Study on the Properties of Waste Apatite Phosphogypsum as a Raw Material of Prospective Applications

Waste and Biomass Valorization, Vol. 0, iss. 0 (2018) (online first)This paper presents the results of the study on chemical and the physical properties of waste phosphogypsum (PG) of apatite origin from the former chemical plant Wizow, Poland which are important for further processing and economic use. The research was carried out to verify whether the waste might be useful as a raw material for rare earth elements (REE) recovery and the manufacture of building materials. The following methods were chosen: X-ray diffraction, scanning electron microscopy with an energy-dispersive X-ray detector, atomic absorption spectrometry, inductively coupled plasma spectrometry, differential thermal analysis, thermogravimetry, and gamma spectrometry with natural radioactive contamination analyzer. It has been proven that the chemical physical properties of phosphogypsum provide an opportunity to utilize this waste material as a source of REE and raw material for building purposes. PG contains an overall amount of REE in the interval of 0.343–0.637% by mass and does not show radioactivity level which would exclude it from construction purposes. The presented results serve as the basis for currently available technological directions in the management of apatite PG for useful trade products, which creates a chance for the elimination of its storage necessity by further processing

Magnetic Properties of La0.9A0.1MnO3 (A: Li, Na, K) Nanopowders and Nanoceramics

Nanocrystalline La0.9A0.1MnO3 (where A is Li, Na, K) powders were synthesized by a combustion method. The powders used to prepare nanoceramics were fabricated via a high-temperature sintering method. The structure and morphology of all compounds were characterized by X-ray powder diffraction (XRD) and scanning electron microscopy (SEM). It was found that the size of the crystallites depended on the type of alkali ions used. The high-pressure sintering method kept the nanosized character of the grains in the ceramics, which had a significant impact on their physical properties. Magnetization studies were performed for both powder and ceramic samples in order to check the impact of the alkali ion dopants as well as the sintering pressure on the magnetization of the compounds. It was found that, by using different dopants, it was possible to strongly change the magnetic characteristics of the manganites

In vitro photodynamic diagnosis of atherosclerotic wall changes with the use of mono-l-aspartyl chlorin e6. A preliminary report

Background: Although several methods for atherosclerosis detection are available, none of them seems to be accurate enough to identify the vulnerable atheromatous plaque. Photodynamic diagnosis (PDD) and therapy (PDT) - a new method evaluated for neoplasm treatment, is a modern approach for detecting and treating atherosclerosis.Aim: To asses in vitro the capability of PDD with the use of chlorin e6 to detect atherosclerotic plaque and the usefulness of this method as a feedback system for photoangioplasty treatment.Methods: 30 specimens of human aorta and 15 specimens of human coronary arteries were examined. The samples were soaked with chlorin e6 and then washed out. The luminescence spectra were then collected. All samples were examined with light microscopy.Results: Tissue fluorescence is seen as green light. We noted a very strong red fluorescence of chlorin e6 originating from lipid-rich plaque. We established a quantitative factor (R) which is the ratio of chlorin e6 red intensity in its 660 nm maximum to the area of green luminescence centred at 515 nm. The highest value of R was reached at the atheromatous samples, followed by calcified and normal ones R2=3.51±0.62, R3=1.63±0.31, and R1=1.51±0.15, respectively. A statistically significant difference was noted between groups two and one, and between groups two and three (R2=3.51±0.62 vs. R3=1.63±0.31,

Understanding continuous wave laser-induced chemical reactions at micro- and nano-diamond-glass interface under infrared excitation

This work addresses the issue of laser-induced white light generation by nano- and micro-diamond powder and the accompanying redox processes occurring at the surface of the particles. The broadband white light is generated by near infra-red continuous wave laser (975 nm) on micro and nano-diamond powders sealed in lightbulb-like devices. It is shown that the emission from diamond samples is a highly nonlinear process with apparent saturation close to 1 W of the optical excitation power. Multiband mechanism and mixed hybridization at particle surface are further discussed as a possible origin of the white light emission. Changes in the sp2/sp3 ratio upon the laser excitation are here discussed in terms of molecular dynamics simulations. Observed surface changes related to diamond graphitization are considered further as possible pathways for chemical reactions at the interface of the glass and diamond samples. Obtained results bring relevant physical premises according to the possible mechanism responsible for the white emission from diamond-like carbon materials, its mechanisms, and an essential figure of merit considering the diverse applicability of this phenomenon in various electronic devices.This work was financed from the The National Centre for Research and Development POIR.01.01.01-00-0779/21 grant.Peer reviewe

Understanding continuous wave laser-induced chemical reactions at micro- and nano-diamond-glass interface under infrared excitation

This work addresses the issue of laser-induced white light generation by nano- and micro-diamond powder and the accompanying redox processes occurring at the surface of the particles. The broadband white light is generated by near infra-red continuous wave laser (975 nm) on micro and nano-diamond powders sealed in lightbulb-like devices. It is shown that the emission from diamond samples is a highly nonlinear process with apparent saturation close to 1 W of the optical excitation power. Multiband mechanism and mixed hybridization at particle surface are further discussed as a possible origin of the white light emission. Changes in the sp ^2 /sp ^3 ratio upon the laser excitation are here discussed in terms of molecular dynamics simulations. Observed surface changes related to diamond graphitization are considered further as possible pathways for chemical reactions at the interface of the glass and diamond samples. Obtained results bring relevant physical premises according to the possible mechanism responsible for the white emission from diamond-like carbon materials, its mechanisms, and an essential figure of merit considering the diverse applicability of this phenomenon in various electronic devices

Gallato Zirconium (IV) Phtalocyanine Complex Conjugated with SiO₂ Nanocarrier as a Photoactive Drug for Photodynamic Therapy of Atheromatic Plaque

A new conjugate of gallato zirconium (IV) phthalocyanine complexes (PcZrGallate) has been obtained from alkilamino-modified SiO2 nanocarriers (SiO2-(CH2)3-NH2NPs), which may potentially be used in photodynamic therapy of atherosclerosis. Its structure and morphology have been investigated. The photochemical properties of the composite material has been characterized. in saline environments when exposed to different light sources Reactive oxygen species (ROS) generation in DMSO suspension under near IR irradiation was evaluated. The PcZrGallate-SiO2 conjugate has been found to induce a cytotoxic effect on macrophages after IR irradiation, which did not correspond to ROS production. It was found that SiO2 as a carrier helps the photosensitizer to enter into the macrophages, a type of cells that play a key role in the development of atheroma. These properties of the novel conjugate may make it useful in the photodynamic therapy of coronary artery disease

Controlling the Magnetic Properties of La_0.9A_0.1Mn_0.9Cr_0.1O₃ (A: Li, K, Na) Powders and Ceramics by Alkali Ions Doping

Nanocrystalline La0.9A0.1Mn0.9Cr0.1O3 (A: Li, K, Na) powders have been synthesized by combustion method. The powders were used to prepare ceramics by high-pressure low-temperature sintering technique. For all samples the structure, elemental composition and morphology were studied using X-ray diffraction (XRD), Raman spectroscopy, Energy-Dispersive X-ray Spectroscopy (EDS) and Scanning electron microscopy (SEM). Magnetic properties were studied using magnetometry methods and the valency changes of the cations after alkali ions doping were studied using X-ray photoelectron spectroscopy (XPS). The influence of the sintering pressure on the structural and magnetic properties of the manganites doped with different alkali ions and chromium was also investigated. Magnetization properties were studied as a function of sintering pressure and type of the dopant. Chemical doping with alkali ions as well as external pressure significantly changed the magnetic properties of the compounds. It was found that the magnetic properties of the manganites could be predictably modified through the use of a suitable dopant element

Impact of alkali ions codoping on magnetic properties of La0.9A0.1Mn0.9Co0.1O3 (A: Li, K, Na) powders and ceramics

The aim of the work was to check how the introduction of alkali and cobalt ions into a manganese structure can affect the structural disorder and, in consequence, lead to the changes (improvements) of magnetic properties. The high-pressure sintering technique was applied to check if the external factor can modify the magnetization of manganites. Nanocrystalline La0.9A0.1Mn0.9Co0.1O3 (where A is Li, K, Na) powders were synthesized by the combustion technique. The respective powders were used for nanoceramics preparation by the high-pressure sintering technique. The structure and morphology of the compounds were studied by X-ray powder diffraction, scanning electron microscopy and energy-dispersive X-ray spectroscopy. Magnetization studies for all compounds were performed in order to check the changes induced by either codoping or the sintering pressure. It was found that the type of the dopant ion and sintering pressure produced significant changes to the magnetic properties of the studied compounds. Alkali ions lead to the stabilization of Co ions in the +2 oxidation state and the formation of positive exchange interactions Mn3+–Mn4+ and Co2+–Mn4+ and the subsequent increase in remanent magnetization. High sintering pressure leads to a decrease in grain size and reduction of long-range ferromagnetic order and lower magnetization