Critical parameters in cost-effective alkaline extraction for high protein yield from leaves

Leaves are potential resources for feed or food, but their applications are limited due to a high proportion of insoluble protein and inefficient processing. To overcome these problems, parameters of alkaline extraction were evaluated using green tea residue (GTR). Protein extraction could be maximized to 95% of total protein, and, after precipitation by pH adjustment to 3.5, 85% of extracted protein was recovered with a purity of 52%. Temperature, NaOH amount, and extraction time are the protein yield determining parameters, while pH and volume of extraction liquid are critical parameters for production cost. The cost of energy and chemicals for producing 1 t GTR proteins is minimized to 102€, and its nutritional value is comparable to soybean protein. Furthermore, this technology was successfully applied to other sources of biomass and has potential to be used as a part of an integrated bio-refinery process.     

凹凸棒石-针铁矿改性麦秸木质陶瓷的微观结构

以凹凸棒石、针铁矿和小麦秸秆为原料,添加少量的环氧树脂作为黏结剂,在适宜的温度和气氛下煅烧,同步完成了生物质碳化、凹凸棒石热活化及针铁矿的还原,获得了具有高气孔率和强磁性的凹凸棒石-针铁矿改性麦秸木质陶瓷,利用XRD和SEM分析了原料质量比及焙烧温度对其物相及微观结构的影响。结果表明:凹凸棒石-针铁矿改性麦秸木质陶瓷是一种非晶态多孔质碳素材料,在相同温度下,原料的质量比对其物相几乎无影响;随着焙烧温度的升高,凹凸棒石的特征衍射峰逐渐消失,凹凸棒石-针铁矿改性麦秸木质陶瓷中有新的物相产生。     

污泥干化芦苇床芦苇中多环芳烃的含量分布

通过现场试验,考查了多环芳烃（PAHs）从污泥向芦苇的转移以及PAHs在芦苇各部位的分布情况。受试芦苇植于污泥干化芦苇床内,芦苇床规格3 m×1 m×1.3 m,其中高度含0.65 m填料层和0.65 m超高。试验进行了3 a,包括2 a的污泥负荷期和1 a的闲置期。2 a负荷期内共进泥8.4 m(含水率99.14%),污泥PAHs含量平均5.69 mg·kg -1。原生芦苇茎和叶中的PAHs含量相对较高,达到2.198和2.583 mg·kg -1 (DW),分别是芦苇根PAHs含量的2.44和2.87倍,且以低环PAHs为主。运行结果表明,受试芦苇对污泥中的PAHs产生了明显的富集作用。运行第2年9、10和11月取污泥干化芦苇床芦苇样品并进行检测,发现芦苇根茎叶内PAHs含量呈逐月升高趋势;第3年11月芦苇根茎叶所含PAHs总量分别为7.642、7.713、7.946 mg·kg -1 (DW),相对原生芦苇分别提高了8.50、3.52和3.08倍,且以低环PAHs为主,根茎叶低环PAHs含量占PAHs总量的55.14%、56.96%和44.59%。芦苇中PAHs的含量与植物含脂率具有显著的正相关关系,而与芦苇的含水量无关。     

A new application of giant reed waste material for ammonium removal

Excess nitrogen is one of the main causes of eutrophication in water bodies. In this study, the undesirable agricultural lignocellulosic material giant reed was used to remove ammonium ions from aqueous solutions. Batch experiments were conducted to investigate the effect of various parameters such as contact time, initial ammonium concentration, adsorbent dosage, pH, particle size, agitation rate and phosphate coexisting during the ammonium adsorption process. The ammonium sorption capacity of fibrous giant reed (FGR) at equilibrium was 12.49?mg?N/g with a maximum removal efficiency of 76% observed within 30?min at pH range of 6.5–9.5. Results revealed that the Freundlich isotherm model fitted better with the sorption process than the Langmuir model, and the adsorption process was well described by pseudo-second-order kinetic model. FT-IR analyses indicated that complexation and ion exchange could be the main mechanisms for the ammonium removal by FGR. Results revealed that FGR has a sorption capacity comparable to that of other natural sorbents with the advantage of greater availability with no cost.     

脱硫石膏-秸秆新型复合墙体材料性能的研究

介绍了一种新开发的轻质墙体材料.这种墙体材料由脱硫石膏和秸秆按一定比例组合并掺入适量外加剂加水拌合而成.其质量轻(干密度仅为720 kg/m3),有足够的强度(1～3 d强度大于10 MPa,14 d强度大于20 MPa),耐久性好.脱硫石膏-秸秆复合料处于碱性环境下(浆液pH值=11),秸秆不易腐蚀,潮湿环境下也有较好的耐久性.由于脱硫石膏是电厂烟气脱硫的副产品,秸秆是收获果实后的废弃物,因此,新开发墙体材料的推广应用极有助于减轻或避免烟气中SO2和秸秆燃烧烟尘对大气的污染,以及对其它方面造成的损害.     

PVC/秸秆类纤维复合材料性能

为比较不同秸秆类(芦苇秸秆、稻秸秆、麦秸秆)纤维对其制备复合材料性能的影响,以芦苇秸秆、稻秸秆、麦秸秆为填充材料,以聚氯乙烯(PVC)为基体材料,采用挤出成型工艺制备3种PVC/秸秆类纤维复合材料。对3种秸秆纤维进行了成分分析,对它们制备的复合材料进行了力学性能和吸水性能测试,并对3种复合材料进行了FTIR分析,用SEM观察了复合材料拉伸断面微观结构。结果表明,3种秸秆类纤维中,芦苇秸秆的纤维素、半纤维素和木质素含量最高,其制备的PVC复合材料结合界面和力学性能最佳,PVC/芦苇秸秆纤维复合材料拉伸、弯曲和冲击强度分别为36.79 MPa,67.19 MPa和7.01 k J/m2,比PVC/麦秸秆纤维复合材料分别提高了104.62%,89.7%,99.72%。3种PVC/秸秆类纤维复合材料中PVC/芦苇秸秆纤维复合材料24 h吸水率最低,比PVC/麦秸秆纤维复合材料降低67.36%。     

Optimization of the technological properties of porcelain tile bodies containing rice straw ash using the design of experiments methodology

This study examines the effects of replacing fluxing and filler materials with rice straw ash (RSA) in manufacturing porcelain stoneware tile, using the design of experiments (DOE) methodology. The results of the characterization were used to obtain statistically significant, valid regression equations, relating the technological properties of the dried and fired test pieces to the raw materials content in the unfired mixtures. The regression models were analysed in relation to the X-ray diffraction and scanning electron microscopy results and used to determine the most appropriate combinations of traditional raw materials and RSA to produce porcelain stoneware tiles with specific technological properties. The studied range of tile body compositions: clay (40 wt%), feldspar (20–50 wt%), feldspathic sand (5–20 wt%), and RSA (0–25 wt%) was shown to be appropriate for porcelain stoneware tile manufacture.     

Purification of Biorefinery Lignin with Alcohols

After hydrothermal pretreatment and enzymatic hydrolysis of wheat straw, a slurry rich in lignin but with a high content of inorganic substances, especially silica, and residual carbohydrates is produced. This slurry was used to develop an ethanol organosolv separation method to produce silica-free lignin fractions. The addition of para toluene sulphonic acid (PTSA) and the use of two alternative long-chain alcohols, oleyl alcohol or nonylphenol, were tested. In every reaction, two lignin fractions were produced and their molecular size and elemental composition were characterized. The yield of each fraction and the change in MWD were studied as a function of temperature and solid to liquid ratio. At 100, 150, and 200°C and with the use of PTSA, high-purity lignin fractions were obtained. After lignin fractionation with nonylphenol, a liquid silica-free product with high lignin content was obtained in yields between 17 and 72%.     

玉米秸秆热解特性及动力学分析

以玉米秸秆为原料, 利用热重分析法研究其热解的特性及动力学。根据TG和DTG曲线, 研究玉米秸秆的热解特性, 采用Flynn-Wall-Ozawa(FWO)和Kissinger-Akahira-Sunose(KAS)两种等转化率法计算玉米秸秆热解的活化能, 并结合主曲线法和Coats-Redfern(C-R)法探讨了玉米秸秆热解遵循的机理方程。研究结果表明: 玉米秸秆热解过程可分为干燥脱水、过渡、主热解和炭化4个阶段, 随着热解升温速率增大, TG和DTG曲线向高温侧偏移; 利用FWO和KAS法计算得到的表观活化能分别为181.7和181.5 kJ/mol; 利用主曲线法和C-R法求解出玉米秸秆热解的机理方程遵循Avrami-Erofeev方程, 当α=0.1~0.5时, n=3, f(α)=1/3(1-α)[-ln(1-α)]^-2; 当α=0.5~0.7时, n=2, f(α)=1/2(1-α)[-ln(1-α)]^-1。