文冠果壳基活性炭制备工艺优化与性能表征

文冠果壳为文冠果榨油后的废弃物,为避免环境污染,充分利用这种废弃物制成高附加值的活性炭,该研究以文冠果壳为原料,采用磷酸活化法制备活性炭,以固液比、磷酸浓度、活化时间和活化温度为自变量,活性炭的碘吸附值为因变量,经响应面试验优化制备工艺,探究文冠果壳活性炭的吸附性能。结果表明,通过响应面试验优化得到最佳工艺条件：固液比1∶1 g/mL,磷酸浓度71%,活化时间158 min,活化温度540℃,此时碘吸附值为(1 127.377±2.406) mg/g,与预测的碘吸附值误差仅为0.390%。与文冠果壳相比,经活化得到的活性炭水分和灰分明显降低,C元素质量分数升高至69.702%;活性炭的比表面积为841.438 m²/g,总孔容为0.593 cm³/g,平均孔径为4.361 nm,孔隙结构发达,主要以介孔为主,且官能团主要为羰基。因此可以用文冠果壳制备出吸附性能好的活性炭,该结果可为磷酸活化法制备文冠果壳基活性炭的工业化生产提供一定参考。     

响应面法优化茉莉花茶茶多糖提取工艺

本实验以茉莉花茶为供试材料,优化茶多糖的提取工艺,旨在提高茶多糖的提取率,为茶叶深加工提供理论依据。在单因素实验的基础上,利用Box-Benhnken的中心组合设计,选定温度、水料比和沉淀茶多糖时所用的乙醇浓度3个因素分别选3水平进行中心组合实验,通过响应面分析实验,拟合出数学模型：Y=6.55＋1.30A＋0.83B＋1.10C-0.092AB＋0.11AC＋0.34BC-1.56A2-0.64B2-1.48C2。利用该函数关系来优化茶多糖提取条件,最终确定茶多糖的最佳浸提条件为：浸提温度100℃;水料比为26.8;乙醇浓度为90%。在该条件下茶多糖得量有所提高,且验证值为7.8610mg/g,比单因素最高提取率高25.6%,表明响应面法可有效用于茶多糖提取方法的优化。     

油茶壳热解产物特性及热解炭制备活性炭工艺优化

为了探究热解终温对油茶壳热解产物特性的影响,实现油茶壳热解多联产产物的有效利用,该文研究了油茶壳300～700℃热解过程中气、液、固的得率,特性和能量分布规律,讨论了油茶壳热解炭制备活性炭的工艺条件。研究表明,随着热解终温的升高,生物质炭得率下降,不可凝气体得率上升,生物质油得率则呈现先上升后下降的变化趋势。生物质炭的能量产率高达47.21%～81.59%,是油茶壳热解的主要产物,随着热解终温的升高,其固定碳含量增大,BET比表面积先增加后减小,在600℃达到最高值278 m2/g。油茶壳活性炭制备的最佳工艺条件活化温度850℃,活化时间1.5 h,水蒸气用量与炭的比2.0,此条件下的活性炭得率为37.47%,碘吸附值为825 mg/g,BET比表面积为736 m2/g。该研究为油茶壳热解多联产工艺及产物的综合有效利用提供参考依据。     

黑曲霉固体发酵产木聚糖酶的响应面优化设计及其酶学性质的研究

本研究采用响应面法的中心组合对影响黑曲霉(aspergillus niger JL 15)固体发酵产木聚糖酶的条件进行了优化.以橘皮粉为基质,补充碳源、氮源,以及含水量和发酵时间对木聚糖酶产量具有显著影响(P<0.05).模拟二次多项式回归预测模型,并建立自变量与响应值的回归方程,获得各因素的最佳水平,即:甘油、硫酸铵的添加量分别为4.2%和3.1%,含水量为61%,发酵时间为73.4 h,木聚糖酶活性最大预测值达922.9 U/g干发酵产物,验证值为917.7 U/g干发酵产物,高出基础培养基酶活3.2倍.酶学性质分析研究表明,黑曲霉木聚糖酶(XylA)的最适温度和最适pH分别为55oC和pH 5.0.XylA的K_m和V_(max)值分别为9.24 mg/mL和54.05 μmol/min/mL.Mn~(2+)、Zn~(2+)和斗和Mg~(2+)对XylA活性具有促进作用,而Fe~(3+)和cu~(2+)对XylA活性具有明显抑制作用.HPLC分析结果表明,XylA的水解桦木木聚糖和麸皮不溶性木聚糖的产物均为木糖至木六糖,主要产物为木三糖.     

秸秆微波水热炭和活性炭理化及电化学特性

为了解秸秆微波酸催化水热炭和碱活化活性炭形成机制和理化特性演变规律,该研究开展了不同柠檬酸质量分数下的秸秆微波水热和活性炭的制备试验,并研究了水热炭和活性炭理化及其电化学特性。结果表明,随柠檬酸质量分数的增加,秸秆水热炭的产率、挥发份和H含量减少,而其灰分、固定碳、C和高位热值增加,且酸质量分数为10%后趋于稳定。柠檬酸质量分数为10%时,水热炭的碳微球结构最丰富,其比表面积和孔体积最大,且以中孔为主。10%柠檬酸水热炭在900℃下经KOH活化后的活性炭产率为8%～11%,活化气体产率为32%～35%,且以CO和H2为主。900 ℃活性炭的比表面积为1 250～1 570 m2/g,总孔体积为1.00～1.20 cm3/g,孔径为3.55～4.10 nm,且以中孔和微孔为主。当电流密度为1 A/g,水稻、玉米和油菜秸秆活性炭的比电容分别为160.54、150.12和155.17 F/g,且循环5 000次后的电容保持率分别为91.04%、88.12%和89.06%,表现出较好的循环稳定性。水稻秸秆水热炭和活性炭的产率、灰分、碳转化率、能量转化率、比表面积、总孔体积、比电容和电容保持率最大。     

豆腐干超声卤制的响应面试验及工艺优化

为研究超声卤制过程中不同工艺参数对豆腐干单位能耗与品质的影响,本试验以新鲜豆腐干为原料,选取超声功率、超声时间、超声温度、盐浓度为试验因素,以豆腐干的含盐量、单位耗能、色差值(ΔE值)、咀嚼性、回复性为指标,进行响应面试验,建立回归模型,分析影响各指标的主次因素及因素间的交互作用,采用遗传算法优化豆腐干超声卤制的工艺参...     

响应面法优化糟醉带鱼的湿腌工艺

采用响应面法优化糟醉带鱼的湿腌工艺。在单因素试验基础上,根据中心组合试验设计原理,采用三因素三水平的响应面分析法,以糟醉带鱼的感官评分为响应值进行回归分析。结果表明,糟醉带鱼湿腌时,盐水浓度对其品质的影响最为显著,适宜的腌制工艺为:腌制温度20℃、盐水浓度21%、腌制时间3 h,在此条件下制得的糟醉带鱼品质较好,感官评分最优,达80.00分,与模型预测值基本相符。     

不同炭化温度下玉米秸秆和沙蒿生物炭的结构特征及化学特性

掌握不同生物炭材料的结构特征和化学特性是合理利用生物炭的基础。通过无氧炭化法制备了不同炭化温度下的玉米秸秆生物炭和沙蒿生物炭,对比了不同材料和不同炭化温度下生物炭性质的差异。结果表明:炭化温度低于400℃时,两种材料生物炭的孔隙结构保存完整,600℃以上时,两种材料生物炭的蜂窝状结构均遭到破坏,玉米秸秆生物炭被破坏得更严重;同一炭化温度下,玉米秸秆生物炭的比表面积及总孔容和平均孔径均大于沙蒿生物炭,两种生物炭的比表面积随炭化温度的升高均增大,总孔容呈"V"形变化;两种材料的生物炭均呈碱性,炭化温度越高,pH越大,400℃~800℃,每升高10℃,玉米秸秆生物炭和沙蒿生物炭的pH均以0.02的幅度增加,同一温度下,玉米秸秆生物炭的pH大于沙蒿生物炭,在400℃、600℃和800℃下分别比沙蒿生物炭高0.31、0.35和0.29单位;随炭化温度的升高,玉米秸秆生物炭和沙蒿生物炭的C、P、K和灰分含量增加,400℃~800℃,玉米秸秆生物炭的C、P、K含量以炭化温度每升高10℃分别增加2.94、0.11、0.20 g/kg的幅度变化,沙蒿生物炭也以4.35、0.07、0.24 g/kg的幅度增加,与此同时,玉米秸秆生物炭的N、H含量以每升高10℃分别以0.13 g/kg和0.86 g/kg的幅度降低,沙蒿生物炭的N、H含量分别以0.04 g/kg和0.82 g/kg的幅度下降,S含量无明显变化,C/N和C/H增大,且不同材料生物炭的元素含量差异显著;两种材料生物炭的N、P、K有效性随炭化温度的升高均下降,400℃~600℃,玉米秸秆生物炭和沙蒿生物炭的速效N含量分别下降了57.89%和19.05%,800℃时两种生物炭的速效N均接近0 mg/kg,400℃~800℃玉米秸秆生物炭和沙蒿生物炭的速效P含量分别降低了67.41%和52.36%,此时速效K含量也分别降低了45.62%和90.16%。总之,不同材料和炭化温度对生物炭的物理特征和化学特性都有较大影响。     

红松种子壳多酚物质的提取及抗氧化特性

该文选取超声波辅助提取法,采用单因素试验及响应面设计,研究了超声波提取时间、温度、乙醇浓度及料液比对红松种子壳中多酚类化合物提取的影响。并利用Fenton体系、1,1-二苯基-2-苦苯肼(DPPH·)体系及邻苯三酚体系测定其提取成分的抗氧化活性。结果表明,松壳中多酚成分提取的最佳工艺条件为:超声提取时间2.80h、料液比1∶26.36(g/mL)、乙醇浓度42.86%、提取温度80℃,多酚得率7.96mg/g。在此优化条件下,红松种子壳提取物对羟自由基(甲基紫法)、DPPH·自由基及超氧阴离子均具有较强清除作用,半数抑制浓度分别为6.67×10-4、2.34×10-2、3.97mg/mL。     

响应面法优化块菌多糖的超声波辅助提取工艺

利用响应面分析法对超声波辅助提取块菌多糖的工艺进行优化。在单因素试验的基础上,以超声时间、功率、温度和液料比为自变量,以多糖提取率和多糖含量共为响应值,进行Box-Behnken中心组合试验,回归分析确定最优工艺条件。分析各个因素的显著性和交互作用后,得出最优工艺条件为:超声功率140 W、处理时间36min、处理温度50℃、液料比40∶1,多糖理论提取率为18.42%,实际提取率为18.15%,相对误差为1.47%;多糖理论含量为74.70%,实际含量73.89%,相对误差为1.08%。     

出菇次数调控菌糠基碳孔隙结构与载硫电极储锂性能分析

针对食用菌培养基废弃物（菌糠）的资源浪费与环境污染问题,该研究提出以不同出菇次数菌糠为原材料,高温碳化制备系列菌糠基多孔碳,并应用于锂硫电池正极中作为碳骨架材料,探究出菇次数对孔隙结构和电化学储锂性能的影响。结果表明,出菇1次菌糠基多孔碳为蜂窝状网络结构,出菇3次菌糠基多孔碳为小颗粒状;出菇0、1、3次菌糠基多孔碳比表面积分别为 147.54、270.88和258.39 m2/g;出菇 1 次菌糠基多孔碳具有完整导电网络,载硫后相对于出菇0、3次菌糠基,表现出最高的可逆比容量（916.81 mAh/g）和较好的动力学性能。出菇1次菌糠基多孔碳经KOH活化后,获得具有发达三维孔道的海绵状多孔碳（AMRC-Ⅰ）,比表面积增大为1 591.06 m2/g,孔径2～5 nm的介孔比例为88.03%,初始放电比容量为1 111.31 mAh/g,100 次循环后保持355.99 mAh/g的可逆比容量,循环更加稳定。该研究表明出菇次数可以调控菌糠基多孔碳的微观结构,进而影响载硫正极的电化学储锂性能,可为菌糠废弃物的高价值利用提供新思路。     

稻草秸秆活性炭的制备及其表征

利用廉价的农业废弃物稻草秸秆,选择磷酸氢二铵为活化剂在不同的活化温度和预氧化条件下来制备活性炭。应用N2吸附－脱附等温曲线对产品表面孔结构进行表征,采用热重分析来研究稻草秸秆的活化过程。结果表明,同其他处理方法相比,先浸泡后预氧化处理并在700℃下活化制得的样品不但有最大的比表面积（1078．21m^2·g^-1）,其得率和碘吸附值也最大,分别为39．75％和636mg·g^-1热重分析表明磷酸氧二铵的浸泡可以增加稻草秸秆的热稳定性。不论是否经过预氧化,制得的样品平均孔径在2-3nm。（NH4）2HPO4的浸泡可以明显地增加样品的比表面积从而增加其吸附性能。     

Response surface optimization of cultivation conditions for yield of tomato (Lycopersicon esculentum Mill.) in greenhouses

There is a great potential for greenhouse tomato fruit yield improvement in China for the low yield per hectare. We evaluated the effects of multi-factors (plant density, nitrogen (N) and K₂O fertilizer) on fruit yield of tomato (Lycopersicon esculentum Mill. cv. Jinfan 4) by response surface methodology with a 5-level-3-factor central composite design. A multivariate quadratic regression model of fruit yield was established. Results showed that N fertilizer was the most significant for fruit yield, followed by K₂O fertilizer and plant density. Fruit yield showed a parabolic trend with increasing fertilizer levels or plant density. There was a significant interaction effect between plant density and fertilizer levels. Optimal conditions were obtained: 4.83 × 10⁴ plants ha^?1 for density, 262 kg ha^?1 for N and 513 kg ha^?1 for K₂O. Under these conditions, the predicted fruit yield was 119,381 kg ha^?1, while the actual fruit yield from verification test was 121,005 kg ha^?1.     

土壤矿物吸附和土壤团聚体对土壤有机碳含量的影响研究

Soil organic carbon (SOC) can act as a sink or source of atmospheric carbon dioxide; therefore, it is important to understand the amount and composition of SOC in terrestrial ecosystems, the spatial variation in SOC, and the underlying mechanisms that stabilize SOC. In this study, density fractionation and acid hydrolysis were used to assess the spatial variation in SOC, the heavy fraction of organic carbon (HFOC), and the resistant organic carbon (ROC) in soils of the southern Hulunbeier region, northeastern China, and to identify the major factors that contribute to this variation. The results showed that as the contents of clay and silt particles (0--50 μm) increased, both methylene blue (MB) adsorption by soil minerals and microaggregate contents increased in the 0--20 and 20--40 cm soil layers (P < 0.05). Although varying with vegetation types, SOC, HFOC, and ROC contents increased significantly with the content of clay and silt particles, MB adsorption by soil minerals, and microaggregate content (P < 0.05), suggesting that soil texture, the MB adsorption by soil minerals and microaggregate abundance might be important factors influencing the spatial heterogeneity of carbon contents in soils of the southern Hulunbeier region.     

Clay mineralogy,specific surface area and micromorphology of polygenetic soils from Eastern Kansas

The objective of this study was to evaluate the relationship between clay mineralogy, specific surface area (SSA) and micromorphology in polygenetic Konza soil series. Physical, chemical and mineralogical analyses were performed on disturbed soil samples, and micromorphological investigations of selected horizons were done on undisturbed soil samples. X-ray diffraction indicated that lower part of each parent materials has more mectite and less clay mica content than that of the upper horizons in each parent material. Greater amounts of smectite can be attributed to transformation product of the clay mica in to smectite, eluviation from upper horizons or originated from parent material. Specific surface area of upper horizons in each parent material tended to increase to lower horizons. Clay content gradually increased from surface (21%) to the lower part (～48%) of the solum. Clay in Bt horizons had strong birefrengent, sharp boundary, and strong orientation pattern. SSA, clay content increase, clay mineralogy and oriented clay features agreed to one another. Therefore, this relationship gives opportunity to make predictions on extend of SSA and related soil processes by looking at one of these features.     

Effects of pyrolysis temperature and feedstock type on biochar characteristics pertinent to soil carbon and soil health: A meta-analysis

Biochar amendment to soil is utilized globally as an approach to enhance carbon storage and to improve soil functioning. However, biochar characteristics and related improvements of soil functioning depend on biochar production conditions. Systematic evaluation of corresponding biochar characteristics is needed for more targeted and efficient biochar application strategies. Herein, we systematically review the effects of biochar pyrolysis temperature (175–950°C) and feedstock (corn stover, switchgrass and wood) on selected biochar characteristics (carbon content, H/C ratio, nitrogen content, pH, specific surface area, ash content and pore volume). These specific characteristics were selected as being pertinent to soil organic carbon sequestration and soil health improvement. Despite numerous studies on these topics, few have numerically quantified the effects of pyrolysis temperature. Our results show that high pyrolysis temperature (>500°C) increased carbon content and pore volume for wood biochar compared with low pyrolysis temperature (≤500°C). The high pyrolysis temperature decreased the H/C ratio and nitrogen content but increased pH, specific surface area and ash content regardless of feedstock. Compared with corn stover biochar and switchgrass biochar, wood biochar had higher carbon content and larger specific surface area but lower nitrogen and ash contents regardless of pyrolysis temperature. The higher biochar carbon content might be derived from higher lignin and cellulose contents of wood feedstock. Wood feedstock had 76%–109% more lignin and 27%–47% more cellulose than corn stover and switchgrass. Corn stover biochar had higher pH, and switchgrass biochar had larger pore volume than wood biochar. Our study indicates that the targeted production of biochar with specific characteristics can be facilitated by the selection of pyrolysis temperature and feedstock type. For amending soil with biochar, more operationally defined biochar production conditions and feedstock selection might be a way forward to wider acceptance and better predictability of biochar performance under field conditions.     

固体碳源填充床反应器脱除污水硝态氮效能的预测模型

为了预测固相反硝化反应器出水的硝酸盐浓度,优化工艺参数,以聚羟基丁酸戊酸共聚酯[Poly(3-Hydroxybutyrate-co-3-Hydroxyvalerate),PHBV]作为反应器的碳源和生物膜载体,对受硝酸盐污染的水进行生物反硝化脱氮。采用Box-Behnken试验设计,利用响应曲面法研究了反应器出水硝态氮浓度与进水硝态氮浓度、水力停留时间(hydraulic retention time,HRT)和温度之间的关系,建立了以出水硝态氮浓度为响应值的二次多项式回归模型。该数学模型可以定量描述进水硝态氮浓度、HRT和温度对出水硝态氮浓度的影响,模型预测值与试验值能吻合较好。方差分析结果表明,进水硝态氮浓度、温度和HRT及其交互作用对响应值均具有显著性影响(P<0.05)。