Mohan Dinesh, Shi Jenny, Nicholas Darrel D, Pittman Charles U, Steele Philip H, Cooper Jerome E
Department of Chemistry, Mississippi State University, Mississippi State, MS 39762, USA
Chemosphere. 2008 Mar;71(3):456-65. doi: 10.1016/j.chemosphere.2007.10.049.
Pine wood, pine bark, oak wood and oak bark were pyrolyzed in an auger reactor. A total of 16 bio-oils or pyrolytic oils were generated at different temperatures and residence times. Two additional pine bio-oils were produced at the National Renewable Energy Laboratory in a fluidized-bed reactor at different temperatures. All these bio-oils were fractionated to obtain lignin-rich fractions which consist mainly of phenols and neutrals. The pyrolytic lignin-rich fractions were obtained by liquid-liquid extraction. Whole bio-oils and their lignin-rich fractions were studied as potential environmentally benign wood preservatives to replace metal-based CCA and copper systems that have raised environmental concerns. Each bio-oil and several lignin-rich fractions were tested for antifungal properties. Soil block tests were conducted using one brown-rot fungus (Gloeophyllum trabeum) and one white-rot fungus (Trametes versicolor). The lignin-rich fractions showed greater fungal inhibition than whole bio-oils for a impregnation solution 10% concentration level. Water repellence tests were also performed to study wood wafer swelling behavior before and after bio-oil and lignin-rich fraction treatments. In this case, bio-oil fractions did not exhibit higher water repellency than whole bio-oils. Comparison of raw bio-oils in soil block tests, with unleached wafers, at 10% and 25% bio-oil impregnation solution concentration levels showed excellent wood preservation properties at the 25% level. The good performance of raw bio-oils at higher loading levels suggests that fractionation to generate lignin-rich fractions is unnecessary. At this more effective 25% loading level in general, the raw bio-oils performed similarly. Prevention of leaching is critically important for both raw bio-oils and their fractions to provide decay resistance. Initial tests of a polymerization chemical to prevent leaching showed some success.
松木、松树皮、橡木和橡树皮在螺旋式反应器中进行热解。在不同温度和停留时间下共生成了16种生物油或热解油。另外两种松树生物油是在国家可再生能源实验室的流化床反应器中于不同温度下生产的。所有这些生物油都进行了分馏以获得富含木质素的馏分，这些馏分主要由酚类和中性物质组成。通过液 - 液萃取获得富含热解木质素的馏分。对全生物油及其富含木质素的馏分作为潜在的环境友好型木材防腐剂进行了研究，以替代引发环境问题的金属基铬化砷酸铜（CCA）和铜系统。对每种生物油和几种富含木质素的馏分进行了抗真菌性能测试。使用一种褐腐菌（密粘褶菌）和一种白腐菌（云芝）进行了土块试验。对于10%浓度水平的浸渍溶液，富含木质素的馏分比全生物油表现出更强的真菌抑制作用。还进行了防水性测试，以研究生物油和富含木质素的馏分处理前后木片的膨胀行为。在这种情况下，生物油馏分的防水性并不比全生物油更高。在10%和25%生物油浸渍溶液浓度水平下，对未浸出木片进行的土块试验中比较原始生物油，结果表明在25%浓度水平下具有优异的木材防腐性能。原始生物油在较高负载水平下的良好性能表明没有必要进行分馏以生成富含木质素的馏分。一般来说，在这个更有效的25%负载水平下，原始生物油表现相似。防止浸出对于原始生物油及其馏分提供抗腐性至关重要。一种用于防止浸出的聚合化学品的初步测试取得了一些成功。
