied identified the following optimum values: 14.17 V for A, 1 mg/L for B and 70 % for C, giving Y1 of 215.377 μS/cm and Y2 of 0.279 mg/L.

Similar to most wetlands, the Florida Everglades landscape was altered to promote agriculture and human settlement, significantly altering the natural hydrologic regime. Once former agricultural land located within Everglades National Park (ENP), the Hole-in-the-Donut (HID) wetland restoration program became the first mitigation bank project in Florida. The HID program utilized a restoration technique of complete soil removal to effectively eradicate an invasive plant species. This research investigated the effects of the vegetation and soil removal on the hydrologic conditions of the HID, specifically evapotranspiration and water chemistry. Annual evapotranspiration rates were determined for the region using remotely sensed data and compared to the acres restored over a 15-year period. Groundwater and surface waters were collected from both inside the HID and from adjacent areas within ENP for major cations and anions and total nutrient concentrations. Evapotranspiration rates were found to decrease from a mean of 1083.4 mm year−1 in the year 2000 to 891.6 mm year−1 in 2014 as the restored area increased to 4893 acres. Concentrations of ions and nutrients were lower in groundwater and surface water within the restored areas compared to adjacent areas. We conclude that the lack of soil cover (along with reduced evapotranspiration rates) contributed to the lower ion and nutrient concentrations in the surface water and groundwater within the HID. [ABSTRACT FROM AUTHOR]

ABSTRACTAn effective ligand for the Ullmann-type C–N coupling reaction in water has been obtained using a novel tactic, namely, introducing a third group into the ligand to both improve the ligand’s water solubility and enhance the ligand’s coordinating ability. Applying this method, we have developed an effective ligand for the Cu-catalyzed amination of aryl halides, in particular, for aryl chlorides in water. The substrate diversity of the catalyst system, relatively less time required (6–12 h), and water as the reaction solvent make it attractive in both academia and industry.

Reversible or movable cross-links based on host-guest interactions in supramolecular materials create functions such as enhanced mechanical properties and stimulus responsiveness. A supramolecular complex on a polymer side chain achieves the described functions as a reversible cross-link. Generally, 1:1 complex is utilized as a cross-link for the host-guest interaction based-supramolecular materials, but herein, the 1:2 complex between γ-cyclodextrin (γCD) and methyl viologen terminated undecyl acrylate (VC11) was chosen to cross-link three polymeric chains. The obtained supramolecular hydrogels γCD-VC11 (x, y) (x and y represent the mol% of the γCD and VC11 units in feeding, respectively) was prepared by radical copolymerization with acrylamide as a mainchain monomer. Tensile test revealed that toughness (Gf) of γCD-VC11 (x, y) maximized at water content (Wc) ≈ 40 wt.%. The maxima of Gf depended on the amount of γCD and VC11 units. Through dynamic mechanical analysis, Arrhenius style plots between horizontal shift factors and temperature determined activation energies (Ea) of each γCD-VC11 (x, y) and MBAAm (0.5). Ea of MBAAm (0.5) monotonically decreased with the increasing Wc. On the other hand, slope of Ea of γCD-VC11 (x, y) changed at Wc ≈ 40 wt.%. Simultaneously considering results of the tensile tests and DMA, the reversible cross-links formed by γCD and VC11 in γCD-VC11 (x, y) function effectively at appropriate Wc.

Clear-cutting removes a stand cover suddenly, thus impacting soil-surface conditions by the expected increase in the humus breakdown rate, due to the addition of more precipitation and solar radiation. The impacts of removing a forest were studied at a site with deep sandy soils dominated by Scots pine, where three treatments, including a stand left on site, whole-tree harvesting treatment, and stem-only harvesting treatment, were established. Clear-cut precipitation and sub-canopy throughfall were measured. The non-replicated treatments were equipped with lysimeters at depths of −10 cm and −70 cm and in addition, three exploratory wells were drilled to sample groundwater in each of the treatments. The volume and chemistry of the water samples were periodically analyzed. The mean throughfall was 84% of open-area precipitation and the pH of the water penetrating the canopy was significantly lower overall, although the subcanopy samples were only slightly more acidic. Significant differences among the treatments were shown in throughfall (total organic carbon, TOC), shallow subsurface water (pH, TOC, NO3−), subsurface water at the 70-cm depth (NO3−) and also groundwater (pH, TOC, NO3−), where some of the differences had been observed before the stand parts were clear-cut. Limits for drinking water were exceeded in groundwater pH, as the values from both clear-cut sites fell below pH 6.5 following clear-cutting. TOC greater than 5 mg·L−1 was found in the Q1-2020 samples, whereas groundwater nitrate remained low, even though the three wells differed significantly from each other. Due to the non-replicated design of the experiment, generalization of the outcomes is a matter of further research. [ABSTRACT FROM AUTHOR]

Soap is a substance now taken for granted, but there is uncertainty, myth and misinformation about its development, and little scholarly attention has been paid to the likely circumstances surrounding its discovery. As part of a MSc in Experimental Archaeology, a project collated the earliest mentions of proto-soaps, reassessed previous experimental conclusions, and developed testable scenarios to explore how soap was first discovered, suggesting that the degreasing of fatty cloths after straining perfumed fats and oils may provide the conditions under which soap was first reliably and repeatedly observed. This paper offers a condensed version of this work. [ABSTRACT FROM AUTHOR]

We present the synthesis of new chiral water-soluble dimeric capsules by the multicomponent Mannich reaction between charged amino acids (glutamic acid or arginine), resorcinarene, and formaldehyde and by subsequent self-assembly. The zwitterionic character of the backbones enables electrostatic interactions between arms and induces self-assembly of dimeric capsules, namely, (L-ArgR)2 and (L-GluR)2, in water with a wide range of pH, as demonstrated by NMR, diffusion coefficient measurement, and circular dichroism. The assembly/disassembly processes are fast on the NMR timescale. This mode of dimerization leaves side chains available for additional interactions and creates chiral cavities of mixed hydrophobic/hydrophilic character. According to this characteristic, capsules do not bind fully nonpolar or fully polar guests but effectively encapsulate a variety of chiral molecules with mixed polar/apolar characters (aliphatic and aromatic aldehydes, epoxides, alcohols, carboxylic acids, amines, and amino acids) with moderate strength. We also demonstrate the formation of heterocapsules (GluR) (ArgR) (homo- and heterochiral) that utilize additional interactions between charged acidic and basic side chains and have better encapsulation properties than those of the homodimers.

Abstract The use of pesticides in agriculture is known to have environmental impacts, namely it leads to underground and spring water contamination. Thus, it turns out that nowadays general‐endeavor towards the sustainability of farmer production requires novel strategies to capture pesticides from water and soils. We propose a methodology based on molecular dynamics simulations to identify polymers that are potentially featured to be applied for pesticide remediation in water and soils. We have employed cymoxanil (CYM), glufosinate ammonium (GLF), imidacloprid (IMI) and mancozeb (MAN) as pesticides, and have tested polymers with different characteristics as removing agents. Specifically, we have investigated oligomers of polypropylene (PP), poly(acrylic acid) protonated (PAAH) and deprotonated (PAA), and chitosan protonated (CTH) and deprotonated (CT). It has been found that all oligomers show a certain degree of selectivity concerning the interaction with the tested pesticides.

Water data collected from 33 lakes across the Upper Midwest in two sampling regimes spanning ~ 20 years were used to detect changes in water chemistry. Significant increases in chloride, total dissolved solids, and pH, and decreases in magnesium were observed between the two datasets. Rates of change per year were greatest for Cl (0.088 mg L−1 yr−1) and TDS (1.88 mg L−1 yr−1), with road salt application and an increase in impervious surfaces related to urbanization being the suggested causes. The decrease in atmospheric sulphate deposition over the time period was a likely driver for higher pH. Principal component analyses of 10 water chemistry variables for each sampling period were compared using Procrustes rotation, with sample scores from 2013 representing the change in water chemistry (ΔWC). Correlations between mean annual temperature (r = 0.545, p = 0.001) and total annual precipitation (r = −0.672, p = 0.000) with ΔWC warranted the development of a regression model that explained 50% of the variance in the ΔWC (adjusted r2 = 0.50, p < 0.001). The two datasets, collected 20 years apart, reveal trends similar to those observed in other studies. [ABSTRACT FROM AUTHOR]

The results of long-term studies of a group of aufeis-forming Buluus groundwater sources are given. A stow, which has been formed by the spring, contains the drainage area of the suprapermafrost–intrapermafrost aquifer, which is widespread in the sand deposits of the bestyakhskaya terrace of the Lena River in Central Yakutia. The analysis of observations of 1964–2017 showed stable water chemistry in Buluus spring at the long-term scale. Considerable seasonal variations of water chemistry are typical of low-discharge springs, which start functioning after becoming free of aufeis. The spring water also shows higher concentrations of lithium and fluorine. The possible causes of the different chemistry of spring water are discussed, with special attention paid to the local activity of rock freezing and thawing processes in the aufeis valley. It is shown that groundwater samples are to be taken from all springs in the areas of their group discharge with the aim to assess the effect of natural and technogenic factors on the permafrost–hydrogeochemical conditions. [ABSTRACT FROM AUTHOR]

The carbonate chemistry of freshwater systems can range from inorganic carbon‐limited to supersaturated with respect to the atmosphere, and the pH of these systems can vary temporally and spatially from alkaline to acidic. Determining how these heterogeneous systems respond to increases in atmospheric CO2 is critical to understanding global impacts of these changes. Here, we synthesize 22 studies from a variety of systems to explore the effects of elevated CO2 on freshwater chemistry and microalgae, which form the base of autotrophic food webs. Across the variability in freshwater systems, elevated CO2 significantly affected water chemistry by decreasing pH and increasing dissolved inorganic carbon. Microalgae were also affected by elevated CO2 with measured increases in (1) nutrient acquisition through microalgal carbon‐to‐nutrient ratios, (2) photosynthetic activity, and (3) growth. While these effects were measured from controlled experiments, the results indicate a wide range of potential freshwater ecosystem effects from elevated atmospheric CO2. Our synthesis also identified several knowledge gaps. Generally, larger sample sizes and studies of longer duration are needed for more robust analyses and conclusions. Additionally, more field experiments across a range of freshwater ecosystem types and studies involving benthic species and multiple trophic levels are needed to strengthen global predictions across the broad variability found within and among freshwater systems. [ABSTRACT FROM AUTHOR]

The 47 Lake Regions of Florida and the six total phosphorus and five total nitrogen zones developed from those regions, provide a spatial framework for lake water quality management. Among 44 of the regions, median lake water and shallow groundwater chemistries were positively and significantly correlated for pH (R2 = 0.13), specific conductance (R2 = 0.54), total alkalinity (R2 = 0.21). sodium (R- = 0.62). chloride (R- = 0.63), calcium (R2 = 0.36). magnesium (R2 = 0.48). sulfate (R- = 0.12), TP (R- = 0.32), potassium (R2 = 0.34) and silica (R2 = 0.16). Median mainland (excluding the Keys) groundwater specific conductance values exceeded lake water values by a factor of 1.7 but ranged from 0.52 to 4.1 in the different regions. Groundwater (R2 = 0.88) and lake water (R" = 0.86) temperatures were inversely correlated with latitude (warmer in south Florida than north Florida). Groundwater pH (R" = 0.63). total alkalinities (R2 = 0.77), specific conductance (R2 = 0.80), sodium (R" = 0.96). and chloride (R" = 0.97) also increased moving southward. Groundwater pH (R2 = 0.38), alkalinity (R- = 0.52) and specific conductance (R2 = 0.58) were inversely correlated with land elevation increases. The Luke Regions of Florida could, therefore, potentially serve as a spatial framework for shallow groundwater management. [ABSTRACT FROM AUTHOR]