Order Cl Research Articles

Binder-free La(OH)3 supported activated carbon fiber electrode with N-doped C layer for efficient phosphate electrosorption

Binder-free La(OH)3 supported activated carbon fiber (ACF) electrode with modification of N-doped C layer (named LNA) was developed for phosphate (P) electrosorption. The optimum electrosorption of P on LNA was achieved at pH = 4 and voltage = 4 V. The electrosorption capacity was 6.5 times that without voltage, and adsorption rate also increased by 9 times. The presence of 0.1 mol/L inorganic anions improved the electrosorption efficiency in the order of Cl->NO3–>SO42->HCO3–>CO32–. The regeneration study revealed that LNA still exhibited a high electrosorption capacity (29.91 mg/g) after 5 cycles. The mechanism of phosphate electrosorption of LNA was analyzed by kinetics, isotherms, FTIR and XPS, etc. The adsorption kinetics followed the pseudo-second-order model, and the adsorption equilibrium data were well described by the Langmuir isotherm. The Langmuir maximum electrosorption capacity of LNA was 70.66 mg/g. The electrosorption of phosphate was controlled by ion exchange, electrostatic attraction and the formation of surface complexes. N-doped C layer affected the local electronic structure of La and strengthened the interaction with lanthanum hydroxide, promoting the electrosorption of phosphate. The results demonstrated that LNA is a promising electrosorption material for efficient phosphate recovery.

(Invited) Effects of Halide Anion Type and Alkyl Chain Length on Hydrogen Bonding in Eutectic Solvent System

Deep eutectic solvent (DES), formed by the intermolecular hydrogen bonding between its components of an H–bond acceptor (HBA) and an H–bond donor (HBD), has been extensively studied in the area of material synthesis, catalysis, electrochemistry, etc. The properties of DES including melting point, color, density, viscosity, conductivity, etc. are closely related to the H-bond network. Establishing an understanding of the H-bond structure offers an opportunity to fine-tune these properties.Hence, in this study, we systematically investigated the effects of halide anion type and alkyl chain length on the hydrogen bond network of a series of eutectic solvent systems and attempted to establish an unambiguous H-bond correlation with the conductivity. We varied the halide anion from Cl− to I− (Cl−, Br−, I−) and the alkyl chain length from methyl to butyl (n c = 1, 2, 4), and performed FTIR and conductivity measurements. Results show that the OH stretching peak exhibits a blue shift with the halide anion varies in the order of Cl−, Br−, I− when compared with the neat ethylene glycol (Figure 1a), indicating an increase in H-bond strength. A similar trend can be found with the increasing alkyl chain length as well. A stronger H-bond network inhibits the mobility of these halide anions in the eutectic system, as a result, the conductivity will decrease as shown in Figure 1b. Further probing the H-bond network with ultrafast spectroscopy is currently underway. Figure 1. (a) FTIR spectrum of neat EG and TBAX:EG(1:10) sample, X= Cl−, Br−,I−. (b) Trend between the OH stretching peak shift (vs. neat EG) and conductivity of these investigated samples.AcknowledgememtsThis work was supported as part of the Breakthrough Electrolytes for Energy Storage (BEES), an Energy Frontier Research Center funded by the U.S. Department of Energy, Office of Science, Basic Energy Sciences under Award # DE-SC0019409 Figure 1

Efficient degradation of imidacloprid in soil by thermally activated persulfate process: Performance, kinetics, and mechanisms

Imidacloprid (IMI) as a first-generation commercial neonicotinoid has been frequently detected in the environment in recent years. In this study, the efficient degradation of IMI in soil by a thermally activated persulfate (PS) process was investigated. The degradation efficiencies of IMI were in the range of 82–97% with the PS dosage of 10 mM, when the initial concentrations of IMI were 5–50 mg/kg in the soil. Degradation of the IMI was fitted with a pseudo-first-order kinetic model under different reaction temperatures. Inhibition effects of the common inorganic anions on the IMI degradation in the system followed the order Cl- > HCO3- > H2PO4- > NO3-. Soil pH and soil organic matter were also main factors affecting the degradation of IMI. The degradation efficiencies (64–97%) of three other typical neonicotinoids (acetamiprid, clothianidin, and dinotefuran) indicated that the thermally activated persulfate process could be used for remediation of neonicotinoid-contaminated soil. Quenching experiments indicated that the major reactive species in IMI degradation were SO4•-, O2•-, and •OH. Six degradation intermediates of IMI were inferred in the soil, and degradation pathways of IMI included hydroxylation, denitrification, C-N bond break and further oxidation.

Effect of Halogens in Bis(haloaryloxyl)pyrazine Host Crystals on the Room Temperature Phosphorescence Properties of Bisbenzofuropyrazine Guest Luminophores

Several title host crystals including guest luminescent compounds exhibit apparent room temperature phosphorescence (RTP) along with fluorescence under atmospheric conditions. The lifetime of RTP is a marked function of the halogen atoms, decreasing in the order of Cl > Br > I, while the phosphorescence efficiency depends on the structural compatibility of the guests in the host crystals.

Study on Extraction Performance of Vanadium (V) from Aqueous Solution by Octyl-Imidazole Ionic Liquids Extractants

It is worth it to explore the extraction performance for vanadium by the imidazole ionic liquids. The extraction of vanadium (V) was studied using [Omim]Cl, [Omim]Br, and [Omim][BF4] as extractants. The effects of various diluents, equilibrium time, extraction temperature, and anion species were investigated. The structure-activity relationship of vanadium and ILs was discussed by calculating the lattice energy of ILs based on the Glasser theory and the volume of anions. The results show that n-pentanol is the optimum diluent. Under the extraction conditions of an equilibrium time of 60 s and extraction temperature of 25 °C, the extraction rates of V (V) by [Omim]Cl, [Omim]Br, and [Omim][BF4] reached 97.93%, 96.59%, and 87.01%, respectively. Furthermore, based on the Glasser theory, the lattice energy of ionic liquids decreased in the order [Omim]Cl > [Omim]Br > [Omim]BF4. The volume of the anions increased in the order Cl− < Br− < BF4− < HVO42−. The extraction rate of V (V) depended on the size of the anions and the strength of the interaction between the anion and imidazolium cation. The results of counterevidence experiments verified the larger the anion volume, the easier it is to combine with cation in the organic phase, and the lattice energy of extracted compound is lower. The statistical analysis showed that the effect of the equilibrium time and temperature were not significant in the model, and the anions species showed a significant effect on the extraction efficiency of V (V).

Biosorption of arsenite (As[III]) using Saccharomyces cerevisiae SRCM 501804 isolated from Korean turbid rice wine

The potentiality of Saccharomyces cerevisiae SRCM 501804 to remove arsenite (As[III]) in an aqueous solution was investigated in this study. The S. cerevisiae SRCM 501804 was isolated from Korean turbid rice wine (Makgeolli). The S. cerevisiae SRCM 501804 was characterized by phylogenetic analysis, Fourier transform infrared (FT-IR) spectroscopy, visual minerals technologies (MINTEQ) model, and point of zero charge (pHpzc). The relationship between the factors (pH, biosorbent dosage, contact time, and concentration) and biosorption capacity was investigated. The S. cerevisiae SRCM 501804 was removed 31.1–90.1% of the As(III) depending on the initial biomass dosage within 1 h. Co-existing anions in aqueous solution showed a negative influence on the biosorption performance of As(III) in the order Cl− > NO3 − > SO4 2− > CO3 2−. The results of isotherms and kinetics suggested the Langmuir (R 2 > 0.95) and Pseudo-second order (R 2 > 0.99) models fit well with the equilibrium experimental data. The maximum biosorption capacity (qm ) of S. cerevisiae SRCM 501804 biomass for As(III) was found to be 113.9 mg/g from Langmuir isotherm. Based on the results, it can be concluded that the biomass of S. cerevisiae SRCM 501804 could be used as an effective bio-sorbent for As(III) biosorption in an aqueous solution.

Hydrochemistry and Application of GIS in Groundwater Quality in Nagalapura Taluk, Bellary District, Karnataka, India

The assessment of groundwater quality is essential for the conservation of natural resources. Hence, this study aims to assess the hydrochemistry of groundwater in and around the Nagalapura Taluk in Bellary district, Karnataka, India. The groundwater quality variables are mapped using a Geographic Information System (GIS). For the hypothesis, the mean value of ten groundwater quality variables was obtained from 50 bore well samples (2016-2018). To assess the lead ions and type of water, the USSL, SAR, and Na% were measured. Ionic ratio and Gibbs graphs were used to demonstrate the chemical reactions in the water samples. ArcGIS was used for spatial analysis of the quality variables. The results showed the order of Cl- > SO42- > HCO3- with water types Na+-Cl- and Cl-, and the order of Na+ > Mg++ > Ca++ > K+ with Na+ and Mg++ as the dominant anion and cation, respectively. The hydrochemistry of groundwater is determined by the geological structure in 64 percent of the water samples examined. The Wilcox diagram shows that no-alkali exposure to the crops is expected. Forty one samples (82%) fit within the C3-S1 group; this category is fit for irrigational needs. Only 01 and 03 samples showed maximum SAR during two seasons like pre-monsoon and post-monsoon periods. The maps showed that groundwater in the selected sites is usually of higher quality, whereas the presence of dolomite indicates a reduction in water quality.

Source analysis and health risk assessment of groundwater pollution based on multivariate statistical techniques in Kashgar Delta Area, Xinjiang, China.

In this study, 63 groundwater samples were collected in the Kashgar Delta Area in Xinjiang in 2016, and then, the samples were tested and the test results were analyzed. Multivariate statistical techniques were used to determine the sources of pollution, and the USEPA (United States Environmental Protection Agency) model was used to assess the long-term health risk of groundwater to adults and children in the study area. The concentrations of groundwater chemical Na+, Cl-, SO42-, NH4+-N, TDS, F-, I-, As, Fe, Mn, Pb, Hg, pH, TH, and CODMn, which exceed the permissible level in the study based on groundwater quality index and possibly pose a potential threat to the health of the residents in the area, which are mainly influenced by geological conditions. The source of the pollutants is the dissolution of minerals in the aquifer medium, which is greatly affected by the high-salinity groundwater environment, pH conditions, redox conditions, and evaporation and concentration effect. The values of the noncarcinogenic health risk index HQn follow the descending order of Cl- > F- > As > Fe > Mn > Pb > Hg > NH4+-N; There are eight nonarcinogens and one carcinogen in groundwater of which Cl- is the dominant noncarcinogenic factor, while As is the main carcinogenic pollutant in the study area. The health risk ratio results show that Cl- and As are the main pollutants that pose the greatest threat to both adults' and children's health, and they should be considered as the primary indicators for health risk management and control.

Water quality index and hydrogeochemistry of Otukpo area, Benue State, North Central Nigeria

The research is aimed to assess the surface and groundwater quality in Otukpo area and environs, Benue State, North Eastern Nigeria. Sixteen water samples were collected from 7 boreholes, 7 hand duck wells and 2 rivers. The water samples were analysed chemically and bacteriologically using spectrophotometric, titrimetric and membrane filtration methods. Analytical results indicated that the groundwater in the area is acidic, fresh and moderately hard. The order of abundance of the cations were in Na+<K+<Mg2+<Ca2+ while the anions were in the order of Cl-<HCO3->SO42-<NO3-. Principal Component Analysis (PCA) identified four factors that accounts for 69.73% of the total variance. Correlation analysis, Principal Component Analysis (PCA) and Hierarchical Cluster Analysis (HCA) revealed pollution from application of agricultural fertilizers, anthropogenic contamination and rock-water interaction as the major processes responsible for the modification of surface and groundwater chemistry of the research area. The Gibbs diagram plot shows that, the sample points fall under rock dominance and weathering zones, which suggested precipitation, induced chemical weathering with the dissolution of rock-forming minerals. The piper diagram classified groundwater samples as Ca-Mg-HCO3 water type. Water Quality Index (WQI) values range from 22.05 to 56.13 which indicated good and excellent water category. The SAR values range from 0.02 to 0.66 the values belong to the excellent category and is suitable for irrigation. The overall result revealed that, the water in the research area is suitable for domestic, industrial and irrigation activities.

Through Silicon Via Filling with Suppression Breakdown of PEG–Br– in Absence of Accelerator

The effects of halide ions on the adsorption of polyethylene glycol (PEG) and through-silicon via (TSV) filling were investigated. Halide ions on a Cu surface assist the adsorption of PEG, and the suppression effect of PEG–halide ion layers increases in the order of Cl– < Br– < I−. For all halide ions, suppression breakdown and negative differential resistance were observed, suggesting that the three halide ions with PEG potentially induce Cu bottom-up filling. However, we confirmed that only Br− enables Cu bottom-up filling, whereas Cl– results in conformal deposition and I– cannot complete bottom-up filling due to the low Faradaic efficiency. The PEG-Br– provides sufficient suppression strength, facilitating the formation of passive–active regions and enabling defect-free Cu filling without an accelerator. This study indicates that the property of the suppression layer contributes significantly to Cu bottom-up filling based on a passive–active filling mechanism.

Evaluation of groundwater quality in Jampali coal mine, Raigarh, Chhattisgarh, India

AbstractGroundwater is the main source of water for drinking, industrial, and irrigation uses for most nations. Groundwater quality deterioration occurs due to urban, agricultural, mining, and industrial expansions. This research deals with the assessment of groundwater quality index, correlation, clustering analysis, and major ions chemistry around Jampali opencast coal mine of Raigarh district, Chhattisgarh, India, where groundwater is the main source of drinking water. A total of 28 groundwater samples were collected from the different stations in the month of April 2019 and 11 physicochemical parameters were examined. The results of the physicochemical analysis showed that cation abundance follows the order Na+ &gt; K+ &gt; Mg2+ &gt; Ca2+ in the groundwater, while anion abundance follows the order Cl− &gt; NO3− &gt; SO42− &gt; F−. A strong positive correlation is observed between TDS–EC, TDS–Mg2+, TDS–Na+, TDS–Cl−, TDS–SO42− (r = 0.999, 0.871, 0.872, 0.846, and 0.801) and EC–Mg2+, EC–Na+, EC–Cl−, EC–SO42− (r = 0.871, 0.873, 0.846, 0.802). The two clusters demonstrate a blended genesis connected to anthropogenic and geogenic measures. Based on calculated water quality index (WQI) values, groundwater falls under two classes: excellent and good water. WQI values of the study region depict that 85.72% of samples come under the excellent category and 14.28% in the good category.

Extraction Behavior of Germanium in Kelex 100 and LIX 63 Systems

AbstractIn this study, 7‐(4‐ethyl‐1‐methyloctyl)‐8‐quinolinol (HL, Kelex 100) and 5,8‐diethyl‐7‐hydroxydodecane‐6‐oxime (LIX 63, HA) were employed to recover Ge(IV) from sulfuric acid solutions in the presence of singly charged inorganic anions. Under comparable conditions, the germanium extraction efficiency was in the order Cl−&lt;NO3−&lt;I−&lt;&lt;CNS−. In the presence of thiocyanate ion, the germanium complexes extracted by Kelex 100 and LIX 63 were [GeL3]+[CNS]− and Ge(OH)2A(CNS) respectively. An increase in the pH values was shown to lead to a decrease in the extraction of Ge(IV) with HL from sulfate‐thiocyanate solutions. At pH values of ≥5.9, the degree of germanium recovery is &lt;2.0 % which makes stripping with alkaline aqueous solutions possible. When adding bis(2,4,4‐trimethylpentyl)acid (HR, CYANEX 301) to the HL and HA mixture, a significant synergistic effect takes place. The composition of the extracted complex with Kelex 100 was found to be [GeL3]+[R−]. The use of extraction systems based on both Kelex 100 and LIX 63, and on their mixture with CYANEX 301 in the presence of thiocyanate ion is of undoubted practical interest for hydrometallurgical processes to recover germanium..

Elemental composition of Eucheuma cottonii and Gracillaria sp. using scanning electron microscope-energy dispersive spectroscopic analysis

Indonesia is a major producer of the E. cottonii seaweed and Gracillaria sp. in the world. The farmers usually dry that seaweeds before sending them to plant factories to be processed into carrageenan or agar. In the present work, E. cottonii and Gracillaria sp. seaweed’s chemical composition were observed using Scanning Electron Microscope-Energy Dispersive Spectroscopic (SEM-EDS) analysis, and the distribution of the main salt-minerals in the surface and the cross-section thallus of both samples were conducted. The results showed that the surface of E. cottonii contains the following order of elements Cl> K> Na> S> Ca> C> O> Si> Al> Mg> Fe> Mn> Zn and in the cross-section contains order of elements S> Cl> K> C > O> Na> Mg> Ca> Al> Zn> Fe> Si> Mn. Whereas on the surface of the Gracillaria sp. showed the presence of elements in the following order Cl> K> Si> C> O> Al> S> Fe> C> Mg> Na> Mn> Zn and on the cross-section found elements in the following order Cl> K> C> O> S> Na> Si> Al> Mg> Fe> Ca> Zn> Mn. The EDS mapping on both seaweeds surface and cross-section showed a random distribution of salt-forming elements Na, K and Mg. Furthermore, the presence of a higher amount of K, Na, adequate amount Mg, and other essential elements indicated both seaweeds’ potential to be developed for salts with special functional properties.

Hydrochemical Characterization of Groundwater Quality in Nkalagu District, Southeastern Nigeria

Hydrochemical characterization of groundwater quality in Nkalagu District, southeastern Nigeria was carried to determine the main factors controlling the chemistry of groundwater and its suitability for drinking and irrigation purposes. Sixty (60) groundwater samples collected from boreholes and hand-dug wells in different parts of the area were analyzed for a range of physiochemical parameters and heavy metal constituents. The results show that concentration of the major ions were in the order Cl-&gt;HCO3-&gt;SO42-&gt;NO3- and Na&gt;Ca2+&gt;Mg2+&gt;K+. The groundwater samples are slightly acidic with pH of 5.28 to 8.04; moderately hard with TH of 112.88 to 467.78 mg/l. The district is mainly controlled by carbonate and silicate mineral weathering based on the available result. Three main flow regimes were identified with Q-mode cluster analysis. Based on the WQIanalysis results, the groundwater quality in the district was classified, generally as ‘poor’ to ‘excellent’ for drinking purpose. Groundwater quality for drinking purpose were noted to deteriorates as one move from west towards the east of the district, while the north and south part pf the study area indicated the best quality in the district. Groundwater quality for irrigation purpose showed excellent quality based on the United States Salinity Laboratory and Wilcox diagrams. For future use of groundwater resource in the district we recommend implementation rules and guidelines in the area to enhance health and preserve groundwater sources in the district.

The Impact of Halogen Substituents on the Synthesis and Structure of Co-Crystals of Pyridine Amides.

Strategies for co-crystal synthesis tend to employ either hydrogen- or halogen-bonds between different molecules. However, when both interactions are present, the structural influence that they may exert on the resulting assembly is difficult to predict a priori. To shed some light on this supramolecular challenge, we attempted to co-crystallize ten aliphatic dicarboxylic acids (co-formers) with three groups of target molecules; N-(pyridin-2-yl)picolinamides (2Pyr-X), N-(pyridin-2-yl)nicotinamides (3Pyr-X), N-(pyridin-2-yl)isonicotinamides (4Pyr-X); X=Cl/ Br/ I. The structural outcomes were compared with co-crystals prepared from the non-halogenated targets. As expected, none of the reactions with 2Pyr-X produced co-crystals due to the presence of a very stable intramolecular N-H···N hydrogen bond. In the 3Pyr series, all six structures obtained showed the same synthons, –COOH···N(py) and –COOH···N(py)-NH, that were found in the non-halogenated parent 3Pyr and were additionally accompanied by structure directing X···O(OH) interactions (X=Br/I). The co-crystals of the unhalogenated parent 4Pyr co-crystals assembled via intermolecular –COOH···N(py) and –COOH···N(py)-NH synthons. Three of the analogues 4Pyr-X co-crystals displayed only COOH···N(py) and –COOH···N(py)-NH interactions. The three co-crystals of 4Pyr-X with fumaric acid (for which no analogues structures with 4Pyr are known) formed –COOH···N(py)-NH and –NH···O=C hydrogen bonds and showed no structure-directing halogen bonds. In three co-crystals of 4Pyr-I in which –COOH···N(py)-NH hydrogen bond was present, a halogen-bond based –I···N(py) synthon replaced the –COOH···N(py) motif observed in the parent structures. The structural influence of the halogen atoms increased in the order of Cl < Br < I, as the size of σ-holes increased. Finally, it is noteworthy that isostructurality among structures of the homomeric targets was not translated to structural similarities between their respective co-crystals.

Anion binding properties of a hollow PdL-cage.

The hollow [PdL][BArF]2 complex 1 of a tetra-pyridyl (py) ligand (L) has a [Pd(py)4]2+ coordination environment. Addition of coordinating anions resulted in the formation of a neutral species with Pd(py)2(anion)2 coordination environment (12A). These species bind further to the coordinating anions in the order Cl− > N3− > Br− > I− > AcO− with Ka1 : 1 ≤ 414 M−1. With relatively non-coordinating anions 1 remains intact and displays 1 : 2 binding behaviour dominated by the 1 : 1 stoichiometry in the order NO3− (∼105 M−1) » ClO4− and BF4− (∼103 M−1). As evidenced by crystal structure data, DFT calculations and {1H–19F}-HOESY NMR with BF4−, the anions are bound by charge assisted [C–H]+···anion interactions.

APPLICATION OF STABLE ISOTOPES TO EVALUATE THE INTERACTION BETWEEN SURFACE WATER AND GROUNDWATER IN NORTH EAST OF DIYALA, IRAQ

It had been adopted two reliable techniques which are hydro-chemical and stable isotopes to study the interaction between groundwater and surface water in Wand dam northeastern of Diyala. Eighteen water samples were collected from Wand dam, piezometers, groundwater pumping wells, spring, accumulation basins, and irrigation water during two periods; June and November 2017. The concentrations of cations in Wand dam water order to Ca2+&gt; Na+&gt; Mg2+&gt; K+, SO4&gt; Cl-&gt; HCO3-. The concentrations of cations in the samples collected from groundwater, irrigation water, springs and accumulation basins order to Na&gt; Ca&gt; Mg2+&gt; K+, Ca2+&gt; Na+&gt; Mg2+&gt; K+, Na+&gt; Ca2+&gt; Mg2+&gt; K+ and Ca2+&gt; Na+&gt; Mg2+&gt; K+ respectively and the anions concentrations have order Cl-&gt; SO4&gt; HCO3-, SO4-&gt; Cl-&gt; HCO3, Cl-&gt; SO4&gt; HCO3 and SO4-&gt; Cl-&gt; HCO3- in groundwater, irrigation water, springs and accumulation basins respectively. There are three groups of water types based on isotopic composition; group A which noted in the Wand dam water, the piezometers Nos. 3 and 4, accumulation basin No.7 and irrigation water. Versus standards Group A is enriched by deuterium and oxygen-18, which show the effect of evaporation. Group B is distinguished by isotopic composition enrichment in groundwater as well as piezometer No. 7 than other piezometers due to the difference of the wells depth. Group C shows that the water samples collected from accumulation basin No.1 and springs have enriched stable isotopes. There is a spatial and temporal variation of isotopic contents and hydro-chemical properties of water samples which could be due to different recharge sources, evaporation processes, and origin of the water. Based on concluded information, there is no evidence proving any interconnection between the water of Wand dam and other water resources, except piezometer No. 5 which could be because of the presence of the permeable bed.

Selenium oxyanion exchange with Mg(II)-Fe(III) and Fe(II)-Fe(III) layered double hydroxides

Immobilization of selenium oxyanions from water resources is a helpful strategy to mitigate exposure to Se at concentrations toxic to human and ecosystem health. Pyroaurite-type minerals are layered double hydroxides with high anion exchange capacity with relevance in subsurface environments and applicable to water treatment technologies. Three types of Mg(II)-Fe(III) pyroaurites and Fe(II)-Fe(III) green rusts were evaluated in kinetic studies to determine the influence of different interlayer anions on the uptake of dissolved selenate (SeO42−) and selenite (HSeO3−, SeO32−). Selenate and selenite uptake extents with pyroaurites were controlled by the identity of the interlayer anion according to the order Cl−> SO42−> CO32−, as predicted by known interlayer anion preferences for LDH. The kinetics of Se uptake typically expressed a rapid initial anion exchange step followed by a slow re-exchange back to solution due to competition with expelled interlayer anions. Excess dissolved interlayer anions and high pH values exacerbated this reverse exchange of Se. The results suggest Se oxyanions taken up by pyroaurites may not be firmly sequestered. Selenate uptake by redox-active green rust appears to be subject to the same interlayer anion preference as non-redox active pyroaurite, suggesting that the ability of green rust to reduce selenium oxyanions may be limited by the anion exchange process.

Occurrence of Uranium in Groundwater from Cuddalore District Tamil Nadu Aided by Geospatial and Statistical Techniques

An attempt has been made to examine uranium distribution in groundwater from Cuddalore district, Tamil Nadu, India. Groundwater occurs under porous sedimentary, fractured, and weathered hard rock formations ranging in age from recent sediments to the oldest Archean formations. A total of 186 groundwater samples were collected during Pre- Monsoon (May) and Post-monsoon (January) and analyzed for major cations, anions, and uranium using standard procedures. Major anions and cations follow the order Cl- &gt;H4SiO4&gt;HCO3- &gt;NO3- &gt; Na+&gt; Ca2+&gt; Mg2+&gt;K+&gt;SO42- &gt; F-&gt; PO43- irrespective of seasons. Uranium in groundwater ranges from 0.1 micro gram per liter (µg/l ) to 24.67 µg/l with average 1.82 µg/l. The spatial representation maps isolated areas of higher and lower uranium and statistical analysis inferred uranium sources to the groundwater environment.

Effects of Different Counter Anions on Solid-State Electron Transfer in Viologen Compounds: Modulation of Color and Piezo- and Photochromic Properties.

Charge transfer (CT) and electron transfer (ET) underlie the various applications of viologen compounds. However, the CT and ET in solids are still insufficiently understood and difficult to control, which is challenging but fundamental to the design of multifunctional materials. Our strategy is to attempt a delicate control of CT and ET by subjecting model compounds to pressure. In this work, a series of viologens of the same cation with different anions show anion-dependent color and piezo-/photochromism due to ground-state CT and stimuli-induced ET; the ease of solid-state ET can be tuned in the order of Cl- > Br- > I-/BF4-/PF6-/ClO4-. With in situ high pressure UV-vis experiments, we also observed unexpectedly the pressure-induced solid-state ET in [H2bcpV]·I2 besides the pressure modulation of the CT absorption. It proves pressure is a more powerful stimulus than light in tuning solid-state CT and ET.