Electrochemical Deposition of Lead for Water Quality Sensing

Lead contamination in drinking water can pose serious health risks to humans, and can often go undetected as a result of corrosion of lead infrastructure installed in buildings constructed prior to 1986. Thus, there is an unmet need for timely, cost-effective, and onsite monitoring of lead in drinking water. Here, we have designed a four-electrode system to reliably respond to electrodeposited lead oxide that provides a near real-time indication of lead presence. To better understand this detection mechanism, we investigated the temporal and spatial electrochemical deposition of lead using potential response data, scanning electron microscopy (SEM), fractal dimension (fD), and COMSOL Multiphysics® finite element analysis. Our results suggest that the deposition of lead oxide on the sensor is diffusion limited. Such fundamental understanding of the detection mechanism is critical to improve and shorten the detection time of the sensor. We used this information to improve the detection time and reliability of the signal by reducing the electrode gap distance and agitating the solution. This study provides a path for further optimization of a continuous electrochemical sensor for onsite monitoring of lead in drinking water.

Alkaline refining of crude lead: a method of arsenic removal and the behavior of arsenic in the process

In this work, the alkaline refining of arsenic in crude lead was studied with a mixture of sodium hydroxide and sodium carbonate as alkaline refining agents. Taking the arsenic removal rate as the research object, the effects of reaction temperature, holding time, Na2CO3:NaOH, the dosage of refining agent were investigated. The arsenic removal rate is 79.09% under the optimum experimental conditions as follows: reaction temperature 823 K, holding time 60 min, Na2CO3:NaOH 1:4, refining agent dosage 10%. The oxidation purification mechanism of arsenic was studied by XPS, SEM-EDS, XRD and FT-IR. The results show that arsenic in the crude lead is gradually oxidized by oxygen and lead oxide during arsenic removal process, and the arsenic trioxide is eventually converted into sodium arsenate (Na3AsO4) and lead arsenate (Pb2As2O7) in the slag.

Six-week inhalation of lead oxide nanoparticles in mice affects antioxidant defense, immune response, kidneys, intestine and bones

Due to widespread use in various industrial processes, the risk of inhalation exposure to lead oxide nanoparticles (PbO NPs) is growing and limited information evokes the need for hazard assessment...

The X-ray Sensitivity of an Amorphous Lead Oxide Photoconductor

The photoconductor layer is an important component of direct conversion flat panel X-ray imagers (FPXI); thus, it should be carefully selected to meet the requirements for the X-ray imaging detector, and its properties should be clearly understood to develop the most optimal detector design. Currently, amorphous selenium (a-Se) is the only photoconductor utilized in commercial direct conversion FPXIs for low-energy mammographic imaging, but it is not practically feasible for higher-energy diagnostic imaging. Amorphous lead oxide (a-PbO) photoconductor is considered as a replacement to a-Se in radiography, fluoroscopy, and tomosynthesis applications. In this work, we investigated the X-ray sensitivity of a-PbO, one of the most important parameters for X-ray photoconductors, and examined the underlying mechanisms responsible for charge generation and recombination. The X-ray sensitivity in terms of electron–hole pair creation energy, W±, was measured in a range of electric fields, X-ray energies, and exposure levels. W± decreases with the electric field and X-ray energy, saturating at 18–31 eV/ehp, depending on the energy of X-rays, but increases with the exposure rate. The peculiar dependencies of W± on these parameters lead to a conclusion that, at electric fields relevant to detector operation (~10 V/μm), the columnar recombination and the bulk recombination mechanisms interplay in the a-PbO photoconductor.

A Comprehensive Description on Ethnopharmacology and Therapeutics of Murdarsang: A Review

Murdarsang is a mineral that contains pbo, or lead oxide is an important medicine in the Unani system of medicine (USM) due to its multiple therapeutic properties. It can be prepared manually with different methods and used in different forms. Etymologically, it is known as 'Litharge' which is derived from Greek 'Litharguros' (lithos meaning stone and arguros for silver) which forms as a 'waste' during the last stage of silver smelting. Throughout human history, lead and lead minerals have been used for medicinal purposes. Galena was used as an eye salve in pre-dynastic Egypt, as well as by the ancient Indian civilisations of Mohendro-Daro and Harappa between 3200 and 2800 BC. Dioskourides in his De Materia Medica says about lithargyros that one is made from sand called molybditis which is roasted until it is totally burned, another from silver, a third from lead. According to Unani system of medicine Murdarsang possess different properties such as Astringent, Agglutinant, mildly Detergent, Desiccant, Anti-inflammatory Refrigerant, Corrosive and Rarefying properties. It is used as a base for making ointments. It composes the drugs and reduces the intensity of their dissolution, corrosion and astringency. It also have a corrosive, Resolvent and Insecticidal action. Many pharmacological activities mentioned in Unani medicine are validated, and many activities need further exploration due to the immense therapeutic scope in this drug. The current review designed to give an overview on the historical, chemical constituents, pharmacological and therapeutic effects of Murdarsang. Keywords: Murdarsang, Litharge, Lead oxide, Unani system of medicine.

Study the Effect of Weight Fractions of Different Powders on the Attenuation Performances of the Epoxy Composite

Among all types of radiation, X-ray has always garnered the most interest, owing to the growing availability of X-ray tubes in industry, research institutions, and medical facilities. In this research, the linear (μl) and mass (μm) attenuation coefficient, half value layer (HVL) and mean free path (λ) of the epoxy polymer-based composites which includes both lead oxide (Pb3O4), mixture of (Fe2O3 + Pb3O4) and barium sulfate (BaSO4) with different weight percentages were determined experimentally for the incident photon energies of (29-35 kV) emitted from (X-rays) source. The dispersion of the filler was also investigated using a scanning electron microscope to examine the composites morphology. The obtained results showed that adding these powders to epoxy has an effect on the X-ray shielding abilities of the prepared composites, meaning that there is a direct relationship between the weight ratios of the composite material with the linear (μl) and mass (μm) attenuation coefficient, and an inverse relationship with the half value layer (HVL) and free path rate (λ). While changing the X-ray shield with applied voltages showed a behavior opposite to what was mentioned above. The result also shows that the lead oxide (Pb3O4) composites yield better attenuation performance than the pure epoxy and the other two composites, especially at high weight fraction (50 Wt.%) of this filler, which due to the high density of these fillers and fine dispensability in the polymer matrix.

Gamma Irradiation and the Radiation Shielding Characteristics: For the Lead Oxide Doped the Crosslinked Polystyrene-b-Polyethyleneglycol Block Copolymers and the Polystyrene-b-Polyethyleneglycol-Boron Nitride Nanocomposites

This work aimed to research the efficiency of gamma irradiation and shielding characteristics on the lead oxide (PbO) doped the crosslinked polystyrene-b-polyethyleneglycol (PS-b-PEG) block copolymers and polystyrene-b-polyethyleneglycol-boron nitride (PS-b-PEG-BN) nanocomposites materials. The crosslinked PS-b-PEG block copolymers and PS-b-PEG-BN nanocomposites mixed with different percentage rates of PbO were used to research gamma-ray shielding characteristics. The synthesis of the copolymer was done by emulsion polymerization methods. The characterization and morphological analyses of irradiated samples were explored handling with the Nuclear Magnetic Resonance (NMR), Fourier Transform Infrared Spectroscopy (FTIR), Gel Permeation Chromatography (GPC), Thermogravimetric Analysis (TGA), and Scanning Electron Microscope (SEM) methods. The gamma-rays that were emitted from the E 152u source were observed with a High Purity Germanium (HPGe) detector system and examined with a GammaVision computer program. Our samples, including the different percentage rates of the PS-b-PEG (1000, 1500, 10,000), BN, and PbO, were irradiated in various gamma-ray photon energy regions (from 121.78 keV to 1408.01 keV). Then, Linear-Mass Attenuation Coefficients (LACs-MACs), Half-Tenth Value Layer (HVL), Mean Free Path (MFP), and Radiation Protection Efficiency (RPE) values of the samples were calculated. Via crosschecking the acquired data from samples with and without PbO and BN, it was observed that, if the different percentage rates by weight nano-powder of PbO and BN are added in the polymer mixture, it can be used as a convenient shielding material against gamma rays.

Investigations of regularities in the accumulation of hydrogen-reduced slags in circulation circuits with lead-containing coolants

The paper presents a computational analysis of regularities in the accumulation of slags during the interaction of lead and lead-bismuth coolants with oxygen gas. Oxidation of lead-containing coolants will cause the formation of lead oxide, while the formation of bismuth oxide is unlikely. Dosed supply of oxidizing gas to lead-containing coolants makes it possible to oxidize, selectively, chromium and nickel to their oxides without the slag formation from solid lead oxide. Regularities were studied which are involved in the lead oxide formation during the interaction of lead-containing coolants with oxygen gas. It has been found that, in the process of interacting with oxygen gas, a lead-bismuth alloy is oxidized 1.7 times as intensively as lead, this being explained by the presence of bismuth in the alloy. Bismuth is oxidized more intensively than both lead and the lead-bismuth alloy. The inert gas overpressure during depressurization does not prevent air oxygen from entering the circuit, and the dependence of the nitrogen and oxygen flow into the circuit on the argon flow out of the loop is close to linear regardless of the circuit state (cold, without coolant; heated, without coolant; heated, with circulating coolant). Oxygen is a chemically active impurity and is absorbed by the circuit; it is therefore important to control nitrogen in the gas spaces of the reactor and research plant circuits with lead-containing coolants. This will make it possible to signal, in a timely manner, the ingress of oxygen into the circuit and to take measures required to avoid or reduce the scale of the slag formation from lead oxides.