落叶松基复合材料SiO2@C的制备及其对染料的吸附行为研究

以落叶松木屑为原料,SiO2为孔结构调控剂,采用一步原位掺杂法制备了落叶松基SiO2@C复合材料,探讨了炭化温度、模板剂SiO 2对复合材料孔结构及吸附性能的影响。利用扫描电镜(SEM)、透射电镜(TEM)、氮气的吸附/脱附、拉曼光谱、X射线衍射仪(XRD)、傅里叶红外光谱(FT-IR)仪和X射线光电子能谱(XPS)对复合材料进行表征,并以乙基紫染料为模型物研究了复合材料的吸附行为。研究表明:随着炭化温度由700℃升高至900℃,SiO2@C复合材料的形貌由交联的球形形貌转变为网状结构,孔隙结构由整体无序向局部有序转变,比表面积由538 m^2/g提高到780 m^2/g;经900℃炭化制备的复合材料SiO2@C-900具有较高的比表面积和有序的孔隙结构,对乙基紫染料的吸附值高达378 mg/g,在温度55℃,pH值7的最佳吸附条件下,对乙基紫染料的脱除率达99%;重复利用5次后,脱除率仍在97%以上,说明复合材料稳定性良好。SiO2@C复合材料对染料的吸附符合Langmuir吸附等温模型,吸附动力学符合准二级动力学,即主要是化学吸附。     

The effect of oxygen fumigation of sawdust medium on the yield and yield-components of greenhouse cucumbers

Greenhouse cucumbers were planted in sawdust-filled plastic bags which were fumigated with oxygen at each feeding. Treated plants produced 20% more cucumbers and 18% more fresh and dry weight than controls, but mean fruit length was 1.0 cm lower in treated plants. Fruit dry weight yield of treated plants did not depend on any particular yield component, while 58.6% of the yield variability of control plants was accounted for by the number of cucumbers produced per unit leaf area.     

杉木屑栽培香菇的研究

为降低香菇栽培对阔叶树资源的消耗和研究杉木屑代替杂木屑栽培香菇的可行性，通过对杉木屑与杂木屑的化学成分的分析检测、杉木屑栽培配方与品种筛选、香菇营养与毒性检测等试验．结果表明，杉木屑除半纤维素含量明显较低外，其它化学组成及含量与杂木屑基本相近，可部分替代杂木屑栽培香菇，添加比例需严格控制在50％以内，才能保持杂木屑常规配方的香菇产量水平，若杉木屑的添加比例控制在30％以内，香菇产量显著高于杂木屑常规配方，同时发现添加10％的棉籽壳有促进发菌和提高香菇产量的效果。杉木屑栽培的香菇营养成分与杂木屑香菇相当或更优，食用安全、可靠。     

Sowing methods and mulch affect 1+0 northern red oak seedling quality

The effects of sowing depth, seedling density and mulches on northern red oak seedling survival and growth were evaluated in Wilson State Forest Nursery in southwest Wisconsin, USA. Sowing depths between 2.2 and 6.3 cm, combined with sowing densities of 75 and 150 acorns · m^-2, made up five sowing method plots. Mulch treatments of ground corncobs aged 1 year, hardwood sawdust aged 2 years, and no mulch made up 3 subplot treatments. Treatments resulted in a range of densities from 18 to 148 seedlings · m^-2. Mulch delayed emergence and increased seedling survival. Increasing sowing depth also delayed emergence. Corncob mulch increased root collar diameter; however, hardwood sawdust, aged for 2 years, decreased both root collar diameter and the number of permanent first-order lateral roots. Increasing sowing depth decreased root dry mass but increased shoot dry mass. Increasing density from 18 to 148 seedlings · m^-2decreased root dry mass in this study.     

锯屑掺入量对快速固化水泥刨花板性能的影响

就不同的细料(锯屑)掺入量对快速固化水泥刨花板的性能的影响作了探讨,结果表明:锯屑的掺入对水泥刨花板的密度、静曲强度、内结合强度和厚度膨胀率均有一定的影响,当锯屑的掺入量占木质原料总量的20% ～ 30%时,既可以改善板的性能,又可以提高木质原料的利用率.     

磷酸-复合活化剂法制竹屑活性炭的研究

以竹屑为原料,用磷酸 复合活化剂(由磷酸添加一种酸性化合物A和一种盐类化合物S)法制备活性炭。研究了磷酸 复合活化剂用量、炭活化温度、炭活化时间等对活性炭的得率、灰分和pH值的影响,确定了适宜的制备竹屑活性炭工艺条件:磷酸浓度为38°Be′/60℃、添加剂A2%、添加剂S4%(A和S以磷酸质量分数计)、炭活化温度450℃、炭活化时间3h。在此条件下所得活性炭的得率为36%、灰分含量4.8%、pH值4.6。对竹屑活性炭的吸附性能、比表面积和孔隙性质也进行了分析。结果表明:竹屑活性炭的比表面积为1500m2/g、比孔容积1.10mL/g、平均孔隙半径1.46nm、焦糖脱色率(A法)120%和亚甲基蓝吸附值225mg/g。     

锯木屑蒸汽爆破预处理制备糠醛的研究

以锯木屑为原料,采用蒸汽爆破进行预处理,然后酸催化提取糠醛。探讨了预处理温度、爆破压力、预处理时间及液料比等因素对糠醛得率的影响。采用响应面法建立二次回归模型,并对预处理工艺进行了优化。研究结果表明:预处理能有效的促进锯木屑的降解,提高糠醛的得率。在预处理温度为216℃、爆破压力1.8 MPa、预处理时间6 min、液料比3∶1(mL∶g)时,糠醛的得率(79.13%)比相同条件下未进行蒸汽爆破预处理的试样(55.35%)提高了23.78个百分点。     

硼酸催化制备木屑活性炭工艺及孔结构特征

以木屑为原料,磷酸为活化剂,硼酸为催化剂制备活性炭。通过正交实验考察了活性炭制备过程中磷屑比、硼酸添加量,活化温度和活化时间等因素对活性炭性能的影响。实验结果表明:生产活性炭的最佳工艺条件为磷屑比为1.5∶1,硼酸的添加量为1%,活化温度是400℃,活化时间为60 min,此时活性炭的得率为33.5%,亚甲基蓝吸附值为225 mg/g,碘吸附值为855 mg/g。添加硼酸的制备方法要比传统的用磷酸制备时的条件更加温和,通过调整工艺条件,可以改变活性炭产品的孔隙结构,生产出用于不同环境的液相吸附专用活性炭。     

Relationship between soil organic matter and micropores in a long-term experiment at Ultuna,Sweden

Our study showed that long‒term addition of organic matter to a fine textured soil (36.5% clay, 41% silt, 22.5% sand) resulted in an increase of both macro‒ and microporosity in the top soil layer. In terms of changes of the absolute pore volume, macropores were of main importance. However, in relative terms, the increase of microporosity was comparable to that of macroporosity (75% and 90%). Changes in porosity upon different organic matter levels had a marginal effect on the water storage capacity. Micropores with diameters in the range of 1—30 μm were highly significantly correlated to soil organic matter characteristics showing that there is a non‒uniform distribution in relation to pores. Mechanisms leading to disproportionally high concentrations of soil organic matter in relation to micropores are discussed.     

木屑及其水热炭的热解特性和动力学对比

为全面了解木屑及其水热炭的差异,获取更多关于水热炭作为化工燃料的使用特性。该文使用热重分析仪和傅里叶红外光谱仪对比研究了木屑及其水热炭在热解过程(10℃/min升温速率)中的失重特性及其官能团变化,分析了升温速率(10、20、30℃/min)对2种样品热解失重过程的影响,采用DAEM(分布活化能模型)计算了2种样品不同转化率下的活化能。结果表明:1)在200℃反应6 h得到的木屑水热炭,化学结构与木屑相似。2)在热解过程(10℃/min升温速率)中,木屑与水热炭最大失重速率分别为0.817%/℃和1.224%/℃,温度为353.57℃和363.42℃;不同终温下半焦红外光谱分析发现,水热炭更易解聚,其碳化速度更快。3)对比3种不同升温速率下2种样品的失重曲线可知,水热处理没有影响热滞后现象,样品焦炭生成量与升温速率无关,焦炭生成量平均值水热炭大于木屑。4)DAEM模型适用于2种样品热解反应活化能的求解,木屑及其水热炭活化能分别为99.33~252.72 k J/mol和63.77~211.68 k J/mol,当转化率在0.30到0.80范围时,木屑的活化能高于水热炭。研究结果为木屑水热炭热化学转化制备焦炭提供理论依据。