Membranes for Cation Transport Based on Dendronized Poly(Epichlorohydrin-Co-Ethylene Oxide). Part 2: Membrane Characterization and Transport Properties

In this paper, we report on the preparation and characterization of membranes out of two side-chain liquid crystalline copolymers, dendronized at two different extents (20 and 40%, CP20 and CP40, respectively). The membranes were characterized by atomic force microscopy (AFM), field-emission scanning electron microscopy (FESEM), contact angle (CA) analysis, and water uptake. Moreover, transport properties were studied by methanol and proton conductivity experiment and by linear sweep voltammetry (LSV). For the sake of comparison, the behavior of the grafted copolymers was compared with the unmodified copolyether CP0 and with Nafion 117. Results demonstrated that in CP20 and CP40, cation transport depends on the presence of defined cationic channels, not affected by water presence; the comparison between LSV experiments performed with different alkaline cations suggests that CP40 possesses channels with larger diameters and better-defined inner structures.

Dynamics of Changes in Selected Soil Traits in the Profiles of Arable Soils Anthropogenically Alkalised by the Cement and Lime Industry within the Kielecko-Łagowski Vale (Poland)

This study presents the influence of the cement and lime industry on the physical and chemical properties of arable soils. In spite of using modern forms of environmental protection against dust emissions, this type of industry causes unfavourable phenomenon of excessive alkalisation of soil. This process is relatively rare in Poland. However, in the Świętokrzyskie Province, it has been responsible for the largest transformation of soils in recent years. The analysis included soil samples taken from five profiles located in the vicinity of Dyckerhoff Polska Sp. z o.o. Nowiny Cement Plant. The study results obtained in 2019 were compared with those obtained in 1978 and 2005. The most attention was paid to soil pH; CaCO3 content; organic carbon and nitrogen content; concentrations of available components such as P2O5, K2O and Mg; and the saturation level of sorption complex with alkaline cations. It was found that long-term imission of pollutants caused significant changes in the basic soil properties, which remain in soils despite the evident decrease in the cement-lime dust emission. These include high pH values, excessive CaCO3 content, high soil saturation with alkaline cations and decreases in total carbon content, which were especially visible in soil humus horizons.

A critical review of the variation in rainwater acidity in 24 Chinese cities during 1982–2018

Rainwater is an essential pathway to remove fine particulate matter and dissolved atmospheric pollutants (e.g., SO2, HNO3, and NH3). Acid rain (pH < 5.6) has been a severe environmental issue in China since the 1970s, adversely impacting ecosystem health. This study focuses on the influence of anthropogenically induced anions (SO42– and NO3–) and alkaline cations (Ca2+ and NH4+) on acid rain in Chinese cities. In this review, cities with high population density east of the Hu Huanyong Line that divides China geographically according to its uneven economic development were studied. Coastal and central areas of China to the east of the line are characterized by a much faster developing economy and rapid urbanization. The observed trends and spatial variability of acidity and chemical composition in rainwater are discussed in relation to industrialization and environmental changes in China. Over the past 3½ decades, the precipitation pH in the urban regions has exhibited reduced acidity. A mixed nitric–sulfuric acid rain type has become prominent due to the significant decrease in SO42– via desulfurization. Ca2+ levels have decreased, while NH4+ has increased slightly due to more vehicular transportation. In addition, the neutralization capacity of Ca2+ and NH4+ has decreased from north to south. Overall, the acid rain problem in Chinese cities has been alleviated in recent years.

Coastal Sediment as an Ameliorant in Post-Mining Land Management

Coastal sediment is a sediment resulting from sedimentation of eroded materials from up land through river flows that are deposited around the coast. It usually contains a lot of alkaline cations, especially Na so that it is good enough to decrease soil acidity. The use of coastal sediment must be considered carefully because it has a high level of salinity, which can inhibit plant growth and even cause death. Coastal sediment as an ameliorant can replace the role of lime in increasing the pH and base saturation of soil. Applying coastal sediment to sandy or post-gold mining soils can reduce soil acidity, increase soil CEC and soil base saturation, as well as the availability of nutrients, especially nutrients, phosphorus, potassium, calcium and magnesium. Improvement of some of these soil properties will encourage increased growth and crop yields in post gold mining land.

Counterion effect on sulfonatocalix[n]arene recognition

Sulfonatocalixarenes, like other ionic receptors, possess counterions that can affect the molecular recognition process. In the present review it is shown that the competitive effect of the alkaline cations frequently used as counterions determines not only the magnitude of the external guest association constant, but also the stoichiometry of the complexes. Experimental evidences are shown about the interaction of the counterions with sulfonatocalixarene, allowing to quantify its association equilibrium constants. The counterions recognition will be a competitive process that must be taken into account when investigating the interaction of calixarenes with an external guests. When the external guest is a neutral molecule it will be possible to form ternary complexes where the counterion shows a competitive and cooperative effect. By increasing the size of the receptor, sulfonatocalix[6] and sulfonatocalix[8]arene, the complexity of the system is increased due to the formation of counterion complexes with stoichiometries 1:1 and 1:2. In the presence of an external guest, the formation of heteroternary complexes with 1:1:1 stoichiometries including a counterion and an organic cation will be possible.