Boron Leaching Research Articles

Leachability of boron from wood treated with natural and semi-synthetic polymers and calcium precipitating agent

Introduction Several fixation systems to limit or decrease boron leachability from treated wood have been developed. Some attempts have relied on limiting of water penetration of treated wood using water repellents, monomer and polymer systems. On the other hand, non-toxic polymers such as proteins were tried to reduce amount of boron leached from wood (Thevenon et al. 1997, 1998). Their results showed that protein borates such as albumin and soja protein borates greatly retarded the leaching of boron from treated wood via formation of salt. In addition, precipitation of boron in wood via a calcium precipitating agent NHA (N‘Nnaphthaloylhydroxylamine) also has potential to reduce boron leachability (Kartal and Green 2002). This paper presents results from a preliminary study to reduce the leachability of boron using natural polymers including naturally occurring polysaccharides, carboxy methylcellulose as a synthetic polymer, and NHA.

Alkali-activated cementitous materials: Alternative matrices for the immobilisation of hazardous wastes: Part I. Stabilisation of boron

Boron is a nonmetal element that is present in nature in many kinds of minerals and in a lot of industrial products of public use. The importance of this element lies in the fact that boron compounds are present in some water streams from nuclear power plants (Pressure Water Reactor [PWR]) and that the boron-soluble salts modify Portland cement hydration retarding setting and hardening, and negatively affecting its durability characteristics. Thus, the main objective of this research was to study the efficiency against boron of the solidification systems based on alkali-activated fly ashes. Results show that boron does not significantly alter the hardening process of the new matrices. The presence of boron hardly modifies mechanical strengths of activated fly ashes and additionally, boron leaching tests indicate that this stabilisation/solidification system is more effective than traditional ones.

Biodegradable lightweight construction boards based on tannin/hexamine bonded hemp shaves

, with a dry I.B. strength of up to 0.34 MPa, a formaldehyde release well within the emission class E1 and certificate as normal flammable and not burning dripped off (DIN 4102-B2) were fabricated by mixing hemp shaves with a borate-modified mimosa tannin-hexamine binder and press the masses as fast as 6 s/mm thickness at 70°C to one-layer boards. Different drying processes indicate that fast drying at ˜100°C is needed both for satisfactory strengths and for a sufficient dimension stability performance of soaked samples, but, as well for a lower boron leaching during soaking. For dry environments the resistance to fungal attack is sufficient enough to have boards for interior application.

Enhancement of the biological resistance of wood by phenylboronic acid treatment

Phenylboronic acid (PBA) was tested in terms of boron leachability from treated wood. In addition, the fungal and termiticidal efficacy of PBA-impregnated sugi (Cryptomeria japonica D. Don) wood was tested against the decay fungi Coriolus versicolor (L. ex Fr.) Quel. and Tyromyces palustris (Berk. et Curt) Murr., representing white-rot and brown-rot fungi, respectively, and the Formosan subterranean termite Coptotermes formosanus Shiraki. Ion chromatography analysis of hot water extracts of treated wood before and after leaching indicated that PBA is considerably resistant to water leaching, and saturation of the treatment solution increased the fixation ratio of boron in wood, whereas boric acid could not remain in wood impregnated even with the saturated solution. Decay test results revealed the excellent bioactive performance of PBA. Wood treated with 0.34% PBA solution was found resistant to both decay fungi, even after running-water leaching for 10 days and treatment with 1.00% PBA completely inactivated the Formosan subterranean termite for the leached specimens. Weight gain levels were 0.18% w/w (0.46kg/m3) and 0.99% w/w (2.49kg/m3) for these concentration levels, respectively, after being leached by running water. Contrary to the general belief that boron is a slow-acting toxicant against termites and unable to prevent mass loss of treated wood, PBA acted rapidly, and the mass loss caused by termites was low.

Boron leaching Deemed to Be a Beneficial Use

An Oregon Appellate court ruled that boron leaching was a beneficial use for which water could be appropriated.

An approximate model for boron drive diffusions in oxidizing ambients

The linear diffusion equation may be transformed to a moving reference frame which corresponds to a linear-parabolic or experimental oxide growth law. The resulting partial differential equation is separable and may be Laplace transformed. If the initial distribution is piecewise constant the solutions may be written in terms of Kummer functions in the transform domain. Use is made of this fact for a drive diffusion in an oxidizing ambient. The initial distribution is approximated by a rectangle and a two-region solution is used to determine all coefficients. The inversion of the solution to the time domain is accomplished by numerical residue techniques. The amount of boron which is lost to the oxide is computed and approximate relationships are given which allow its computation without the aid of a computer. It is found that boron leaching is controlled by the first few minutes of oxidation and may involve as much as 90% of the boron due to the deposition. Experimental data is presented which supports the theory.