High-efficiency 2D nanosheet exfoliation by a solid suspension-improving method

Two-dimensional (2D) materials with mono or few layers have wide application prospects, including electronic, optoelectronic, and interface functional coatings in addition to energy conversion and storage applications. However, the exfoliation of such materials is still challenging due to their low yield, high cost, and poor ecological safety in preparation. Herein, a safe and efficient solid suspension-improving method was proposed to exfoliate hexagonal boron nitride nanosheets (hBNNSs) in a large yield. The method entails adding a permeation barrier layer in the solvothermal kettle, thus prolonging the contact time between the solvent and hexagonal boron nitride (hBN) nanosheetand improving the stripping efficiency without the need for mechanical agitation. In addition, the proposed method selectively utilizes a matching solvent that can reduce the stripping energy of the material and employs a high-temperature steam shearing process. Compared with other methods, the exfoliating yield of hBNNSs is up to 42.3% at 150°C for 12 h, and the strategy is applicable to other 2D materials. In application, the ionic conductivity of a PEO/hBNNSs composite electrolytes reached 2.18×10−4 S cm−1 at 60°C. Overall, a versatile and effective method for stripping 2D materials in addition to a new safe energy management strategy were provided.

High Dilutions of a Drug of Covid-19 Origin Show Difference in Ranks

High dilutions (HDs) of drugs, used in Homeopathy, are prepared in aqueous EtOH (ethanol) through serial dilution accompanying mechanical agitation or succussion, and are called potencies. The potencies from the rank 12 onwards are too dilute to contain any original drug molecules. Do the potency ranks show any difference from each other? Do serial dilution and succussion contribute to the difference in potency ranks? This study aims to address these two questions. The throat swab of a Covid-19 patient was preserved and diluted with aqueous EtOH 90% to prepare the mother tincture (MT) and five different potencies of Covid named Covidinum. These potencies and their solvent media were analysed by electronic and vibrational spectroscopy. Charge transfer (CT) and proton transfer interactions occur during preparation of the potencies. The FT-IR spectra of all the test samples after normalization show difference from each other with respect to O-H stretching and bending (v2) bands. Serial dilution and succussion contribute to the observed difference in ranks and CT interactions.

Extraction of Ta and Nb from a Coltan Bearing Ore by Means of Ammonium Bifluoride Fluorination and Sulfuric Acid Leaching

A novel approach for Ta and Nb extraction consisting of the pre-treatment of a coltan-bearing ore with an ammonium bifluoride sub-molten salt and subsequent acid leaching has been studied. The effects from ore granulometry, ammonium bifluoride (ABF) to ore mass ratio, temperature and duration of fluorination on the degree of Ta and Nb extraction were examined. The ABF to ore ratio and process temperature were found to have the most pronounced impact on extraction efficiency. The following optimal process conditions were determined: ore granulometric fraction (−75 + 45 µm), ABF-ore (5/1), fluorination temperature (200 °C) and fluorination time (2.5 h). Maintaining these parameters enabled about 94% of Ta and 95% of Nb to be brought into solution during the sulfuric-acid-leaching stage. A comparison of the proposed method with previously reported studies suggests that due to the effects of mechanical agitation and the recirculation of the HF-containing gaseous phase back into the process, the dosage rate of ABF at the fluorination stage could be reduced significantly without sacrificing the overall recovery of Ta and Nb. In such a way, the approach could offer added environmental benefits since release of fluoride-containing effluents into the environment could be limited.

Use of Poly(vinyl alcohol)-Malic Acid (CLHPMA) Hydrogels and Chitosan Coated Calcium Alginate (CCCA) Microparticles as Potential Sorbent Phases for the Extraction and Quantitative Determination of Pesticides from Aqueous Solutions

Pesticides are used worldwide to increase crop yields in agriculture. However, their toxicity and accumulation capacity can make them toxic to the environment, animals and humans. In the case of workers chronically exposed to these substances, they must be sampled continuously, so urine is an excellent option. In this sense, this study proposes to use poly(vinyl alcohol)-malic acid hydrogels, and chitosan-coated calcium alginate as new sorbent phases to be used in pesticide determination processes in urine. To better understand the behavior of these materials in the capture and desorption process, molecular dynamics simulations (MDS) were used, and desorption experiments were performed, using mechanical agitation, ultrasound, and pH variation in the desorption process, in order to optimize the parameters to obtain better recoveries. Under the optimal experimental conditions, the maximum recoveries were of the order of 11% (CFN), 3% (KCF), 53% (DMT), 18% (MTD) and 35% (MTL). Although the recoveries were not exhaustive, they are a first approximation for the use of these new sorbent phases in the determination of this type of compound in aqueous solutions and urine.

Differential Impact of the Prior Mix by Stirring in the Biodegradation of Sunflower Oil

Fats and oils present in wastewater are usually eliminated by physical and biological processes. In this experience, the fatty wastewaters are treated biologically, and it assesses the impact of the mix in the fats and oils biodegradation and carried out the experiments in a laboratory scale unit. The biodegradation of fats and oils was analysed in two sceneries, with mix previous by mechanical agitation and without mix. Key parameters were monitored, such as the concentration of fats and oils in the influents and effluents, mass loading, and the efficiency of biodegradation. The mass loading range was similar in both sceneries. In the experimental activated sludge plant without mix, the biodegradation of fats and oils reached levels in the range of 28 to 42.5%. For the wastewater treatment plant with a previous mix by mechanical agitation, the levels of biodegradation of fats and oils ranged from 64 to 75%. Therefore, considering the efficiency of the biodegradation of fats and oils in both sceneries, the results indicated that the level mix is a high incidence.

Effective Removal of Barrier Layer on the Surface of Low-Nickel Matte in an FeCl3-HCl-H2O Solution

Using ferric chloride as an oxidant, here, we investigated the leaching effect of low-nickel matte in a flow field produced by mechanical agitation. The factors affecting a leaching reaction, such as stirring speed, leaching time, low-nickel matte particle size, and inert abrasive quartz sand, were studied. X-ray diffraction (XRD), X-ray fluorescence spectroscopy (XRF), a laser particle size analyzer, optical microscopy (OM), a scanning electron microscopy (SEM) with an energy dispersive X-ray detector (EDS), and a Raman spectrometer were used to characterize the materials before and after the leaching reaction. The contents of the main metal ions such as Ni, Cu, and Co in the leaching solution were analyzed by inductively coupled plasma atomic emission spectroscopy (ICP-AES). Using the control variable method, the optimal experimental conditions were as follows: 2 mol/L FeCl3—0.5 mol/L HCl-H2O system with low-nickel matte and quartz sand (mass ratio is 1:5) and leaching at 90 °C for 8 h. The results showed that the blocking effect of the solid product sulfur layer was effectively removed and continuous leaching was realized. The leaching efficiencies of Ni, Cu, and Co were 98.9%, 99.3%, and 98.1%, respectively.

Preparation and characterization of lanolin-based condensate and its utilization as a nonionic softener for wool fabric surface

Two forms of pollutants are usually discharged from scouring of wool fleece; namely the effluent liquid phase and the solid phase. These phases comprise a significant quantity of wool wax which would be a suitable candidate for valuable products and applications. This work is devoted to extraction, recovery, and characterization of lanolin from wool fleece from different sheep breeds to assign possible ways for its utilization in the textile field. The results show that the amount of wool wax extracted from coarse wool fleece as well as its chemical composition and physical properties are almost similar to those extracted from other finer wool fleece. The aim of this work is further devoted to separation and characterization of fatty acids (FAs) from the extracted wool wax. The separated wool FAs were esterified with poly ethylene glycol (PEG) to obtain a condensate which was utilized as a nonionic softener for wool. The alteration in morphology of the coated wool fabric was assessed using scanning electron microscopy. The results revealed that the WFA/PEG-coated fabrics exhibit reduced surface roughness and improved resistance to felting shrinkage during mechanical agitation.

The impact of polychlorinated biphenyls on the bioluminescence rates of the Black Sea ctenophore Mnemiopsis leidyi A. Agassiz (Ctenophora: Lobata)

The toxic impact of a mixture of polychlorinated biphenyls Aroclor 1254 (PCB) on the luminescence characteristics of the ctenophores Mnemiopsisleidyi A. Agassiz was studied. The control group was kept in an aquarium without a toxicant; experimental individuals were placed in three aquariums with water with PCB concentrations of 1, 10, and 100 µg -1 with an exposure of 15, 30, 40 and 60 minutes. Bioluminescence of M. leidyi was studied using the “Svet” complex. The toxic impact of PCBs caused a decreased amplitude and duration of luminescence at all given concentrations, whereas one-hour exposure to mechanical agitation resulted in a maximum decrease by 35% in the glow duration. At a PCB concentration of 1 μg ∙ L -1 , a maximum decrease in the luminescence intensity by a factor of 20 was observed compared with the control group.

Tannin-Furanic Foams Formed My Mechanical Agitation: Influence of Surfactant and Ingredient Ratios

With increasing demand of alternatives to oil-based lightweight materials, the development of tannin-based foams is getting more and more attention. In this paper, an alternative to traditionally used solvent-evaporation in the production of tannin-foams is presented. Mixing the tannin-furanic resin with different amounts of ionic and non-ionic surfactants at high agitational speed allows for the formation of highly porous, mechanically stable tannin-foams. Investigations on the influence of surfactant type and ingredient ratios on the foaming behavior and properties of the final foams were conducted. Materials obtained via this route do present extraordinary compression resistance (about 0.8 MPa), good thermal insulation (40 mW/m·K) and are suitable as a wastewater treatment agent at the end-of-life. It was shown that during mechanical blowing, homogeneous cross-sections and almost perfectly round pores form, leading to the high compression resistance. Investigations by means of Fourier transform infrared and 13C nuclear magnetic resonance spectroscopy show that the milder reaction environment leads to more linear poly(furfuryl alcohol)-tannin chains. This new type of tannin foam allows for use in various different fields of application ranging from durable building insulation to wastewater treatment.

Electro-oxidation of fish meal industry wastewater in a stirred batch reactor using a Ti/RuO2 anode

Fish meal is used as feed for fish, dogs and cats, and in the pharmaceutical industry. Direct electro-oxidation has been used to treat fish meal industry effluent and organic pollutant removal, and was studied in this project. The anode used was titanium coated with ruthenium oxide and the cathode was stainless steel. In addition to organic pollutants, color removal was also studied. The varying parameter was current density, and those used were 10, 20, 27, and 34 mA/cm2. The effects of mechanical agitation and the inter-electrode distance on pollutant removal were also studied. The highest TOC and color removal (both 82%) were achieved at 34 mA/cm2, using mechanical agitation with 1.5 cm electrode spacing. Without agitation, TOC removal efficiency was 72%. The results show that electro-oxidation can be an effective secondary treatment for fish meal industry effluent.