Performance optimization of microbial electrolysis cell (MEC) for palm oil mill effluent (POME) wastewater treatment and sustainable Bio-H2 production using response surface methodology (RSM)

Microbial electrolysis cells (MECs) are a new bio-electrochemical method for converting organic matter to hydrogen gas (H₂). Palm oil mill effluent (POME) is hazardous wastewater that is mostly formed during the crude oil extraction process in the palm oil industry. In the present study, POME was used in the MEC system for hydrogen generation as a feasible treatment technology. To enhance biohydrogen generation from POME in the MEC, an empirical model was generated using response surface methodology (RSM). A central composite design (CCD) was utilized to perform twenty experimental runs of MEC given three important variables, namely incubation temperature, initial pH, and influent dilution rate. Experimental results from CCD showed that an average value of 1.16 m³ H₂/m³ d for maximum hydrogen production rate (HPR) was produced. A second-order polynomial model was adjusted to the experimental results from CCD. The regression model showed that the quadratic term of all variables tested had a highly significant effect (P < 0.01) on maximum HPR as a defined response. The analysis of the empirical model revealed that the optimal conditions for maximum HPR were incubation temperature, initial pH, and influent dilution rate of 30.23 ^°C, 6.63, and 50.71%, respectively. Generated regression model predicted a maximum HPR of 1.1659 m³ H₂/m³ d could be generated under optimum conditions. Confirmation experimentation was conducted in the optimal conditions determined. Experimental results of the validation test showed that a maximum HPR of 1.1747 m³ H₂/m³ d was produced.     

微波辅助固相合成法制备查尔酮类的工艺研究

三种不同方法合成甲氧查尔酮类化合物,筛选和优化合成工艺。采用酸催化高温法、羟基保护法和微波辅助碱催化法进行羟醛缩合反应,制备目标化合物,并以反应产率为指标筛选合成方法,优化反应条件。结果表明:用三种方法所得到的目标化合物产率分别为8.9%、9.27%和57.60%。微波辅助碱催化反应的最佳条件:设定微波功率150 W、反应时间100 s,温度80℃。微波辅助碱催化方法具有产率高、反应时间短、节能和环保等特点、是绿色合成甲氧查尔酮类化合物的有效方法之一。     

芜菁子挥发油、多糖的组成及挥发油抗菌活性的研究

目的用3种方法提取芜菁子挥发油,对挥发油的抗菌作用进行定性和定量分析,并对芜菁子挥发油及多糖的组成进行分析。方法采用水蒸气蒸馏法、溶剂萃取法和同时蒸馏萃取法提取芜菁子挥发油,气相色谱-质谱联用法分析挥发油的组成。运用滤纸片扩散法和二倍稀释法检验芜菁子挥发油对大肠杆菌、金黄色葡萄球菌和绿脓杆菌的抑菌作用。利用水提醇沉法提取残渣中的多糖,酸水解后进行薄层分析。结果 3种方法提取的挥发油分别鉴别出21、7、14种成分。水蒸气蒸馏法提取挥发油中异硫氰酸酯类化合物占45.95%,同时蒸馏萃取法的为31.35%,溶剂萃取法提取挥发油无异硫氰酸酯类化合物。定性定量的抑菌实验结果显示,3种方法所得的挥发油对大肠杆菌、金黄色葡萄球菌和绿脓杆菌均有良好的抑制作用,水蒸气蒸馏法提取的挥发油的抑菌效果最好。在高效G板上,以乙酸乙酯:异丙醇:水=26:14:7(V:V:V)为展开剂,芜菁子多糖的分离效果较好,可鉴别出芜菁子多糖中的果糖和半乳糖。结论芜菁子挥发油对大肠杆菌、金黄色葡萄球菌、绿脓杆菌均有一定的抑制作用,可能与其中含有异硫氰酸酯类和腈类化合物有关。     

Line and point cluster models for spatial health data

Spatial cluster modelling of small area disease incidence and mortality has previously focused on clusters where excess risk is distributed around fixed points, and the aim is the reconstruction of these points (cluster centers). Often there is a need to assess clusters of a different form, such as around roads or river systems. These clusters are often linear or can be approximated by combinations of several linear segments. In this paper the recovery of point and line clusters is considered jointly. An example application is given where both linear or point clustering could be present.     

Layer-by-layer films of chitosan,poly(vinyl sulfonic acid), and platinum for methanol electrooxidation and oxygen electroreduction

We describe an approach for manipulation of biodegradable chitosan and poly(vinyl sulfonic acid) (PVS) in layer-by-layer (LBL) film adsorbed onto gold via ionic attraction. H₂PtCl₆ was deposited onto the LBL film, with chitosan/PVS layers serving as templates to yield metallic platinum. In electrochemical experiments this LBL film exhibited electrochemical stability, low permeability to methanol and conduction/diffusion of proton to maintain the electrolytic connection. The Pt/chitosan/PVS electrode also displayed electroreduction of molecular oxygen. With these features, this Pt/chitosan/PVS film may be used between the catalyst layer and the proton exchange membrane (PEM) in direct methanol fuel cells (DMFC) and biofuel cells.     

A novel approach to synthesizing highly active Ni2P/SiO2 hydrotreating catalysts

Silica-supported nickel phosphide particles with high dispersion were obtained by treating nickel metal particles on a support with 10% PH₃/H₂. Because the phosphidation occurred at relatively low temperature, the small nickel phosphide particles had the same size as the metal particles, and this size was maintained. The resulting catalysts were characterized by CO and O₂ chemisorption, XRD, and ³¹P MAS NMR spectroscopy. The influence of the nickel source on the metal dispersion of the catalysts was investigated. The resulting silica-supported nickel phosphide catalysts proved to be very active in the hydrodesulfurization of dibenzothiophene and the hydrodenitrogenation of o-methylaniline in the presence and absence of H₂S.     

气相色谱-质谱法测定葡萄中苯醚甲环唑的不确定度评定

目的：评定气相色谱-质谱法测定葡萄中苯醚甲环唑时的不确定度。方法：根据GB 23200.8—2016 《食品安全国家标准 水果和蔬菜中500种农药及相关化学品残留量的测定 气相色谱-质谱法》建立模型,根据JJF 1059.1—2012《测量不确定评定和表示》对不确定度来源进行分析量化。结果：本方法测定苯醚甲环唑的合成不确定度为2.258%,扩展不确定度为0.0451,葡萄中苯醚甲环唑测定结果为（0.06047±0.00273）mg/kg,k=2。结论：本方法不确定度主要来源为标准溶液配制及其曲线拟合,重复性测定对实验结果准确性影响较小。     

Precursors of the zeolite ZSM-5 imaged by Cryo-TEM and analyzed by SAXS

The microstructural evolution in the nucleation stage of a synthesis reaction of ZSM-5 zeolite was studied, with particular emphasis on the role of the organic cation, TPA⁺ (tetrapropylammonium). Direct observation of the microstructure was achieved by cryo-transmission electron microscopy (cryo-TEM). The quantitative evaluation of the structural units was obtained by small-angle X-ray scattering (SAXS) measurements. In the presence of the organic cation TPA⁺, we found globular structural units 5 nm in diameter that aggregate to elongated bodies 44 nm long. The globular structural units were found in reaction mixtures with or without the organic template TPA-OH, as long as the pH of the initial solution was kept above 11.6. Without TPA⁺, aggregation to cylindrical particles was not observed after 2 h of heating, and no ZSM-5 crystallinity was attained at the end of the reaction (after 8 d). These results suggest that the zeolite ZSM-5 building blocks are globular structural units, 5 nm in diameter, containing silica, alumina, organic cation, and water, which fuse together to produce elongated aggregates that may compose the final unit cell. It is concluded that the globular structural unit is a cluster of tetrapods similar to those found in the final ZSM-5 crystals.     

Review of the structural characterization,quality evaluation,and industrial application of Lycium barbarum polysaccharides

BackgroundLycium barbarum polysaccharides (LBPs) are considered to be the major bioactive components in L. barbarum. Due to the considerable health benefits of LBPs, and the significant research interest in LBPs, quality evaluation of LBPs and their related products is imperative for ensuring their efficacy and safety. The bioactivities of polysaccharides are closely associated with their physicochemical properties, which can be easily monitored via chemical techniques. Therefore, analysis of physicochemical properties is a more straightforward and viable approach for the quality control of polysaccharides.Scope and approachIn this review, special techniques for the structural characterization of LBPs are summarized and discussed. In addition, quality evaluation approaches of LBPs that have never been emphasized are highlighted herein. Furthermore, industrial applications of LBPs are reviewed and discussed.Key findings and conclusionsHigh-performance anion-exchange chromatography coupled with pulsed amperometric detection is one of the most effective techniques for analysis of both acidic and neutral LBPs. Size-exclusion chromatography coupled with multi-angle laser light scattering and refractive index detection is able to determine absolute molecular weights, chain conformations, and contents of LBPs. Fingerprinting analysis and saccharide mapping analysis are effective approaches for quality evaluation of LBPs. However, the lack of appropriate quality evaluation approaches indicates an unreliable regulation of LBPs and their related products. This reveals the deficiency in the quality control of commercial products. Thus, the development of reliable approaches for pharmacological activity-based quality control of LBPs and their related products must be extensively investigated.     

新疆胡萝卜籽油脂肪酸GC-MS分析

采用索氏提取法从两种新疆胡萝卜籽中提取油脂,并通过GC-MS对两种胡萝卜籽油中的脂肪酸组成及其相对含量进行了分析.结果表明:两种胡萝卜籽油中脂肪酸组成主要为油酸、亚油酸、棕榈酸、硬脂酸,其不饱和脂肪酸含量较高,且油酸含量超过75％.