Boron Salts Research Articles

Retención y absorción de solución de sales de boro de diez maderas mexicanas

Boron salts are a wood protector agent with a wide spectrum in their fungicidal and insecticide action and of low toxicity, odorless, colorless and nonflammable, and their application is one of the most effective preservation strategies. This research aims to determine the density of wood, absorption and retention of the boron salts of ten Mexican woods. The working hypothesis proposed in this investigation is that wood retention capacity of boron salts depends mainly on the species and is independent of its density and porosity. Thirty liters of boron salts solution with a concentration of 3 % were prepared, the wood specimens were impregnated by following the “hot-cold bath” method. It was designed an experiment that compared means of the density of wood, the absorption and the retention, as the response variables, assessed for each one of the ten wood species. Wood species was considered as the variation factor. Absorption of Boron salts varied between 136 kg/m3 and 476 kg/m3. Average values of the boron salts retention for all species were higher than lower retention toxicity limit reported in previous researches (0.2 kg/m3 to 4.7 kg/m3). It was concluded that each species has different boron salts retention. Absorption capacity is specific to each species and it is not related to the wood density.

Preservación de la madera usando productos naturales

Wood preservation using natural productsIt is a current concern in the wood preservation field to avoid the use of toxic chemicals and develop new technologies based on low environmental impact agents and sustainable principles. Under this expectation, an intended state-of-the-art is introduced on the application of natural products such as traditional tar and wood oils as well as tannins and plant extracts. A particular revision to heartwood chemical components is offered. The combined methods of using natural and chemical components are reviewed, considering as outstanding the mixtures of natural organic constituents with cooper and boron salts that seem to be under encouraging experimentation. Fungicides and anti-termite applications are commented as well the leaching problem of inorganic salts. Chemical modification of wood structure through the formation of adducts and the treatment with nanomaterials are promising tools that will change the actual view and performance of wood preservation techniques.

Hydrogel-based boron salt formulations for wood preservation

Mixing boron with two thermoreversible hydrogels, obtained from an amphiphilic tripeptide and a carbamate derivative of glycerol, respectively, allows the formation of a supramolecular network that incorporates boron and significant amounts of water upon gelification of the solution when the temperature decreases. Hydrogels obtained from these gelators were impregnated in pine sapwood blocks using vacuum pressure treatment and subjected to leaching. Results indicated that incorporation of boron salts in the hydrogel network effectively protected the wood from degradation caused by the brown rot fungus Poria placenta and from attack by termites also even after leaching. It is believed that these hydrogels fill the tracheid cell walls and lumens, limiting the leachability of boron salts when the wood is humidified.

Inhibitory impact of plant nutritional compounds on Xanthomonas citri subsp. citri, the causal agent of bacterial canker of citrus

Six essential plant micronutrients, copper (Cu), iron (Fe), zinc (ZN), manganese (MN), molybdenum (Mo) and boron (B) salt compounds, were investigated for their potential antibacterial activity against a group of 32 Xanthomonas citri subsp. citri (Xcc) isolates, as representative of the Iranian population of bacterial of citrus canker disease agents, and the sensitivity patterns of the isolates were characterized. For all tested compounds, a significant antibacterial activity against representative Xcc strains was determined. Bacterial growth was severely inhibited by Cu, Fe, Zn, Mn and Mo at 1/2 MIC, MIC and MBC concentrations, whereas B had only a moderate to slight impact. Among the salt compounds, Zn had the lowest MIC (0.6-1.25 mM) and MBC (2.5 mM). The highest MIC and MBC values were obtained for Mo at the dose of 30-40 mM and 40-50 mM, respectively. The results showed that 62.5% of the tested bacterial isolates were less susceptible to Fe, Zn, Mn and Mo and more susceptible to Cu and B. Nevertheless, only 37.5% of them showed a high degree of susceptibility to most of the compounds.

Synthesis of novel organic-ligand-doped sodium bis(oxalate)-borate complexes with tailored thermal stability and enhanced ion conductivity for sodium ion batteries

A series of novel organic-ligand-doped sodium bis(oxalate)-borate complexes, including sodium bis[salicylato(2-)]-borate (NBSB), sodium[salicylato benzenediol]borate (NBDSB), sodium bis[oxalate]-borate (NBOB) and its derivatives NBOB(C2H2O4)0.2, NBOB(C7H4O3)0.2, NBOB(C7H4O3)0.6, NBOB(C6H6O2)0.15 and NBOB(C6H6O2)0.3 fabricated by solid-state reaction are firstly developed as new-type electrolytes for sodium ion batteries. These resulting sodium boron salts possess good solubility in an abroad range of organic solvents (such as PC, AN, DMF, PC + AN, PC + DMF), tailored thermal stability from 300 to 353 °C, improved ion conductivity (>1 × 10−3 S cm−1), environmental friendliness and low cost. Therefore, we believe that these new-type sodium boron salts show great potential as a new class of electrolyte for high-performance sodium ion batteries.

Synthesis of Tetrachalcogenide-Substituted Phenalenyl Derivatives: Preparation and Solid-State Characterization of Bis(3,4,6,7-tetrathioalkyl-phenalenyl)boron Radicals

We report the synthesis and properties of a series of spiro-bis(3,4,6,7-tetrachalcogenide-substituted-phenalenyl)boron salts and two of the corresponding tetrathioalkyl-substituted spiro-bis(phenalenyl)boron radicals [tetrathiomethyl (10) and tetrathioethyl (11)] in which all of the active positions of the phenalenyl (PLY) nucleus are functionalized. In the solid state, radicals 10 and 11 exist as a weak π-dimers due to the steric congestion of the thioalkyl groups in the superimposed PLY units. As a result, the spins are localized in the isolated (nonsuperimposed) PLY rings, and the structure, magnetic susceptibility measurements, and band structure calculations confirm that these PLY units are unable to undergo strong intermolecular interaction as a result of the orientation of the thioalkyl groups.

Investigation and mapping of risk areas for harmful boron content and the relationship to salt and sodium content in soils of Soke Plain, Aydin, Turkey

In the Great Meandros Basin, the boron content of irrigation water is considerable, up to 21.1 mg L−1. This results in boron accumulation in soils of Soke Plain over an area of ∼25 000 ha. This study aimed to determine soil boron levels and map risk areas in Soke Plain for boron content. Large-scale soil maps were used. Soil sampling points were determined by visual interpretation of LANDSAT5-TM satellite views. One hundred soil samples were taken from a depth of 0–30 cm. Analysis showed that soil boron content ranged between 1.92 and 31.04 mg kg−1. Soil boron contents were interpolated to create risk distribution maps for soil boron levels in Soke Plain. Furthermore, Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) satellite views were used to monitor restrictions in plant growth due to the high boron contents. A geographic information system (GIS) database of the area was established. Ninety-six percent of the study area had high to toxic boron levels. Positive correlations between soil boron content and salt and sodium contents indicate that soil management needs to consider the strong influence of the Mediterranean climate and irrigation water quality on the decline in soil fertility due to high soil boron content.

Study on Purification and Removal of Iron from Alloy Anode

Residue of alloy anode generated in three-layer liquid electrolytic purifying method is refined, the state of iron in raw materials is analysed. The state (morphology) changes of iron refined by different refining agent are investigated. Results show: 40% of boron salts or phosphate as the main component of refining agent adding 15% NaCl、20% KCl、15% CaF2、5% NaF、5% cryolite, melting the residue of alloy anode at 1100°C and 1200°C respectively, the crystal could be incubated to grow up fully, it is benefit for collecting iron. When the soaking time is 150min, iron component in alloy is 4.8%,it reaches the standard taking back into the aluminum refining process.

Antifungal efficacy of environmentally friendly wood preservatives formulated with enzymatic‐hydrolyzed okara, copper, or boron salts

Okara, an organic waste product obtained from soy milk production, was used with copper chloride or sodium borate to formulate new wood preservatives as a substitute for expensive wood preservatives, such as copper-azole-based preservatives and ammoniacal copper quaternary. Before formulating the preservatives, okara was hydrolyzed by enzymes (cellulase, pectinase, and protease) to augment penetration and fix the biocide salts of the preservatives into wood blocks. The preservatives were injected into wood blocks by vacuum pressure to measure the treatability of the preservatives. The treated wood blocks were placed in hot water for 3 d to measure leachability. The treatability and leachability of the preservatives were affected by the type and loading amount of enzymes and the addition of sodium borate into okara-based wood preservative formulations. The treatability and leachability of the preservatives formulated with copper chloride and okara hydrolysates were 63.38 and 3.15%, and those of the preservatives with copper chloride, okara hydrolysates, and sodium borate were 61.47 and 3.32%, respectively. Despite the hot water leaching, wood blocks treated with preservatives formulated with 2% cellulase, pectinase, and protease hydrolyzed okara, CuCl(2), and sodium borate showed only 1.98% average weight loss against Fomitopsis palustris over 12 weeks. Microscopic observation revealed how okara-based preservatives work in wood blocks. Okara has potential as a raw material for cost-effective and environmentally friendly wood preservatives.

Interaction of datolite concentrate with ammonium hydrodifluoride

The interaction of datolite concentrate with ammonium hydrodifluoride were studied. Under heating, ammonium hydrodifluoride fluorinates datolite to form complex fluoroammonium salts of boron, silicon, and impurity metals. The activation energy and rate constants were calculated for the reaction of datolite concentrate with ammonium hydrodifluoride in the range 100–150°C. The composition of the volatiles formed upon the heating of the fluorinated concentrate was studied, the temperature parameters of the evolution of boron and silicon to the gas phase were determined, and a process for separating these elements was proposed.

Environmentally friendly wood preservatives formulated with enzymatic-hydrolyzed okara, copper and/or boron salts

Novel biocides, such as copper azole (CuAz) and ammoniacal copper quaternary (ACQ), are extensively used as substitutes for chromate copper arsenate (CCA) in wood preservation. However, the expense of these biocides has necessitated the development of cost-effective and environmentally friendly wood preservatives. This study was conducted to investigate the effectiveness against decaying fungi of the preservatives formulated with enzymatic-hydrolyzed okara (OK), which is an organic waste produced from the manufacture of tofu, CuCl(2) (CC) and/or Na(2)B(4)O(7).10H(2)O (B). With the addition of NH(4)OH as a dissociating agent, the addition of OK facilitated the target retention of most of the OK/CC and OK/CC/B preservative formulations in wood blocks. The OK-based wood preservatives (OK-WPs) were stable against hot-water leaching. When compared with control and CC-treated wood blocks, the leached wood blocks treated with OK/CC and OK/CC/B formulations showed excellent decay resistance against both Postia placenta and Gloeophyllum trabeum, especially when OK was hydrolyzed by Celluclast at a loading level of 0.1 ml/g. Scanning electron microscopy (SEM) and SEM-energy dispersive X-ray (SEM-EDX) spectrometry analyses demonstrated that preservative complexes, such as OK-CC and OK-CC-B, existed in the wood blocks treated with OK/CC and OK/CC/B formulations. This study results support the potential application of OK-WPs as environmentally friendly wood preservatives capable of replacing CuAz and ACQ.

Geoecology of ecosystem recovery at an inactive coal mine site, New Zealand

Ecological restoration of the Wangaloa coal mine in southern New Zealand is hindered by a range of geoecological factors. The site has some substrate acidification (down to pH 1) and acid rock drainage with discharge waters initially down to pH 4, although this has since risen to ca. pH 6. Surface and ground waters develop elevated sulfate (up to 700 mg/kg) during oxidation of pyrite in coal and quartz in waste rock. Coal has elevated boron content (up to 450 mg/kg) and surface waters on coal-rich waste rock have up to 6 mg/L dissolved boron. Evaporation causes formation of salt encrustations dominated by gypsum with minor boron salts. Boron is bioavailable and may be at toxic levels (>200 mg/kg) in some plants. Quartz-rich waste rock is readily eroded, and develops a cm-scale low-nutrient quartz pebble armouring layer with low water retention properties. All waste rocks including loess siltstone have low nutrient contents, and low moisture retention properties, that are barely sufficient for plant establishment. Native plants introduced to the site during rehabilitation have grown on loess substrate (up to fivefold increase in height over 3 years), with poor or no growth on coal-rich and quartz-rich substrates. In contrast, natural colonisation of manuka (Leptospermum scoparium) has been most effective at revegetation on even the most hostile substrates. This natural revegetation has been facilitated by islands of manuka established accidentally during 60 years of mining history. Manuka from local genetic stock is most viable for this revegetation, and introduced manuka seedlings have had a 70% mortality rate. Natural plant colonisation is the key step in overall ecosystem recovery, and invertebrates rapidly colonise beneath new shrubs irrespective of the nature of the substrate from vegetation islands that have high invertebrate numbers and species richness.

Mechanism of boron tribromide electroreduction

This study was carried out to investigate the electrochemical behavior of boron tribromide in dimethlyformamide. The reduction of the compound was found to follow a CE mechanism. The kinetic parameters and the diffusion coefficient were calculated by the use of ultramicrodisc electrodes and chronoamperometry. The number of electrons transferred was found to be 2 by rotating disc and ultramicro disc electrodes and 3 by coulometry. These results are in good accordance with those obtained from molten boron salts. This study is important in regard to electrochemical boronizing at low temperatures.

Efficacy of wood preservatives formulated from okara with copper and/or boron salts

As a substitute for high-cost copper azole (CuAz) and alkaline copper quaternary (ACQ) wood preservatives, alternative wood preservatives were formulated with okara, which is an organic waste from the production of tofu, and copper chloride and/or borax. Each preservative was used in treatment of wood blocks in a reduced-pressure method to measure its treatability. The treated wood blocks were placed in hot water for 3 days to examine the stability of the preservatives against hot-water leaching. The preservatives successfully penetrated into wood blocks, probably due to the use of ammonium hydroxide as a dissociating agent. However, the stability of okara-based preservatives dropped as the concentration of acid in the solutions used for hydrolysis of okara increased. The treatability and leachability of the preservatives were not affected by hydrolysis temperature but were negatively affected by the addition of borax. Leached wood blocks treated with okara-based preservatives and exposed to decay fungi Gloeophyllum trabeum and Postia placenta over 12 weeks showed good decay resistance. Okara-based wood preservatives can protect wood against fungal attack as effectively as CuAz, and have potential for use as environmentally friendly wood preservatives.

Chemiluminescence of BO 2 to map the creation of thermal NO in flames

The aim of this study is to detect and map the local conditions that generate thermal NO in flames. According to the Zeldovich mechanism, the formation of NO comes from the local conjunction of a high concentration of atomic oxygen and a temperature above a critical high level imposed by the high activation energy of the rate-limiting reaction. The green light emitted when a flame is seeded with boron salts is a chemiluminescence from the BO ∗ 2 that is chemically formed in its excited state when BO reacts with atomic oxygen. As the rate of this oxidation is also strongly increasing with temperature, the chemiluminescence of BO 2 depends on the concentration of atomic oxygen and on the temperature in a way similar to the formation rate of thermal NO. This double analogy suggests the possibility of an experimental in situ simulation of the formation rate of thermal NO or at least the use of the chemiluminescence of BO 2 to map the sites where thermal NO is being created. Spectroscopic experiments and comparisons with numerical simulations have been performed to test the feasibility of this technique in laminar premixed and diffusion methane/air flames. The agreement is good except in the burnt gases of fuel-rich flames. Imaging strategies with different spectral filters have been developed in the same flames to overcome the problem of interference from soot radiation in diffusion flames.

Resonating Valence Bond Ground State in Oxygen-Functionalized Phenalenyl-Based Neutral Radical Molecular Conductors

We report the preparation, crystallization, and solid-state characterization of the first two members of a new family of spiro-bis(1,9-disubstituted phenalenyl)boron neutral radicals based solely on oxygen functionalization, and we show that this strategy significantly lowers the electrochemical disproportionation potentials (DeltaE), in comparison with other spiro-bis(1,9-disubstituted phenalenyl)boron salts. In the solid state, these radicals pack in a continuous array of pi-pi-stacked phenalenyl units with very short intermolecular carbon...carbon contacts. These two radicals are among the most highly conducting neutral organic solids, with room temperature conductivities reaching 0.3 S/cm. Magnetic susceptibility measurements show that the radicals do not exist as isolated free radicals, and there is significant spin-spin interaction between the molecules in the solid state as expected from the crystal structures and the calculated band structures; the solid-state properties are best rationalized in terms of the resonating valence bond model.

Impact of stereoide fungi on decomposition of oak wood and possibility of its protection

Four stereoide fungi, causers of decay of oak wood, have been investigated as follows: Stereum hirsutum, Chondrostereum purpureum, Stereum rugosum and Xylobolus frustulatus. The field tests have been undertaken in order to determine the influence of the stereoide fungi on the wood of Sessile oak (Quercus petraea) and Austrian oak (Quercus robur). Artificial inoculations with mycelia have been provoked in vital standing trees, as well as in laying trunks. The appearance of dying back symptoms, the rate of mycelia spread through the stem, speed of wound callusing and appearance of fruit bodies or decay symptoms, have been observed. The protection possibility of trunks has been tested as well by using preservatives based on chromo-cupric boron salts, dichlorfluanide and chlorinepyriphos, cupric naphtenates, as well as with antiseptic paste. Microscopically analysis of attacked oak wood has been performed by utilizing of scanning electron (SEM) and standard optical microscope providing normal, fluorescence, polarized and UV light, so that anatomical changes of the wood structure elements influenced by fungal activity have been noted.

BORONIZADO DE ALEACIONES DE BASE COBRE

This paper shows the heat treatment of some copper alloys employing Boron salts. The main objective is to produce a stronger metal layer and smaller friction coeficient than the original alloy, for application on SteelBronze moving parts such as bearings, gears, cams, worm gears and slide mechanisms. The advantage of the method is based on the atom of Boron, smaller than the others, who easily diffusses in the surface of the base metal. Very well defined layers of mono or poly phases Boron compounds may result, having h igh melting point and low friction coefficient, thus reducing wear and exhibiting a better tribological performance.

Stimulatory effect of boron and manganese salts on keratinocyte migration.

Keratinocyte proliferation and migration are essential for the reconstruction of the cutaneous barrier after skin injury. Interestingly, thermal waters which are rich in trace elements (e.g. boron and manganese), are known to be able to improve wound healing. In order to understand the mechanism of action of this effect, our study investigated the in vitro modulation of keratinocyte migration and proliferation by boron and manganese salts, which are present in high concentrations in a thermal water (Saint Gervais). Our in vitro study demonstrated that incubating keratinocytes for 24 h with boron salts at concentrations between 0.5 and 10 microg/ml or manganese salts at concentrations between 0.1 and 1.5 microg/ml accelerated wound closure compared with control medium (+20%). As this acceleration was not related to an increase in keratinocyte proliferation we suggest that boron and manganese act on wound healing mainly by increasing the migration of keratinocytes.

Biodiversity of epiphytic lichens as indicator of air pollution in the geothermal area of Lardello (Tuscany, Central Italy)

The results of a biomonitoring survey carried out in the geothermal area of Larderello (Tuscany, central Italy) using the biodiversity of epiphytic lichens as an indicator of air pollution are reported. A desert was lacking, and stations classified as altered were found only in the surroundings of two old power plants that ceased production in 1992 and 1997, respectively, and installations for the extraction of boron salts. Areas of semi-alteration were found in surrounding areas of all other power plants. The overall pattern of increasing biodiversity with distance from geothermal power plants suggested that air pollution from geothermal installations, chiefly hydrogen sulfide, is the main cause of the observed impoverishment in lichen communities.