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Metals in the workplace
Published in Sue Reed, Dino Pisaniello, Geza Benke, Kerrie Burton, Principles of Occupational Health & Hygiene, 2020
Boron is an essential element for plants and animals, including humans. Boron compounds are widely used in applications from household cleaning products (e.g. detergents and bleaches) to boron-fibre technology. Borax and boric acid are used in smelting, glazes for ceramic ware, and production of glass and glass-related products (e.g. insulation and textile fibreglass, Pyrex), and borax is still used in fireproofing of pulped-cellulose insulation, low-activity insecticide mixtures and leather tanning. These compounds do not pose significant hazards in normal use, and consequently the exposure standard is from 2 to 10 mg/m3 (TWA), depending on the type of boron compound. H&S practitioners need to ensure that neither inhalation nor ingestion of dusts can occur.
Removal of Boron from Water by Ion Exchange and Hybrid Processes
Published in Arup K. Sengupta, Ion Exchange and Solvent Extraction, 2017
Idil Yilmaz Ipek, Enver Guler, Nalan Kabay, Mithat Yuksel
Elemental boron is rarely found in nature, as it forms a number of complex compounds, such as boric acid, borate, perborate, and others. Much of the boron that is released into the environment by human activity is associated with agriculture and industry.1 Boron compounds have been used in many different applications including fertilizers, insecticides, corrosion inhibitors in anti-freeze formulations for motor vehicles and other cooling systems, buffers in pharmaceutical and dyestuff production, bleaching solutions in paper industries and in detergents, and also as moderators in nuclear reactors where anthropogenic water- soluble boron compounds are often discharged to the aqueous environment.2 Besides, boron is widely distributed in surface and groundwaters, occurring naturally or from anthropogenic contamination, mainly in the form of boric acid or borate salts.3 Water contamination by boron is one of the most widespread environmental problems, since even a few parts per million present in irrigation water can stunt plant growth. The problem of water deboronation is the challenge both for countries with a deficiency of potable water and the rest of world’s communities.3,4
Metals in the workplace
Published in Sue Reed, Dino Pisaniello, Geza Benke, Principles of Occupational Health & Hygiene, 2020
Boron is an essential element for plants and animals, including humans. Boron compounds are widely used in applications from household cleaning products (e.g. detergents and bleaches) to boron-fibre technology. Borax and boric acid are used in smelting, glazes for ceramic ware and production of glass and glass-related products (e.g. insulation and textile fibreglass, Pyrex), and borax is still used in fireproofing of pulped-cellulose insulation, low-activity insecticide mixtures and leather tanning. These compounds do not pose significant hazards in normal use, and consequently the OEL-TWA ranges from 1 to 10 mg/m3, depending on the type of boron compound. H&S practitioners need to ensure that neither inhalation nor ingestion of dusts can occur.
Energetic aspects of elemental boron: a mini-review
Published in Energy Sources, Part A: Recovery, Utilization, and Environmental Effects, 2022
Okan Icten, Birgul Zumreoglu-Karan
Boron is an economic element that has found broad applications in various industrial processes. The world boron consumption is greater than 1.5 million tons/year in terms of B2O3 and increases gradually (Ozdemir and Kipcal 2010). Boron compounds are used in the manufacture of glass, pharmaceuticals, cosmetics, detergents, fertilizers, heat resistant materials such as ceramics and refractories, corrosion inhibitors, high quality steel, flame retardants, neutron absorbers for nuclear installations (Hosmane 2016). The widespread applications of boron compounds have raised serious concerns about their environmental and toxicological effects. During the production of boron compounds, boron is introduced into the environment as waste and accumulates in both aquatic and terrestrial plants. Traces of boron in the form of boric acid or borates are essential for plants and indirectly essential for animal life (Nielsen 2015). However, it is beneficial to plants only in small quantities and, excessive amounts are harmful to plants and agricultural areas. In general, there is a small concentration range between deficiency and toxicity; however, toxicity owing to excess B is much less common in the environment than B deficiency (Howe 1998). Its economic significance on one side and environmental challenges caused by a discharge of boron into the environment on the other side necessitates boron recovery rather than removal from different sources. Some cost-effective methods for recovering boron in a highly purified state from boron-containing scrap materials and natural water resources have been reported (Ezechi et al. 2011). The research in this field is still in progress
Emergence of the half-metallic performance in transition-metal doped BAs semiconductor: a first-principles study
Published in Philosophical Magazine, 2020
A lot of attention in the technological applications has been recently paid to Boron compounds because of the high resistivity, great thermal conductivity and wide band gap [1]. BAs, a member of Boron compounds, is the material with high thermal conductivity which becomes increasingly important for the efficient heat dissipation in the microelectronic applications [2]. There are several experimental and theoretical calculations of BAs semiconductor [3–19]. For the widespread applications, the doping scheme has been utilised to be an effective technique. Using the full potential linearised augmented plane wave (FP-LAPW) scheme, Rezek Mohammad et al. [20] studied the electronic structures of BAs, BP and BPxAs1-x alloys. The lattice parameters, bulk modulus and first-order pressure derivative were mainly sensitive with the compositions (x). The density functional studies of BAs, BN and BNxAs1-x were presented by M. Guemou et al [21]. BNxAs1-x compounds with the concentration from 12% to 76% possessed a direct band gap. S. Chae et al. [22] implemented the hybrid density functional theory calculations to study the formation energies and thermodynamic properties of native point defects, common impurities and shallow dopants in BAs. The higher formation energy was found in donors rather than in acceptors. Besides, the prediction of the p-type character was observed in BAs doped with Be, Si and Ge atom. Employing HSE06 hybrid functionals, the calculations of the BxGa1-xAs electronic band structures as a function of compositions (x) were carried out by Istvan Gulyas et al [23]. The results underlined that this alloy with B content around 18% converted the direct to indirect gap.
Structural evolution and bonding characteristics of neutral Cs2B n clusters
Published in Molecular Physics, 2022
Hang Yang, Yan-Fei Hu, Jun-Jie Ding, Yu-Quan Yuan, Yu Zhao
Boron and its compounds have attracted the extensive attention of researchers because of their abundant excellent properties and chemical structures in recent years [1]. In the meantime, it is also used as hydrogen storage [2] and drug delivery carrier [3] material. The electron-deficient state in which the valence electrons of the B atom are less than the number of valence orbitals, it is beneficial to form covalent bond molecules with most atoms through delocalised multi-centre bonds, so that the properties and structures of boron compounds are rich and diverse. The electron-deficient boron tends to generate planar or quasi-planar clusters at small as well as medium sizes [4], with aromatic structures similar to hydrocarbons [5], this is owing to the π-electron delocalised bonds in the Bn clusters fit the Hückel rule of aromaticity and antiaromaticity in cyclic hydrocarbons [6,7,8]. The delocalised π or σ bonds in Bn clusters predicted by Zubarev [9] and Boldyrev [10] exhibit aromaticity or antiaromaticity. A typical example is the neutral B14 cluster, whose 3D structure was redefined as a planar structure with aromaticity [11]. Among the neutral pure boron clusters, the clusters with an atomic number less than 16 are almost all planar structures, especially the Bn clusters when n = 7–15, which have been proved to be planar structures with aromaticity by experimental and theoretical studies [6,12]. In 2007, Oger's team [13] reported that the B16+ cluster is an intermediate structure of a plane-to-cylindrical when studying cationic boron clusters, namely the minimum value of the first three-dimensional structure appears at n = 17. In the anion system of pure boron clusters [8,14], the planar or quasi-planar structures up to 25 B atoms, even higher anionic boron clusters (B35,36−) continue to exhibit a planar pattern with a hexagonal central hexagonal hole [15,16]. In addition, it was found from Boustani's study [15] that B19 exhibits different structural skeletons at different charge states: B19− is a two-dimensional structure, but neutral and cation B19 are both 3D pyramidal structures, their results show that electrons can influence the geometry of boron clusters. Therefore, it is of great necessity for us to study the 2D and 3D structures of boron clusters in different electronic states for understanding their structural evolution characteristics.