Anthraquinone Sulfonic Acid Research Articles

Anoxic Manganese Bioleaching – Investigation of Scale-up Parameters in a Stirred Bioreactor

Presently huge operation costs arising from aeration and high electron donor requirements accompanied by low metal recovery rates are some impediments to the large-scale application of bioleaching for low-grade ores. The current study investigates key parameters for scaling up anoxic bioleaching, which overcomes some of the above shortcomings, on polymetallic manganese nodules using soil-based manganese-reducing bacterial consortia in a stirred bioreactor. Operating conditions such as carbon source concentration and pulp density were optimized. Parameters like pH, oxidation–reduction potential (ORP), and microbial growth were monitored in the bioreactor in both stirred and non-stirred conditions. The Mn(IV) reduction and dissolution in the bioreactor was 27 (±2.8)% over 30 days, which significantly enhanced to 43 (±1.5)% and 42 (±0.35)% in the presence of humic acid and anthraquinone sulfonic acid, respectively, in 15 days. A maximum dissolution of 21 (±4.1)% Cu, 10 (±3.0)% Ni, 18 (±4.7)% Co and 7 (±3.9)% Fe were also obtained with 100 µM humic acid from the agitated bioreactor in 15 days. The corresponding specific glucose consumption rate per unit mass of ore was found to be 27 mg g−1 day−1, which is 10 times lower than the rates reported previously for aerobic bioleaching methods. The investigation shows that mild agitation can significantly improve the anoxic bioleaching, especially with added electron shuttles, to enable better ore-bacteria interaction and prevent ore compaction during scale-up. The pH and ORP of the system point toward a reductive dissolution of Mn by the organisms.

Interionic hydrogen bonds induced high solubility of quinone derivatives and preliminary study on their application properties in all quinone aqueous redox flow battery

The development of highly water-soluble quinone derivatives is an important research direction for aqueous organic redox flow batteries (AORFBs) of high energy density. In this work, choline cations are substituted for sodium ions to form new ion pairs with quinone sulfonates, and the water solubility of quinone sulfonates derivatives is significantly improved due to the formed interionic hydrogen bond between the CO in anthraquinone sulfonic acid anion and -OH in choline cation. Specifically, 9,10-anthraquinone-2-disulfonic choline salt (AQSCH) and 1, 2-dihydroxy-3, 5-phenyldisulfonic acid dicholine salt (BQDS(CH)2) are synthesized by simple ion exchange and acid-base neutralization. As a result, the solubility of the quinone and anthraquinone sulfonates in water is increased by more than ten times, and the redox reversibility is not significantly affected. The charging-discharging performance of a novel pH-neutral all-quinone aqueous battery with AQSCH and BQDS(CH)2 as the anodic and cathodic active electrolytes respectively, choline chloride as the supporting electrolyte is investigated using a static H-type electrolytic cell, the obtained results verifying the feasibility of using choline as the counter cathion and solubilizer of quinone sulfonates to improve their water solubility in pH-neutral AORFBs.

Electrothermal Modeling and Analysis of Polypyrrole-Coated Wearable E-Textiles.

The inhomogeneity of the resistance of conducting polypyrrole-coated nylon–Lycra and polyester (PET) fabrics and its effects on surface temperature were investigated through a systematic experimental and numerical work including the optimization of coating conditions to determine the lowest resistivity conductive fabrics and establish a correlation between the fabrication conditions and the efficiency and uniformity of Joule heating in conductive textiles. For this purpose, the effects of plasma pre-treatment and molar concentration analysis of the dopant anthraquinone sulfonic acid (AQSA), oxidant ferric chloride, and monomer pyrrole was carried out to establish the conditions to determine the sample with the lowest electrical resistance for generating heat and model the experiments using the finite element modeling (FEM). Both PET and nylon-Lycra underwent atmospheric plasma treatment to functionalize the fabric surface to improve the binding of the polymer and obtain coatings with reduced resistance. Both fabrics were compared in terms of average electrical resistance for both plasma treated and untreated samples. The plasma treatment induced deep black coatings with lower resistance. Then, heat-generating experiments were conducted on the polypyrrole (PPy) coated fabrics with the lowest resistance using a variable power supply to study the distribution and maximum value of the temperature. The joule heating model was developed to predict the heating of the conductive fabrics via finite element analysis. The model was based on the measured electrical resistance at different zones of the coated fabrics. It was shown that, when the fabric was backed with neoprene insulation, it would heat up quicker and more evenly. The average electrical resistance of the PPy-PET sample used was 190 , and a maximum temperature reading of 43 °C was recorded. The model results exhibited good agreement with thermal camera data.

Use of redox mediators for the enhanced degradation of selected nitrophenols

In the present study, sequential anaerobic–aerobic treatment was used for the enhanced degradation of selected nitrophenols. Five identical reactors were used to assess the degradation of 2-nitrophenol and 2,4-dinitrophenol. Reactor 1 was used as control, and another four reactors were operated in anaerobic phase followed by sequential aerobic treatment. The performance of reactors was studied for nitrophenol concentrations of 5, 10, 20 and 40 mg/l and in next phase effect of redox mediators [lawsone and anthraquinone sulphonic acid (AQSA)], along with kinetics of degradation studied for 40 mg/l of nitrophenols. More than 98% degradation of nitrophenols was achieved at lower concentrations but for 40 mg/l removal percentage was reduced, and also COD inhibition was observed. However, with the addition of redox mediators, both nitrophenols and COD removal percentage were greater than 95% and 85%, respectively. Kinetics of degradation revealed that the rate of degradation was found to increase with the increase in concentration of redox mediators from 10 to 20 mg/l, and it was found that degradation was faster with the use of AQSA in comparison with lawsone solution. It indicates that use of redox mediators is favourable for the enhanced degradation of nitrophenols. Sequential anaerobic–aerobic treatment is possible potential treatment method for treating nitrophenolic wastewaters.

Investigation on electrical tuneable separation properties for phase inversion polyaniline membranes doped in various acids

Electrically tuneable polyaniline (PANI) membranes were fabricated via phase inversion and were doped primarily in various acids namely anthraquinone sulfonic acid (ASA), dodecylbenzene sulfonic acid (DBSA), maleic acid (MA) and poly(methyl vinyl ether-alt-maleic acid) (PMVEA) in comparison with secondarily HCl-doped PANI membrane as the pristine ones. It was found that the addition of different dopants in the PANI matrix changed the thickness of the membrane skin structure. From the dynamic contact angle (DCA) analysis, the PANI-ASA and pristine PANI membranes had the greatest permeation tuneability with a faster permeation rate under electric potential. For the effect of tuneable filtration, by using a modified cross-flow membrane filtration system, ASA showed the highest flux tuneability with a tuneable MWCO in the low UF range at an applied voltage of 7 V rather than at 0 V. Accordingly, the electrical tuneability assessment of the membranes has successfully demonstrated the proof of concept that the fabricated PANI membranes doped at various acids could have a different tuneable MWCO, selectivity and/or flux in a pressure filtration system.

Selective enhancement of Mn bioleaching from ferromanganese ores in presence of electron shuttles using dissimilatory Mn reducing consortia

The present study describes anoxic Mn bioleaching of low grade ferromanganese ores using a dissimilatory Mn reducing consortia (MRC). Effect of external addition of electron shuttles such as humic acid and anthraquinone sulphonic acid was studied under same conditions. The MRC were found to be capable of utilizing MnO2 as electron acceptor as evidenced by Mn dissolution in media. In the presence of electron shuttles, Mn extraction was found to be enhanced by 2 to 4 times compared to the case without. A maximum of 58 (±3%) Mn was found to be leached from an amorphous ore while 38 (±2%) Mn was leached from a crystalline ore, in 50 days in presence of 100 μM electron shuttle at 20 g/L S:L ratio. A significant finding was consistently low leaching of Fe under all conditions studied (<50 mg/L or < 5%) and in-situ oxidation of Fe(II) by MnO2 to form insoluble ferric compounds as observed in residues. The presence of electron shuttle enhances reductive dissolution by MRC which favors dissolution of Mn more than Fe under anoxic conditions. X-ray fluorescence spectroscopy and X-ray diffraction peaks of residues confirm that MnO2 is preferentially dissolved than Fe2O3. These findings indicate that anoxic bioleaching can help to selectively recover Mn from low grade ferromanganese ores.

Conducting Leathers for Smart Product Applications

Leather is a unique consumer material possessing a variety of properties such as strength, viscoelasticity, flexibility, and longevity. However, the use of leather for smart product applications is a challenge since it is an electrically insulating material. Here, we report a simple method to produce conducting leathers using an in situ polymerization of pyrrole. The concentrations of pyrrole, ferric chloride, and anthraquinone sulfonic acid and the number of polymerization were optimized to produce maximum conductivity in the treated leathers. The coating of polypyrrole in the treated leathers was probed using Fourier transform infrared spectroscopy, X-ray diffraction, and electron microscopic analysis. We also show that the treated leathers are black through reflectance measurements, thereby suggesting that the use of toxic and expensive dyes can be avoided for coloration process. We further demonstrate that the treated leathers, with a maximum conductivity of 7.4 S/cm, can be used for making conductive gloves for operating touch-screen devices apart from other smart product applications.

Understanding the Performance of Aqueous Organic Redox Flow Batteries

Organic redox flow batteries (ORFB) are considered to be one of the most promising technologies for large-scale energy storage needed for integrating renewable energyrom intermittent sources such as solar photovoltaic and wind-based generation systems [1]. ORFBs are attractive because the proposed materials are potentially low cost, eco-friendly, and sustainable. Organic compounds, such as quinones and their derivatives, can be used as both the positive and negative active material of ORFB, due to their electrochemical reversibility and relatively high charge capacity of 200-490 Ah/kg. The use of water as the solvent lowers the cost and makes the system safe, non-flammable, and highly eco-friendly. Heavy metals such as chromium, vanadium, zinc and lead are completely avoided. Thus, the material cost can be reduced substantially for achieving the DOE-specified target of $100/kWh for the entire battery system.In the present study, we have constructed redox flow cells operating on 0.2 M benzoquinone disulfonic acid (DSQ) and 0.2 M anthraquinone sulfonic acid (AQS). We have measured the rechargeability and current-voltage characteristics. We find that the cells are rechargeable and no loss of capacity was observed in 12 cycles (Figure 1). This result suggests that the quinones are chemically stable under the conditions of cycling. The current-voltage curves were measured as a function of state-of-charge. We found that the power density decreased significantly below the 50% state of charge. This decrease is attributed to the mass transport limitations that can be severe at low reactant concentrations of 0.2 M (Figure 2). Analysis of the current-voltage and impedance data indicate that the power density can be increased by enhancing the solubility of the quinones, increasing the temperature of operation and by modifying the electrode structure to allow for rapid mass transport. In this presentation, we will discuss the improvements in power density achieved by these various approaches. Acknowledgement The work presented here was funded by ARPA-E (Open FOA) and the Loker Hydrocarbon Institute of University of Southern California.

Influence of the scan rate on the morphology of polyaniline grown on conducting fabrics. Centipede-like morphology

We report the apparition of different polyaniline (PANI) morphologies when different scan rates were employed in the electrochemical deposition of PANI on conducting fabrics. The most impressive structure obtained was the centipede-like morphology. PANI was deposited on conducting textiles of polyester covered with polypyrrole (PPy)/anthraquinone sulphonic acid (AQSA) by means of cyclic voltammetry. With the scan rates of 50 mV s −1 and 5 mV s −1 PANI with centipede-like morphology was obtained in the first scans. Globular PANI gained importance for higher number of scans due to the formation of new nucleation sites. When a scan rate of 1 mV s −1 was employed a variety of different morphologies were observed, such as: fibrillar, stalagmite-like, coral-like and plain irregular forms. Such variety of morphologies is due to the slow growth that allowed different types of morphologies.

Electrochemical polymerisation of aniline on conducting textiles of polyester covered with polypyrrole/AQSA

Polyaniline (Pani) has been electrochemically polymerised on conducting textiles of polyester covered with polypyrrole (Ppy)/anthraquinone sulphonic acid (AQSA), obtaining a double conducting polymer layer. Electrochemical syntheses have been performed by means of cyclic voltammetry (CV) and potentiostatic methods. Pani morphology varies with the method of synthesis as it has been corroborated by scanning electron microscopy. EDX analyses have been performed to study zonal composition of the samples. Surface resistivity measurements have been carried out with a 4-point probe equipment. Electrochemical impedance spectroscopy (EIS) and CV have been employed to characterise the electroactivity of the samples in solutions with different pH values. X-Ray photoelectron spectroscopy (XPS) was employed in order to determine the doping level of polyaniline films and the oxidation state of the sample. With the potentiodynamic synthesis the doping level was higher than that obtained with potentiostatic synthesis, however, polymer overoxidation appeared.

Chemical and electrochemical polymerisation of pyrrole on polyester textiles in presence of phosphotungstic acid

Polypyrrole (PPy) was chemically synthesised on polyester (PES) textiles to produce conducting textiles. Two different types of counter ion were employed: anthraquinone sulfonic acid (AQSA) and phosphotungstate (PW12O403-). Textiles covered with PPy were characterised by means of FTIR-ATR, SEM, EDX, cyclic voltammetry (CV), surface resistivity measurements and electrochemical impedance spectroscopy (EIS). Additionally, friction and washing assays were done to test the resistance of the layer of conducting polymer (PPy/PW12O403−). Electropolymerisation of PPy/PW12O403− in acetonitrile medium onto chemically synthesised PES–PPy/PW12O403− showed the improvement of the coating properties.

Characterization of conductive polypyrrole coated wool yarns

Wool yarns were coated with conducting polypyrrole by chemical synthesis methods. Polymerization of pyrrole was carried out in the presence of wool yarn at various concentrations of the monomer and dopant anion. The changes in tensile, moisture absorption, and electrical properties of the yarn upon coating with conductive polypyrrole are presented. Coating the wool yarns with conductive polypyrrole resulted in higher tenacity, higher breaking strain, and lower initial modulus. The changes in tensile properties are attributed to the changes in surface morphology due to the coating and reinforcing effect of conductive polypyrrole. The thickness of the coating increased with the concentration of p-toluene sulfonic acid, which in turn caused a reduction in the moisture regain of the wool yarn. Reducing the synthesis temperature and replacing p-toluenesulfonic acid by anthraquinone sulfonic acid resulted in a large reduction in the resistance of the yarn.

Doping reaction of redox-active dopants into polyaniline

Acid doping of functional protonic acids such as ferrocene sulfonic acid, hydroquinone sulfuric acid, anthraquinone sulfonic acid and phenylazobenzene sulfonic acid as dopants in polyaniline takes place homogeneously and the dopant is incorporated at ca. 100% efficiency(1 dopant/polyaniline 2 units). The doping reaction is dominated by diffusion kinetics, which is influenced by the dopant size. The resulting polyanilines have high conductivity of 10−4–10 S/cm similar to that of perchlorate doped polyaniline. Polyaniline doped with redox dopants shows a multiple redox couple in acidic solution, which is applicable to a charge storage system with high energy density. Copyright © 2000 John Wiley & Sons, Ltd.

Blockade of ATP binding site of P 2 purinoceptors in rat parotid acinar cells by isothiocyanate compounds

Extracellular ATP activates a P 2z-type purinergic receptor (purinoceptor) in rat parotid acinar cells that increases the intracellular free Ca 2+ concentration via the entry of extracellular Ca 2+ through an ATP-sensitive cation channel (Soltoff et al., Am J Physiol 262: C934–C940,1992). To learn more about the ATP binding site of the purinoceptor, we examined the effects of several stilbene isothiocyanate analogs of DIDS (4,4'-diisothiocyanatostilbene-2,2'-disulfonic acid), which block the binding of [ 32PIATP to intact parotid cells (McMillian et al., Biochem J 255: 291–300,1988) and blocked the activation of the P 2z purinoceptor. The ATP-stimulated 45Ca 2+ uptake was blocked by DIDS, H 2DIDS (dihydro-DIDS; 4,4'-diisothiocyanatodihydrostilbene-2,2'-disulfonic acid), and SITS (4-acetamido-4'-isothiocyanatostilbene-2, 2'-disulfonic acid), but not by DNDS (4,4'-dinitrostilbene-2,2'-disulfonic acid), a stilbene disulfonate compound lacking isothiocyanate (SCN-) groups, or by KSCN. The potency of the stilbene disulfonates was related to the number of isothiocyanate groups on each compound. Under the experimental conditions, the ic 50 value of DIDS (∼35 μM), which has two SCN-groups, was much lower than that of SITS (∼ 125 μM), which has only one SCN- group. The inhibitory effects of DIDS appeared to be much more potent than those of SITS due to the kinetics of their binding to the purinoceptors. Eosin-5-isothiocyanate (EITC) and fluoroscein-5-isothiocyanate (FITC), non-stilbene isothiocyanate compounds with single SCN-groups, also blocked the response to ATP and were less potent than DIDS. Trinitrophenyl-ATP (TNP-ATP), an ATP derivative that is not an effective agonist of the parotid P 2z receptor, blocked the covalent binding of DIDS to the plasma membrane, suggesting that ATP and DIDS bind to the same site. Reactive Blue 2 (Cibacron Blue 3GA), an anthraquinone-sulfonic acid derivative that is a noncovalent purinergic antagonist, also blocked the covalent binding of DIDS to the plasma membrane. These results suggest that isothiocyanate compounds interact with the ATP binding site of this P 2 purinoceptor, and that isothiocyanate groups make an important contribution in determining the effectiveness of the stilbene disulfonate compounds in blocking the binding of nucleotide agonists to this purinoceptor.

Flow visualization by redox-reaction dyes

Colour generation by a direct oxidation or reduction reaction at an electrode in aqueous solution does not generate gas, as is necessary to obtain a pH change. Flow visualization in a closed apparatus or porous medium is therefore possible without the interference of bubbles or a detectable density change. A series of anthraquinone sulphonic acid salts has been found that produce good colours upon reduction at a cathode in mildly alkaline solution. Some are soluble enough to be used in salt gradients and react well below the potential needed to evolve hydrogen, so the electrode remains in stable condition. Platinum is not necessary for the cathode, is indeed undesirable. A number of commercial redox dyes that produce colour upon oxidation were also tested. The most practical is methylene blue, which needs a powerful reducing agent to be decolourised. It is instantly reoxidised by dissolved air, a feature that may be useful in studies of gas/liquid transfer or entrainment across stratified boundaries.

Photochemical Image Formation Process for High Density PrintedCircuit Patterns

A new method for fabricating high density printed circuit boards has been investigated. The procedure used for photoselective metal deposition on the substrate consists of five steps: adhesion treatment, sensitization, nucleation, fog inhibition and electroless metal deposition. An adhesive coated substrate was sensitized by introducing an aqueous solution containig anthraquinone sulfonic acid sodium salts, reducible noble metal salts and alcohol. The sensitized substrate was then exposed through a mask to a u.v. light. The noble metal nuclei produced by exposure were developed by electroless copper deposition after rinsing with aqueous solutions containing complex agents. Electrically‐conductive patterns thus obtained can be further intensified by second electroless plate making.

Photochemical reduction of organic electron acceptors in aqueous solutions

The formation of OH radicals in the photoreduction of aqueous solutions of anthraquinonesulfonic acid as the result of electron transfer from water (OH−) to a triplet molecule has been demonstrated.

Separation and determination of anthraquinone sulfonic acid isomers by ion exchange resin

弱酸性陽イオン交換樹脂である Amberlite CG-50 を用いて,塩化ナトリウム水溶液中におけるアントラキノンスルホン酸の吸着性を検討し,塩化ナトリウム溶液の濃度およびpHを適当に選択することによって異性体の間に吸着性の差が生じることを見出した.これを利用して,アントラキノンを水銀触媒の存在下でスルホン化した場合に生成するα-モノ,1,5-,1,6-,1,7-および1.8-ジスルホン酸を4Nおよび 0.5N,pH 1.8の塩化ナトリウム溶液で,また,α-およびβ-モノスルホン酸を0.1N,pH 2.7の塩化ナトリウム溶液でそれぞれ展開して,クロマトグラフ的に分離し,吸光光度法により定量を行なって良好な結果が得られた.本法は塩析クロマトグラフィーの一種であり,異性体の分離に有効であることを認めた.アントラキノンスルホン酸異性体を相互に分離,定量することは,従来の方法ではかなり困難な問題であった.しかし,以上述べたように微酸性の濃厚な塩化ナトリウム水溶液中において,弱酸性陽イオン交換樹脂に対する分子吸着を利用することにより,容易にしかも定量的に分離することが可能であった.本法を他のクロマトグラフ法と比較すると,ペーパークロマトグラフィーではRf値の再現性がわるいため定量的な分離が困難であり,展開液の選択がむずかしい.アニオン交換樹脂を用いるイオン交換クロマトグラフィーでは,異性体の分離はできない.またアルミナ,シリカゲルなどを用いる吸着クロマトグラフィーと異なり,カチオン交換樹脂を吸着剤として使用するため,単なる水洗のみで再生され,くり返し使用が可能であり,展開剤の濃度,pHが一定であれば,いつも一定の保持容量を示し,異性体の分離能もすぐれている特徴がある.

Experimental dental caries; further studies on effect of certain quinones.

Further studies on the effect of different quinone derivatives with varying degrees of acid-formation inhibiting power, as determined in vitro, and with or without vitamin K activity, on dental caries activity were carried out in hamsters. In these studies the following quinone derivatives were tested: Dicalcium salt of methylnaphthohydroquinone diphosphate, methylnaphthohydroquinone disuccinate, anthraquinone sulphonic acid, and dichloronaphthoquinone. The compounds were used in higher amounts than those used in the previous experiment.