Dilute Sodium Hypochlorite Solution Research Articles

Фотометрическое редокс-определение оксоанионов хлора и брома в гипохлоритных дезинфицирующих растворах

Photometric methods using methylene blue for selective and highly sensitive determination of chlorine oxoanions and bromate ions in drinking water disinfectant solutions (sodium and calcium hypochlorites) were developed. Detection limits of anions were (mg/L): 3∙10 −2 (ClO − , ClO 2 − ); 5∙10 −2 (ClO 3 − ); 3∙10 −1 (ClO 4 − ) и 4∙10 −4 (BrO 3 − ). Marginal mass ratios for chlorine oxoanions and bromate ions determination were: hypochlorite − 1 : 50 (ClO 2 − ), 1 : 100 (ClO 3 − , ClO 4 − , BrO 3 − ); chlorite − 1 : 100 (ClO − , ClO 3 − , ClO 4 − , BrO 3 − ); chlorate − 1 : 100 (ClO − , ClO 2 − , ClO 4 − , BrO 3 − ); perchlorate − 1 : 100 (ClO − , ClO 2 − , ClO 3 − , BrO 3 − ); bromate − 1 : 100 (ClO − , ClO 2 − ), 1 : 200 (ClO 3 − , ClO 4 − ). Relative analysis error was 10-15 %. The developed methods were successfully tested for the determination of the above oxoanions in dilute solutions of sodium hypochlorite and calcium. Key words : chlorine oxoanions, bromate ions, redox determination, photometry, sodium hypochlorite, calcium hypochlorite (Russian) DOI: http://dx.doi.org/10.15826/analitika.2013.17.4.014 E . V . Nayanova , E . V . Elipasheva , G . M . Sergeev Lobachevsky State University , Nizhny Novgorod, Russian Federation

Rechargeable antimicrobial coatings for poly(lactic acid) nonwoven fabrics

A novel heterocyclic N-halamine acetate homopolymer was synthesized and characterized by ATR-IR, NMR and MALDI-TOF spectroscopy and TGA and DSC analysis. The homopolymer was coated onto poly(lactic acid) (PLA) meltblown nonwoven fabric, and the surfaces were rendered biocidal upon exposure to dilute sodium hypochlorite solution. The coatings were quite stable versus UVA and florescent light exposure. Moreover, they exhibited long-term shelf-life stability, and they were rechargeable when oxidative chlorine on the surfaces was partially exhausted after three months storage. It was found that the chlorinated fabrics exhibited effective antimicrobial activity with about six logs inactivation of Staphylococcus aureus and Escherichia coli O157:H7 within 30 min of contact time. The coated PLA possesses potential for use in antimicrobial food packaging, filters, and hygiene products.

305 安定化次亜塩素酸水による化学的水処理技術の開発と防疫対策への応用(水・排ガス処理(物理化学処理))

The author reports the development of the new chemical water treatment technology using the aqueous of stabilization hypochlorous acid. This stabilization solution is prepared by the low environmental loading manufacturing equipment for very precise fluid control using diffusion phenomena. It is prepared from dilute hydrochloric acid and aqueous solution of sodium hypochlorite without the electrolysis. The work environment of the preparation process is very good, since the preparative procedure without using or generation of the chlorine. The prepared aqueous solution is high precise continuously prepared with optionally designated for the available chlorine concentration; 10 ppm < [available Cl] < 200 ppm, and the hydrogen ion exponent (the pH value; 5.0 < pH < 6.8). In addition, the aqueous solution is very long life, and it is possible to storage and/or prevails. This functional water is a solution presenting slightly acidic or neutrality without having the corrosiveness, since the hydrochloric acid is not contained in forming solution. Since it has the powerful oxidizability, this solution manifests very powerful pasteurization effect and deodorizing effect. This aqueous solution is used in order to deal with water supply, intermediate process water, and wastewater. It is widely applied in medicine, food processing, agriculture, livestock industry, fisheries field and so on. In addition, the author also reports applications of this technology for prevention of epidemics countermeasure.

Effects of Simple Abrasive Combing and Pretreatments on the Properties of Pineapple Leaf Fibers (Palf) and Palf-Vinyl Ester Composite Adhesion

Despite being mechanically and environmentally sound, pineapple leaf fibers (PALF) are of little use in Malaysia and the least studied for composite applications. In this study effects of abrasive combing and simple pretreatments on PALF and their adhesion to vinyl ester were investigated. In pineapple leaves, PALF are present in top lamina as large vascular bundles and bottom lamina as fine strands. Tensile strength and modulus of fine PALF strands are 155% and 134% higher than those of vascular bundles respectively. Abrasive combing reduced PALF diameters by 50.3% resulting in finer bundles with 48.6% higher modulus and 51.5% greater strength without much negative effects on fiber integrity. Water-soak did not change PALF tensile properties significantly, while dilute sodium hypochlorite (NaOCl) solution improved PALF modulus and strength by as much as 123% and 35% respectively while reducing elongation at break by 47%. Dilute solution of NaOCl changed PALF structurally through higher crystallinity and closer packing resulting in increased tensile strength and modulus. PALF thermal stability was also enhanced. PALF-vinyl ester adhesion improved due to bleach pretreatment indicated by significantly reduced fiber pull-out length of broken PALF-vinyl ester composites. Morphological study using scanning electron microscope was used to confirm the findings. This study indicated that abrasive combing and simple pretreatment of dilute sodium hypochlorite are potential techniques to produce cost-effective PALF for reinforcing plastics.

Antimicrobial polyethylene terephthalate (PET) treated with an aromatic N‐halamine precursor, m‐aramid

AbstractA commercial m‐aramid as N‐halamine precursor has been coated onto polyethylene terephthalate (PET) fabric surface by pad‐dry‐curing process. The process is accomplished by padding the scoured PET fabric through the homogeneous m‐aramid solution, drying at 150°C for 3 min, and curing at 230°C for 3 min. The PET surface coated with m‐aramid was characterized using fourier transform infrared‐attenuated total reflection (FTIR‐ATR) spectroscopy, X‐ray photoelectron spectroscopy (XPS), and scanning electron microscopy (SEM). FTIR exhibits new bands in the 1645 and 1524 cm−1 regions as characteristic of m‐aramid bands, which indicate the PET fabric coated with m‐aramid. XPS results show a distinguishable peak at binding energy 398.7 eV, which confirms the nitrogen atom of m‐aramid on the PET surface. In addition, SEM image shows a layer of coating onto the PET surfaces, which demonstrates the presence of m‐aramid coating on the surface of the PET. After exposure to dilute sodium hypochlorite solution, exhibition of antimicrobial activity on the coated PET is attributed to the conversion of N‐halamine moieties from the N‐halamine precursor. The chlorinated PET showed high antimicrobial activity against Gram‐negative and Gram‐positive bacteria. The chlorinated PET coated with 10% m‐aramid exhibited about 6 log reductions of S. aureus and E. coli O157:H7 at a contact time of 10 and 30 min, respectively. Furthermore, the antimicrobial activity was durable and rechargeable after 25 wash cycles. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009

Simple and versatile methods for the fabrication of arrays of live mammalian cells

Single-step methods for the generation of patterned surfaces on hydrogels are presented. Poly(vinyl alcohol) films covalently bonded on glass cover slips and commercially available hydrogel-coated polystyrene plates were used as cell-repellent surfaces. Cell-adhesive domains were created by spotting dilute solutions of sodium hypochlorite onto the surfaces. Alternatively, domains supporting cell attachment were created by exposure to UV light from a xenon excimer lamp, employing a contact mask. Rat skeletal myoblast cells, HEK 293 human embryonic kidney cells and Caco-2 colon carcinoma cells adhered and spread exclusively on modified areas. The surfaces are durable for weeks under cell culture conditions and re-usable after removal of the cells by trypsin treatment. Arrays of adhesive spots seeded with cells at a low density permitted dynamic monitoring of cell proliferation. Selected colonies can be harvested from the surfaces by means of local trypsination. Thus, these techniques may provide useful tools for the isolation of clonal cell populations. Additionally, we demonstrate the possibility of surface-mediated gene delivery from the micro patterns. We show that DNA, complexed with a lipid reagent, can be adsorbed on modified poly(vinyl alcohol) coatings, resulting in spatially controlled adhesion and reverse transfection of HEK 293 cells.

Pd-Catalyzed TCE Dechlorination in Groundwater: Solute Effects, Biological Control, and Oxidative Catalyst Regeneration

The performance of a Pd-on-γ-Al2O3 catalyst for dechlorination of trichloroethylene (TCE) was evaluated in synthetic and real groundwater. Low initial TCE conversions were used to provide maximum sensitivity to changes in catalyst activity. TCE conversions of >24% were maintained in DI water for 60 days using 0.5 g of 1% (w/w) Pd-on-γ-Al2O3 and a retention time of 4.3 min. Slow catalyst deactivation was reversed by treatment with a dilute sodium hypochlorite solution. The presence of high concentrations of H2CO3, HCO3-, CO32-, SO42-, and Cl- did not adversely affect catalyst activity. TCE conversion increased 30% upon increasing the solution pH from 4.3 to 11. The presence of 87 mg/L SO32- or 0.4 mg/L HS- caused rapid catalyst deactivation, presumably due to chemisorption to active sites. Dilute sodium hypochlorite solutions regenerated catalysts deactivated by HS- and SO32-. Sulfate-reducing bacteria that developed in natural groundwater amended with H2 deactivated the catalyst, but activity was restored...

Use of microwave energy to disinfect a long-term soft lining material contaminated with Candida albicans or Staphylococcus aureus

Statement of problem. Soft lining materials have been found to be more susceptible to microbial adhesion than acrylic resin base materials. Denture hygiene is essential to maintain the serviceability of the denture, and microwave energy has been suggested for denture disinfection. Purpose. The purpose of this study was to determine the effectiveness of microwave energy in the disinfection of a long-term soft lining material. Material and methods. A long-term soft lining material was contaminated with known microorganisms and the reduction of organism counts after test disinfection regimes calculated. The disinfection regimes were microwaving for 5 minutes, leaving dry overnight, and soaking overnight in a dilute sodium hypochlorite solution. The test microorganisms were Candida albicans or Staphylococcus aureus . Results. For both organisms, soaking in sodium hypochlorite reduced the number of viable adherent microorganisms recovered significantly more than exposure to microwave energy, which led to greater reduction than leaving the lining material dry overnight ( p < 0.001, Wilcoxon nonparametric signed rank test). Conclusion. With reference to the tested microorganisms, disinfection of Molloplast-b soft lining material in dilute sodium hypochlorite solution proved to be more effective than exposure to microwave energy, which in turn was more effective than leaving the lining dry overnight. (J Prosthet Dent 1998;79:454-8.)

A hypochlorite-fast metachromatic quick stain for human megakaryocytes.

Megakaryocytes in aspirates of normal and abnormal human bone marrow displayed rose-pink metachromasia when stained with a violet polymethine dye. The color of the megakaryocytes persisted when the stained sample was exposed to a dilute solution of sodium hypochlorite. Under the same conditions, other hematopoietic cells became colorless. This stain may be useful for demonstrating megakaryocyte from both healthy and diseased bone marrow specimens.

The Internal Structure of Coir (Coconut) Fiber

The source of commercial coir fiber (actually, a vascular strand) is the massive fibrous husk (3-5 cm thick) surrounding the coconut. This paper reports a SEM study of some aspects of this interesting fiber. The specimens were sputter coated with Au Pd and observed with 4 KV accelerating voltage.A cut cross section of a retted coir fiber is seen in Figures 1 and 2. A high degree of porosity is apparent; a core of the vascular or conductive bundle is seen surrounded by a large area of elongated sclerenchymatous cells which are cemented together into a composite with pectins or hemicelluloses.The sclerenchymatous cells may be separated by a maceration process, in this work a dilute solution of sodium hypochlorite. A bent, partially macerated coir fiber showing the configuration and orientation of the cells is given in Figure 3. A completely separated cell showing its general shape and pits is shown in a light photomicrograph in Figure 4.

The Degradation of Water‐soluble Azo Compounds by Dilute Sodium Hypochlorite Solution

The decolorization of azo dyes by sodium hypochlorite solution has been followed spectrophotometrically and a technique developed for determining the half‐life of the process as a convenient measure of the reaction rate. A study of a series of 2‐arylazo‐1‐naphthol‐3,6‐disulphonic acids suggests that electronic, steric and possibly other effects influence the reaction rate, and that degradation involves initial attack at a nitrogen atom of the hydrazone form, by the electrophilic chloronium ion. Sulphonic and carboxylic acid groups located ortho to the azo linkage are particularly effective in retarding the rate of degradation.The dyes 4‐(4‐sulphophenylazo)‐1‐naphthol (I) and 4‐(4‐sulphophenylazo)‐1‐(2‐chloro‐4‐amino‐s‐triazinylamino)‐naphthalene‐6‐sulphonic acid (II) were investigated in more detail to determine the effect of pH on the reaction rate, the number of molecules of sodium hypochlorite involved in the decolorization reaction the nature of the decomposition fragments. This information, together with the fact that the O‐ and N‐ methyl homologues of I were extremely resistant to degradation, enabled a mechanism to be postulated for the reaction.

Studies on Sulphur in Acetylene Gas Generated by Dry Type Generators and Method of Gas Purification

Removal of sulfur components by washing with a dilute sodium hypochlorite solution from acetylene generated in a dry type generator has been studied.Calcium carbide containing more than 1 wt% calcium sulfide gave crude acetylene which contained sulfur components at a level of 1 × 10-1-1 × 10-2 vol% calculated as hydrogen sulfide. The white crystal extracted from the precipitates in the mist separator after purification was found to be α, β, α', β'-tetrachlorodiethyl sulfoxide. Optimum pH of the purification solution was 7.3-6.5, and the effect of the chlorine content was also clarified. Pre-washing of crude acetylene with 10% aqueous sodium hydroxide before the treatment with the sodium hypochlorite proved very effectivefor the removal of hydrogen sulfide.

Fluorescein-labeled beta-glucosidase as a bacterial stain.

Fluorescein isothiocyanate-labeled beta-glucosidase was used as a simple staining reagent with selected gram-positive and gram-negative organisms. Staining in situ appeared to be dependent on the presence of accessible glycosidic-type linkages in the bacterial cell wall. Extensive wall damage or lysis did not occur when stained cells were suspended in washing and mounting solutions. The apparent specificity of labeled enzyme for wall substance was tested by blocking reactions, staining of isolated cell walls, and failure to stain substances lacking appropriate glycosidic linkages. Severe cell wall lesions were produced after prolonged contact with labeled enzyme, and this phenomenon may also be related to staining specificity. Gram-negative organisms and spores were poorly stained unless protected glycopeptide substrate was previously exposed by treatment of cells with thioglycolic acid or dilute alkaline sodium hypochlorite solution. A potential for staining tissues and cell lines may also exist. Some possible applications of labeled enzymes are briefly discussed.

Fluorescein-labeled β-Glucosidase as a Bacterial Stain

Fluorescein isothiocyanate-labeled beta-glucosidase was used as a simple staining reagent with selected gram-positive and gram-negative organisms. Staining in situ appeared to be dependent on the presence of accessible glycosidic-type linkages in the bacterial cell wall. Extensive wall damage or lysis did not occur when stained cells were suspended in washing and mounting solutions. The apparent specificity of labeled enzyme for wall substance was tested by blocking reactions, staining of isolated cell walls, and failure to stain substances lacking appropriate glycosidic linkages. Severe cell wall lesions were produced after prolonged contact with labeled enzyme, and this phenomenon may also be related to staining specificity. Gram-negative organisms and spores were poorly stained unless protected glycopeptide substrate was previously exposed by treatment of cells with thioglycolic acid or dilute alkaline sodium hypochlorite solution. A potential for staining tissues and cell lines may also exist. Some possible applications of labeled enzymes are briefly discussed.

A method for securing the snail, Lymnaea stagnalis jugularis (Say), free from bacteria

Individual eggs obtained from isolated egg masses of the snail Lymnaea stagnalis jugularis (Say) were surface sterilized with the aid of a dilute solution of sodium hypochlorite. After subsequent washing in a favorable salt solution (designated SX), 90% of such treated eggs would hatch. The yield of living specimens that were obtained bacteria-free ranged up to 100%.

Accelerated oxidation of cotton cellulose in presence of reducing substances—Part III

(1) The measurement of oxidation potential of dilute solutions of sodium hypochlorite has been carried out at 30° C. by a method used successfully by various investigators. (2) The values of the oxidation potential at 30° C. are higher than those at 20° C. The differences in the potentials become more and more marked with reduction in the pH of the hypochlorite solution. (3) A correction of pH × 0·06 volts to the measured potentials at 30° C. does not show any maximum value over the pH region examined. A sharp change in the direction of pH-corrected oxidation potential curve, however, occurs at about the same pH at which a maximum is obtained at 20°C. (4) There exists no similarity between the corrected oxidation potential-pH curve at 30° C. and a curve showing relation between oxygen uptake or fluidity and pH at 30° C. Nabar, Scholefield and Turner1 had shown a striking resemblance between these curves at 20° C.

Accelerated Oxidation of Cotton Cellulose in Presence of Reduced Cibanone Orange R

THE rate of oxidation of cellulose by dilute solutions of sodium hypochlorite has been shown to be accelerated if certain vat dyes are also present in the reduced form upon the fibre1,2. Ferrous hydroxide precipitated on cellulose exerts a similar influence on the rate of oxidation3. The mechanism of this acceleration is not yet clear. It has been suggested2 that the difference between the oxidation potential of the oxidizing agent and the reduction potential of the vat dye may be the determining factor in the acceleration of the oxidation. The present investigation deals with the measurement of reduction potentials of vat dyes upon the fibre and their influence on the acceleration of the rate of oxidation of the cellulose substrate by dilute sodium hypochlorite solution.

Reduction Potentials of Ferrous Hydroxide

THE accelerated oxidation of cellulose in the presence of ferrous hydroxide by dilute solutions of sodium hypochlorite, buffered to different hydrogen ion concentrations, has been studied by Nabar and Turner1. It was shown that the maximum absorption of oxygen and the maximum attack on cellulose occurred at about pH. 6.4. From similar earlier investigations, with leuco vat dyes as accelerators, Nabar, Scholefield and Turner2,3 had shown that the maximum oxygen uptake and the maximum oxidation of cellulose occurred at about pH. 7.4. The obvious dependence of the oxidizing intensity of sodium hypochlorite solutions on the specific substance present on cellulose may be attributed to the differences in their physico-chemical properties, such as reduction potentials, ease of oxidation, etc. The present work was undertaken to study the reduction potential of ferrous hydroxide and examine its influence on the oxidation mechanism.

Oxidising Agents and Vat-dyed Cotton

IN the course of an investigation into the action of oxidising agents upon cotton dyed with vat dyestuffe, we have obtained evidence of a simple relationship between the stable potential set up when a platinum electrode is dipped into a dilute solution of sodium hypochlorite, and the amount of chemical modification produced when this solution acts, under standard conditions, upon pure cotton cellulose dyed with the reduced or leuco form of certain vat dyestuffs. These results may prove of interest to those engaged in a study of the chemistry of cellulose and similar polymolecular compounds and also to those who are working on phenomena of oxygen transfer facilitated by a chemically labile substance.