Preparation and Characterization of MgO-Modified Rice Straw Biochars

Rice straw is a common agricultural waste. In order to increase the added value of rice straw and improve the performance of rice straw biochar. MgO-modified biochar (MRBC) was prepared from rice straw at different temperatures, pyrolysis time and MgCl₂ concentrations. The microstructure, chemical and crystal structure were studied using X-ray diffraction (XRD), a Scanning Electron Microscope (SEM), Fourier transform infrared spectroscopy (FTIR), nitrogen adsorption desorption isotherms and Elementary Analysis (EA). The results showed that the pyrolysis temperature had significant influence on the structure and physicochemical property of MRBCs. MRBC-2 h has the richest microporous structure while MRBC-2 m has the richest mesoporous structure. The specific surface area (from 9.663 to 250.66 m²/g) and pore volume (from 0.042 to 0.158 cm³/g) of MRBCs increased as temperature rose from 300 to 600 °C. However, it was observed MgCl₂ concentrations and pyrolysis time had no significant influence on pore structure of MRBCs. As pyrolysis temperature increased, pH increased and more oxygen-containing functional groups and mineral salts were formed, while MgO-modified yield, volatile matter, total content of hydrogen, oxygen, nitrogen, porosity and average pore diameter decreased. In addition, MRBCs formed at high temperature showed high C content with a low O/C and H/C ratios.     

麦草造纸黑液中木质素的提取及结构分析

采用有机溶剂萃取的方法从麦草造纸黑液中提取木质素,并采用红外光谱（FT—IR）、^1H NMR、紫外光谱等方法对其结构进行了表征．试验表明,所提取的木质素具有明显的紫丁香基和愈疮木基苯环结构．同时测定了木质素的元素组成和甲氧基含量,并计算得到经典的C9结构模型,其结构形式为C9H8.89O1.17（OCH3）1.39.     

环氧氯丙烷改性稻草

环氧氯丙烷改性稻草;稻草;环氧氯丙烷;醚化;改性     

水葫芦木质素的提取及其苯胺吸附性能

采用碱提法从生态入侵植物水葫芦中提取木质素,利用傅立叶红外光谱(FT-IR)和扫描电镜(SEM)等手段对所获得的木质素进行表征,研究了水葫芦木质素对水中苯胺的吸附性能,考察了溶液p H值、吸附时间、初始浓度等因素对水葫芦木质素吸附苯胺的影响。当Na OH溶液浓度0.1 mol/L,提取时间4 h,温度100℃,料液比1∶20时,水葫芦木质素的收率最大为6.81%。红外图谱显示,在1 456~1 656 cm-1处存在木质素的芳香环骨架振动吸收峰;扫描电镜显示,木质素呈大量细小的颗粒,木质素颗粒表面存在许多微小的孔状结构,有利于吸附作用的发生。在室温下,溶液p H 6.0,苯胺初始浓度为150 mg/L,吸附剂用量为5 mg,吸附时间120 min时,水葫芦木质素对苯胺的最大吸附容量为12.2 mg/g。苯胺吸附实验数据拟合符合准二级动力学模型以及Langmuir吸附等温模型。水葫芦木质素对苯胺的吸附以单分子层化学吸附为主,属于优惠吸附。相同吸附条件下,水葫芦木质素对湖泊水样中苯胺的吸附与实验模拟水样的吸附效果相近。水葫芦木质素可作为富集分离材料用于分析样品制备以及水中污染物的吸附。     

水稻秸秆石油醚和乙醇萃取物的组成分析

用石油醚和乙醇在索式萃取器中对水稻秸秆进行了萃取,萃取物用傅里叶转换红外光谱仪（FTIR）和气相色谱 质谱联用仪（GC/MS）分析。 结果表明,乙醇和石油醚的萃取率分别为8%和6%。 萃取物中共检测到40种物质,主要分为醇酚（APs）、醛、酮、酸、酯、烃（HCs）及含氮化合物（ONs）7种类别。 其中,石油醚萃取物中酯、HCs和APs 3类物质含量较高,总的相对含量为91.7%;乙醇萃取物中HCs、酸、酯及APs含量较高,总的相对含量为83.9%。 该研究在开发稻秆的高附加值利用方面具有重要的基础理论意义。     

麦草碱木素及其热化学降解产物相对分子质量分布的测定

以pH=10的0．1mol/L NaNO3溶液为流动相，在Ultrahydrogel柱上测定麦草碱木素及其热化学降解产物的相对分子质量分布，测定碱木素降解产物所用洗脱液宜用pH10的0．1mol/LNaNO3水溶液，比较了由于样品结构特性和物理性质差异而造成的流动行为的差异，并确定两种样品各自的色谱条件。     

水稻秸秆的改性及其对重金属Cu2+的吸附

重金属Cu2+可直接或间接危害人体,作为天然吸附剂的农业废弃物因价廉易得、来源广泛、吸附高效等优点备受青睐。本文选用水稻秸秆（RS）为吸附原料,分别经酸、碱改性后得到H2SO4-RS和NaOH-RS,通过FT-IR、SEM和BET对改性前后吸附材料的表面官能团、表观形貌和结构等理化性质进行分析,考察投加量、吸附时间、初始Cu2+浓度和离子强度对吸附效果的影响,并结合吸附动力学、吸附等温线和热力学模型对吸附过程进行探讨。结果表明：改性水稻秸秆对Cu2+达到吸附平衡所需的投加量和时间较之未改性RS大大减少,去除率由42.0%分别提升至85.9%（H2SO4-RS）和90.0%（NaOH-RS）;随初始Cu2+浓度和离子强度的增大,RS的吸附性能显著降低,H2SO4-RS有所降低,而NaOH-RS只是稍有下降,NaOH-RS对150 mg/L含Cu2+溶液的去除率仍达到84.2%,离子强度cNaCl = 0.1 mol/L时去除率维持在86.1%。吸附动力学和吸附等温实验表明水稻秸秆对Cu2+的吸附符合准二级动力学模型和Langmuir吸附等温模型;热力学分析显示,相同温度下RS、H2SO4-RS和NaOH-RS吸附Cu2+过程的ΔG逐渐减小,且改性后两种吸附剂的ΔG均小于0,ΔH由改性前的正值转变为负值,说明水稻秸秆改性后吸附Cu2+的自发性更强,为自发的放热过程。     

Adsorption of Hazardous Azorhodanine Dye from an Aqueous Solution Using Rice Straw Fly Ash

The potential of using rice straw fly ash (RSFA) as low-cost adsorbents for the removal of hazardous azorhodanine (AR) dye from aqueous solution was investigated. The effects of different variables in the batch method as a function of solution pH, contact time, concentration of adsorbate, adsorbent dosage, and temperature were investigated, and optimal experimental conditions were ascertained: 0.05 g for initial dye concentration of 20–100 mg/L at pH 2. The experimental equilibrium data were tested by the isotherm models, namely the Langmuir and Freundlich adsorption and the isotherm constants were determined. The kinetic models, pseudo-first-order and pseudo-second-order, were employed to analyze the kinetic data. The activation energy of adsorption was also evaluated and found to be +10.89 kJ.mol^?1, indicating that the adsorption is physisorption. Various thermodynamic parameters, such as Gibbs free energy, entropy, and enthalpy of the ongoing adsorption process, have been calculated and found to be spontaneous and exothermic, respectively.     

稻壳中乳突状硅质体的提取与表征

利用湿化学法从稻壳中提取了乳突状硅质体，并利用TEM、小角XRD和NMR等手段对其进行了表征。实验结果表明乳突状硅质体是一种由平均粒径为3.6 nm的SiO2纳米粒子组成的非晶介孔材料。氮吸附-脱附测量表明硅质体的BET比表面积为355.9 m2/g， 平均孔径为5.8 nm。     

Selective Supercritical CO2 Extraction and Biocatalytic Valorization of Cucurbita pepo L. Industrial Residuals

The valorization of biomass residuals constitutes a key aspect of circular economy and thus a major challenge for the scientific community. Among industrial wastes, plant residuals could represent an attractive source of bioactive compounds. In this context, a residue from the industrial extraction of Cucurbita pepo L. seeds, whose oil is commercialized for the treatment of genito-urinary tract pathologies, has been selected. Supercritical CO₂ technology has been employed as a highly selective “green” methodology allowing the recovery of compounds without chemical degradation and limited operational costs. Free fatty acids have been collected in mild conditions while an enrichment in sterols has been selectively obtained from sc-CO₂ extracts by appropriate modulation of process parameters (supercritical fluid pressure and temperature), hence demonstrating the feasibility of the technique to target added-value compounds in a selective way. Obtained fatty acids were thus converted into the corresponding ethanol carboxamide derivatives by lipase-mediated biocatalyzed reactions, while the hydroxylated derivatives of unsaturated fatty acids were obtained by stereoselective hydration reaction under reductive conditions in the presence of a selected FADH₂-dependent oleate hydratase.     

Modification of Rice Straw for Heavy Metal Ion Adsorbents by Microwave Heating

Summary: Cellulose in rice straw was chemically modified by phosphorylation using conventional heating or microwave heating. Rice straw pretreated by NaOH solution gave the highest phosphorus content when it was phosphorylated using microwave heating at 450 watt (7.07%P, ion exchange capacity 2.60 meq/g). The 3 hour-reaction in oil bath yielded the modified rice straw with lower of phosphorus content (6.32%P) and higher ion exchange capacity (2.99 meq/g) than that of microwave heating. The feasibility of the modified rice straw as cation sorbents for removing heavy metal was investigated. Cd²⁺, Cr³⁺ and Pb²⁺ were used as sorbates. In sorption test of 40 ppm with 2.0 g/L of the modified rice straw, both modified rice straws could adsorb metal ions faster than the commercial ion exchange resin (dowax) at the time less than 60 min. The modified rice straw prepared by microwave heating (A-MCW2) could remove 90% of Cd²⁺ and Cr³⁺ in 60 minutes and remove 99% of Pb²⁺ after 30 min.     

Preparation and Evaluation of Carboxymethylated Lignin as Dispersant for Aqueous Graphite Suspension Using Turbiscan Lab Analyzer

Carboxymethylated lignin (CML) was prepared from wheat straw alkali lignin (WAL) via carboxymethylation modification. The characterizations using FTIR, ¹³C NMR, and ¹H–¹³C HSQC NMR suggest that carboxyl groups are introduced into WAL structure successfully and there are two different active sites substituted by carboxymethyl groups. Moreover, the dispersion efficiency of CML was evaluated using the Turbiscan Lab analyzer. Effects of CML dosage and suspension pH on the dispersion stability of aqueous graphite suspension were investigated. The result shows that the dispersion stability of aqueous graphite suspension prepared with CML of 1.0% dosage at suspension pH 6.7 is obviously improved.      

木质素热解生物油组成成分与分子尺寸分布特性分析

选用脱碱木质素作为原料,以热裂解气质联用技术(Py-GC/MS)研究木质素在350～600℃下热解产物成分和含量,并利用Joback法、 Lijie法和Tahami法3种基团贡献法计算了生物油各组成成分的临界参数和动力学直径,对木质素热解油产物的分子动力学直径分布特性进行计算.结果显示,愈创木基结构、紫丁香基结构、苯酚类、邻苯二酚类和芳烃类等5种芳香族化合物是350～600℃下木质素热解生物油的主要组成成分,其中愈创木基结构化合物的平均峰面积百分比达到70.7%.随着反应温度从350提高到600℃,分子动力学直径在0.560～0.610 nm区间内的木质素热解油组分含量从14.6%增加至31.3%.木质素热解生物油主要产物的动力学直径在0.560～0.710nm,表明一些孔径尺寸在此范围内的分子筛如SSZ-20、 ZSM-5和Beta可作为木质素裂解制备高品质芳烃燃料的催化剂.     

磷酸丙酮法木质纤维素预处理中木质素的分离与表征

在木质纤维素制取乙醇过程中,合理高效地分离出木质素并加以利用,可以提升纤维乙醇整体工艺的经济性。 以杨木粉为原料,从木质素产率和改性程度的角度出发,分析对比了3种预处理方法所提取的木质素。 结果表明,磷酸丙酮法所得木质素产率达到15%~25%,碱法蒸煮法和有机溶剂所得木质素仅占到9.58%和13.47%。 红外吸收光谱结果表明,磷酸丙酮木质素在1608、1507和1463 cm-1等处具有相对最强的吸收信号,在1650 cm-1处也有共轭羰基吸收峰,因此磷酸丙酮木质素的改性程度相对较小,核磁共振氢谱表征也同时验证了这一结果,这种木质素适于进一步的开发利用。 低压常温下的磷酸丙酮预处理方法可以有效提升纤维乙醇工艺的经济性。     

对甲苯磺酸掺杂聚吡咯的合成、表征及其对金属镁的防腐蚀性能研究

以对甲苯磺酸为掺杂剂, 三氯化铁为氧化剂, 化学氧化吡咯制备了对甲苯磺酸掺杂聚吡咯. 考察了掺杂剂与氧化剂的用量对掺杂聚吡咯电导率的影响, 得到了高电导率聚吡咯的优化条件, 用UV, IR和SEM对其结构和形貌进行了表征. 结果表明, n(对甲苯磺酸)∶n(吡咯)∶n(三氯化铁)＝0.75∶1∶0.5时, 合成的聚吡咯的形貌规则, 电导率达42.7 S•cm^－1. 以聚吡咯为功能成分, 环氧树脂为成膜物质, 得到一种功能膜, 旋涂于金属镁表面, 采用极化曲线和开路电位考察了含有聚吡咯的膜层对金属镁的防腐蚀性能. 结果表明, 含有聚吡咯的膜层对金属镁有很好的防腐蚀性能, 腐蚀电流为0.0981 A, 腐蚀电位为－0.88 V, 在膜层与金属镁之间形成了一层钝化膜.     

Effects of Rice Straw Powder (RSP) Size and Pretreatment on Properties of FDM 3D-Printed RSP/Poly(lactic acid) Biocomposites

To develop a new kind of environment-friendly composite filament for fused deposition modeling (FDM) 3D printing, rice straw powder (RSP)/poly(lactic acid) (PLA) biocomposites were FDM-3D-printed, and the effects of the particle size and pretreatment of RSP on the properties of RSP/PLA biocomposites were investigated. The results indicated that the 120-mesh RSP/PLA biocomposites (named 120#RSP/PLA) showed better performance than RSP/PLA biocomposites prepared with other RSP sizes. Infrared results showed that pretreatment of RSP by different methods was successful, and scanning electron microscopy indicated that composites prepared after pretreatment exhibited good interfacial compatibility due to a preferable binding force between fiber and matrix. When RSP was synergistically pretreated by alkaline and ultrasound, the composite exhibited a high tensile strength, tensile modulus, flexural strength, and flexural modulus of 58.59, 568.68, 90.32, and 3218.12 MPa, respectively, reflecting an increase of 31.19%, 16.48%, 18.75%, and 25.27%, respectively, compared with unmodified 120#RSP/PLA. Pretreatment of RSP also improved the thermal stability and hydrophobic properties, while reducing the water absorption of 120#RSP/PLA. This work is believed to provide highlights of the development of cost-effective biocomposite filaments and improvement of the properties of FDM parts.     

Preparation and Characterization of Size-Controlled Lignin Nanoparticles with Deep Eutectic Solvents by Nanoprecipitation

Lignin nanomaterials have wide application prospects in the fields of cosmetics delivery, energy storage, and environmental governance. In this study, we developed a simple and sustainable synthesis approach to produce uniform lignin nanoparticles (LNPs) by dissolving industrial lignin in deep eutectic solvents (DESs) followed by a self-assembling process. LNPs with high yield could be obtained through nanoprecipitation. The LNPs were characterized by dynamic light scattering (DLS), transmission electron microscopy (TEM), scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), and gel permeation chromatography (GPC). Distinct LNPs could be produced by changing the type of DES, lignin sources, pre-dropping lignin concentration, and the pH of the system. Their diameter is in the range of 20–200 nm and they show excellent dispersibility and superior long-term stability. The method of preparing LNPs from lignin–DES with water as an anti-solvent is simple, rapid, and environmentally friendly. The outcome aids to further the advancement of lignin-based nanotechnology.     

对甲苯磺酸掺杂聚吡咯的合成、表征及其对金属镁的防腐蚀性能研究

以对甲苯磺酸为掺杂剂, 三氯化铁为氧化剂, 化学氧化吡咯制备了对甲苯磺酸掺杂聚吡咯. 考察了掺杂剂与氧化剂的用量对掺杂聚吡咯电导率的影响, 得到了高电导率聚吡咯的优化条件, 用UV, IR和SEM对其结构和形貌进行了表征. 结果表明, n(对甲苯磺酸)∶n(吡咯)∶n(三氯化铁)＝0.75∶1∶0.5时, 合成的聚吡咯的形貌规则, 电导率达42.7 S•cm^－1. 以聚吡咯为功能成分, 环氧树脂为成膜物质, 得到一种功能膜, 旋涂于金属镁表面, 采用极化曲线和开路电位考察了含有聚吡咯的膜层对金属镁的防腐蚀性能. 结果表明, 含有聚吡咯的膜层对金属镁有很好的防腐蚀性能, 腐蚀电流为0.0981 A, 腐蚀电位为－0.88 V, 在膜层与金属镁之间形成了一层钝化膜.     

木质素负载钯催化剂的制备及对Heck反应的催化性能

以天然木质素和PdC l2为原料,合成了木质素负载钯催化剂,用IR、XPS、TG、DTA等对其进行了表征.研究表明,该催化剂在空气氛围中能催化丙烯酸与芳基碘的Heck反应,并有一定的重复使用性能.