Comparison between Sulfuric Acid-phenol and Sulfuric Acid-anthrone Methods Used for Determination of Polysaccharides in Shoots of Aralia elata (Miq.) Seem.

Sulfuric acid-phenol and sulfuric acid-anthrone methods were used to detect polysaccharide content in shoots of Aralia elata（ Miq.） Seem.,and the conversion factor to glucose was measured with refined polysaccharides. Comprehensive evaluation was carried out by linear relationship,precision,reproducibility,stability and recovery rate. The results showed that the linear relationship between glucose concentration and absorbance was good when glucose concentration was0-40 μg/ml,and the average recovery rate was equal to or higher than 97. 00% with good reproducibility（ RSD 〈 1. 60%,n = 5）. It revealed that the two methods were accurate and reliable,and suitable for the determination of polysaccharide content in the shoots of A. elata. Polysaccharide content detected by sulfuric acid-phenol and sulfuric acid-anthrone methods was 19. 31% and 20. 40% respectively.

The impacts of ambiguity in preparation of 80% sulfuric acid solution and shaking time control of calibration solution on the determination of transparent exopolymer particles

The quantification of transparent exopolymer particles(TEP) by colorimetric method is of large error and low repeatability,one major reason of which is related to the absence of clear definition and evaluation for part steps of the original method.It is obscure that the 80% sulfuric acid solution,acted as the extraction solution in the determination of TEP,is prepared based on a volume ratio or mass ratio.Furthermore,the change of solubility of recently available Gum Xanthan(GX) from the market means that the original protocol is no longer applicable,and the grinding of GX stock solution with a tissue grinder is replaced by shaking with a rotating shaker in the study to prevent the excessive dissolution of GX.We found that different preparation techniques could result in the varied concentrations of 80% H_(2)SO_(4).The duration of shaking during the preparation of standard solution significantly affected the slope of the calibration curve,which caused different correction results of TEP.The impacts of different extraction solution concentrations and shaking time of GX solution on the quantification of TEP were investigated based on the field sampling and laboratory analysis.The extraction capacities of H_(2)SO_(4) with different concentrations for Alcian Blue were distinct,but had limited effect on the final measuring result of TEP.The change of the standard curve slope came along with the variation of shaking time,which markedly altered the detection limit and calibration result,and the extended shaking time was in favor of the determination of low-concentration TEP.It was suggested that the extraction solution concentration,shaking time and filtration volume of standard solution are required to be well controlled and selected to obtain more accurate results for TEP with different concentrations.

Effects of Sulfur Fertilizer Application Methods on Grain Protein Content During Filling Stage of Winter Wheat

[ Objective] The experiment aimed to provide a theoretical base of optimal cultivation management for the high yield and good quality and high efficiency of winter wheat. [ Method] The effects of two sulfur fertilizer application methods on dynamic changes of grain protein content and glutenin content of Yumai 49 and Yumai 66 during wheat grain filling stage were studied under the field conditions. [Result] Both the grain protein and glutenin content of two cultivars were increased by sulfur fertilizer, particularly, the effects on Yumai 49 were more significant.[ Conclusion] The grain content and glutenin content of different wheat cultivars could be increased by taking different sulfur fertilizer application methods.

Sulfur-resistant methanation over MoO_3/CeO_2–ZrO_2 catalyst: Influence of Ce-addition methods

In this paper, Ce_(0.2)Zr_(0.8)O_2 composite supports were prepared by different Ce-addition methods including impregnation of cerium(CeZr-imp), impregnation of citric acid and cerium(CeZr-CA) simultaneously and deposition precipitation method(CeZr-DP), respectively. The as-prepared supports were applied to prepare 10 wt% MoO_3/Ce_(0.2)Zr_(0.8)O_2 catalysts for sulfur-resistant methanation. The N_2 adsorption/desorption,X-ray diffraction(XRD), Raman spectroscopy(RS), X-ray photoelectron(XPS), temperature-programmed reduction by hydrogen(H_2-TPR) were undertaken to get textural properties, morphological information and structures of the catalysts. The results showed that Mo O_3 was highly dispersed on the surface of these three supports and Ce was mostly of coexisted in Ce^(4+)/Ce^(3+) redox pairs. Compared with Mo/CeZrimp, the CO conversion increased by 10% and 15% for Mo/CeZr-CA and Mo/CeZr-DP, respectively. This was mainly attributed to the larger specific surface area, Ce^(3+) concentration and content of active MoS_2 on the surface of catalysts.

Quantum Chemical Study of Potential Energy Surface in the Formation of Atmospheric Sulfuric Acid

A new potential energy surface （PES） for the atmospheric formation of sulfuric acid from OH＋SO2 is investigated using density functional theory and high-level ab initio molecular orbital theory. A pathway focused on the new PES assumes the reaction to take place between the radical complex SO3.HO2 and H2O. The unusual stability of SO3.HO2 is the principal basis of the new pathway, which has the same final outcome as the current reaction mechanism in the literature but it avoids the production and complete release of SO3. The entire reaction pathway is composed of three consecutive elementary steps： （1） HOSO2＋O2-＋SO3.HO2, （2） SO3.HO2＋H20-＋SO3·H2O·HO2, （3） SO3.H20.HO2-＋H2SO4＋HO2. All three steps have small energy barriers, under 10 kcal/rnol, and are exotherrnic, and the new pathway is there- fore favorable both kinetically and therrnodynarnically. As a key step of the reactions, step （3）, HO2 serves as a bridge molecule for low-barrier hydrogen transfer in the hydrolysis of SO3. Two significant atmospheric implications are expected frorn the present study. First, SO3 is not released from the oxidation of SO2 by OH radical in the atmosphere. Second, the conversion of SO2 into sulfuric acid is weakly dependent on the humidity of air.

STUDIES ON THE REACTION OF SULFUR,SELENIUM AND TELLURIUM WITH SODIUM HYDROXIDE UNDER PHASE TRANSFER CATALYSIS(Ⅱ).A CONVENIENT METHOD FOR THE SYNTHESIS OF BI(ACYL)DISULFIDES

A simple and general method for the synthesis of bi(acyl)disulfides is reported.Sulfur is allowed to react with sodium hydroxide to give sodium disulfide at 65℃ under PTC,which can react with acyl halides to afford bi(acyl)disulfides in good to excellent isolated yields.The effects of solvents and phase transfer catalysts are discussed.

溶剂法提纯硫磺的工艺研究

为了解决天然气净化过程中副产物硫磺提纯难度大、提纯后硫磺纯度低的问题,结合溶剂萃取法操作简单、成本低等优势,利用相似相溶的原理,以CS2为溶剂设计了一种用溶剂法提纯硫磺的工艺。通过干燥时间考察了硫磺渣中的含水量,以硫磺产率为指标,考察了硫磺渣干燥时间、液固比、浸取时间、浸取温度和球磨粉碎对硫磺产率的影响,并通过XRD及ICP分析了纯化后硫磺的纯度。结果表明,硫磺渣干燥时间为60 min、液固比(体积质量比,m L/g)为8∶1、浸取时间为30 min、浸取温度为30℃及球磨成粉时,硫磺产率最佳。相较于传统的熔融法(85.7%)和气化法(85.37%)工艺,溶剂法工艺提纯硫磺后产率高达87.8%,提高了2.5%左右,且提纯后硫磺的纯度高达99.89%。该溶剂法提纯硫磺的工艺具有产率较高且纯度高、操作简单的优势,为有效处理硫磺提纯提供了技术路线,同时在硫磺纯化方面具有广阔的应用前景。

流动注射法检测枸杞中二氧化硫残留量的方法比较及风险评估

近年来自动化检测设备以及对应方法相继涌现,本研究使用在线蒸馏-流动注射法与国标中酸碱滴定法、离子色谱法对枸杞中二氧化硫残留量进行检测比较。结果表明,三种方法的测定结果并无显著性差异。在线蒸馏-流动注射法RSD在1.5%~2.4%之间,加标回收率在86.1%~92.7%之间,因其具有自动化程度高、检测周期短的优势,更适合大批量样品的快速准确检测。用在线蒸馏-流动注射法对106批次红枸杞中的二氧化硫残留量进行检测分析,并对枸杞中的二氧化硫残留量进行暴露风险评估。结果显示,二氧化硫超标率达21.7%,枸杞中二氧化硫残留尚未对健康构成威胁。

高频燃烧红外吸收法测定铜铅锌多金属矿中的碳、硫

铜铅锌多金属矿中的碳、硫元素对矿产开采、钢铁冶炼及环境保护等方面有着重要的影响,对碳、硫的准确、快速定量检测至关重要,但未见有对铜铅锌多金属矿中的碳、硫同时测定的研究。将铜铅锌多金属矿中碳、硫含量科学分为C1、C2、S1、S2四段,并分别对样品称样量、助熔剂加入比例及种类等因素进行探究,建立了高频燃烧红外吸收法测定铜铅锌多金属矿中的碳、硫的方法,并通过标准物质验证了方法的准确度、精密度与再现性。结果表明,C1、C2、S1、S2称样量分别为0.200 0、0.100 0、0.100 0、0.100 0 g,助熔剂组合方式为Fe+W=(0.6000+0.6000)、(0.6000+0.6000)、(0.9000+0.6000)、(0.6000+0.600 0) g为最佳实验条件。C1、C2、S1、S2曲线的相关系数分别为0.999 4、0.995 9、0.999 9、0.998 9,测定结果的相对标准偏差(RSD,n=11)分别为1.3%、1.5%、1.3%、1.3%,使用3种不同型号的红外碳硫仪进行对比实验,相对标准偏差(RSD,n=11)为0.56%~6.5%。结果均显示,方法准确、可靠,满足铜铅锌多金属矿中碳、硫的同时、准确快速定量检测的要求。

综合法二氧化氯生产系统废水除铬实例

以某浆纸厂含铬废水处理工程实例为研究对象,针对综合利用自产化学药品和现有设备开发的间歇性六价铬(Cr^(6+))综合处理系统,探讨了二氧化氯车间Cr^(6+)废水产生原因及性质,根据不同的反应池pH值、反应温度、反应时间和硫磺投加量对废水中Cr^(6+)还原效果的影响,确定了二氧化硫还原法去除Cr^(6+)的最佳反应条件,并结合实际生产数据,展示了Cr^(6+)还原效果。结果表明,有效去除高浓度含铬废水中Cr^(6+)的条件为:pH值=2~4、反应温度控制在40~60℃、硫磺投加量为理论反应所需投加量的1.4~1.6倍、反应时间40 min。3次二氧化氯车间停修废水出水中Cr^(6+)含量均低于0.005 mg/L,总铬含量均低于0.06 mg/L,符合《污水综合排放标准》(GB 8978—1996)中的要求,证实了间歇性Cr^(6+)综合处理系统处理的有效性。

低温加氢催化剂CT6-13在硫磺尾气处理系统的应用

中国石油四川石化有限责任公司硫磺回收装置采用加氢还原吸收工艺及专用加氢催化剂进行尾气处理。将低温加氢催化剂CT6-13与常规加氢催化剂CT6-5B从物性、装填方法及预硫化、技术性能等方面进行了对比。深入对比分析CT6-5B和CT6-13在尾气加氢反应器的应用情况,发现采用CT6-13催化剂,节能降耗效果明显,尾气排放满足总硫不大于50μL/L、SO_(2)排放浓度不大于100 mg/m^(3)的设计要求。配套高效脱硫剂CT8-26及烟气洗涤技术,可实现开工过程尾气达标排放及日常运行过程尾气SO_(2)排放浓度不大于5 mg/m^(3)的超低排放。在节能降耗的同时解决了开停工及异常工况下的绿色生产及制约硫磺回收装置尾气焚烧炉长周期运行瓶颈问题。

低温液相法从脱硫废渣中制备不溶性硫磺

HPF脱硫废渣是煤气脱硫工序的副产物,含有焦油、铵盐、酚、萘等多种杂质,是煤化工企业难以处理的固体废弃物。通过萃取-结晶技术,得到了纯度高于99.97%的高纯度硫磺。在较低的温度条件下,用提纯的硫磺制备了不溶性硫磺,通过三因素三水平正交试验,得到了低温液相法的最佳工艺条件。采用化学分析、差热、热重分析和X射线衍射分析技术,对产品的结构和性质进行了分析定性。试验结果表明,不溶性硫磺晶体结构和普通硫磺存在显著差异,具有较好的热稳定性。

H_(2)SO_(4)/ZnCl_(2)复合活化微波法制备污泥活性炭研究

以城市剩余污泥为原料,H_(2)SO_(4)和ZnCl_(2)为复合活化剂,采用微波法制备污泥活性炭,研究微波活化温度、功率、辐照时间及固液比对污泥活性炭碘吸附值影响,并利用TG、BET、FTIR、SEM等对产物进行表征。结果表明:当固液比1∶1.5、微波功率2000 W、活化温度600℃和辐照时间20 min时,污泥活性炭碘吸附值最高约为1360 mg·g^(-1)。与干污泥相比,加活化剂干污泥的热解仍为3个阶段,但半焦生成焦炭阶段的失重有较大提高,污泥活性炭的比表面积约为331 m^(2)·g^(-1),表面可见大小不一且未被堵塞的孔洞,平均孔径约为13 nm,有相对较多的含氧官能团。

响应曲面法优化梅花鹿茸多糖提取工艺

以梅花鹿茸多糖为研究对象,首次采用超声波提取法、热水浸提法、水提醇沉法相结合的方式优化提取工艺。单因素实验基础上,利用BBD实验设计原理进行四因素三水平的响应面实验。苯酚硫酸法测定多糖含量,紫外光谱和FT-IR光谱分析检测纯度。结果表明:最佳提取工艺条件下,超声液料比34∶1、超声时间43 min、浸提温度54℃、浸提时间2 h,多糖提取率达2.02%,多糖含量70.05%,不含核酸和蛋白质等成分并具有典型多糖结构,表明优化的梅花鹿茸多糖提取工艺切实可行,优化结果优于先前工艺。

3种测定广式酱油中总糖含量的方法比较

该研究通过比较直接滴定法、苯酚硫酸法、蒽酮硫酸法3种方法测定广式酱油总糖含量的差异,并对这3种方法进行方法学验证,以期筛选出一种适合广式酱油总糖含量测定的方法。结果显示,直接滴定法、苯酚硫酸法和蒽酮硫酸法分别在0.50~8.00、0.00~0.08和0.00~0.08 mg/mL范围内线性关系良好。直接滴定法、苯酚硫酸法和蒽酮硫酸法的精密度试验的RSD值分别为1.07%、0.05%、0.05%,重现性试验的RSD值分别为0.88%、3.93%、3.24%,直接滴定法在24 h内显色稳定,苯酚硫酸法和蒽酮硫酸法在1 h内显色稳定。而在加标回收率试验中,蒽酮硫酸法的平均加标回收率较高,为168.04%,RSD值为2.97%,直接滴定法的平均加标回收率为104.67%,RSD值为2.07%,苯酚硫酸法的平均加标回收率为103.85%,但其RSD值为8.04%,蒽酮硫酸法测定酱油总糖含量的准确度低于其他两种方法。因此,直接滴定法和苯酚硫酸法的精密度、重现性、稳定性良好,理论上均具有可行性,蒽酮硫酸法不适合用于广式酱油总糖含量的测定。酱油中总糖含量是反映酱油品质的基本指标之一,筛选出适合酱油总糖含量的检测方法,对实际酱油生产监控和产品加工过程的品质控制都有重要意义,同时也为酱油总糖含量测定方法标准的制定提供一定的实验参考。

二氧化钛制备技术研究进展

TiO_(2)具有优异的白度、消色力等颜料性能,是物理、化学性质稳定的功能材料。综述了工业生产TiO_(2)制备方法的现状和研究进展,分析各种制备方法的优势、劣势和发展前景。硫酸法能制备锐钛型和金红石型二氧化钛,并且可以制备不同类型的功能材料产品,氯化法只能制备金红石型产品,硫酸法与氯化法将会长期共存。氯化法中的熔盐氯化技术与中国的钛资源现状更加契合,沸腾氯化法的技术瓶颈和对高钛渣原料的严苛要求是下一步中国二氧化钛行业面临的急需解决的问题。新工艺技术中盐酸法对原料的要求简单,能够生产不同晶型和性能的Ti O_(2),最具有工业化发展前景。今后,各种工业制备方法的发展方向必须向清洁、绿色、低碳和废物综合利用的方向发展,以满足日益严苛的环保要求和国内钛资源现状。

白牛肝菌、白松露、松茸中多糖和氨基酸含量对比

以白牛肝菌、白松露、松茸烘干片为研究对象,分别采用苯酚-硫酸法和异硫氰酸苯酯衍生化法对其多糖、氨基酸的含量及氨基酸种类进行了测定和对比分析。结果表明白牛肝菌、白松露、松茸烘干片中多糖含量分别为质量分数3.739%、2.739%、4.378%,总氨基酸质量比含量分别为124.83、88.76、33.29 mg/g。三者均含有赖氨酸(Lys)等17种游离氨基酸,但同一种氨基酸在三者中的含量差异较大。提示3种不同品种的珍稀食用菌中多糖和氨基酸含量具有一定的差异,但总体而言其多糖含量均较高,且氨基酸种类齐全、含量丰富。

高硫石油焦脱硫方法研究现状与展望

介绍了石油焦中硫的存在形态及分布,详细叙述了化学氧化脱硫、高温煅烧脱硫、微生物脱硫和溶剂萃取法脱硫方法的优缺点,对比了脱硫机理,总结了高硫石油焦脱硫的研究进展,对于石油焦脱硫的未来发展方向提出了展望。

锂云母酸浸液萃取除杂

锂云母酸法浸出液含有大量杂质金属,使用传统化学沉淀法会引起大量产物损失。为了降低浸出液除杂过程中的产物损失,使用溶剂萃取法进行萃取除杂工艺研究。通过对不同萃取剂组合萃取除杂效果的研究,确定使用P204作为萃取剂。考察了萃取过程中不同因素的影响,并使用H_(2)O_(2)预氧化水相里的Fe^(2+),强化萃取效果。结果表明:在有机相组成为30%P204+70%磺化煤油、料液初始pH为2.4、相比O/A=1、萃取时间10min和振荡频率300 r/min的单级萃取最佳条件下,铁除杂率为99.89%、铝除杂率为31.23%、锂和铷的萃取率分别为7.63%和14.85%。相比于化学沉淀法,锂和铷的回收率得到了30%左右的提高。

中药材二氧化硫残留量快速检测方法及其适用性比较

目的试验两种二氧化硫含量的快速检测方法并比较其适用性。方法考查了凯氏定氮仪+滴定法和快速检测试剂盒对中药材中二氧化硫检测结果的准确度和可行性。结果凯氏定氮仪+滴定法测定结果与2020版《中国药典》中二氧化硫含量方法测定结果基本一致。结论凯氏定氮仪+滴定法测定法,结果准确,可用于部分中药材的二氧化硫残留量检测,具有简便、快速、准确等特点,而快速检测试剂盒的检测结果适用比例较低。