Effect Of Perchlorate Ions Research Articles

ATR-FTIR spectroscopic studies on aqueous LiClO4, NaClO4, and Mg(ClO4)2 solutions

The ATR-FTIR spectra of aqueous LiClO4, NaClO4, and Mg(ClO4)2 solutions with ClO4− concentrations ranging from 0 to 3.00 mol dm−3 were obtained. After subtracting the spectra of pure water, positive peaks on the high wavenumber side and negative peaks on the low wavenumber side of the O–H stretching bands are observed in the difference spectra. The positive peaks appear constantly at about 3580 cm−1 independent of cation, which are assigned to the water molecules weakly hydrogen-bonded with ClO4−. However, the negative peaks appear at 3203, 3196, and 3254 cm−1 for LiClO4, NaClO4, and Mg(ClO4)2 solutions, respectively, and the peak areas show significant difference with increasing the concentration of perchlorate anions and are dependent on cations. The negative peaks are attributed to the “structure breaking” effect of perchlorate ions on the hydrogen bond network of water, which is in agreement with Raman spectroscopic studies. Besides the “structure breaking” effect of ClO4− on destroying the strong hydrogen bonds of the water molecules with fully hydrogen-bonded five-molecule tetrahedral nearest neighbor structure, the difference of the negative peaks are the results of the different “structure making” effect of the three cations, which is consistent with the ability of the polarization and hydration, in the order of Na+ < Li+ ≪ Mg2+. The overall shifting of the v3 band of perchlorate ions towards low wavenumber with increasing the concentration of perchlorates is attributed to the presence of solvent separated ion pairs, i.e., M⋯(H2O)n⋯ClO4−. The symmetric stretching vibration (v1) of perchlorate ions, which is an infrared inactive mode for free perchlorate ions, shows a weak band at ∼930 cm−1 in a wide concentration range of the three systems. The appearance of the weak band is considered as the perturbation of the ZnSe/water interface on perchlorate ions.

Effect of perchlorate ion on the textural and catalytic activity of zirconia

Synthesis and physico-chemical characterization of hydrous zirconia gel were carried out. The perchlorate sorption properties of hydrous zirconia were found to be appreciable and a loading of about 9 wt% was possible in an equilibrium solution of 0.1 M HClO 4. Formation of perchlorated zirconia has been investigated using XRD, TG/DTA and FTIR. Nitrogen adsorption desorption isotherms at liquid nitrogen temperature were used to explore the surface area and porosity of the samples. The nitration of chlorobenzene was used as the test reaction. It was observed that finely divided zirconia with mesoporous texture can be prepared using preshaped precipitating medium. The XRD patterns revealed that perchlorate ion stabilizes the tetragonal phase of zirconia. TG/DTA and FTIR studies supported the presence of perchlorate moiety in the sample. The surface acidity measurement using different organic bases irreversibly adsorbed on zirconia surface showed that perchlorated samples are highly acidic up to a temperature of 250°C, which drastically decreased on further heating. The material modified with perchlorate ion was found to be an efficient and selective catalyst for solvent-free mononitration of chlorobenzene.

Electrochemical degradation of phenol in aqueous solution on bismuth doped lead dioxide : a comparison of the activities of various electrode formulations

This paper describes the development of electrochemical processes for the oxidative degradation of toxic organic chemicals in waste waters. Doped bismuth lead dioxide anodes have been tested by the kinetic study of phenol anodic oxidation in aqueous solution. The main products during oxidative degradation of phenol are 1,4- benzoquinone, maleic acid and carbon dioxide. Several deposits of Bi2O5–PbO2 on Ti/(IrO2–Ta2O5) substrates have been prepared by anodic oxidation of Pb2+ and Bi3+ in aqueous solutions containing perchloric acid to increase the solubility of bismuth. To study the effect of perchlorate ions, the efficiency of the PbO2 deposit prepared from lead nitrate in an aqueous solution (pure PbO2) was compared with that of a deposit prepared from perchloric acid solution (perchlorate doped PbO2). Although the phenol is oxidized at the same rate on the two deposits, the charge corresponding to the total elimination of 1,4-benzoquinone is three times higher for perchlorate doped PbO2 than for pure PbO2. Phenol degradation is more efficiently carried out on a PbO2 anode doped with perchlorate and with bismuth than on the same electrode doped only with perchlorate. Among the electrodes tested in this work, the pure PbO2 anode is the most efficient for phenol degradation. It is assumed that certain active sites on the anode occupied by perchlorate ions do not participate in the transfer of oxygen atoms and that for the PbO2 electrode doped with bismuth, oxygen evolution is favoured to the detriment of oxygen atom transfer.

The influence of perchlorate ions on complex charging transients in amphibian striated muscle.

1. The effects of perchlorate ions on intramembrane charge movements were examined under different conditions of ryanodine receptor (RyR) modification in intact voltage-clamped amphibian skeletal muscle fibres studied in the gluconate-containing solutions previously reported to emphasize the features of q gamma at the expense of those of the q beta charge. 2. The introduction of graded increases in perchlorate concentration to the experimental solutions selectively shifted the threshold of appearance of the q gamma 'hump' currents to more negative test potentials at which they actually appeared in the absence of prior q beta transients at perchlorate concentrations of 4.0-8.0 mM. Such findings suggested that the delayed (q gamma) transitions can take place independently of any previous exponential (q beta) decay. 3. These kinetic effects were accompanied by hyperpolarizing shifts in the transition potentials (V*) of the steady-state voltage dependences of either the overall or the isolated q gamma charge. These shifts were graded with concentration and reached their maximum effects at 4.0-8.0 mM perchlorate. However, both the total charge (Qmax) and the steepness factor (k) remained conserved at values consistent with a system that included significant contributions from the steeply voltage-sensitive q gamma component (overall charge: Qmax approximately 19-21 nC microF-1, k approximately 7-9 mV; q gamma component alone: Qmax approximately 10-12 nC microF-1, k approximately 4-6 mV). This contrasts with earlier reports on the effects of perchlorate in fibres that were studied in sulphate- or methanesulphonate-containing extracellular solutions. 4. Perchlorate (8.0 mM) restored the 'hump' waveform associated with q gamma charge movements that had previously been obliterated by the prior application of fully effective (0.1 mM) concentrations of either ryanodine or daunorubicin. 5. Perchlorate similarly reversed the positive shift in the transition potential of the q gamma component that was brought about by such RyR modification (from V* approximately -40 mV back to V* approximately -60 mV). In contrast, the values of either Qmax (overall charge, 19-21 nC microF-1; q gamma component, 10-13 nC microF-1) or k (overall charge, 7-9 mV; q gamma component, 4-6 mV) remained conserved through all these experimental manoeuvres. 6. The inclusion of perchlorate also reversed the action of 2 mM tetracaine and restored delayed q gamma transients to an extent that was graded with concentration (0.5-8.0 mM perchlorate). There was an accompanying recovery of the steeply voltage-dependent steady-state (q gamma) component consistent with a competitive interaction between these agents upon the q gamma intramembrane charge. 7. The present findings suggest that perchlorate exerts a specific action upon the q gamma charge in independent transitions that are driven by the tubular membrane field. Its interactions with the known RyR inhibitors that nevertheless conserve both the charge and its voltage sensitivity suggest a primary action upon the RyR that in turn exerts reciprocal actions upon the voltage sensor.

Perchlorate and the relationship between charge movement and contractile activation in frog skeletal muscle fibres.

1. The effects of perchlorate ions (1-8 mM) on intramembrane charge movement, myoplasmic Antipyrylazo III Ca2+ transients and contractile activation were examined in voltage-clamped cut skeletal muscle fibres of the frog. 2. Perchlorate shifted both the voltage dependence of charge movement and the rheobase of the strength-duration relation for contraction threshold towards more negative membrane potentials. 3. Both charge movements and myoplasmic Ca2+ transients were much slower at the new rheobase in the presence of perchlorate than in the control solution but there was no change in the threshold amount of charge or in the calculated peak binding of Ca2+ to troponin C. 4. The peak release rate had a steeper voltage dependence than the non-linear charge, but a lower concentration (2 mM) of perchlorate shifted both voltage dependences equally without altering the maxima in the amount of charge and in the rate of Ca2+ release. 5. The voltage dependence of the difference between total charge and charge at the threshold of Ca2+ transients agreed well with the voltage dependence of the rate of Ca2+ release in both the presence and absence of perchlorate. 6. It is concluded that the effect of perchlorate on contractile activation can be accounted for by its action on the intramembrane charge movement responsible for contraction, without significant effects on subsequent Ca2+ release from the sarcoplasmic reticulum or on Ca2+ binding to regulatory sites of troponin C.

Effect of perchlorate ion on the solvent extraction of chromium (III) with 1-(2-pyridylazo)-2-naphthol

Effect of perchlorate ion on the solvent extraction of chromium (III) with 1-(2-pyridylazo)-2-naphthol

Effect of perchlorate ion on mercury(2+) ion-promoted hydrolysis of cobalt(III)-coordinated glycine esters. Correcting and error

Effect of perchlorate ion on mercury(2+) ion-promoted hydrolysis of cobalt(III)-coordinated glycine esters. Correcting and error

The effect of perchlorate ion and some pharmacological agents on the sensitivity of the frog (Rana pipiens) rectus abdominis to acetylcholine.

Die Reaktion des mit Eserin vorbehandelten musculus rectus abdominis des Frosches auf Acetylcholin liess sich durch Oxotremorin (2.0·10−5 M), Arecolin (2.0·10−5M), Aceclidin (1.0·10−4 M) und Carbachol (2.0·10−7 M) verstarken, wahrend Atropin (1.0·10−5 M) hemmend wirkte. Perchlorationen in Konzentrationen uber 2 · 10−4 M sensibilisierten den Froschmuskel erheblich und reduzierten die Grenzdosis, bei der eine Potenzierung durch Substanzen mit muskarinahnlicher Wirkung beobachtet wird. Alle beschriebenen Reaktionen liessen sich durch Gehirnextrakte verstarken, in denen zuvor Acetylcholin durch Kochen in alkalischer Losung zerstort worden war.

Effect of monofluorosulphonate, difluorophosphate and fluoroborate ions on the iodine uptake of the thyroid gland.

SEVERAL inorganic anions have been found to interfere with the normal function of the thyroid gland1–3, the perchlorate and thiocyanate ions being outstanding in this group. On the other hand, it has been shown that other common anions, including chloride, bromide, fluoride, sulphate, phosphate and bromate ions, have no significant effect on the iodine uptake and retention in the gland. The effect of perchlorate ions suggests a competition for some sites in the thyroid1. This assumption is supported by the fact that perchlorate ions concentrate in the gland4. Further, it was shown4 that perchlorate ions do not undergo metabolization, thus excluding the possibility that they are involved in some enzymatic redox system. This behaviour of the perchlorate ion distinguishes it from other inorganic thyroid blocking agents like thiocyanate ions which have been shown to be metabolized and not to accumulate in the gland2. It occurred to us that the competition between perchlorate and iodide ions may be due to their similar monovalency and size. It is hard to compare the size of a spherical ion like iodide with that of a tetrahedral complex ion like perchlorate. Still we may compare the calculated volumes. The volume of ClO4 − may be calculated taking r(O=) = 1.33 A. From the radius of I−, r(I−) = 2.16 A., we may find its volume. We find for the volumes of ClO4 − and I− the values 3.94 and 4.23 × 10−23 cm.3 respectively. The experimental value6 for the ionic volume of ClO4 − is 4.05 × 10−23 cm.3.