Boric Acid Equivalent Research Articles

Boron quantification using ion chromatography tandem triple quadrupole mass spectrometry. Application to retention analysis in boron-treated wood

Boron compounds play a crucial role in various industries, and accurate quantification of boron is essential for quality control and environmental monitoring. This study presents a simple, rapid, and reliable method for determining boron in aqueous solutions using suppressed ion chromatography coupled to electrospray ionisation-triple quadrupole mass spectrometry (IC-ESI-QqQ-MS). Boric acid (B(OH)3) was retained as the tetrahydroxyborate ion (B(OH)4−) on a CarboPac PA300-4 μm anion-exchange column using isocratic elution with 40 mM KOH. During the neutralization process at the suppressor, B(OH)4− was converted to B(OH)3, which subsequently generated the metaborate ion [BO2]− (m/z 43) within the electrospray ionisation source. By employing a pseudo-selected reaction monitoring (SRM) transition from m/z 43 to m/z 43, the method achieved a limit of detection (LOD) of 2.45 μg/L of boron, the lowest reported in the literature to-date for an IC-based method. The analytical performance of the method demonstrated no carry-over issues, no matrix interferences, and excellent intra- and inter-run repeatability of 2.03% and 3.41%, respectively. The method was applied to the evaluation of boron uptake and retention by Tasmanian Oak timber blocks, treated by dip-diffusion in a boric acid solution of 2.5% Boric Acid Equivalent (BAE, m/m) under controlled laboratory conditions. Quantitative determination of the retained and unretained boron allowed a mass balance evaluation and confirmed the accuracy and reliability of the method, with recoveries ranging from 99.3% to 100.2%.

Prediction and evaluation of borate distribution in Eastern black spruce (Picea mariana var. mariana) wood products

Borate distribution and content in re-wetted brush-treated Eastern black spruce (Picea mariana var. mariana) blocks were investigated by near-infrared spectroscopy (NIRS). Samples were brush-treated with 40 % glycerol-based DOT (Na2B8O13 4H2O) and then conditioned for different durations (5, 9, 20, and 30 days) at high relative humidity (approaching 100 %). The effect of a glue-line on the borate distribution and content was also evaluated. Borate penetration depth was estimated in the radial direction in wood block samples. The evaluation of borate’s diffusion gradient in terms of boric acid equivalent was conducted on the whole radial plane of the other portion of wood samples that were sliced every 0.4 cm in the radial direction. The effect of glue-lines was evaluated using two wood strips glued together. Calibration models achieved R2 ranging from 0.4 to 0.5 and root-mean-square error (RMSE) ranging from 0.28 to 0.31 %. The statistic for validation achieved R2 ranging from 0.3 to 0.4 and RMSE ranging from 0.31 to 0.34 %. NIRS had some predictive abilities for borate distribution and borate concentration using the projection to latent structures-PLS regression method.

Long-term performance of fused borate rods for limiting internal decay in Douglas-fir utility poles

Abstract The ability of boron to diffuse from fused boron rods into surrounding wood was investigated on pentachlorophenol-treated Douglas-fir poles. Boron readily diffused into the wood surrounding the treatment holes and was present at protective levels in most poles within 1 year after application. The protected zone was generally confined to the treatment zone. Effective levels of boron were still present in this zone 15 years after treatment. Attempts to correlate the presence of decay fungi with residual boron levels indicated that these fungi were sometimes present in zones with boron at the lower threshold level of 0.5 kg m-3 boric acid equivalent (BAE), but most of the isolations could be explained by localized variations in distribution. Boron rods provided excellent long term protection against internal decay in Douglas-fir poles.

Effects of polyvinyl alcohol on leachability and efficacy of boron wood preservatives against fungal decay and termite attack

In this study, the use of polyvinyl alcohol (PVA) as boron fixative agent was investigated. Two levels of PVA (2.5 and 4%) were evaluated with disodium octaborate tetrahydrate (DOT) at three concentrations (1, 2 and 4% boric acid equivalent (BAE)) using a double vacuum impregnation process on Scots pine sapwood specimens. Leaching was performed according to a laboratory leaching procedure. Boron analysis using atomic absorption spectrometer showed a significant reduction in boron leachability for the samples treated with both concentrations of PVA when compared to the stand-alone boron treatment leading to boron retentions capable of preventing wood biological degradations. Decay resistance of the leached specimens was evaluated using the brown rot fungus Poria placenta. Even if complete protection was not fully achieved, an improvement in decay resistance was observed for the samples treated with DOT in presence of PVA. This leak of efficacy was attributed to a decrease in the biological activity of the complexed boron against fungi. Durability of treated wood against termite attack, evaluated using Reticulitermes santonensis, indicated a significant enhancement for the samples treated in presence of the fixative agent compared to the pure boron treatment.

Boron impregnation treatment of Eucalyptus grandis wood

Eucalyptus grandis is suitable for small timber purposes, but its wood is reported to be non-durable and difficult to treat. Boron compounds being diffusible, and the vacuum-pressure impregnation (VPI) method being more suitable for industrial-scale treatment, the possibility of boron impregnation of partially dry to green timber was investigated using a 6% boric acid equivalent (BAE) solution of boric acid and borax in the ratio 1:1.5 under different treatment schedules. It was found that E. grandis wood, even in green condition, could be pressure treated to desired chemical dry salt retention (DSR) and penetration levels using 6% BAE solution. Up to a thickness of 50 mm, in order to achieve a DSR of 5 kg/m 3 boron compounds, the desired DSR level as per the Indian Standard for perishable timbers for indoor use, it was found that neither the moisture content of wood nor the treatment schedule posed any problem as far as the treatability of E. grandis wood was concerned.

Borate Protection of Softwood from <I>Coptotermes acinaciformis</I> (Isoptera: Rhinotermitidae) Damage: Variation in Protection Thresholds Explained

Laboratory and field data reported in the literature are confusing with regard to "adequate" protection thresholds for borate timber preservatives. The confusion is compounded by differences in termite species, timber species and test methodology. Laboratory data indicate a borate retention of 0.5% mass/mass (m/m) boric acid equivalent (BAE) would cause > 90% termite mortality and restrict mass loss in test specimens to < or = 5%. Field data generally suggest that borate retentions appreciably > 0.5% m/m BAE are required. We report two field experiments with varying amounts of untreated feeder material in which Coptotermes acinaciformis (Froggatt) (Isoptera: Rhinotermitidae) responses to borate-treated radiata (Monterey) pine, Pinus radiata D. Don, were measured. The apparently conflicting results between laboratory and field data are explained by the presence or absence of untreated feeder material in the test environment. In the absence of untreated feeder material, wood containing 0.5% BAE provided adequate protection from Coptotermes sp., whereas in the presence of untreated feeder material, increased retentions were required. Furthermore, the retentions required increased with increased amounts of susceptible material present. Some termites, Nasutitermes sp. and Mastotermes darwiniensis Froggatt, for example, are borate-tolerant and borate timber preservatives are not a viable management option with these species. The lack of uniform standards for termite test methodology and assessment criteria for efficacy across the world is recognized as a difficulty with research into the performance of timber preservatives with termites. The many variables in laboratory and field assays make "prescriptive" standards difficult to recommend. The use of "performance" standards to define efficacy criteria ("adequate" protection) is discussed.

An economical treatment schedule for boron impregnation of Eucalyptus grandis wood: Commercial trial of partially dried material

Being non-durable, Eucalyptus grandis wood needs treatment with preservative chemicals. As vacuum-pressure impregnation treatment being more suitable for commercial applications, and boron chemicals being environment-friendly for indoor uses, an economical treatment schedule (15 minutes initial vacuum of -85 kPa followed by a pressure of 1300 kPa for 15 minutes and a final vacuum of -85 kPa for 5 minutes) developed at the Kerala Forest Research Institute was tested for its commercial suitability for treating E. grandis wood with boron chemicals. A pooled mean dry salt retention (DSR) of 7.7 kg m -3 was achieved for wood in partially dried condition with average moisture content of around 32%, using a 6% boric acid equivalent (BAE) solution. This confirms the success of the schedule for commercial application, as the DSR achieved is much higher than the standard specification of many countries.

Xylophagous insects: developments in feeding assays

Xylophagous insects: developments in feeding assays

Utilização de bórax por difusão no tratamento de preservação de lâminas de sumaúma (Ceiba pentantra (L.) Gaertn.)

O objetivo deste trabalho foi comparar três diferentes intervalos de tempo para difusão do bórax, visando a preservação de lâminas de sumaúma. O tratamento foi a aplicação por aspersão de 30 ml de solução, a 4% de concentração de bórax. Na pesquisa, optou-se pela retenção de 0,500% de equivalente de ácido bórico (EAB), com base na massa das lâminas secas. Avaliou-se a retenção nos tempos de difusão de 15, 150 e 270 minutos. Por meio da análise química quantitativa, foram verificados os níveis de retenção por espectrofotometria, obtendo-se 0,462, 0,457 e 0,440% de EAB, respectivamente, para os tratamentos de 15, 150 e 270 minutos, que não diferiram estatisticamente entre si pelo teste Tukey (p&lt;0,05). Os resultados indicam uma boa difusão do bórax aos 15 minutos, o que demonstrou ser uma alternativa como tratamento preservante de madeira.

Preservative properties of vapor-boron-treated wood and wood-based composites

The treatability of wood (sapwood ofCryptomeria japonica D. Don) and wood-based composites (particleboard, waferboard, medium-density fiberboard, plywood) with vapor-boron was good, and the treated materials proved to be resistant to decay fungi and subterranean termites in laboratory bioassays. No difference in effectiveness was noted between vapor-boron and liquid-boron treatment of wood. Toxic threshold values determined for solid wood were 0%–0.24%, 0.26%–0.51%, and 0.26%–0.51% BAE (boric acid equivalent), respectively, against the white-rot fungusTrametes versicolor (L.: Fr.) Pilat, the brown-rot fungusFomitopsis palustris (Berk. et Curt.), and the subterranean termiteCoptotermes formosanus Shiraki. A concentration of less than 1% BAE seemed sufficient to control biological attacks on composites, although the toxic limits could not be determined more accurately because of the tested range of boron retention. High boron retention was needed to meet the performance requirements for slow-burning materials when a fire-retardant agent was not incorporated into the glue line.

A pilot plant investigation of boron treatment of rubber wood: Arriving at an economical treatment schedule

An economical treatment schedule (15 minutes initial vacuum of 85kPa; 15 minutes pressure of 1000 kPa; 5 minutes final vacuum of 85kPa; was arrived at for treating air-dried rubber wood in a pilot plant cylinder. Treating with 3% BAE (boric acid equivalent) solution resulted in a dry salt retention of 13.1 kg/m3. Also, the study showed that green rubber wood can be treated to required chemical retention level by employing the above treatment schedule and by increasing the concentration of the treatment solution to 6% BAE.

Borate protection of hoop pine(Araucaria cunninghamii)sapwood from attack by subterranean termites(Coptotermesspp., Isoptera: Rhinotermitidae)

Summary Field bioassays were conducted with two Australian Coptotermes species to determine protection of hoop pine sapwood afforded by borate compounds. Coptotermes lacteus (Froggatt) was examined in winter and Coptotermes acinaciformis (Froggatt) in winter, spring and late summer at two localities in the state of Queensland. Sapwood blocks were placed in plastic containers and attached to termite mounds or infested trees. Termite response was determined by mass loss over five weeks and modelled. C. lacteus was relatively benign in winter and for 1.0 and 2.5% mass loss, mean borate retentions of 0.20 and 0.06% m/m boric acid equivalent (BAE), respectively, were derived. With C. acinaciformis, for 1.0 and 5.0% mass loss, mean borate retentions ranged from 0.49 and 0.25% BAE. respectively, in winter, to 0.76 and 0.47% BAE. respectively, in late summer. These results support conclusions from earlier laboratory studies conducted elsewhere. Total prevention of damage by field populations of termites was not a...

Effect of Polyborate Pre-treatment on the Shear Strength Development of Phenolic Resin to Sitka Spruce Bonds

Pre-treating the constituents of wood-based composite panels with fungitoxic chemicals prior to lay-up and pressing offers some advantage over post-pressing treatment. Boron is a strong candidate pretreatment chemical for this application but it influences the bonding mechanisms that must occur during hot pressing. In the present study, the effects of boron loading level (A to 15% boric acid equivalent, BAE) on the strength development rates of small phenol formaldehyde-to-wood (sitka spruce) test bonds was investigated. Each bond (15 mm x 15 mm overlap) was formed under pre-selected time (20 to 240s) and temperature (70, 80 or 95 °C) conditions and immediately thereafter tested in shear mode, this enabled three approximately isothermal bond strength development curves to be constructed for each boron loading level investigated. All levels of boron pretreatment hastened initial strength development rates, although levels above 7.5% BAE had diminishing effects on isothermal rates - with possible decreases at very high (15% BAE) levels. Though not exactly reproducing conditions that occur around bonding sites in panels during pressing, the techniques described may aid in our basic Understanding of the mechanisms affected by chemical pretreatment. © Copyright 1993 by Walter de Gruyter

The chemical analysis of disodium octaborate in preserved softwoods

A method is described for the rapid determination of the boric acid equivalent of disodium octaborate tetrahydrate in the core and cross-section of diffusion treated softwoods such as Baltic redwood, western hemlock and Sitka spruce. A sawcut is made through the sample and the boron-containing compounds are leached from the sawdust with sodium hydroxide solution and determined by the spectrophotometric measurement of the red rosocyanin complex formed between boric acid and curcumin. The standard deviation is ± 0·009 per cent.

The extraction and determination of disodium octaborate in Sitka spruce

A method is described for the rapid determination of the boric acid equivalent of disodium octaborate tetrahydrate in Sitka spruce. The boroncontaining compounds are leached from thin sections of wood with sodium hydroxide solution and determined by the spectrophotometric measurement of the red complex formed between boric acid and curcumin.The procedure is particularly useful for the study of the distribution of boron-containing preservatives in wood.