Treesearch

Adsorption of orthophosphate anions in aqueous solution by cationized milled solid wood residues was characterized as a function of sorbate-to- sorbent ratio (=0.001-2.58 mmol of P/g substrate), pH (3-9), ionic strength, I (no I control; 0.001 and 0.01 M NaCl), reaction time (4 min to 24 h), and in the presence of other competing anions (0.08-50 mM SO4 2-; 0.08-250 mM NO3-). Sorption isotherms revealed the presence of two kinds of adsorption sites corresponding to high and low binding affinities for orthophosphate anions. Consequently, a two-site Langmuir equation was needed to adequately...

Flotation deinking is a common practice for removing ink from wastepaper, and it is becoming a key process in many recycling paper mills. Flotation deinking was successfully introduced to the paper recycling industry in the 1980s, and its applications in wax removal, sticky control, and fiber fractionation have attracted great research interest. A successful flotation process has three major efficient subprocesses: the detachment of the ink particles from the fibers, the effective adhesion of the ink particles onto air bubble surfaces, and the removal of froth and ink particles from...

More efficient adsorption media are needed for removing dissolved phosphorus in surface water runoff. We studied the use of cationized pine bark as a sorbent for dissolved phosphorus in water. Cationized pine bark was prepared by treating extracted milled pine bark with polyallylamine hydrochloride (PAA HCl) and epichlorohydrin (ECH) in aqueous medium. Attachment of PAA HCl to the bark was monitored by percentage of weight gain and nitrogen content. Changes in bark surface chemistry were characterized by zeta potential and inverse gas chromatography measurements. Energy dispersive x-ray...

Remediation processes for recovery and reuse of chromated-copper-arsenate-(CCA) treated wood are not gaining wide acceptance because they are more expensive than landfill disposal. One reason is the high cost of the nutrient medium used to culture the metal tolerant bacterium, Bacillus licheniformis, which removes 70-100% of the copper, chromium, and arsenic from CCA-treated southern yellow pine (CCA-SYP) in a two-step process involving oxalic acid extraction and bacterial culture. To reduce this cost, the nutrient concentration in the culture medium and the ratio of wood to nutrient...

In this study, three possible improvements to a remediation process for chromated-copper-arsenate (CCA) treated wood were evaluated. The process involves two steps: oxalic acid extraction of wood fiber followed by bacterial culture with Bacillus licheniformis CC01. The three potential improvements to the oxalic acid extraction step were (1) reusing oxalic acid for multiple extractions, (2) varying the ratio of oxalic acid to wood, and (3) using a noncommercial source of oxalic acid such as Aspergillus niger, which produces oxalic acid as a metabolic byproduct. Reusing oxalic acid for...

This paper presents finite element analyses that are being used to analyze and estimate the structural performance of a new product called 3D engineered fiberboard in bending and flat-wise compression applications. A 3x3x2 split-plot experimental design was used to vary geometry configurations to determine their effect on performance properties. The models are based on a simple corrugated geometry. Both 2D and 3D analyses were used for the compression and bending simulations, respectively. The material properties used in this analysis were obtained from tensile tests of flat panels made...

At present most inventory work is conducted to increase our knowledge of fungal diversity and to learn about habitat preferences and geographic distributions of different taxa. A recent development in that respect is the inventory of target taxa for conservation purposes legally mandated as part of the federally approved management plan for old growth forests in the Pacific Northwest (Forest Ecosystem Management Assessment Team 1993; O’Dell et al. 1996; Molina et al. 2001). Although no nonlichenized fungus is protected yet by that plan, 225 species of old-growth-associated macrofungi in...

The Forest Products Laboratory uses the cone calorimeter for the initial evaluation of the flammability of untreated and fire retardant treated wood products. The results of various studies are reviewed using a model presented at the 12th Annual BBC Conference on Flame Retardancy. The model uses data from the cone calorimeter to provide measures of fire growth propensity based on material bulk properties and surface fire growth propensity and to provide an estimate of the ASTM E 84 flame spread index. In a study on the fire performance of treated wood exposed to elevated temperature, wood...

We investigated how biopulping modifies chemical and physical properties of wood and how these changes affect the properties of the resulting fiber. Mechanical and chemical testing revealed wood cell changes during 2 weeks of colonization by Ceriporiopsis subvermispora. Typical mechanical properties, such as modulus of elasticity and maximum load, tracked reductions in energy needed for mechanical refining to pulp. The data indicate the fiber saturation point of spruce increased from 29% to 42% during biopulping. At the same time, titratable acid groups increased up to 62%. Chemical...

An overview of wood preservatives currently used for timber bridges is presented through a series of case studies from different regions of the United States. New wood species and preservative treatment options for timber bridges have made choosing the appropriate preservative more complicated. The compatibility of wood species and preservative treatment is often overlooked but can be very important to the durability of timber bridge components. More technical guidance is needed for bridge designers who are not familiar with wood preservative treatments. The current trend is toward the use...