Transformation mechanism of nutrient elements in the process of biochar preparation for returning biochar to soil

Returning biochar to soil is a heavily researched topic because biochar functions well for soil improvement. There is a significant loss of nutrients, which occurs during biochar preparation before biochar is returned to soil,thereby seriously undermining biochar's efficacy. Therefore, the transformation mechanisms of biochar p H,mass, nutrients and metals during pyrolysis under different atmospheres and temperatures were studied such that the best method for biochar preparation could be developed. Several conclusions can be reached:(1) a CO_2 atmosphere is better than a N_2 atmosphere for biochar preparation, although preparation in a CO_2 atmosphere is not a common practice for biochar producers;(2) 350 °C is the best temperature for biochar preparation because the amount of nutrient loss is notably low based on the premise of straw transferred into biochar; and(3) transforming mechanisms of pH, N, P and K are also involved in the biochar preparation process.     

V-P-O催化剂制备方法研究进展

简要介绍了五种V-P-O催化剂的制备方法(传统法、气溶胶法、火焰沉积法、气相法和固态法)和三种耐磨催化剂的制备方法(浸渍法、包容法、嵌入法)。传统法是制备V—P-O催化剂最基本的方法;气溶胶工艺是一种快速干燥制备催化剂的方法;火焰沉积技术是制备纳米级钒磷氧化物的方法之一。     

Application of the seed-film method for the preparation of structured molecular sieve catalysts

The seed-film method has been applied for the preparation of various materials of potential interest as structured molecular sieve catalysts. The method has proven to be very flexible and allows for the reproducible preparation of a number of molecular sieve–substrate combinations as well as the control of the materials’ properties of importance in catalytic applications such as zeolite loading, film thickness, film density and crystal orientation. The preparation of thin molecular sieve films on ceramic foams, -alumina pellets and porous alumina supports as well as various metal surfaces is described. The preparation of zoned coatings with a compositional gradient is also discussed.     

Elucidating the unintentional p-type nature of spinel Co3O4: A defect study using ab-initio calculation

Co₃O₄ is one of the most widely used materials in energy and environmental field due to its unintentional p-type nature, which depends on the preparation conditions. In this study, we investigated the origin of the unintentional p-type conductivity of Co₃O₄ by calculating all possible intrinsic point defects. We found that the octahedral cobalt vacancy and tetrahedral cobalt vacancy are the sources of unintentional p-type doping. Using charge balance theory, we analyzed the effect of preparation condition on intrinsic defect-induced doping. In most of preparation condition, the formation of these cobalt vacancies plays a dominant role and the spontaneous formation of p-type doping is unavoidable. However, if there is ample oxygen and the temperature is low during the preparation, the unintentional p-type doping can be avoided. This theoretical work on defects provides a crucial clue to optimize Co₃O₄ for various electrochemical applications.     

In Situ Monitoring of Lipid Phase State Make Target Lipid Mixtures Similar to Intercellular Lipid in the Stratum Corneum

In this study, lipid structural change is monitored using Raman spectroscopy during heat treatment, along with the impact of lipid states on the structural and physical properties during the preparation process of the dried and hydrated lipid mixture (LM) similar to intercellular lipid in stratum corneum. The microstructures and thermal behavior of these LMs change depending on the melting of lipid ingredients in the preparation process. It is recognized that variable temperature Raman spectroscopy (VT‐Raman) is a useful and attractive tool for the sensitive in situ monitoring of lipid state changes and lipid melting. The LMs can incorporate D₂O into their structures regardless of preparation temperature due to increasing lattice distance by hydration. These results suggest that monitoring lipid structural changes during the heating step is important to precisely prepare target LMs. Practical Applications: This study reveals that VT‐Raman is a useful and attractive tool in in situ monitoring of lipid state change and lipid melting. The monitoring of the preparation process by VT‐Raman is necessary to precisely prepare the target LM similar to intercellular lipid of stratum corneum because the microstructures and thermal properties of these LMs change depending on the melting of lipid ingredients during the preparation process.     

Au/ZnO and Au/Fe2O3 catalysts for CO oxidation at ambient temperature: comments on the effect of synthesis conditions on the preparation of high activity catalysts prepared by coprecipitation

The preparation of Au/ZnO and Au/Fe₂O₃ catalysts using two coprecipitation methods is investigated to determine the important factors that control the synthesis of high activity catalysts for the oxidation of carbon monoxide at ambient temperature. In particular, the factors involved in the preparation of catalysts that are active without the need for a calcination step are evaluated. The two preparation methods differ in the manner in which the pH is controlled during the precipitation, either constant pH throughout or variable pH in which the pH is raised from an initial low value to a defined end point. Non-calcined Au/ZnO catalysts prepared using both methods are very sensitive to pH and ageing time, and catalysts prepared at a maximum pH = 5 with a short ageing time (ca. 0–3 h) exhibit high activity. Catalysts prepared at higher pH give lower activity. However, all catalysts require a short operation period during which the oxidation activity increases. In contrast, the calcined catalysts are not particularly sensitive to the preparation conditions. Non-calcined Au/Fe₂O₃ catalysts exhibit high activity when prepared at pH ≥ 5. Calcined Au/Fe₂O₃ prepared using the controlled pH method retain high activity, whereas calcined catalysts prepared using the variable pH method are inactive. The study shows the immense sensitivity of the catalyst performance to the preparation methods. It is therefore not surprising that marked differences in the performance of supported Au catalysts for CO oxidation that are apparent in the extensive literature on this subject, particularly the effect of calcination, can be expected if the preparation parameters are not carefully controlled and reported.     

Development of high performance catalysts for the production of vinyl acetate monomer

Two types of highly active and selective vinyl acetate monomer (VAM) catalysts have been developed in our lab via traditional lab preparation and high-pressure reactor performance test methods. Experimental results are presented here. Degussa is now engaged in high-throughput (HT) VAM catalyst powder preparation and HT (50 parallel reactor) testing to accelerate the development of new higher performing commercial catalysts. Our first results on HT are presented here. Though HT systems in both catalyst preparation and testing have existed for over a decade, HT heterogeneous catalyst preparation methods have been very slow to develop. The HT preparation system described here provides a versatile method of preparing commercially relevant catalysts as required by Degusssa. The HT reactor test system described here uses plant operating conditions and provides reliable STY and selectivity data on par with that obtained from conventional lab VAM test systems. Both the HT preparation and HT test systems combined allow for significant increases in the commercialization rate of new catalysts.     

Tunning the Nb addition to Sb-V-O catalysts for an efficient promotion of the ammoxidation of propane to acrylonitrile

The effect of niobium dopant on Sb-V oxide catalysts supported on alumina is reported with the purpose of understanding the promoting effect of Nb and preventing the non-desired inert SbNbO₄ phase. Two different catalyst syntheses have been tested: the most common in which Sb is added as Sb₂O₃ suspension and a novel one in which it is molecularly dissolved as a tartrate complex. The effect of adding Nb to alumina-supported Sb-V oxide catalysts depends on the preparation method. The preparation via Sb₂O₃ suspension affords segregated Sb oxide, which results in lower Sb-V interaction. The preparation via Sb tartrate complex affords molecularly dissolved Sb species that combine more easily with V or Nb species. The higher dispersion of Sb in the tartrate method also promotes its interaction with Nb dopant. The Sb tartrate preparation method is preferred for binary Sb-V supported oxide catalyst, while the Sb₂O₃ suspension method is preferred for Nb-promoted Sb-V supported oxide catalyst, which results in a very efficient catalyst for propane ammoxidation.     

生物质基葡萄糖二酸的研究与展望

葡萄糖二酸是一种葡萄糖衍生物,是可以制备多种聚合物的平台化合物原料,被认为是“最具价值的生物炼制产品”之一,在化工、食品和医药等领域具有巨大的经济价值。目前,生物质基葡萄糖二酸的制备主要包括化学法和微生物法。在对葡萄糖二酸性质、应用和测定方法介绍的基础上,重点介绍化学制备法和微生物法合成法的研究现状,并对今后的发展进行展望。     

Standard vapour mixtures by means of a multi-capillary flow-proportioner

A dynamic method is described for the preparation of standard gaseous mixtures of condensable vapours such as water vapour, gas odorants or hydrocarbons with an accuracy of better than ·5%. The possible concentration range is from a few parts per miliion to saturation level. The method is also suitable for the preparation of multi-vapour mixtures.     

New humic plant growth stimulant based on the neogene brown coals of Belarus

Data on a technology for the manufacture of a new biologically active humic preparation based on the Neogene brown coals deposited in Belarus are presented. The physicochemical properties of the preparation are given, and its biological activity is evaluated; the results of plant cultivation tests in the basic crops of the region—potatoes and grain crops—are also considered.     

A two-stage preparation of mesophase pitch from the vacuum residue of FCC decant oil

The preparation of mesophase pitch as a precursor for the high-performance carbon fiber from a vacuum residue of FCC-decant oil (FCC-DOVR) was studied, applying a two-stage heat treatment to improve the pitch yield as well as its liquid crystal properties. The present two-stage preparation consisted of the pressurized heat treatment (1–5 MP) of the first stage at 430–480°C and the successive heat treatment under 13–260 Pa at 430°C. Such a two-stage preparation increased the yield of the spinnable mesophase pitch of 100% domain texture with lower softening point to 45% from 22% by the single-stage one from the same feedstock. Spinning properties of the mesophase pitch were excellent to allow smooth spinning for longer than 15 min and random orientation of mesogen molecules in the tranverse section of the fiber perpendicular to the fiber axis. The chemistry of the two-stage preparation for the higher yield and better properties as the fiber precursor is briefly discussed.     

对乙酰氨基酚口服液的制备工艺改进及质量研究

目的：制备对乙酰氨基酚的口服液,并考察其质量;方法：通过对乙酰氨基酚和丙二醇、甘油等辅料合理搭配,得到对乙酰氨基酚口服液,并依照《中华人民共和国药典》对其质量进行了研究;结果：工艺操作简单,口服液质量稳定;结论：采用该方法制备对乙酰氨基酚口服液工艺可行,口味合适、质量稳定性好。     

马铃薯渣综合利用研究现状及进展

马铃薯渣是马铃薯淀粉加工产业的一种副产物,常被作为垃圾废弃掉,造成资源浪费和环境污染。实际上,马铃薯渣中含有许多有价值的成分,具有被开发利用的潜力。目前,马铃薯渣的综合利用主要集中在以下几方面:提取膳食纤维和果胶;制备高蛋白高能量饲料;制备新型黏合剂、胶黏剂和吸附材料;制备燃料酒精、生物质混合燃料和能量气体;制备种曲、醋、酱油及可食性膜等。综述了马铃薯渣目前综合利用的研究现状及进展。     

A New Way for Silver Alumina Catalyst Preparation

Abstract  

A new preparation of silver supported alumina catalysts, with highly dispersed and stable silver particles, is reported. The preparation, performed from a mixture of silver oxide and alumina, consists simply of heating this mixture under an oxidizing gas containing a water vapour concentration higher than 5.0 mol% in a temperature range between 903–948 K.     

New alternatives to graphite for producing graphene materials

Graphite (natural or synthetic) is the primary source for graphene materials preparation by the top down technology. The preparation of synthetic graphite requires temperatures above 2500 °C which represents a high energy cost. Herein we demonstrate that graphene materials can be prepared directly from a pregraphitic material using two of the most widely used procedures (chemical route and solvent exfoliation). In this way, extreme graphitization temperatures are avoided. In general terms, the graphene materials obtained from the pregraphitic materials exhibit similar characteristics to those obtained from graphite. These findings represent a breakthrough in the preparation of graphene materials by the top-down technology with clear environmental and economic advantages.     

Transmission Electron Microscopy Observations of Micelle Structure in a Vinyl Acetate-based Microemulsion

Abstract

One of the biggest challenges in studying micro-emulsions is the precise determination of the spatial structure of their micelles, to the extent that very scarce literature is available on this subject. In this work, a study of the various preparation techniques for the Transmission Electron Microscopy (TEM) analysis of a micro-emulsion of the vinyl-acetate/water/surfactant system is presented. The results indicate that the preparation method is a determining parameter if meaningful results are to be obtained.     

Accelerated Zincations for an Efficient and Mild Functionalization of Aromatics and Heterocycles

An improved process for the preparation of aromatic and heteroaromatic diorganozinc reagents and their subsequent reaction with electrophiles is presented. The new method, featuring the use of a 2,2,6,6‐tetramethylpiperidyl (TMP) magnesium base in the presence of zinc chloride (ZnCl₂), is superior to the previous methods, which require the preparation of zinc bases. Specifically, the shorter reaction times under mild conditions provide an easier and more practical process, while the use of only a slight excess of the amide allows the isolation of products in high yields. These improvements are particularly significant for the large‐scale preparation of organozincs and their subsequent reactions. Remarkably, beside the high kinetic activity, a wide range of functional groups is tolerated and sensitive heteroaromatics can easily be converted into the corresponding organometallic reagents and reacted with various electrophiles.     

Synthesis and properties of magnetite/polypyrrole core–shell nanocomposites and polypyrrole hollow spheres

In this work a new route for preparation of core–shell nanoparticles composed of an iron oxide core and a polypyrrole (PPy) shell is explored. During the preparation procedure the initially formed iron(0) core is converted to magnetite. It is demonstrated, that the magnetite cores can completely be dissolved by reaction with acid. Furthermore the dissolution of iron oxide cores by electrolysis also is possible. The resulting PPy hollow spheres as well as the core–shell nanocomposites are electrochemically active.     

Axial wall height effect on failure of adhesively luted computer assisted design/computer assisted manufactured ceramic crowns on preparations containing advanced total occlusal convergence

Computerized dentistry advocates promote that CAD/CAM adhesive technology compensates for traditional crown preparation recommendations. This study was to investigate the effect of preparation axial wall height on retention of adhesively-luted, all ceramic crowns manufactured by computerized methods. Maxillary molars were prepared with a 20 ° total occlusal convergence with preparation axial wall heights of 4, 3, 2, and 1 mm as well as an additional group containing a flat surface. The preparations were scanned with a computer acquisition device with crowns milled and prepared from a lithium disilicate ceramic material. The crowns were adhesively luted to the prepared tooth surfaces and then tested under static loading at a 45 ° angle to the tooth long axis on a universal testing machine until failure. Analysis with Kruskal-Wallis/Dunn’s found that crowns with 2, 3, and 4 mm preparation axial wall height had similar failure loads and demonstrated significantly greater failure load resistance than the zero and 1 mm axial wall height groups. However, failure mode analysis revealed that the 2 mm axial wall height group demonstrated universal adhesive failures as the zero and 1 mm axial wall height groups. Under the conditions of this study, some evidence is provided that adhesive technology may provided some compensation for less than optimal preparation features as the 3 mm axial wall height preparations demonstrated equivalent failure mode as the recommended 4 mm axial wall height preparations. However, further fatigue studies are warranted.