Direct Determination of Potassium-Sodium Activity Ratio in Soil Suspension with Two Ion-Selective Electrodes

A K+-selective electrode and a Na+-selective electrode were used to construct a measuring cell without liquid-junction for the determination of the ion activity ratio of K+ to Na+ in soil suspensions. The measured cell potential was not affected by the total electrolyte concentration when the total cation concentration was 10-1-10-3 mol L-1 and the concentration ratio CK+ / CNa+. was 10:1 to 1:50. When the concentration ratios were equal to 1and the total electrolyte concentrations were 10-2 and 10-3 mol L-1, the ion activity ratio measurement would not be affected by pH in the pH range of 3.5 to 11.5 and 4.4 to 11 respectively. Ions other than H+ have no remarkable influence on the measurement. The ion activity ratio of K+ to Na+ measured directly in soil suspension agree well with those in centrifuged supernant solution. The relative deviation was within 4%. From the measured ion activity ratio, the difference of the bonding energies of K+ and Na+ ions was calculated.

Synthesis of potassium hexatitanate whiskers using hydrothermal method

High quality potassium hexatitanate whiskers were hydrothermally synthesized in one step under moderate temperature and pressure conditions. Effects of the titanium source and reaction conditions on the hydrothermal reaction rate, product phase component, and morphology of whiskers were investigated. The results show that the reactivity of hydrated titania, anatase TiO2, and rutile TiO2 with KOH decreases in turn, and with hydrated titania as titanium source, it is difficult to obtain potassium hexatitanate whiskers with good morphology. In contrast, uniform potassium hexatitanate whiskers with a length of 10-20 μm and a diameter of 200-700 nm were obtained using anatase TiO2 as titanium source. The investigation demonstrates that the initial KOH concentration, annealing temperature and time, molar ratio of K2O/TiO2, etc. significantly affect the morphology of the as-synthesized whiskers. The optimized synthesis condition is as follows： anatase as a titanium source 10 wt.% KOH solution; annealing temperature and time of 300℃ and 5 h, respectively; K2O/TiO2 molar ratio of 5, etc. A rhombic potassium hexatitanate was prepared under the optimum condition and the whisker grew along the [110] direction. The reaction mechanism was discussed.

Preparation of CeO_2 Nanoparticles and Its Application to Ion-selective Electrodes Based on Acetyl Cellulose

CeO2 nanoparticles with an average diameter of about 30 nm were prepared by sol-gel method at lower temperature. The gel, transformed from the aqueous solution of metal nitrate and citric acid, can be combusted completely at lower temperature. The redox behavior and the crystallization process of the dried gel were studied by thermogravimetric analysis and infrared spectroscopy. The synthesized powders were characterized by X-ray powder diffraction and transmission electron microscopy. In addition, rare earth elements ion-selective electrodes based on acetyl cellulose were prepared using ultra fine cerium oxide powders.

Preparation of Layered Potassium Titanate Whiskers with Large Length-diameter Ratio by KDC Method

Pure K2Ti4O9 whiskers were prepared by KDC（Kneading-Drying-Calcination） method with TiO2 and K2CO3 as raw materials. The influences of TiO2/K2CO3 molar ratio（RT/K）, calcination temperature（TC） and cooling process on phase composition and morphology of the whiskers were investigated by TG-DSC（thermo gravimetric-differential scanning calorimeter）, XRD（X-ray diffraction）, and SEM（scanning electron microscope）. Pure K2Ti4O9 potassium titanate whiskers with large length-diameter ratio（r）（over 250） can be obtained at RT/K = 2.9 and TC = 950 ℃.

Effects of Tillage Methods on Soil Available Phosphorus and Available Potassium in the Loess Plateau

In order to find out the effects of long-term no-tillage operation on soil available phosphorus and available potassium in the loess plateau, a suitable high-yield and high-efficiency tillage technology system was established. In the Changwu loess plateau agri-ecological experiment station of the Northwest A&F University of Changwu County, Shaanxi Province, the no-tillage experimental field for three consecutive years was selected. In September 2015, no-tillage, tillage, and rotary tillage were carried out before winter wheat was sowed. After the harvest of winter wheat in 2016, the contents of available phosphorus and available potassium in 0-30 cm soil layer under three tillage methods were analyzed. The results showed that in the 0-30 cm soil layer, the soil available phosphorus and available potassium decreased with the increase of the soil depth in the three tillage methods. The content of available phosphorus and available potassium in 10-20 cm soil layer and 20-30 cm soil layer decreased by 16.07%, 32.74%, 15.54% and 27.08%, respectively, and there were significant differences ( P <0.05). Under different tillage methods, the soil available phosphorus content in the 0-10 cm soil layer significantly reduced by 11.31% compared with no-tillage. The soil available potassium content under tillage and rotary tillage significantly reduced by 6.16% and 4.97%, respectively ( P <0.05). Compared with no-tillage, the soil available phosphorus content in the 20-30 cm soil layer significantly reduced by 18.12%. The soil available potassium content under tillage and rotary tillage methods significantly reduced by 17.17% and 9.22%, respectively ( P <0.05). Therefore, in the long-term no-tillage dry loess plateau, it is necessary to conduct proper tillage or rotary tillage.

Novel Bilayer-Shelled N,O-Doped Hollow Porous Carbon Microspheres as High Performance Anode for Potassium-Ion Hybrid Capacitors

With the advantages of high energy/power density,long cycling life and low cost,dual-carbon potassium ion hybrid capacitors(PIHCs)have great potential in the field of energy storage.Here,a novel bilayer-shelled N,O-doped hollow porous carbon microspheres(NOHPC)anode has been prepared by a self-template method,which is consisted of a dense thin shell and a hollow porous spherical core.Excitingly,the NOHPC anode possesses a high K-storage capacity of 325.9 mA h g^(−1)at 0.1 A g^(−1)and a capacity of 201.1 mAh g^(−1)at 5 A g^(−1)after 6000 cycles.In combination with ex situ characterizations and density functional theory calculations,the high reversible capacity has been demonstrated to be attributed to the co-doping of N/O heteroatoms and porous structure improved K+adsorption and intercalation capabilities,and the stable long-cycling performance originating from the bilayer-shelled hollow porous carbon sphere structure.Meanwhile,the hollow porous activated carbon microspheres(HPAC)cathode with a high specific surface area(1472.65 m^(2)g^(−1))deriving from etching NOHPC with KOH,contributing to a high electrochemical adsorption capacity of 71.2 mAh g^(−1)at 1 A g^(−1).Notably,the NOHPC//HPAC PIHC delivers a high energy density of 90.1 Wh kg^(−1)at a power density of 939.6 W kg^(−1)after 6000 consecutive charge-discharge cycles.

Integrating Geochemical and Geophysical Method in Coexistence of Oil and Potassium to Identify K-rich Brine:Research and Application in Southwestern Sichuan

Lithology of Triassic in southwestern Sichuan is consistent with the whole basin,and there is no discussion about stratum division,the difference is stratum denudation which is made by the uplifting of Luzhou uplift,especially

雪茄烟苗期钾素营养特征及干物质的积累

为提高雪茄烟的品质,明确雪茄烟育苗阶段干物质积累及钾素吸收利用特性的很有必要,试验采用溶液培养方法,研究钾素供应水平(不供钾、正常供钾(1 L霍格兰氏营养液含有506 mg硝酸钾)、超量供钾(1 L霍格兰氏营养液含有506 mg硝酸钾+523.23 mg硫酸钾)对雪茄烟烟苗生长状况、干物质积累量及钾素吸收利用特性的影响。结果表明,钾素显著影响雪茄烟苗期形态建成。就烟苗农艺性状而言,水培45 d时,株高、茎围、最大叶长和最大叶宽均以正常供钾处理最高,分别为31.67、2.30、21.17、11.17 cm;烟苗干物质积累而言,不供钾处理在水培过程中干物质积累较为缓慢,超量供钾处理在水培15~30 d时累积量很小且缓慢,而水培30~45 d时积累量急剧增加;在钾素方面,与CK相比,超量供钾处理提高了烟株钾素含量,但钾素利用率却有所降低,在水培15、30、45 d时分别降低了1.48%、18.24%、11.45%。综上,缺钾从开始即影响烟苗生长,根系生长受抑制,缺钾症状典型特征15 d后逐步显现;钾素过量时,烟株前期长势稍好,中后期增效不明显,干物质积累在烟苗生长前期积累量小且缓慢,且钾素利用率低于正常施钾处理。

HNO_(3)-H_(2)O_(2)消解体系对植物中磷和钾元素的快速定量分析

为研究不同酸溶消解体系对植物样品中磷、钾测定的影响,分别采用H_(2)SO_(4)-H_(2)O_(2)、HNO_(3)-HClO_(4)、HNO_(3)-H_(2)O_(2)和王水-H_(2)O_(2)等4种酸体系对灌木枝叶标准物质(GBW07603)进行酸溶消解处理,使用电感耦合等离子体发射光谱仪(ICP-OES)测定其中磷、钾的含量,筛选最优的酸溶消解体系.结果表明,HNO_(3)-H_(2)O_(2)消解法对植物样品消解彻底且消解后溶液澄清,测定结果的准确度和精密度最高,安全性好,是最佳消解体系.加酸量±10%对HNO_(3)-H_(2)O_(2)消解法测定磷、钾元素含量结果没有显著影响,但消解温度对其影响较大,最适消解温度为150—180℃.在最优条件下,磷的检出限和测定限分别为0.004 g·kg^(−1)和0.018 g·kg^(−1);钾的检出限和测定限分别为0.06 g·kg^(−1)和0.25 g·kg^(−1);对8种不同植物标准物质中磷和钾测定值均在标准值范围内,且相对标准偏差和相对误差都小于±5%;对4种不同植物标准物质的加标回收率在91%—106%之间.因此,HNO_(3)-H_(2)O_(2)消解结合ICP-OES测定方法能满足不同植物的测定要求,可用于大批量样品的快速检测分析.

动物性饲料原料中铁元素含量的快速检测方法研究

研究旨在建立一种利用分光光度法快速检测动物性饲料原料中铁元素含量的方法。采用两种分光光度法(邻菲罗啉法和硫氰酸钾法)对动物性饲料原料灰分中铁元素进行检测。结果显示:试验确定原料中铁元素以Fe^(3+)形式存在,选择硫氰酸钾法作为后续试验的检测方法,优化后硫氰酸钾法的最适条件为:灰化时间3.5 h、检测波长480 nm、硫氰酸钾溶液体积1.0 mL、显色时间10 min、显色反应温度30℃,显色反应过程无须避光。在此参数下测定得到标准曲线在1~20 mg/L范围内具有良好线性关系(R2>0.999 0),方程为y=0.071 5x+0.009(R^(2)=0.999 4)。硫氰酸钾法的稳定性好、准确度高、抗干扰性强,批次内相对标准偏差为1.03%~2.05%,6批次鸡肉粉样品加标回收率为98.02%~101.03%,10~50倍Fe^(3+)浓度的Na^(+)、K^(+)和Ca^(2+)不会干扰Fe^(3+)含量的检测,具有替代原子吸收光谱法进行快速检测的可行性。使用两个方法同时测定11种动物性原料样品中铁元素含量的结果差异不显著(P>0.05)。研究表明,试验建立的硫氰酸钾法可用于宠物食品动物性饲料原料中铁元素含量的快速检测。

秸秆不同还田模式下磷钾释放特征及其对玉米产量的影响

连续两年(2021—2022年)在吉林省四平市设置田间定位试验,采用尼龙网袋法测定覆盖(SM)和翻压(SB)两种秸秆还田方式和不施氮肥(N0)、180 kg·hm^(-2)(N180)两种施氮水平下秸秆磷、钾释放率,旨在明确黑土区玉米秸秆磷、钾释放规律对还田方式和氮肥管理的响应及其对玉米产量的影响。结果表明,还田方式与施氮显著影响秸秆磷、钾释放,SB处理秸秆磷两年累积释放率平均为69.7%,显著高于SM处理的54.5%;与N0处理相比,施氮处理秸秆磷释放率提高了12.3%。SB处理秸秆钾两年累积释放率平均为95.6%,显著高于SM处理的94.2%;而施氮对秸秆钾累积释放影响同样显著,肥料氮素投入使秸秆钾累积释放率提高1.1%。通过对秸秆磷、钾替代潜力的估算,认为秸秆磷对磷肥(P2O5)替代潜力较低,为9.1 kg·hm^(-2);但秸秆钾对钾肥(K_(2)O)替代潜力较高,为141.0 kg·hm^(-2)。两年间还田方式对玉米产量无明显影响,但玉米穗粒数存在一定差异。SB处理玉米穗粒数为430粒·穗^(-1),显著高于SM处理的409粒·穗^(-1)。而施氮则明显促进了产量的形成,提高了玉米产量,与N0处理相比,两年玉米产量平均增加7707 kg·hm^(-2)。通过结合秸秆磷、钾养分释放综合分析,认为在黑土区充足氮素供应条件下以翻压方式进行秸秆还田,秸秆释放的磷、钾养分有利于穗粒的形成,从而保障产量稳定。

碱性过硫酸钾-紫外分光光度法测定水质总氮方法的改进

水质总氮是指示水体富营养化的重要标志物,因此,开发测定水体中总氮的准确方法,对研究水体中的污染物来源、污染程度及总氮的地球化学循环过程具有重要意义。测定水质样品中的总氮,通常采用碱性过硫酸钾-紫外分光光度法,但该法对空白吸光度有严苛的要求,空白吸光度一旦超过0.030,就有可能导致测定结果严重偏低,其中,过硫酸钾的纯度和存放时间可能对测定结果影响最大;同时,采用比色管捆绑方式高温高压消解水质样品,导热较慢,消解时间偏长,捆绑时一旦比色管上的标签或记号脱落,容易导致样品混乱;样品保存条件不当也很容易造成测定结果偏低。为提高水质样品中总氮测定结果的准确性和效率,本文通过对国内外不同厂家生产的过硫酸钾进行总氮空白吸光度和存放时间对比实验,然后对两种消解方法进行消解时间对比实验,最后,对比了两种不同水质样品保存方法对测定结果的影响。对比实验结果表明:国产优级纯碱性过硫酸钾存放时间在30天内,其水质总氮空白吸光度均小于0.030;在124℃条件下,使用插置法消解样品,只用20min就能使样品消解完全;对酸化后的水质样品,其保质期从1天延长至7天。研究认为,选用国产优级纯过硫酸钾和改良过的插置法消解水质样品,与捆绑法相比,其水质总氮检出限更低,消解效率更高,且不容易出现互相污染和样品错位等情况,提高了水质总氮测定的准确度。

Synthesis of platy potassium magnesium titanate and its application in removal of copper ions from aqueous solution

Platy potassium magnesium titanate (K0.8Mg0.4Ti1.6O4, KMTO) was synthesized by a flux method. The potential application of KMTO in removing copper ions from water pollutants was investigated. The crystal phases of specimens were identified by XRD. The morphology and structural information were characterized by SEM and TEM. The adsorption behavior under different conditions was investigated, including different pH values and different initial copper ion concentrations. The results show that the maximum adsorption capacity of Cu(II) ions is 290.697 mg/g, and almost 99.9% of Cu(II) ions can be removed, which is much higher than that of other sorbents reported. The kinetics of KMTO for the adsorption of Cu(II)ions was studied and the best fit can be obtained by the pseudo-second-order model. Adsorption isothermal data can be well interpreted by the Freundlich equation (R2=0.991). In conclusion, this study highlights that KMTO is a potential material for the efficient removal of heavy metal ions in polluted water. It also opens up a new opportunity for the applications of platy KMTO.

高锰酸钾法氧化还原滴定实验的课程思政设计

以“高锰酸钾法氧化还原滴定实验”为基础,结合水质化学耗氧量(COD)监测应用,进行实验课程思政创新设计。案例通过引入梯度化COD水样为检测对象,结合工业废水排放监管探索性实践,以及研讨身边水污染治理实例等,引导学生关注水污染防治等社会问题,激发其保护生态环境的责任感和国家生态文明建设服务意识。

二氧化锰的晶型控制及其对罗丹明B的降解研究

以高锰酸钾、四水氯化锰和少量浓盐酸为原料,利用水热法实现了MnO_(2)由α晶型向γ晶型再向β晶型的转变,采用X射线衍射(XRD)、X射线光电子能谱(XPS)和扫描电镜(SEM)等表征方法分析了MnO_(2)的晶型转化机理。利用高级氧化法以制备的MnO_(2)为催化剂对罗丹明B(RhB)进行了催化降解研究,探寻了催化效果最好的MnO_(2)晶型并推理出RhB的降解路径。结果表明:随着水热反应时间的延长,α-MnO_(2)逐渐向具有较小隧道尺寸的γ-MnO_(2)、β-MnO_(2)转变;3种晶型的MnO_(2)活化PMS对RhB均具有显著的降解效果,降解效率为α-MnO_(2)>γ-MnO_(2)>β-MnO_(2);紫外-可见吸收光谱分析说明MnO_(2)活化PMS降解RhB的路径为RhB先经过逐步脱乙基化转变成罗丹明、再生成其他有机小分子、CO_(2)和H2O。

烧结机头灰浸出提取高纯度氯化钾的研究

为了实现烧结机头灰中的氯化钾高附加值利用,以某钢铁企业的烧结机头电除尘灰和高盐碱性洗脱水为原料,采用预处理-高盐废水协同水洗脱钾-真空抽滤-除杂与脱色-固液分离-分盐结晶的工艺路线,设计了BoxBehnken试验,建立浸出温度、液固比和搅拌速率3个因素与烧结机头灰钾脱除率之间的数学模型,采用响应曲面(Box-Behnken)法对烧结机头灰钾脱除率工艺进行优化,并通过氯化钠和氯化钾在不同温度下的溶解度大小进行分盐结晶。实验结果表明:响应曲面分析得出3个因素对烧结机头灰中钾的脱除率的影响程度由大到小依次为浸出温度、液固质量比、搅拌速率;浸出过程最佳的工艺条件是浸出温度为51.45℃、液固质量比为2.85∶1、搅拌速率为674 r/min,30 min时钾的脱除率为93.89%;含钾滤液经过除杂脱色处理后,利用NaCl-KCl-H_(2)O水盐体系相图,控制蒸发条件进行分盐结晶,使闪发终点控制在氯化钾单固相结晶区内,可得到纯度为92%氯化钾产品。

熔盐法合成三钼酸钾超长纳米线及其生长机理研究

本文以硝酸锂-硝酸钠-硝酸钾三元硝酸盐为反应介质,以三氧化钼为原料,研究了反应温度、反应物/熔盐比例和清洗方式等因素对三钼酸钾纳米线制备的影响规律。进一步采用X射线衍射仪、扫描电子显微镜和透射电子显微镜对产物的结构和形貌进行表征。结果表明,在410℃反应40分钟,随后使用50%的乙醇冰水溶液洗涤,可以得到直径约200 nm、长径比超过2000的三钼酸钾超长纳米线。当反应温度低于160℃时,三氧化钼尚不能与熔盐反应。当反应温度高于170℃时,开始析出三钼酸钾纳米线。通过能谱分析可知,本研究中熔盐法制备的三钼酸钾纳米线的生长机理遵循溶解-析出的反应机制。降温过程中溶解的钼离子逐渐过饱和析出,进而与熔盐中的钾离子反应,形成三钼酸钾一维结构。

环境监测中两种COD测定方法的对比研究

环境监测中的化学需氧量(COD)是评估废水中有机物污染程度的关键指标。本研究对比了两种常用的COD测定方法:传统重铬酸钾法和快速光谱法。通过对两种方法的原理、优缺点进行分析,结果表明,传统重铬酸钾法准确度高,但操作繁琐、耗时且对环境有害,而快速光谱法操作简便、快速,适合快速的现场监测,但容易受其他物质的干扰。本研究为环境监测领域选择COD测定方法提供了科学依据。

不同灌溉和钾肥浓度对秋葵生理生化指标的影响

以秋葵为研究对象,采用盆栽试验,研究了润湿灌溉、仅有承隔盘、以色列新一代灌溉和传统灌溉方式下不同钾肥浓度对秋葵常用生理生化指标的影响。结果表明,灌溉方式和钾肥浓度对秋葵植株叶片叶绿素含量具有显著的影响,润湿灌溉条件下秋葵植株叶片叶绿素含量较高,最大值达到22.55 mg/g,受钾肥浓度的影响较小;相同钾肥浓度下,秋葵植株根系活力表现为润湿灌溉≈仅有承隔盘>传统栽培≈以色列新一代灌溉;秋葵植株叶片中硝酸还原酶活性受钾肥浓度影响较小,润湿灌溉≈仅有承隔盘>以色列新一代灌溉>传统栽培,以色列新一代灌溉极显著高于传统灌溉。

手动膜片钳检测盐酸罗哌卡因及其右旋异构体对HEK293细胞hERG电流的影响

目的研究比较盐酸罗哌卡因和盐酸罗哌卡因右旋异构体对高表达hERG钾通道的HEK293细胞hERG电流的影响。方法用手动膜片钳检测转染后hERG钾通道稳定表达的HEK293细胞电流,多菲莱德做阳性药,将盐酸罗哌卡因和盐酸罗哌卡因右旋异构体依次稀释成30.00、10.00、3.33、1.11、0.37μmol·L^(-1),依次作用于细胞,记录电流变化,计算抑制率。结果盐酸罗哌卡因0.37、1.11、3.33、10、30μmol·L^(-1)对电流Iherg-tail的抑制率分别为(6.12±0.30)%、(13.04±1.20)%、(19.21±0.33)%、(35.56±0.66)%、(65.37±4.17)%,IC_(50)为19.482μmol·L^(-1)(n=15)。盐酸罗哌卡因右旋异构体0.37、1.11、3.33、10.00、30.00μmol·L^(-1)对电流Iherg-tail的抑制率分别为(4.13±3.43)%、(7.34±5.60)%、(9.49±2.75)%、(16.60±0.87)%、(31.36±1.45)%,IC_(50)>30μmol·L^(-1)(n=15)。阳性对照药品多菲莱德0.00185、0.00556、0.01667、0.05000、0.15000μmol·L^(-1)对电流Iherg-tail的抑制率分别为(7.81±2.77)%、(19.67±1.88)%、(57.16±4.39)%、(89.71±3.55)%、(99.66±0.89)%、IC_(50)为0.015μmol·L^(-1)(n=15)。结论和阳性对照药品多菲莱德比较,盐酸罗哌卡因对hERG通道为弱抑制作用,盐酸罗哌卡因右旋异构体对hERG通道为无明显抑制作用。