Pulsed laser ablation in liquids (PLAL) is an approach for the direct synthesis of nanoparticles from the bulk material. In the present work, silver and gold nanoparticles (NPs) were synthesized ...using the PLAL technique, and obtained water colloid suspensions were characterized by TEM–EDX, ICP-OES, UV–VIS, and DLS methods. On the other hand, Laser-Induced Breakdown Spectroscopy (LIBS) is a well-recognized and versatile analytical technique for the element analysis of solid samples. However, obtaining improved spectral intensity and detection sensitivity are still great challenging tasks, especially for an alternative and cost-effective LIBS setup based on TEA CO
2
laser. Considering these demands, this work aimed to investigate a promising approach to signal enhancement based on the deposition of noble NPs on the plastic sample. The effect of NPS on the enhancement of the LIBS signal has been investigated. LIBS experiments were carried out in air at atmospheric pressure and obtained spectra with a high signal-to-background (SBR) ratio. This study shows that signal enhancement can be achieved followed by the lower limits of detection by increasing the ablation amount rate.
(1) Background: An increasing use of pharmaceutics imposes a need for the permanent development of efficient strategies, including the tailoring of highly specific new materials for their removal ...from the environment. Photocatalytic degradation has been the subject of increasing interest of the researchers in the field. (2) Methods: This paper is focused on the investigation of the possibility to deposit a thin metal layer on a TiO2 surface and study its photocatalytic performance for the degradation of ciprofloxacin using a combination of theoretical and experimental methods. (3) Results: Based on the extensive DFT screening of 24 d-metals’ adhesion on TiO2, Cu was selected for further work, due to the satisfactory expected stability and good availability. The (Cu)TiO2 was successfully synthesized and characterized with XRD, SEM+EDS and UV-Vis spectrophotometry. The uniformly distributed copper on the TiO2 surface corresponds to the binding on high-affinity oxygen-rich sites, as proposed with DFT calculations. The photocatalytic degradation rate of ciprofloxacin was improved by about a factor of 1.5 compared to the bare non-modified TiO2. (4) Conclusions: The observed result was ascribed to the ability of adsorbed Cu to impede the agglomeration of TiO2 and increase the active catalytic area, and bandgap narrowing predicted with DFT calculations.
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•ABS based on Pluronic and salts or IL were applied to extract active compound from drugs.•PL6200/citrate ABS showed recovery efficiencies up to 98% and was further ...optimized.•Fractionation was successfully performed using C4mim-IL in the Pluronic-based ABS.•An efficient integrated platform with ecofriendly components was proposed.
Unused/expired pharmaceuticals can be regarded as a source of valuable compounds. Valorization of active pharmaceutical ingredients (APIs) from pharmaceutical waste, as an alternative to widely adopted treatment by incineration, is a big challenge in terms of designing green, efficient, scalable and sustainable separation methods. Concerning these demands, this work aimed to investigate and propose new integrated extraction technology based on aqueous biphasic systems (ABS) with eco-friendly components namely, poloxamer (Pluronic PE 6200) and one of two salts (sodium citrate, cholinium dihydrogenphosphate) or ionic liquid (1-butyl-3-methylimidazolium chloride). Liquid-liquid equilibria of each ABS were determined at room temperature followed by partition experiments in the biphasic medium to evaluate the most favorable systems for APIs extraction (acetaminophen and caffeine from one commercial product, and theophylline from the other). The finely designed ABSs were then employed to separate APIs from pharmaceutical solids and fractionate them. The results show that citrate-based ABS induces the strongest salting-out effect leading to extraction of all APIs to the Pluronic-rich phase with high recovery efficiencies between 79.4 and 97.90%; insoluble compounds were removed as residues while hydrophilic excipients remained in the citrate-rich aqueous phase. Ionic liquid/PL6200-based ABS was further applied to fractionate acetaminophen and caffeine toward opposite phases. These results underpin the viability and adjustability of PL6200-based ABSs within an integrated process, by a deftly selected salting-out agent, as a sustainable and efficient alternative platform with the great potential to be implemented on a larger scale.
In this work, Ag-doped ZnO nanoparticles are obtained via pulsed laser ablation of the Ag-coated ZnO target in water. The ratio of Ag dopant in ZnO nanoparticles strongly depends on the thickness of ...the Ag layer at the ZnO target. Synthesized nanoparticles were characterized by XRD, XPS, SEM, EDS, ICP-OES, and UV–VIS spectrophotometry to obtain their crystal structure, elemental composition, morphology and size distribution, mass concentration, and optical properties, respectively. The photocatalytic studies showed photodegradation of methylene blue (MB) under UV irradiation. Different ratios of Ag dopant in ZnO nanoparticles influence the photodegradation rate. The ZnO nanoparticles doped with 0.32% silver show the most efficient photodegradation rate, with the chemical reaction constant of 0.0233 min−1. It exhibits an almost twice as large photodegradation rate compared to pure ZnO nanoparticles, showing the doping effect on the photocatalytic activity.
The purpose of this study is to evaluate the feasibility of using the originally developed Laser Induced Breakdown Spectroscopy (LIBS) laboratory setup for the qualitative analysis of human tooth ...tissues and tooth restorations. Plasma was induced by the infrared TEA (Transversally Excited Atmospheric) CO
2
laser in the air under atmospheric pressure. Optical emission spectra with sharp and well-resolved spectral lines and a negligibly low background were obtained. The results of the qualitative analysis showed the presence of various elements in the tooth tissues (P, Ca, and Mg), as well as trace elements within restorations such as Zn, Sn, Cu, Ag, and Hg. The estimated temperatures of plasma for composite, dentin, and amalgam were 21,000 K, 16,200 K, and 13,300 K respectively. The electron density deduced from the Stark-broadening line profiles varies from 8.5 × 10
17
cm
− 3
for amalgam, 2 × 10
18
cm
− 3
for composite, and 1.9 × 10
18
cm
− 3
for dentin. The surface of the tooth tissue was imaged with a scanning electron microscope (SEM), showing that dentin contains pores, cavities and bubbles. The results indicated that the alternative and cost-effective LIBS system can be used as a useful tool for further research on laser-induced plasma in dentistry. These insights are useful in the field of laser dentistry, where lasers are commonly utilized to treat teeth.
Archeological mortars are often composed of highly inhomogeneous materials and detailed analysis in most cases can be quite difficult. In this work, a Laser-Induced Breakdown Spectroscopy (LIBS) ...equipment with microscopic-scale spatial resolution was used to image the distribution of elements on real archeological samples of mortars and construction material used in the foundations of the Smederevo Fortress (Republic of Serbia). A double-pulse Nd:YAG at the fundamental wavelength (λ = 1064 nm) and a CCD spectrometer coupled with a commercial microscope were used to generate the plasma and acquire the LIBS spectra. Thanks to the combined use of an unsupervised clustering algorithm and the calibration-free procedure, the results obtained show that it is possible to obtain a good discrimination between materials of different composition, allowing a quick classification for further mineral-petrographic investigations.
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•Elementary imaging on highly inhomogeneous samples.•LIBS mapping application on historical mortar samples.•Performed CF-LIBS analysis on average spectrum, to estimate the elemental composition of the different zones of the sample.
A part of the Raša Bay (western Croatia) is an estuary that is fed by the sediment load from the Raša River. The local area had been affected by the former Raša coal industry. The aim of this study ...was to determine levels of hazardous trace elements (HTEs) in bottom estuarine sediments, fish and mussels collected from two sites downstream of the Raša River mouth, and a wild boar’s kidney donated by hunters. The pseudo-total concentrations of 21 HTEs in sediments were obtained by the X-ray fluorescence (XRF) technique. The results showed that sediment collected closest to the former Raša coal separation unit Štalije was enriched in V, Sr, Ni, Cu, and Pb. Concentrations of HTEs in flathead grey mullet, wild blue mussels, and wild boar were obtained by inductively coupled plasma mass spectrometry (ICP-MS). The results showed that Pb, Cd and Hg in fish and wild mussels were not elevated compared to the Regulation levels of contaminants in food. Lead and Cd in the kidney of a wild boar exceeded the prescribed maximum values for food. This study warrants further geochemical investigations of the Raša Bay environment.
Silver nanoparticles (AgNPs) have been recognized for widespread biological applications due to their antimicrobial and anti-inflammatory effect, especially in dentistry and for wound healing. Many ...features determine their beneficial or toxic potential, such as their synthesis type, size, morphology, coating, and concentration. Most synthesis types rely on the use of synthetic chemicals, which contributes to their toxicity. We present an environmentally friendly method for “green” synthesis of AgNPs from the silver target by pulsed laser ablation in liquid (PLAL) using citrate as the stabilizing agent. Since AgNPs already have many dental applications, we examined their antibacterial effect against supragingival biofilm-forming bacteria and bacterial strains known to cause resistant dental infections. Their impact on human fibroblast cells’ cytotoxicity, proliferation (measured by XTT and Ki-67 immunofluorescence), pro/antioxidant balance, and lipid peroxidation (measured by PAB and LPP) was evaluated. AgNPs1 (21 nm) and AgNPs2 (15 nm) spherical nanoparticles with good overall stability were obtained. The highest tested dose of smaller nanoparticles (AgNPs2) displays not only an effective antibacterial effect against the tested oral bacteria strains but also a pro-oxidant and cytotoxic effect on fibroblast cells. Lower doses do not affect bacterial survival but increase the cell proliferation and metabolic activity and show an antioxidative effect, suggesting that different concentrations display a substantially opposite effect. Compared to larger AgNPs1, smaller AgNPs2 possess more potent biological effects, indicating that size plays a pivotal role in their activity. Such opposite outcomes could be important for their medical application, and high concentrations could be used for the inhibition of dental biofilm formation and resistant dental infections as well as proliferative conditions, while low doses could be beneficial in the treatment of atrophic and inflammatory disorders. Finally, we showed that silver-targeted PLAL, using citrate as a stabilizing agent, produces biologically potent nanoparticles that could have many applications depending on their size and concentration.
The main goal of this study was to examine the efficiency of a newly isolated fungus from quince, Aspergillus tubingensis FAT43, to produce the pectinolytic complex using agricultural and industrial ...waste as the substrate for solid state fermentation. Sugar beet pulp was the most effective substrate inducer of pectinolytic complex synthesis out of all the waste residues examined. For endo-pectinolytic and total pectinolytic activity, respectively, statistical optimization using Placked-Burman Design and Optimal (Custom) Design increased production by 2.22 and 2.15-fold, respectively. Liquification, clarification, and an increase in the amount of reducing sugar in fruit juices (apple, banana, apricot, orange, and quince) processed with pectinolytic complex were identified. Enzymatic pre-treatment considerably increases yield (14%-22%) and clarification (90%). After enzymatic treatment, the best liquefaction was observed in orange juice, whereas the best clarification was obtained in apricot juice. Additionally, the pectinolytic treatment of apricot juice resulted in the highest increase in reducing sugar concentration (11%) compared to all other enzymatically treated juices. Optimizing the production of a highly active pectinolytic complex and its efficient utilization in the processing of fruit juices, including the generation of an increasing amount of waste, are the significant outcomes of this research.
The application of an alternative laser-induced breakdown spectroscopy (LIBS) method based on transversely excited atmospheric (TEA) CO
2
laser was investigated for the first time for estimating the ...hardness of metallic materials. The human eye-safe (TEA) CO
2
laser, operating at 10.6 µm, was used for plasma generation. The LIBS spectra were recorded by employing a cost-effective CCD camera for the time-integrated and spatial resolved measurements. The cast iron and aluminum alloys samples with different hardness have been tested. The ratio between the magnesium ionic and neutral lines in LIBS spectra was applied for estimating the material hardness. In addition, the hardness of all samples included in this study was determined using the conventional method for material hardness determination, i.e. Vickers hardness test. The linear dependence of magnesium lines intensity ratio on the sample’s hardness was obtained for both kinds of materials. Profilometric measurements were used to verify that the newly-introduced method is almost nondestructive for the investigated metals. The results obtained in the present work confirmed the potential of using this original LIBS system not only for the fast elemental analysis but also for the direct estimation of the hardness of metals and alloys.
