potassium permanganate

2.1. Materials

Antimony with a purity of 99% (obtained from Stanchem Sp. z o.o. (Niemce, Poland)) and potassium manganate(VII) with a purity of 99% (obtained from STANDARD P.P.H. (Lublin, Poland)) were used to produce pyrotechnic compositions. The grain analysis of both components was performed using a FRITSCH ANALYSETTE 22 MicroTec plus laser particle size analyzer. The samples were dosed into the measuring cells by means of a vacuum dosing unit with the application of ultrasound in order to break up the agglomerates of particles. Volume-based particle size distributions were determined on the basis of laser beam diffraction. Measurements were made in the range of 0.08–2000 µm. The detected grains were divided into 102 classes in terms of their diameter (n = 102). The beam obscuration value was 8.0%.

1. Introduction

Two dominant peaks are visible on the DTA curve for the Sb/KMnO4 composition (with 60 wt% antimony content) heated in the air atmosphere []. The first one is the exothermic decomposition of KMnO4, which takes place at a temperature of about 300 °C. Another sharp exotherm (ignition of the composition), occurring at a temperature of about 500 °C, comes from the oxidation of Sb with oxygen from the air (as evidenced by the rapid increase in the mass of the sample in the TG curve). An important observation of the authors of Ref. [] is the finding of a wide, exothermic peak on the DTA curve without changing the mass of the sample above the temperature of 500 °C during the test with inert gas (nitrogen). This fact is the basis for a hypothesis that, in such conditions, secondary reactions can take place in the system. On the basis of the area under the DTA curve, the total heat of the reaction for the tested composition in the air atmosphere was determined at ∆H = 2.11 kJ g−1. The total thermal effect of the reaction in a nitrogen atmosphere was not determined in Ref. [].

1. Introduction

Based on the results of the thermal analysis presented in the literature, the combustion products should be expected to contain compounds derived from the thermal decomposition of potassium manganate(VII) and the products of antimony oxidation by the released oxygen. The occurrence of secondary reactions between the products of KMnO4 decomposition and the oxidation products of Sb is not confirmed. However, this possibility should not be rejected. In Ref. [], on the basis of the DTA and TG curves, the two-stage decomposition of KMnO4 was confirmed and the reactions reported in the literature for the first stage of the thermal decomposition of KMnO4 at approx. 290 °C and, for the second stage, at 620 °C were quoted. The solid products of KMnO4 decomposition can be: K2MnO4, K3MnO4 and solid solutions of K2O and MnO2. According to the authors of Ref. [], Sb2O3 and Sb2O4 are the most likely products of antimony oxidation during thermal analysis conducted in the air atmosphere. The first one occurs between 300 and 500 °C, the second one at 600 °C.

1. Introduction

Two dominant peaks are visible on the DTA curve for the Sb/KMnO4 composition (with 60 wt% antimony content) heated in the air atmosphere []. The first one is the exothermic decomposition of KMnO4, which takes place at a temperature of about 300 °C. Another sharp exotherm (ignition of the composition), occurring at a temperature of about 500 °C, comes from the oxidation of Sb with oxygen from the air (as evidenced by the rapid increase in the mass of the sample in the TG curve). An important observation of the authors of Ref. [] is the finding of a wide, exothermic peak on the DTA curve without changing the mass of the sample above the temperature of 500 °C during the test with inert gas (nitrogen). This fact is the basis for a hypothesis that, in such conditions, secondary reactions can take place in the system. On the basis of the area under the DTA curve, the total heat of the reaction for the tested composition in the air atmosphere was determined at ∆H = 2.11 kJ g−1. The total thermal effect of the reaction in a nitrogen atmosphere was not determined in Ref. [].

2.5. Heat of Combustion

Combustion heat measurements were made using the KL-12 calorimeter produced by Precyzja Bit from Poland. A cylindrical steel calorimetric bomb with a capacity of 350 mL was placed in a steel vessel containing distilled water. The calorimetric system has been described in detail in []. Pellets of Sb/KMnO4 compositions weighing from 4 to 9 g were pressed. The diameter of the pellets was 15 mm. A resistance wire made of the Kanthal D alloy (69% Fe, 22% Cr, 6% Al, 3% Zn and Si) was pressed into each pellet. The wire was 20 cm long, 2 mm in diameter and had a mass of 0.045 g. The resistance of the wire was 42.88 Ω m−1. The part of the wire that was pressed into the pellet was coiled into a spiral to increase its contact surface with the composition. The wire did not burn down during the tests but was broken due to the rapid increase of temperature. The heat released as a result of glow-up of the wire was not taken into account in determining the heat of combustion of the samples. The samples were placed in 4 mL quartz crucibles. Combustion heat measurements were made in an atmosphere of inert gas (argon) at various initial pressures.

2.1. Fiber Extraction and Treatment

Butea parviflora (BP) is a woody climber belonging to the Fabaceae family. It is found in the regions of Kanniyakumari, Tamil Nadu. The whole plant is fibrous, but the strength and texture vary from the outer to inner space. Due to its strength, bark fibers of Butea plant are used by locals for tying, knotting, and binding requirements. Bark contains 1% rotenone, which is used as an insecticide. In order to separate mature fibers from the plant, a metal teeth tool is used. Collected fibers are treated in distilled water and potassium permanganate; treatment involves soaking of fibers in 0.1 M NaOH solution for 20 min, followed by 15 min in the same molarity of potassium permanganate at 27 °C. Treated fibers are rinsed in distilled water. Fibers are first drained in shade, then dried completely using a vacuum desiccator. Variation in soaking time and concentration of KMnO4 will bring varying results. Different treatments at 0.025% and 0.05% of KMnO4 on the Musa plant eliminated the non-cellulosic debris and manifested the crystalline and tensile property of fiber. The delignification process that takes place during permanganate action facilitates the rearrangement of microfibrils, resulting in an improvement in crystallinity. Moreover, the wetting of fibers in 0.1% KMnO4 induces capillary forces that increase their resistance to water []. . presents water and KMnO4 treated BP fibers.

Abstract

Humans are the only species who generate waste materials that cannot be broken down by natural processes. The ideal solution to this waste problem would be to employ only compostable materials. Biodegradable materials play a key role in creating a safer and greener world. Biodegradability is the gift that keeps on giving, in the sense of creating an Earth worth living. The future is thus best served by green energy, sustainability, and renewable resources. To realize such goals, waste should be considered as a valuable resource. In this context, Zea mays (Zm) root fibres, which are normally considered as agricultural waste, can be used as reinforcing substances in polymer matrices to produce structural composite materials. Before being used in composites, such fibres must be analysed for their physical properties. Chemical treatments can be employed to improve the structural quality of fibres, and the changes due to such modification can be analysed. Therefore, the current work examines the effect of permanganate treatment on the surface properties of Zm fibres. The raw and potassium permanganate-treated samples were assayed for various properties. Physical analysis of the fibre samples yielded details concerning the physical aspects of the fibres. The thermal conductivity and moisture absorption behaviour of the samples were analysed. Chemical analysis was employed to characterize the composition of both treated and untreated samples. p-XRD was employed to examine the crystalline nature of the Zm fibres. Numerous functional groups present in each sample were analysed by FTIR. Thermogravimetric analysis was used to determine the thermal stability of Zm fibres. Elemental analysis (CHNS and EDS) was used to determine the elemental concentrations of both raw and treated samples. The surface alterations of Zm fibres brought on by treatment were described using SEM analysis. The characteristics of Zm roots and the changes in quality due to treatment were reviewed, and there were noticeable effects due to the treatment. Both samples would have applications in various fields, and each could be used as a potential reinforcing material in the production of efficient bio-composites.

Potassium permanganate treatment on natural fibres

Zea mays (Zm) root fibres were chemically pre-treated with alkali solution and then with permanganate solution in the present work. They were then tested for the changes in their qualities related to being better reinforcement materials for polymer composite-based products.

Abstract

Background/Objectives: Adaptation can reduce or completely eliminate the effectiveness of antibiotics and antiseptics at clinical concentrations. To our knowledge, no studies have examined fungal adaptation to antiseptics. This study aimed to preliminarily investigate the potential for Candida albicans adaptation to eight antiseptics. Methods: The minimal inhibitory concentration (MIC), drug susceptibility, adaptation to antiseptics, and Karpinski Adaptation Index (KAI) of C. albicans strains were assessed. Results: The antiseptics with the most effective MICs activity against C. albicans were octenidine dihydrochloride (OCT), chlorhexidine digluconate (CHX), and polyhexamethylene biguanide (polyhexanide, PHMB). Sodium hypochlorite (NaOCl) and ethacridine lactate (ET) demonstrated moderate activity, while boric acid (BA), povidone–iodine (PVI), and potassium permanganate (KMnO4) showed the weakest activity. The MIC values for NaOCl and KMnO4 were close to or equal to the clinical concentrations used in commercial products. The studied strains were susceptible to econazole, miconazole, and voriconazole. Resistance to other drugs occurred in 10–30% of the strains. Antifungal resistance remained unchanged after antiseptic adaptation testing. The lowest KAI values, indicating very low resistance risk, were observed for CHX, OCT, and PHMB. PVI and BA presented a low risk, ET a moderate risk. KMnO4 and NaOCl had the highest KAI values, indicating high and very high resistance risk in Candida yeasts. Conclusions: C. albicans strains can adapt to antiseptics to varying extents. For most antiseptics, adaptation does not significantly affect their clinical efficacy. However, due to adaptation, NaOCl and KMnO4 may become ineffective against C. albicans strains even at clinical concentrations.

2.3. Adaptation of Candida albicans Strains to Antiseptics

The studies demonstrated that C. albicans yeasts undergo adaptation when exposed to increasing concentrations of antiseptics. The strains showed weak adaptation to OCT, CHX, PVI, and ET, managing to grow at concentrations several times higher than their respective MIC values. For NaOCl and KMnO₄, adaptation levels were also low but were close to or equal to the initial commercial concentration. This finding suggests that the development of adaptation may lead to the ineffectiveness of commercial products containing NaOCl and KMnO4 against C. albicans. The highest increase in adaptation relative to MIC was observed for BA and PHMB; however, these values were still much lower than the commercial concentrations.

2.3. Adaptation of Candida albicans Strains to Antiseptics

Based on the Karpinski Adaptation Index, the lowest KAI values were observed for CHX, OCT, and PHMB, indicating a very low risk of clinical resistance development in the studied C. albicans strains. PVI and BA had a low risk, while ET posed a moderate risk for clinical resistance development. The highest KAI values were observed for KMnO₄ and NaOCl, indicating a high and very high risk, respectively, of clinical resistance development in Candida yeasts. The results of C. albicans adaptation to antiseptics are provided in . Detailed raw data on the C. albicans adaptation are presented in the .

4.1. Antiseptics

Eight antiseptics were examined in the study: octenidine dihydrochloride (OCT; Schülke & Mayr GmbH, Norderstedt, Germany), polyhexamethylene biguanide (PHMB, Cosmocil PG; Arxada AG, Basel, Switzerland), sodium hypochlorite (NaOCl; Cerkamed, Stalowa Wola, Poland), potassium permanganate (KMnO4; Hasco-Lek S.A., Wrocław, Poland), chlorhexidine digluconate (CHX; Sigma-Aldrich, Poznań, Poland), povidone–iodine (PVI, poly(vinylpyrrolidone)–iodine complex; Sigma-Aldrich, Poznań, Poland), boric acid (BA, Borasol; Herbapol, Poznań, Poland), and ethacridine lactate (ET, Rivanol; Herbapol, Poznań, Poland). The initial concentrations of active substances matched the clinical concentrations found in commercial products used for wound and oral antiseptics: 0.05% (500 µg/mL) OCT, 0.1% (1000 µg/mL) PHMB, 0.01% (100 µg/mL) NaOCl, 1% (10 mg/mL) KMnO4, 0.1% (1000 µg/mL) CHX, 7.5% (75 mg/mL) PVI, 3% (30 mg/mL) BA, and 0.1% (1000 µg/mL) ET.