A Study on the Structure and Behavior of Sinter-free Material for Phosphorous Removal from Waste Water

Oyster shell and cement were taken as the major raw materials to fabricate hollow, tubular and recoverable material for phosphorous removal (P removal) from waste water without sintering. In this paper, the effects of different affecting factors on the sample P removal ratio were discussed to select optimal P removal process conditions. SEM and XRD were used to characterize the microscopic structures and composition of samples, and molybdenum blue spectrophotometry was applied to determine the P content in waste water. Results showed that at 30 ℃ for 2 d, the P removal ratio reached 93.3% when the cement content was 10 wt% and oyster shell powder was 90 wt%. SEM analysis revealed a flaky structure consisting of phosphorus-containing compound in the samples after P removal, and it piled on and maintained the porous structure. In addition, the results also suggested that raising the ambient temperature was benefit to the P removal. The P removal ratio of the material was optimal under neutral and alkali conditions.     

Study of Biomass Calcite as Fine Aggregate of Concrete

The possibility of using crushed oyster shell to partly replace the fine aggregate of concrete was evaluated. The compressive strength and slump of concrete mixture with different amount of crushed oyster shell were tested and thus the appropriate dosage was determined. Additionally, the compatibility with super plasticizer and the stability in Na2SO4 solution were also discussed to prove the feasibility of oyster shell as fine aggregate of concrete. The microstructure of concrete was observed with XRD and SEM techniques. This research provides the basis for the application of waste biomass calcite.     

Researches on the Treatment of Phosphorous Wastewater with Oyster Shells

Based on the analysis of adsorptive features of oyster shells,the researches on the treatment of phosphorous wastewater with oyster shells and the effect of temperature on phosphorus removal were carried out.XRD was used to characterize the crystalline phases,and the main component of oyster shells was shown to be CaCO3.When the pretreatment temperature reached 800 ℃,some CaCO3 decomposed into CaO.As the temperature was further raised,CaO increased gradually.Via SEM testing,the oyster shell was a kind of natural porous materials.The pore wall partially collapsed from 550 to 900 ℃.No obvious porous structure was found at 900 ℃.However,without preheating,the oyster shell phosphorous removal material can not adsorb the phosphorus.Pretreatment made calcium activate,thus greatly increasing the absorption of phosphorus.     

Effect of calcinated oyster shell powder on growth, yield, spawn run, and primordial formation of king oyster mushroom (Pleurotus eryngii)

This study was conducted to evaluate the calcium (Ca) absorption efficacy of king oyster mushroom (Pleurotus eryngii) grown on sawdust medium supplemented with Ca-sources, including oyster shell powder, and to determine the efficacy of oyster shell powder as a calcium supplement on growth, yield, spawn run and primordial formation of P. eryngii. Optimum calcination of oyster shell powder was achieved at the temperature of 620.56 °C. A 1% supplementation of oyster shell powder in sawdust medium did not suppress the mycelial growth of P. eryngii. Also the supplementation of 2% calcinated oyster shell powder to sawdust medium potentially increased the calcium content up to a level of 315.7 ± 15.7 mg/100 g in the fruiting body of P. eryngii, without extension of duration of spawn run and the retardation of the days to primordial formation. These results suggest that the shellfish by-products, including oyster shell powder, can be utilized to develop calcium enriched king oyster mushrooms.     

CaO高温吸附捕集CO2-制备CaO的钙基前驱体材料筛选

价格低廉的CaO材料在高温下能高效吸附捕集CO2气体,被认为是碳减排的有效方法之一．然而,CaO长时间循环碳酸化／煅烧解吸后,其CO2的化学吸附容量下降,稳定性较差,限制了该材料的工业应用．本文采用天然钙源（牡蛎壳和方解石等）和化学试剂（醋酸钙）为钙基前驱材料制备CaO．采用扫描电子显微镜（SEM）,X射线衍射仪（XRD）和氮气吸附仪等手段对制备的CaO材料进行形貌和物理结构的分析表征;在高温和模拟的烟道气氛条件下（10％C02和90％N2）,采用热重分析仪测量CaO吸附CO2的能力和长时间循环碳酸化／煅烧解吸后的稳定性．我们经过与目前所报道的其他钙基吸附材料进行比较,并结合钙基前驱材料的市场价格,发现CaO（醋酸钙）的CO2吸附能力和稳定性较为理想,醋酸钙在高温烟气捕碳方面具有非常好的应用前景．     

A feasibility study into the production of a freeze-dried oyster reference material for paralytic shellfish poisoning toxins

Matrix reference materials are an essential component for the validation and quality control of analytical methodologies for the quantitation of marine biotoxins in shellfish. Given the potential advantages of reference materials in powder form, a study was conducted to assess the feasibility for the production of a freeze-dried oyster tissue reference material containing a range of important paralytic shellfish poisoning toxins. One bulk sample of a wet oyster tissue homogenate was generated following mass culturing of toxic Alexandrium and oyster feeding experiments. The bulk tissue was used to prepare untreated wet frozen aliquots with the remainder being freeze-dried and processed into appropriately-sized powder samples. A pre-column oxidation LC-FLD analysis was used to confirm the absence of any chromatographic artefacts resulting from the processing and to confirm acceptable homogeneity of the tissues. Excellent stability over both the short-term (1 month) and long-term (1 year) of the freeze-dried material was demonstrated as compared with the stability of the untreated wet tissue. A post-column oxidation LC-FLD method was used to confirm the absence of toxin epimerisation in freeze-dried tissues which were observed in the wet tissues. Overall the work showed the feasibility of an approach to produce a homogenous freeze-dried oyster matrix material with enhanced stability in comparison to the untreated wet tissue. The potential for use of the process for preparation of large scale production batches of a freeze-dried CRM for paralytic shellfish poisoning toxins has therefore been demonstrated.     

Electrochemical characterization of a bioceramic material: The shell of the Eastern oyster Crassostrea virginica

The shell of the Eastern oyster (Crassostrea virginica) is composed of multiple incongruent mineralized layers. This bioceramic composite material was investigated to determine the effects of shell thickness, orientation and layer composition on its electrochemical behavior using electrochemical impedance spectroscopy, potentiodynamic polarization and scanning electron microscopy-energy dispersive spectroscopy. SEM-EDS analysis of the oyster shell revealed that the multilayered biocomposite material is composed of calcium carbonate (CaCO(3)). EIS measurements in 3.5wt.% NaCl indicated that the impedance of the whole oyster shell in the low frequency region exhibited high impedance values which exhibited a decreasing trend with increasing immersion time. In terms of overall shell thickness, limiting currents measured by potentiodynamic techniques through the shell were observed to increase when the outer layers of the shell were sequentially removed by grinding, thus decreasing the shell thickness. These limiting current values remained relatively constant when the inner layers of the shell were removed. The impedance values of the oyster shell material as measured by EIS were shown to decrease with decreasing shell thickness. These findings suggest that the prismatic (outermost) shell layer in combination with the soluble organic matrix between all shell layers may influence the ionic conductivity through the oyster shell.     

Synthesis of calcium sulfate hemihydrate whiskers using oyster shells

Herein, the feasibility of preparing long and homogeneous hemihydrate (HH) whiskers using waste oyster shell was investigated. The whiskers formed from the sintered raw material had higher aspect ratios and more uniform morphology than non-sintered. The effect of reaction temperature, reaction time, and concentration were investigated. It was found that the optimum reaction temperature, reaction time, and concentration for stable and well-grown whiskers were 140 °C, 5 h, and 4 wt%, respectively. Direct transition from calcium sulfate dehydrate (DH) to HH was detected by X-ray diffraction (XRD) patterns, and the result showed DH completely transformed to HH after 5 h. The preferred direction of growth along the c-axis was confirmed by XRD pattern, selected area diffraction pattern, and high-resolution transmission electron microscopy (HRTEM).     

柠檬酸溶胶凝胶法制备LiCoO_2电极材料及其表征

目前研究较多的锂离子电池正极材料主要有LiCoO2、LiNiO2和LiMn2O4犤1犦,虽然LiCoO2的成本相对较高,但LiCoO2具有最为优良的电化学性能,如高且平稳的充放电平台、高比容量以及良好的循环性能犤2犦,是目前应用最广泛的商品化电极材料。LiCoO2材料主要采用高温固相法犤3～5犦制备,该方法工艺简单,容易实现大规模生产,但缺点是需要较高的焙烧温度和较长的焙烧时间,且反应原料混合均匀程度有限,易导致非化学计量、非均相以及不规则的颗粒形貌等,因此材料的比容量、循环寿命等电化学性能以及反应的可控性还不甚理想。研究表明犤6犦电极材…     

电极水分对磷酸铁锂电池性能的影响

通过库仑法水分测试仪标定不同水分含量（0.3‰ ~ 0.7‰）的磷酸铁锂正极片,将其制备成软包型锂离子电池,对其电化学循环性能、倍率性能、交流阻抗进行了测试. 结果表明,不同水分含量极片制备的电池循环性能及倍率性能与电极水分含量有密切关系,水分含量在0.4‰ ~ 0.5‰之间时循环性能最优,水分含量超过0.6‰时电化学性能衰减严重,电池的内阻和电化学反应阻抗明显增加. 将循环200周后的软包电池进行拆解,分别使用激光粒度仪、XRD、SEM对循环后磷酸铁锂正极片进行微观形貌分析,发现水分含量超过0.6‰时极片表面发生颗粒破裂现象. XRD晶相分析表明,随着水分含量的升高,衍射峰晶面的位置有所偏移,但主要衍射峰的位置基本相同,晶型并未发生改变.     

高容量的Li1.1Mn2O3.95F0.05锂离子二次电池正极材料

以无水乙醇为分散剂在行星式球磨机中对原料进行预处理后,经固相反应制备了富锂化合物Li1.1Mn2O3.95F0.05,并以该化合物作为锂离子二次电池正极材料,进行了电化学测试。结果表明,加氟后的富锂化合物Li1.1Mn2O3.95F0.05可与LiCoO2相比,可逆容量高达143nA·h/g,且具有良好的循环稳定性,循环115次后,容量保持率在95%以上。SEM和TEM的表征,说明该方法制备的样品颗粒均匀,具有较好的晶体外观,XRD表征,说明该化合物具有完美的尖晶石结构。锂含量的原子吸收光谱(AAS)表征说明该化合物为富锂化合物Li1.1Mn2O3.95F0.05。电化学测试结果和SEM,TEM,AAS表征支持掺氟后的富锂化合物Li1.1Mn2O3.95F0.05晶胞内空缺增大,使锂离子的嵌入脱出更加容易,并且使更多的锂离子参与嵌入脱出反应。     

多级复合孔硅铝材料的合成与表征

采用表面包覆聚电解质的聚苯乙烯小球为模板,制备多级复合孔硅铝材料前体。 经水热晶化处理后焙烧脱模板,获得了多级孔结构的硅铝分子筛材料。 通过X射线衍射、傅里叶红外光谱、N2吸附-脱附、扫描电子显微镜和透射电子显微镜等测试技术对水热晶化不同时间的硅铝材料进行表征。 探讨了水热晶化时间对材料孔道结构的影响。 结果表明,水热晶化时间小于22 h,样品中含有介孔-大孔双连续孔道体系。 晶化时间超过22 h,样品中含有微孔-介孔-大孔多级孔道体系。 晶化36 h的样品,大孔孔壁由纳米级ZSM-5型沸石分子筛晶体构成。     

水泥生料的燃烧固硫特性及其微观反应机理研究

采用SC-132定硫仪对水泥生料的燃烧固硫特性进行了评价，利用XRD、SEM对煅烧样品进行矿相组成分析及矿物形态分析，讨论了水泥生料高温固硫的微观反应机理。结果表明，高温段固硫物相的热稳定性是影响水泥生料固硫效率的决定因素。水泥生料在较宽温度范围内具有85%以上的固硫效率。850 ℃时已有CaSO4形成， 1 050 ℃时CaSO4开始分解。1050℃～1250℃生成耐高温的硫硅酸钙、硫铝酸钙等复合矿物。1300℃时铁铝酸盐固熔体等将硫酸盐的表面包裹，抑制其高温分解，使水泥生料在1300℃时仍有较高的固硫效率。     

添加磷酸氢钙对硅酸三钙骨水泥性能的影响

本文将磷酸氢钙(CaHPO₄·2H₂O,DCPD)添加到硅酸三钙(Ca₃SiO₅,C₃S)骨水泥中,采用X射线衍射(XRD),扫描电镜(SEM),万能力学测试机等手段对不同添加量的骨水泥进行表征,考察添加DCPD对硅酸三钙骨水泥性能的影响。实验表明,C₃S材料中添加10% DCPD有着优于单纯C₃S骨水泥的水化性能,骨水泥的初凝时间从92 min缩短到80 min;添加20%~30% DCPD能提高材料的短期力学强度,可以实现其短期抗压强度的优化;添加30%~40% DCPD的材料有着优良的生物活性与适中的可降解性能。结果表明,通过添加DCPD优化C₃S水泥的性能,对各种不同性能具有DCPD添加量的依赖性。通过进一步优化DCPD添加量,将可能获得优良的生物活性骨缺陷填充材料。     

Influence of chromate reducers on cement hydration

Present research compared the effect of chromate reducers such as ferrous sulphate heptahydrate (FeSO₄·7H₂O) and stannous sulphate dihydrate (SnCl₂·2H₂O) on the hydration of cement paste, using water?cement ratio of 0.5 and sealed in plastic bags without curing for 28 days. Uncured hydration properties of cement paste are investigated in detail by thermogravimetric analysis (TGA) and verified with the use of scanning electron microscopy (SEM) and X-ray powder diffractometry (XRD). This research concluded that the cement paste with 0.1% additives showed better hydration in the uncured condition than the control.

     

Synthesis and characterization of core-shell selenium/carbon colloids and hollow carbon capsules

A novel Se/C nanocomposite with core-shell structures has been prepared through a facile one-pot microwave-induced hydrothermal process. The new material consists of a trigonal-Se (t-Se) core and an amorphous-C (a-C) shell. The Se/C composite can be converted to hollow carbon capsules by thermal treatment. These products were characterized by transmission electron microscopy (TEM), powder X-ray diffraction (XRD), scanning electron microscopy (SEM), selected area electron diffraction (SAED), energy-dispersive X-ray (EDX) spectroscopy, and X-ray photoelectron spectroscopy (XPS).     

Preparation,Structures and Mechanical Properties of Bamboo Shoot Shell Nanofiber/Konjac Glucomannan Aerogels

With bamboo shoot shell nanofibers(BSN) and konjac glucomannan(KGM) as precursor materials, the BSN/KGM aerogels were prepared in different proportions by sol-gel method. The surface morphology, microstructure, characteristic functional groups and thermal properties of BSN/KGM aerogels were characterized by scanning electron microscopy(SEM), infrared spectroscopy(IR), X-ray diffraction(XRD) and thermogravimetric analysis(TGA). The effect of BSN on the structure and properties of BSN/KGM aerogels was also studied. The results showed that the BSN/KGM aerogels possessed network porous structure with compact and homogeneous porosity, high specific surface area and low density. With the increase of BSN, the sheet structure of aerogels was converted into the 3D porous network structure, which contributes significantly higher thermal stability. In addition, the BSN/KGM aerogels showed excellent mechanical properties. The maximum relative compression rate was 62%, suggesting the addition of BSN can enhance the compression properties of the BSN/KGM aerogels.     

EFFECT OF SOLVENT ON ZEOLITE SYNTHESIS

Introductionltistvellknox`nthath}'drothcrmalcn'stallizationisaconventionaltechniqueforzeoliteandmolccularsicvcs}nthcsls.Watcrassolvcntplaystheroleofminerali.ation[ll.Inl985,BibbyandDalcrcportedfirstl}'thes}'nthcsisofsilica-sodaliteinethyleneglycolsol.e.tl2l.Sincetllcn,man}'kindsofzeolitcst"ercpreparedinnon-aqueoussystemsHott'ever,noinformationonthcinfluenccofsolvcntonzcolitcsynthesishasbecnreported.Inthispapcr,t"crcportanintcrcstingcxamplc.Incascsofnosolventandusingx`atcr,cth}'lcneglycolandc…     

多孔活性硅胶的制备及吸附性能的研究

以硅酸钠和氯化铵为原料,通过添加表面活性剂制备高吸附活性的多孔硅胶.采用SEM,IR和XRI)等手段对硅胶样品的结构和形貌进行表征,并利用紫外分光光度法研究硅胶样品对垃圾渗滤液中有机污染物的吸附性能.结果表明,合成的硅胶样品是由纳米量级的无定形二氧化硅颗粒组成的多孔性、疏松状物质,对垃圾渗滤液中的有机物分子具有较强的吸...     

Synthesis of nonionic polyurethanes with hydroxyl-terminated polybutadiene hydrophobic segments and their application in octadecane nanocapsules

Alkane nanocapsule is a kind of promising phase-change material. However, it is difficult to prepare alkane nanocapsule with an elastic shell by traditional method. Therefore, nonionic polyurethane with specially designed structure was synthesized. Octadecane nanocapsule prepared by this polyurethane not only had an elastic shell but also showed some good properties in other aspects. The polyurethane structure was characterized by infrared, hydrogen-1 nuclear magnetic resonance, and gel permeation chromatography. The conductivity of emulsification process was tracked. The average particle sizes of nanocapsules were measured by quasi-elastic light scattering and fell in the range of 240 to 485 nm. Octadecane nanocapsules showed a core–shell structure under transmission electron microscopy. The nanocapsule dispersions had a rather good stability under high-speed shearing and freezing–thawing tests. All of the coalescence ratios were less than 5 wt.% after testing. The fusion enthalpy of nanocapsules reached to 83 J g^?1. It was found that the dried nanocapsule powder had rather good re-dispersion ability, and stable dispersions were obtained simply by agitating the powder into water. Coalescences of re-dispersed dispersions were all less than 1.8 wt.%, and their average particle sizes were in the range of 420 to 675 nm. There was almost no change in fusion enthalpy and melt temperature before and after re-dispersion, which indicated that the polyurethane shell had a good protection of octadecane from leaking out of the nanocapsule.