Potassium Permanganate Treatment Research Articles

Chemical characterization of hibiscus rosa-sinensis plant fibers facilitated through design of experiments and artificial neural network hybrid approach

The integration of natural fibers into Fiber Reinforced Polymers (FRPs) has emerged as a promising avenue for sustainable and high-performance composite materials. Natural fibers, derived from plants, offer notable advantages such as renewability, low cost, and environmental friendliness. Among these natural fibers, Hibiscus Rosa-Sinensis (HRS) plant fibers have gained significant attention owing to their widespread availability and unique mechanical properties. In this study, HRS fibers were chemically treated using Sodium Hydroxide (NaOH), Potassium Permanganate (KMnO4), and Acetic Acid (CH3COOH) at different weight percentages (3, 4, 5 Wt.%) and solutionizing times (1, 2, 3 h) based on Taguchi’s L27 orthogonal array. The fibers, extracted from epidermis of the stems, underwent cleaning and chemical treatment after water retting. The crystallinity index, determined via X-ray Diffraction (XRD), indicated a maximum value of 65.77%. Thermo-gravimetric analysis (TGA) exhibited a degradation temperature of 365.24 °C and a material loss of 63.11%. Potassium Permanganate treatment at 4 Wt.% and 3 h of solutionizing time has yielded the best results. Multi-Layer Perceptron Artificial Neural Network (MLP-ANN) has been successfully applied to accurately predict the output physical characteristics of chemically treated HRS fibers using experimental data. The results are in close alignment with the literature. Scanning Electron Microscopy (SEM) and Energy Dispersive X-ray Spectroscopy (EDS) analyses have provided valuable insights into the microstructure and constituents of the chemically treated HRS fibers. This research emphasises on the effectiveness of the chemical treatment process in enhancing the properties of HRS plant fibers for potential composite applications.

Quantitative and deep learning based fourier transform infrared radiation and tensile characteristics study on chemically treated hibiscus rosa-sinensis plant fibers

Incorporation of natural fibers with Fiber Reinforced Polymers (FRPs) is a promising avenue for sustainable and high-performance composite materials. The fibers, derived from outer bark portion of plants, offer significant merits such as renewability, low cost, and eco-friendly. Unique mechanical and physical properties, and widespread availability of Hibiscus Rosa-sinensis have made them subject of intense research interest. The present study investigated the chemically treatment of HRS Fibers using Sodium Hydroxide (NaOH), Potassium Permanganate (KMnO4), and Acetic Acid (CH3COOH) bat varying weight percentages (3, 4, 5 Wt%) and solutionizing times (1, 2, 3 h) based on Taguchi’s L27 orthogonal array. Fourier Transform Infrared (FT-IR) analysis revealed significant changes in O–H, C–H stretching, C=O moiety, aromatic ring, and C–O/C–C stretching. Potassium Permanganate treatment at 4 Wt% and 3 h of solutionizing time has yielded the best results. Multi-Layer Perceptron Artificial Neural Network (MLP-ANN) has been successfully applied to accurately predict the output physical characteristics of chemically treated HRS fibers using experimental data. Further Single Fiber Pull-out test results in Potassium Permanganate at 4 Wt% and 3 h solutionizing time as best sample with highest Tensile Strength and Modulus. This research underscores the effectiveness of the chemical treatment process in enhancing the properties of HRS plant fibers for potential composite applications.

Enhancing volatile fatty acid production in batch test reactors by modulating microbial communities with potassium permanganate

The shift from conventional wastewater treatment plants to biorefineries is one of the most environmentally and economically sustainable pathways for extracting valuable compounds from waste. Besides chemical-physical processes, microorganisms within sewage sludge utilize organic and inorganic pollutants in the wastewater as nutrients, leading to effective water purification. However, the remaining solid sludge residue, typically destined for specific landfills or incineration, could undergo microbial fermentation to produce volatile fatty acids (VFA), metabolic precursors for biopolymers. Increasing attention has been directed towards optimizing operational parameters to enhance VFA production during sewage sludge fermentation. This study examined the impact of potassium permanganate (PP) on microbial communities during the sewage sludge's acidogenic fermentation. The results highlighted the positive effect of PP treatment, which increased COD production and VFA yield up to 1263.5 mg/L and 664.2 mg COD/L, respectively. The presence of PP significantly enhances VFA yield promoting bacteria positively linked to VFA production.

Exploring the mechanism of Huanglian ointment in alleviating wound healing after anal fistula surgery through metabolomics and proteomics

Anal fistula is a common anal and intestinal disease. The wound of anal fistula surgery is open and polluting, which is the most difficult to heal among all surgical incisions. To investigate the mechanism of Huanglian ointment (HLO) on wound healing after anal fistula incision. The S. aureus infected wound in SD rats were used to imitate poor healing wound after anal fistula surgery. SD rats with wound sites (n = 24) were randomly divided into four groups (Control group, Model group, Potassium permanganate (PP) treatment group, and HLO treatment group). The wound healing rate was evaluated, HE staining was used to evaluate the pathological changes of each group, ELISA was used to detect the secretion of inflammatory factors in each group, and the mechanism was explored through metabolomics and proteomics in plasma rat. Compared to other groups, the rate of wound healing in the HLO group was higher on days 7 and 14. Histological analysis showed that collagen and fibroblast in HLO rats were significantly increased, inflammatory cells were reduced, and vascular endothelial permeability was increased. ELISA results showed that the secretion of inflammatory factors in HLO rats was significantly lower. Significant proteins and metabolites were identified in the wound tissues of the infected rats and HLO-treated rats, which were mainly attributed to Cdc42, Ctnnb1, Actr2, Actr3, Arpc1b, Itgam, Itgb2, Cttn, Linoleic acid metabolism, d-Glutamine and d-glutamate metabolism, Phenylalanine, tyrosine and tryptophan biosynthesis, Phenylalanine metabolism, alpha-Linolenic acid metabolism, and Ascorbate and aldarate metabolism. In conclusion, this study showed that HLO can promote S. aureus infected wound healing, and the data provide a theoretical basis for the treatment of wounds after anal fistula surgery with HLO.

A Study on Shore D Hardness of Areca Husk Fibre Reinforced Polyester Resin Composite: Impact of Fibre Maturity

Areca husk fibre is an agro-waste natural fibre that can be used in reinforced resin composites due to its low density, low cost and higher mechanical strength. Hard composites have applications in the packing industry and automobile industries. Over the years, researchers have been trying to develop lightweight, cheaper and efficient materials for them in daily life. In the present study, the Shore-D hardness level of chemically surface-modified unripe and ripe Areca Husk Fiber (AHF) reinforced polyester resin composites have been investigated. The unripe and ripe AHF are chemically treated through mercerization, potassium permanganate treatment, benzoylation, acrylation and acetylation methodologies to change their fibre-matrix bonding ability. The composites of chemically treated unripe and ripe AHF-reinforced polyester resin composites are fabricated, polyester resin as matrix material and methyl ethyl ketone peroxide (MEKPO) as a hardener. The Shore-D analysis was carried out to study the hardness properties of the composites. In conclusion, The acrylation treated AHF polyester resin composite shows a better harness among the other chemically treatments. Although, the fibre maturity of AHF increases the composite hardness except for benzoylation and acetylation chemical treatments. AHF-reinforced polyester resins can be used as hard materials in various applications such as automobile sectors, the packaging industry and more.

Synthesis of lignin nanoparticle‑manganese dioxide complex and its adsorption of methyl orange

Lignin nanoparticles (LNPs) were synthesized using an anti-solvent method and subsequently loaded with manganese dioxide (MnO2) via potassium permanganate treatment, resulting in the formation of MnO2@LNPs. An extensive investigation was conducted to elucidate the influence of MnO2@LNPs on the decolorization of methyl orange solution. The LNPs were successfully obtained by adjusting the preparation parameters, yielding particles exhibited average sizes ranging from 300 to 600 nm, and the synthesis process exhibited a high yield of up to 87.3% and excellent dispersion characteristics. Notably, LNPs size was reduced by decreasing initial concentration, increasing stirring rate, and adding water. In the acetone-water two-phase system, LNPs self-assembled into spherical particles driven by π-π interactions and hydrogen bond forces. Oxidation modification using potassium permanganate led to the formation of nanoscale MnO2, which effectively combined with LNPs. Remarkably, the resulting MnO2@LNPs demonstrated a two-fold increase in methyl orange adsorption capacity (227 mg/g) compared to unmodified LNPs. The process followed the Langmuir isotherm model and was exothermic.

Biodegradable Green Composites: Effects of Potassium Permanganate (KMnO4) Treatment on Thermal, Mechanical, and Morphological Behavior of Butea Parviflora (BP) Fibers.

This study emphasizes the importance of utilizing biodegradable material Butea parviflora (BP) fiber for sustainable solutions. BP fiber offers numerous ecological benefits, such as being lightweight, biodegradable, and affordable to recycle. The study examines the effects of potassium permanganate (KMnO4) treatment on BP fiber and analyzes its physical and chemical behavior using various methods, including X-ray Diffraction (XRD) analysis, tensile testing, thermogravimetric analysis, thermal conductivity, Scanning Electron Microscopy (SEM), and Fourier Transform Infrared spectroscopic (FTIR) analysis. The results demonstrate that BP fiber possesses low density (1.40 g/cc) and high cellulose content (59.4%), which fosters compatibility between the matrix and resin. XRD analysis indicates a high crystallinity index (83.47%) and crystallite size (6.4 nm), showcasing exceptional crystalline behavior. Treated fibers exhibit improved tensile strength (198 MPa) and Young's modulus (4.40 GPa) compared to untreated fibers (tensile strength-92 MPa, tensile modulus-2.16 GPa). The Tg-DTA thermograms reveal the fiber's thermal resistance up to 240 °C with a kinetic activation energy between 62.80-63.46 KJ/mol. Additionally, the lowered thermal conductivity (K) from Lee's disc experiment suggests that BP fiber could be used in insulation applications. SEM photographic results display effective surface roughness for composite making, and FTIR studies reveal vibrational variations of cellulosic functional groups, which correlates with increased cellulosic behavior. Overall, the study affirms the potential of BP fiber as a reinforcing material for composite-making while emphasizing the importance of utilizing biodegradable materials for sustainability.

Effect of Surface Modification on the Impact Strength and Hardness of Areca Husk Fibre Reinforced Polyester Resin Composite

Reinforced natural fibre composite materials are attracting greater attention in the area of material engineering due to their low density, low cost and higher mechanical strength. In the present study, the Areca Husk Fiber (AHF) was extracted through the retting process. The surface modification of AHF was done by chemical treatments such as mercerization, potassium permanganate treatment, benzoylation, acrylation and acetylation. The surface modification was studied through FE-SEM imaging. The composites of surface modified AHF reinforced polyester resin composites were prepared as per ASTM standards using polyester resin as matrix material and methyl ethyl ketone peroxide (MEKPO) as hardener. The Izod-Charpy impact strength, Hardness (Shore-) hardness analysis was carried out to study the mechanical behaviour of the composites. The results showed that surface modification of AHF can enhance the impact strength of the composite materials but not the hardness of the composites.

Effect of Potassium Permanganate treatment on physico-Chemical and mechanical properties of extracted Pine Needle Fiber

This study investigates the potential of extracted pine needle fiber (PNF) to substitute synthetic fibers in biopolymer composites as a reinforcing material. The study is focused on the surface modification and characterizing of the extracted PNF. Water retting method was used to extract the PNF before being subjected to potassium permanganate treatment. The surface treatment with potassium permanganate resulted in higher density (1058 kg/m3) compared to the untreated fibers (1017 kg/m3). X-ray Diffraction (XRD) analysis shows the surface treatments positively impacted the natural fiber’s crystallinity index (CI). Additionally, the tensile strength of PNF were found to be enhanced on potassium permanganate treatment from 49.67 ± 9.6 MPa (untreated PNF) to 56.75 ± 16.54 MPa (treated PNF). Based on the findings, it can be concluded that the potassium permanganate treated PNF will be suitable to be used as reinforcement in fabricating the ecologically friendly composites.

Examining the effect of permanganate (KMnO4) on bamboo fiber (Bambusa vulgaris) reinforced with bio-resin natural honey (melitera) and pawpaw (Carica papaya) leaves extract

<div class="WordSection1"><p>Bamboo fibers are modified for improved interfacial bonding and reduction of moisture absorption. This is achievable through various treatments. The bamboo fiber's mechanical and chemical properties were examined with a Tensile machine and FTIR instrument. Natural fibers have many advantages over manufactured fibers like low density, low cost, biodegradability, poor compatibility between them and the matrix, relatively high moisture sorption, etc. The treatments are vital to modify the surface properties. For this, potassium permanganate (KMnO<sub>4</sub>) was used in this study. The Fourier transform Infra-red (FT-IR) analysis of <strong>untreated</strong> bamboo fiber showed the presence of the Hydrogen-bonded (O-H) stretch, H-C-H asymmetric and symmetric stretch, C-H stretch of C=O, C≡N stretch, N=O Bend, and C-O stretch. For the <strong>treated</strong> bamboo fiber, the analysis shows similar results.<strong> </strong>Similarly, results of <strong>reinforced</strong> bamboo fiber showed hydrogen-bonded O-H stretch, C-H stretch of C=O, C≡C stretch (C-O stretch), N=O stretch, and N-H bend. <strong>The treated</strong> Bamboo fiber was reinforced with a bio-resin (natural honey and pawpaw extract). Mechanical testing was done to get the tensile strength at increased concentration, and FT-IR was used to get the effects of chemical treatment on the fibers. Potassium permanganate treatment improved the properties with increased concentrations.</p></div>

The impact of potassium permanganate (KMnO4) treatment on the tensile strength of pineapple leaf fiber reinforced with tapioca-based bio resin

PurposeThe impact of potassium permanganate (KMnO4) treatment on the tensile strength of an alkali-treated pineapple leaf fiber (PALF) reinforced with tapioca-based bio resin (cassava starch) was studied.Design/methodology/approachThe PALF was exposed to sodium hydroxide (NaOH) treatment in varying concentrations of 2.0, 3.7, 4.5 and 5.5g prior to the fiber treatment with KMnO4. The treated and untreated PALFs were reinforced with tapioca-based bio resin. Subsequently, they were subjected to Fourier transform infrared (FTIR) and tensile test analysis.FindingsThe FTIR analysis of untreated PALF revealed the presence of O-H stretch, N-H stretch, C=O stretch, C=O stretch and H-C-H bond. The tensile test result confirmed the highest tensile strength of 35N from fiber that was reinforced with 32.5g of cassava starch and treated with 1.1g of KMnO4. In comparison, the lowest tensile strength of 15N was recorded for fiber reinforced with 32.5g of cassava starch without KMnO4 treatment.Originality/valueBased on the results, it could be deduced that despite the enhancement of bioresin (cassava starch) towards strength-impacting on the fibers, KMnO4 treatment on PALF is very vital for improved tensile strength of the fiber when compared to untreated fibers. Hence, KMnO4 treatment on alkali-treated natural fibers preceding reinforcement is imperative for bio-based fibers.

Effect of alkali surface treatment and compatibilizer agent on tensile and morphological properties of date palm fibers‐based high density polyethylene biocomposites

AbstractThe objective of the present study is to develop an environment friendly alternative material based on available and local bio‐source from the wastes of Algerian date palm trees, date palm twigs fiber (DPF) was selected as an effective reinforcing material for high density polyethylene (HDPE) biocomposite. Two types of treatments have been used including sodium hydroxide (NaOH) treatment to obtain DPF1 followed by potassium permanganate (KMnO4) treatment to obtain DPF2 for aim to improve fiber‐matrix compatibility, HDPE biocomposite reinforced with different ratios of DPF1 and DPF2 varying from 10 to 30 wt% were elaborated, characterized, and compared to select the preferred treatment and percent of DPF which can be used with high properties. The results obtained indicates that the incorporating of 30 wt% of DPF2 in HDPE biocomposite led to an improve in the mechanical and morphological properties. In fact, the improvement in interfacial properties improve ultimate biocomposite performance, and thus qualified its use in different industrial application. The maleic anhydride grafted high‐density polyethylene (HDPE‐g‐MA) was incorporated as a coupling agent to the reinforced biocomposite of 30 wt% DPF2/HDPE with two different loading (7 and 10 wt%), Also, the treatments were seen to enhance the tensile strength and elastic modulus. Additionally, the biocomposites observation by scanning electron microscopy (SEM) and atomic force microscopy (AFM) revealed more intimate contact between the fibers and HDEP matrix after surface modification. The results suggested that the successful sample with best characteristics which can be advised is 30 wt% DPF2/HDPE/10 wt% HDPE‐g‐MA, that offer their use in many applications particularly in the automotive industry.

Comparative study of two biocomposites: Effect of date stone flour treated with potassium permanganate as a filler on the morphological and elastic properties

The paper deals with the effect of date stone flour (DSF) as a filler on the elastic properties of biocomposites based on two different matrices, namely, polymethyl methacrylate (PMMA) and green epoxy resin (GER). Potassium permanganate treatment was applied to improve the surface properties of the DSF filler. Fourier transform infrared spectrotroscopy was used to analyze the chemical changes of the functional groups in the untreated DSF and the permanganate treated DSF filler. Different filler content of 10, 20, and 30 wt%, respectively, were used to obtain PMMA/DSF and GER/DSF biocomposites. The elastic properties, namely, longitudinal modulus, shear modulus, bulk modulus, Young’s modulus of elasticity, Poisson ratio, ultrasonic micro-hardness, and acoustic impedance of the biocomposites were determined using the ultrasonic through-transmission method. In addition, the morphology was studied using optical microscopy and scanning electron microscopy. Fourier transform infrared spectrotroscopy analysis results revealed the success of the permanganate treatment. The elastic properties of PMMA/DSF biocomposites were decreased, while an improvement of these properties is observed for GER/DSF biocomposites. Morphological results showed the presence of pores and cracks in the PMMA/DSF biocomposites, which is attributed to poor interfacial adhesion between the DSF filler and the PMMA matrix. However, fewer defects were observed in the GER/DSF biocomposites, which is due to better interfacial adhesion between the DSF filler and the GER matrix.

Fabrication of a type of silk/PEDOT conductive fibers for wearable sensor

Flexible high-conductivity fibers have attracted much attention due to their great potential in the field of wearable electronic devices. However, how to ensure high conductivity and flexibility is still a challenge. In this paper, the flexible silk fibers were used as the substrate, and manganese oxides were generated on the surface by potassium permanganate treatment. On this basis, the flexible high conductivity silk fibers with a resistivity of 1.47 Ω·cm were prepared by in-situ chemical polymerization of 3,4-ethylenedioxythiophene(EDOT) on the surface of silk fibers. The surface morphology and chemical composition of silk fibers were characterized by scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS) and inductively coupled plasma emission spectrometry (ICP). The results confirmed that a large amount of MnO 2 was synthesized and deposited on the surface of the silk fibers. The flexible conductive silk prepared by this method had good temperature sensitivity (- 0.47%/K), good stability and repeatability under cyclic tension, and the relative resistance change rate was 9.1%. Meanwhile, due to the binding force between the surface-active groups of the silk fibers and poly(3,4-ethylenedioxythiophene) (PEDOT), the conductive silk fibers exhibited good stability against water washing, demonstrating a broad application prospects in the field of wearable sensors.

Fabrication and Experimental Analysis of Treated Snake Grass Fiber Reinforced with Polyester Composite

The selection of fiber is predominant for natural fiber‐reinforced polymer composite materials, which should have easy extraction and good bonding with considerable strength. In this paper, some chemical treatments were done on the fiber material to increase interfacial bonding between the snake grass fiber (Sansevieria ehrenbergii) and polyester matrix, such as alkali treatment (NaOH), potassium permanganate treatment, sodium carbonate treatment, hydrogen peroxide treatment, and calcium carbonate treatment. The chopped snake grass fiber‐reinforced polymer composite material was prepared by keeping 25 wt.% of fiber and 30 mm fiber length reinforced with an unsaturated polyester resin that was cured with the help of the catalyst methyl ethyl ketone peroxide (MEPK). Cobalt naphthenate was used as an accelerator. Tribological properties were discussed for the highly potential sample with the help of a pin‐on‐disc wear tester, and the results were analysed by the Taguchi L9 orthogonal array. This paper exhibited the best mechanical and tribological properties among those chemical‐treated fibers used in fiber‐reinforced composite materials and untreated fibers used in fiber‐reinforced composite materials. CaCO3 treatment provided higher tensile strength (45 MPa), impact strength (3.35 J), and hardness (27 BHN). Finally, the mechanical and tribological characterization of the samples was done with the aid of SEM (scanning electron microscope).

Pathology and Proteomics-Based Diagnosis of Localized Light-Chain Amyloidosis in Dogs and Cats.

Amyloidosis is classified according to the amyloid precursor protein, and accurate diagnosis of the amyloidosis type may guide appropriate treatment. Immunohistochemistry and Congo red staining are the most frequently used methods used to distinguish types of amyloidosis, but problems with specificity and sensitivity indicate the need for an alternative diagnostic method. In this study, we evaluated laser microdissection-liquid chromatography-tandem mass spectrometry (LMD-LC-MS/MS) for the diagnosis of amyloid light-chain (AL) amyloidosis in animals. Plasmacytomas with amyloid deposits from 15 dogs and 2 cats were subjected to Congo red staining with or without potassium permanganate pretreatment, immunohistochemistry for kappa and lambda light chains, and LMD-LC-MS/MS. Congo red staining was diagnostic in 12 of 17 cases based on resistance to potassium permanganate pretreatment, but in 5 of 17 cases the pretreatment unexpectedly reduced Congo red staining or abrogated the birefringence and a definitive diagnosis could not be reached. Immunohistochemistry detected kappa or lambda light chains in 6 of 17 cases. With LMD-LC-MS/MS, immunoglobulin lambda light chain was detected in all 17 cases. The amyloid signature proteins ApoA-I, ApoA-IV, and ApoE were detected in 9, 1, and 3 of the 15 canine cases by LMD-LC-MS/MS, but not in the feline cases. In conclusion, LMD-LC-MS/MS consistently determined the amyloid type in all examined specimens, while Congo red staining after potassium permanganate treatment and immunohistochemistry were less sensitive tests.

Improved lignocellulose degradation prior to semi-dry anaerobic digestion of dairy manure via potassium permanganate treatment

Dairy manure (DM) contains high contents of lignocellulosic materials that are difficult to be converted into methane via anaerobic digestion (AD). KMnO4 pretreatment and then semi-dry batch AD tests of DM were conducted at total solids (TS) of 13–15% and 37 ± 2 °C for 35 days. Remarkable improvement on DM degradation was noticed after KMnO4 pretreatment for 8 h, achieving the maximum cellulose and lignin reductions about 49% and 48% respectively at KMnO4 dosage of 100 mg/g-TS. The maximum volatile solids (VS) based daily methane production of 12.38 NL/kg-VS/d and volumetric methane production rate of 0.95 L/L/d were obtained from the semi-dry AD, increasing by 27% and 23% respectively when compared to the control. Firmicutes, Bacteroidetes and Methanosarcina were found to dominate the early stage of semi-dry AD process. In summary, KMnO4 pretreatment can significantly enhance the decomposition of lignocellulose and then methane production from semi-dry AD of DM.

Integration of MnO2 and ZIF-Derived nanoporous carbon on nickel foam as an electrode for high-performance supercapacitors

MnO2 has the highest potential as a supercapacitor electrode; however, its disadvantage in electronic conductivity hinders its widespread use. This study reports the excellent electrochemical performance of MnMC/NF (MnO2 and ZIF-derived nanoporous carbon on nickel foam) composites. MnMC/NF composites are produced when leaf-like Co-ZIF is annealed on nickel foam, followed by potassium permanganate treatment. When the annealing temperature reaches 700 °C, the maximum specific capacitance of 531 F/g is achieved at 1 A/g (456 F/g at 20 A/g) with a rate capability of 85.5%. MnMC/NF700 has a long cyclic stability, and the capacitance retention was 82% after 5000 cycles. The energy density of an assembled device using MnMC/NF700 composite as positive electrodes can reach 38.8 Wh/kg. This is due to the combined effect of nickel substrate's 3D porous structure and the excellent electronic conductivity of ZIF-derived nanoporous carbon. The unique configuration of MnMC/NF composites may provide a referable design for energy storage systems, including materials that have the highest potential for use as supercapacitor electrodes.

Impacts of antibiotic contaminants on Microcystis aeruginosa during potassium permanganate treatment

Application of KMnO4 for preventing the formation of cyanobacterial bloom at early growth stage has not been reported. Antibiotics generate hormesis effects in cyanobacteria at currently reported concentrations, which may negatively affect the control of cyanobacterial bloom. This study assessed the treatment performance of KMnO4 in Microcystis aeruginosa with and without the existence of the antibiotic mixture composed of four simultaneously detected antibiotics in aquatic environments (sulfamethoxazole, ciprofloxacin, amoxicillin and tetracycline). KMnO4 downregulated two chlorophyll a synthetases (chlG and chlM), 14 photosynthesis-related proteins and two microcystin synthetases (mcyB and mcyD) in M. aeruginosa, and reduced chlorophyll a content, photosynthetic activity and microcystin concentration in a dose-dependent manner. Inhibition of photosynthesis and biosynthesis resulted in extended lag phase and decreased growth rate in KMnO4-treated Microcystis aeruginosa. In contrast, mixed antibiotics upregulated 6 oxidation-reduction proteins, a cell division regulatory protein (MAE_37210), 14 photosynthesis-related proteins, 14 biosynthesis-related proteins (including microcystin synthetases mcyA and mcyB) and a microcystin transport protein (mcyH), which consequently reduced oxidative stress, shortened lag phase as well as significantly stimulated (p < 0.05) cyanobacterial growth, photosynthetic activity, microcystin synthesis and microcystin release in KMnO4-treated M. aeruginosa. An optimal dose of 3 mg L−1 was suggested for KMnO4 treatment. Mixed antibiotics should be controlled below a no-impact threshold of 20 ng L−1 (5 ng L-1 for each antibiotic) for eliminating their adverse effects during KMnO4 treatment of cyanobacteria in antibiotics polluted environments.

A MXene‐Coated Activated Carbon Cloth for Flexible Solid‐State Supercapacitor

Herein, a new electrode material HHK‐CC@Ti3C2TX (HHK‐CC = activated carbon cloth, TX = F, O, or OH) for a flexible solid‐state supercapacitor (SSC) is prepared by a simple method. The activated carbon cloth (HHK‐CC) is obtained by treating with potassium permanganate beforehand. The specific area, oxygen‐containing functional group, hydrophilicity, and electrical conductivity of the activated CC are increased significantly after the potassium permanganate treatment. A few layers of Ti3C2TX flakes are coated directly on the HHK‐CC. When the loading Ti3C2TX on the HHK‐CC@Ti3C2TX electrode is 3 mg cm−2, the prepared electrode achieves a high capacitance of 1033 mF cm−2 at the current density of 1 mA cm−2. After assembling as a symmetrical SSC, the flexibility and mechanical strength of the CC are still preserved and no significant capacitance decreasing is observed under the conditions of bending and deformation. The capacitance value remains at 94.2% after 1000 cycles, and a high power density of 0.779 W cm−2 is obtained at the energy density of 4.5 μWh cm−2. This work gives a new strategy for designing flexible supercapacitors.