Volume 3 Issue 1

Milled southern pine wood was modified with sequential treatments of sodium periodate and sodium hypobromite for the purpose of improving copper ion (Cu2+) sorption capacity of the wood when tested in 24-h equilibrium batch tests. The modified wood provided additional carboxyl groups to those in the native wood and substantially increased Cu2+ uptake over that of unmodified wood. Sorption capacity (qe) measured with an unbuffered standard solution increased to a maximum of 7.8 mg Cu2+ ion per gram of wood (treated) from 3.1 mg Cu2+ ion/g wood (untreated). Samples tested were first sodium ion exchanged to keep the pH of the standard solution from declining during the sorption test. The treatment necessary for maximum qe was 3% (w/v) periodate for 24 h and 0.8% (w/v) bromine (as hypobromite) for 24 h; both treatments were at room temperature. These conditions corresponded to the maximum periodate concentration and treatment times tested. To further evaluate the efficacy of modification treatments, weight change after each treatment was determined. Weight loss after the periodate stage for any concentration and time used was minor, indicating the selective nature of this reaction. However, most of the weight loss was incurred after hypobromite treatment. Weight loss corresponding to the greatest increase in sorption capacity was 12.6% total from the combined periodate and hypobromite stages. The increase of carboxylate functional groups in the wood was monitored using FTIR/ATR spectroscopy.

Superabsorbent polymer was prepared by graft polymerization of acrylic acid onto the chain of carboxymethyl cellulose. This superabsorbent polymer was further treated by the solvent precipitation method. We found that the water absorption rate of the treated polymer was greatly increased and the microstructure of the treated polymer was changed from close-grained structures to loose macropores. The swelling processes of the polymers before and after modification fit first-order dynamic processes. The amount of the residual acrylic acid was detected through high performance liquid chromatography (HPLC) with aqueous solution of MOPS of 0.02mol/L (pH=5.70) as the mobile phase. It was found that the amount of the residual acrylic acid decreased from 83.8×10-4 % to 6.7×10-4 % after treatments.

South America has substantial potential to expand its forest plantations and raw material supply. From 1997 to 2005, South America had a high annual growth rate in the production of industrial roundwood, with Brazil and Chile being the most important countries. In the same period, Asia had the only negative regional production growth rate in the world, and China became the largest round wood importer in the world. This paper summarizes the status of production, consumption, imports, and exports of industrial roundwood and forest products in South America. Produc-tion and exports from South America have continually increased at annual growth rates exceeding the forestry sector in general and the U.S. in particular. Based on timber growing investments to date, a strong timber production and forest products manufacturing sector has developed in the Southern Cone countries of Chile, Brazil, Argentina, and Uruguay, and is increasing in other countries in Latin America. There will be continued opportunities for forest plantations and new manufacturing facilities throughout South America, tempered somewhat by perceived country financial and political risks. These opportunities will allow South America to increase its share of world production and increase imports to North America and to Asia. PDF

Energy and environmental issues are among the major concerns facing the global community today. Transportation fuel represents a large proportion of energy consumption, not only in the US, but also world-wide. As fossil fuel is being depleted, new substitutes are needed to provide energy. Ethanol, which has been produced mainly from the fermentation of corn starch in the US, has been regarded as one of the main liquid transportation fuels that can take the place of fossil fuel. However, limitations in the supply of starch are creating a need for different substrates. Forest biomass is believed to be one of the most abundant sources of sugars, although much research has been reported on herbaceous grass, agricultural residue, and municipal waste. The use of biomass sugars entails pretreatment to disrupt the lignin-carbohydrate complex and expose carbohydrates to enzymes. This paper reviews pretreatment technologies from the perspective of their potential use with wood, bark, and forest residues. Acetic acid catalysis is suggested for the first time to be used in steam explosion pretreatment. Its pretreat-ment economics, as well as that for ammonia fiber explosion pretreatment, is estimated. This analysis suggests that both are promising techniques worthy of further exploration or optimization for commercialization.