The aim of this study was to evaluate the effectiveness of the coagulation process using highly polymerised polyaluminium chlorides in reducing the level of pollution of water in a mixture of ...groundwater and surface water. The coagulants used were prehydrolysed polyaluminium chlorides with the trade names PAXHP908 and PAXXL1911 that had alkalinity 85% and different iron contents (<0.01% and 0.7%). The Al species distribution in the PACls (PAXXL1911 ad PAXHP908) samples were analysed by the Ferron complexation timed spectrophotometry. The content of polymer forms of aluminium (Alb) in the tested coagulants was 40%. The worse results in the removal of organic matter (TOC, DOC, UV254), iron, colour and turbidity in the coagulation process were produced by the PAXXL1911, possessing higher content of iron (0.7%). The lower usefulness of the PAXXL1911 was probably caused by the interaction of organic ligands present in the treated water and Fe(III) ions introduced into the water with the coagulant. The effectiveness of the coagulation process with the tested coagulants was also evaluated by measuring the electrokinetic potential ζ, which determines the stability of the colloidal system.
We report here for the first time on a reversible photodynamic bulk optode sensor based on the photoswitching of a spiropyran derivative (Sp). The photoswitching of Sp induces a large basicity ...increase in the polymeric phase, which triggers the extraction of Cl– and H+. Cl– is stabilized by a lipophilic chloride-selective ionophore inside the membrane, while H+ binds with the open form of Sp and induces a spectral change, hence providing the sensor signal. The system was studied with spectroscopic and electrochemical methods.
The force between silica surfaces in NaCl, KCl and CsCl aqueous solutions is studied at pH 5.5 using an atomic force microscope (AFM). As ion concentration is increased, more cations adsorb to the ...negatively charged silica, gradually neutralizing the surface charge, hence, suppressing the electrostatic double layer repulsion and revealing van der Waals attraction. At even higher salt concentrations, repulsion reemerges due to surface charge reversal by excess adsorbed cations. Adsorption grows monotonically with cation radius. At pH 5.5 the smallest ion, Na+, neutralizes the surface at 0.5−1 M, K+ at 0.2−0.5 M, and Cs+ at ∼0.1 M. Titration with HCl to pH 4.0 shifts surface neutralization and charge reversal to lower salt concentrations compared with pH 5.5. When attraction dominates, the force curves are practically identical for the three salts, independent of their concentration.
Ca
2+
-activated Cl
−
channels (CaCCs) are a class of Cl
−
channels activated by intracellular Ca
2+
that are known to mediate numerous physiological functions. In 2008, the molecular identity of ...CaCCs was found to be anoctamin 1 (ANO1/TMEM16A). Its roles have been studied in electrophysiological, histological, and genetic aspects. ANO1 is known to mediate Cl
−
secretion in secretory epithelia such as airways, salivary glands, intestines, renal tubules, and sweat glands. ANO1 is a heat sensor activated by noxious heat in somatosensory neurons and mediates acute pain sensation as well as chronic pain. ANO1 is also observed in vascular as well as airway smooth muscles, controlling vascular tone as well as airway hypersensitivity. ANO1 is upregulated in numerous types of cancers and thus thought to be involved in tumorigenesis. ANO1 is also found in proliferating cells. In addition to ANO1, involvement of its paralogs in pathophysiological conditions was also reported. ANO2 is involved in olfaction, whereas ANO6 works as a scramblase whose mutation causes a rare bleeding disorder, the Scott syndrome. ANO5 is associated with muscle and bone diseases. Recently, an X-ray crystal structure of a fungal TMEM16 was reported, which explains a precise molecular gating mechanism as well as ion conduction or phospholipid transport across the plasma membrane.
Although excellent performance such as high efficiency and stability have been achieved in quantum dot (QD)‐based light‐emitting diodes (QLEDs) possessing an organic/inorganic hybrid device ...structure, the highly expected all‐inorganic QLEDs remain at the bottleneck stage in recent years, resulting from the luminance quenching of QDs caused by inorganic hole transport layer (HTL) and unbalanced charge injection due to large energy barrier for injecting holes from HTL to QDs. Here, it is reported that the solution‐processed inorganic environmentally friendly chloride (Cl)‐passivated tungsten phosphate (Cl@TPA) films serve as HTL. The incorporation of Cl in TPA effectively passivates the oxygen vacancies, which not only avoids the luminescence quenching of QDs by reducing carrier concentration but also facilitates the hole injection from HTL to QDs with a favorable electronic band alignment, thus achieving the record external quantum efficiency of ≈9.27%, among all previous reports about all‐inorganic QLEDs. Most importantly, the resulting all‐inorganic QLEDs with Cl@TPA exhibit a substantial improvement in the operational lifetime (T50 > 105 h under an initial luminance of 100 cd m−2), which is almost 30‐fold higher than the devices with TPA HTL. This work furnishes a promising strategy for highly efficient and stable QLEDs based on inorganic device structure.
It is reported that an all‐inorganic quantum dot light‐emitting diode achieves a record EQE value of 9.27% by using a Cl‐passivated TPA HTL. The oxygen vacancies of TPA passivated by Cl results in the decrease of hole concentration and the increase of work function, which thereby suppresses the interface exciton quenching and promotes the hole injection capability in the device.
The chloride ion, Cl⁻, is an essential cofactor for oxygen evolution of photosystem II (PSII) and is closely associated with the Mn₄Ca cluster. Its detailed location and function have not been ...identified, however. We substituted Cl⁻ with a bromide ion (Br⁻) or an iodide ion (I⁻) in PSII and analyzed the crystal structures of PSII with Br⁻ and I⁻ substitutions. Substitution of Cl⁻ with Br⁻ did not inhibit oxygen evolution, whereas substitution of Cl⁻ with I⁻ completely inhibited oxygen evolution, indicating the efficient replacement of Cl⁻ by I⁻. PSII with Br⁻ and I⁻ substitutions were crystallized, and their structures were analyzed. The results showed that there are 2 anion-binding sites in each PSII monomer; they are located on 2 sides of the Mn₄Ca cluster at equal distances from the metal cluster. Anion-binding site 1 is close to the main chain of D1-Glu-333, and site 2 is close to the main chain of CP43-Glu-354; these 2 residues are coordinated directly with the Mn₄Ca cluster. In addition, site 1 is located in the entrance of a proton exit channel. These results indicate that these 2 Cl⁻ anions are required to maintain the coordination structure of the Mn₄Ca cluster as well as the proposed proton channel, thereby keeping the oxygen-evolving complex fully active.
Oxygen deficiency associated with soil waterlogging adversely impacts root respiration and nutrient acquisition. We investigated the effects of O₂ deficiency and salinity (100 mM NaCl) on radial O₂ ...concentrations and cell‐specific ion distributions in adventitious roots of barley (Hordeum vulgare). Microelectrode profiling measured O₂ concentrations across roots in aerated, aerated saline, stagnant or stagnant saline media. X‐ray microanalysis at two positions behind the apex determined the cell‐specific elemental concentrations of potassium (K), sodium (Na) and chloride (Cl) across roots. Severe O₂ deficiency occurred in the stele and apical regions of roots in stagnant solutions. O₂ deficiency in the stele reduced the concentrations of K, Na and Cl in the pericycle and xylem parenchyma cells at the subapical region. Near the root apex, Na declined across the cortex in roots from the aerated saline solution but was relatively high in all cell types in roots from the stagnant saline solution. Oxygen deficiency has a substantial impact on cellular ion concentrations in roots. Both pericycle and xylem parenchyma cells are involved in energy‐dependent K loading into the xylem and in controlling radial Na and Cl transport. At root tips, accumulation of Na in the outer cell layers likely contributed to reduction of Na in inner cells of the tips.
•The long term durability of geopolymer concrete under marine site was investigated.•The findings provide valuable data for a practice guide line of geopolymer concrete.•The findings could help ...select for fly ash geopolymer concrete used in marine site.
In this research, the effect of sodium hydroxide (Na(OH)) concentrations on chloride penetration, steel corrosion and compressive strength of fly ash-based geopolymer concretes under marine environment were studied. The geopolymer concrete were prepared from class C fly ash with sodium silicate (Na2SiO3) and sodium hydroxide (Na(OH)) solutions. The concentrations of Na(OH) of 8, 10, 12, 14, 16 and 18molar, and the constant molar ratio of SiO2/Al2O3 were used. The 200×200×200mm3 concrete cube specimens with steel bar embedded at coverings of 20, 50 and 75mm were investigated. The specimens were air-cured in laboratory for 28days and then were exposed to tidal zone of marine environment in the Gulf of Thailand. After 3-year exposure, the specimens were tested for compressive strength, chloride penetration and corrosion of embedded steel bar. The results showed that the chloride penetration and corrosion of embedded steel decreased with the increasing of Na(OH) concentration. The steel corrosion was related to the compressive strength of geopolymer concrete. The corrosion is high with the concrete of low compressive strength. In addition, increasing the Na(OH) concentration in geopolymer concrete resulted in a decrease in the chloride binding capacity.
Here, we report highly efficient deoxygenative chlorination of aldehydes and alcohols with a dichloromethyl methyl ether and TiCl4 system. The method converts various aldehydes and alcohols into the ...desired geminal dichlorides or chlorides with good to excellent yields (up to 99 %). Combined with a subsequent Rieche formylation step using the same reagent system, this method provides an efficient approach for synthesis of aromatic dialdehydes. This strategy involves deoxy‐chlorination of the aryl aldehydes followed by a second formylation of more activated benzal chloride derivatives. Dialdehydes can be easily obtained by hydrolyzing the corresponding of dichloromethyl derivative.
The synthesis of chloride and geminal dichloride derivatives through deoxygenative chlorination of aldehydes and alcohols was achieved in good to excellent yields by using dichloromethyl methyl ether and TiCl4. Given the nature of benzal chlorides, deoxygenative chlorination of aldehydes could serve as a platform for installing a second aldehyde on the aromatic ring by combining formylation reactions in the same reagent system.
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