Clay-salt slimes of the “Belaruskali” - novel sorbents for management of liquid radioactive wastes and decontamination of environmental water streams

Journal of Radioanalytical and Nuclear Chemistry - Clay-salt slimes, production wastes from “Belaruskali” (A Belarusian factory, producing potash fertilizers), have been tested as a...     

Effect of Modifying Surfactants on Physical and Mechanical Properties of Granulated Potash Fertilizers

The modifying action of various nonpolar reagents and their mixtures with surfactants on physical and mechanical properties (humidity resistance, degree of hydrophobization, and dynamic strength) of granulated potash fertilizers was studied.     

Fertilizers applied to certified organic tomato culture

The tomato culture demands large quantities of mineral nutrients, which are supplied by synthetic fertilizers in the conventional cultivation system. In the organic cultivation system only alternative fertilizers are allowed by the certifiers and accepted as safe for humans and environment. The chemical composition of rice bran, oyster flour, cattle manure and ground charcoal, as well as soils and tomato fruits were evaluated by instrumental neutron activation analysis (INAA). The potential contribution of organic fertilizers to the enrichment of chemical elements in soil and their transfer to fruits was investigated using concentration ratios for fertilizer and soil samples, and also for soil and tomato. Results evidenced that these alternative fertilizers could be taken as important sources of Br, Ca, Ce, K, Na and Zn for the organic tomato culture.     

Corrections for interferences in a high-speed automatic thermometric analyzer

Continuous flow thermometry can be applied for the analysis of a wide range of substances at a rate of 30 samples per hour. The nature and the extent of interferences inherent in this method are examined. Methods of correction for interferences, or of avoidance of interferences, when the technique is applied to relatively concentrated solutions are described. Titrations of dilute acids in concentrated brine and the determination of potash (K₂O) in fertilizers containing high percentages of ammonia and phosphates are used as extreme examples of interference effects. With simple corrections and minor modifications to the reactions, interferences are reduced to insignificant levels and standard deviations better than 0.5 % are attainable.     

Some important moments in the development of organic elementary analysis

As early as 1784, Lavoisier carried out combustions of organic substances in a glass bell-jar filled with oxygen. No quantitative results were however obtained. In 1810, Gay-Lussac and Thenard burned organic material in a vertical tube with potassium chlorate as oxidizing agent, and analyzed the resulting mixture of gases. Later (1814–1817), Berzelius used a horizontal tube and a mixture of potassium chlorate and sodium chloride, and weighed the water and carbon dioxide formed. In 1831, Liebig described his potash apparatus and created a general method for the analysis of organic substances, in which cupric oxide was the oxidizing agent. The most important advance in organic analysis after LIEBIG is due to Pregl (1912). By his very well known methods of micro-analysis, progress in organic chemistry has been stimulated enormously. The volumetric determination of nitrogen suggested by Dumas in 1833, was developed by Pregl into a micro-method.     

Equilibrium studies on reactive extraction of naproxen enantiomers using hydrophilic ��-cyclodetrin derivatives extractants

A simple and low-cost method using liquid?Cliquid extraction coupled with complexation reactive technique has been developed for enantioselective separation of naproxen enantiomers. Three kinds of modified ??-cyclodextrins including methyl-??-cyclodextrin (Me-??-CD), hydroxyethyl-??-cyclodextrin (HE-??-CD) and hydroxypropyl-??-cyclodextrin (HP-??-CD), were selected as hydrophilic chiral selectors for extraction naproxen from organic phase to aqueous phase. A systematic study of the factors affecting chiral separation performance were investigated. The experiment results obtained show that, HP-??-CD, HE-??-CD and Me-??-CD has stronger recognition abilities for S-naproxen than those for R-naproxen. Among the ??-CD derivatives studied, HP-??-CD has the strongest ability for chiral recognition and separation. Excellent enantioselectivity (a) of 1.59 is obtained under the optimal conditions of pH of 2.5 and temperature of 5 °C.     

Optimal use of instrumental neutron and photon activation analyses for multielement determinations in sewage sludges

A combination of instrumental neutron activation analysis (INAA) and instrumental photon activation analysis (IPAA) methods has been developed for multielement determinations in a variety of sludges and fertilizers. The precision and accuracy of both the methods have been evaluated by analyzing replicate samples, NBS standard reference materials, and an interlaboratory intercomparison sewage sludge sample. The concentration rages of up to 50 elements in raw and chemical sludges, sludge-based fertilizers, and other organic and inorganic fertilizers are reported here. The advantages and limitations of the INAA and IPAA methods are also discussed here.     

How does a double-cage single molecule confine an excess electron? Unusual intercage excess electron transfer transition

To realize the chemistry of a multicage organic molecule with excess electron, as a model, by confining an excess electron inside a double-cage single molecule, the structures of e?@C??F??(NH)?C??F?? (e?@AB) and e?@C??F??(NH)?C??F?? (e?@BB') are obtained at the B3LYP/6-31G(d) + 4s4p theory level. It is confirmed that the excess electron is mainly confined inside one cage with larger interior electronic attractive potential (A for e?@AB and B for e?@BB') in the ground state, while the electron is localized in the other one in the first excited state. Owing to such excess electron localizations, an interesting intercage excess electron transfer transition takes places. This intercage excess electron transfer transition exhibits five characteristics: (1) the excess electron transfer from one cage to another (A → B for e?@AB and B → B' for e?@BB′'); (2) the transition is between the ground and first excited state; (3) the wavelength and strength are the largest; (4) the transition accompanies a significant charge transfer (Δq > 0.8) and molecular dipole moment change (Δμ > 20 D); (5) the transition corresponds to SOMO → LUMO. For the transition, the oscillator strength is larger and the wavelength is shorter for the asymmetric structure (e?@AB) than for the symmetric one (e?@BB'), which indicates that the intercage excess electron transfer transition may be regulated by changing the size of cage. This work is useful for the designs of organic electronic sponges (porous organic electrides), organic conductor with excess electrons, and photoelectric and nanoelectronic devices.     

分光光度法测定化肥中有害成份硫氰酸盐

当SCN 浓度 >5mg/L时对植物尤其是农作物就会产生危害 ,因此 ,控制化肥中SCN- 限量十分必要。测定SCN- 的电位滴定法[2 ] 灵敏度高 ,线性范围宽 ,但样品中Cl- /SCN- >1比例 ,会严重干扰测定 ,必须分离。离子色谱、高效液相色谱大多是针对痕量SCN- ( <1mg/L)测定 ,很有效。化学滴定法要求SCN- > 1 % ,且Cl- 干扰也同样需加以考虑。对于SCN- <0 1mg/L ,甚至 μg/L级的测定 ,更多地用动力学光度法[3] ,但分析样品一定要基体少 (如水样 )。且该法对温度、放置时间要求极严格。本文利用Cu2 +、吡啶 (Py)、SCN- 在氯仿中形成稳定的…     

Formation of electrochromic systems based on noncovalently associated polymer-viologen complexes

New composite electrochromic systems combining the advantages of low-molecular-mass organic electrochroms??high molar-absorption coefficients in the colored state and high switching rates??with good properties of polymers??such as mechanical strength and film-formation ability??are prepared through the incorporation of low-molecular-mass viologens into a carboxyl-containing polymer matrix via noncovalent binding. The formation of noncovalently bound polymer-viologen complexes is confirmed by IR and UV spectroscopy. It is found that the degree of substitution in a viologen molecule strongly affects the character of interaction with the polymer matrix and the electrochromic properties of the composite.     

Molecular inclusion of butylated hydroxyanisole (BHA) into alpha and beta cyclodextrins

BHA (butylated hydroxyanisole) was complexed with ??- and ??-cyclodextrins with the objective of characterizing the thermal stability. From phase solubility diagrams, the association constants for the complexes of ??-CD:BHA and ??-CD:BHA were found as 49.3 and 585 L mol^?1, respectively. To increase the thermal stability of BHA, its molecular encapsulation in ??-CD and ??-CD, was tested using molar ratios of 1:1 and 1:2 (BHA:CD) and the complex preparation techniques of kneading and physical mixture. The products of complexation were characterized by differential scanning calorimetry and thermogravimetry, indicating the formation of a BHA:??-CD complex and showing that the release of the complexed BHA occurs in the temperature range of 280?C350 °C, well above the temperature at which BHA sublimates. Dissolution tests have shown that the BHA: ??-CD complex produced by kneading has high efficiency of dissolution and partition coefficient experiments demonstrated that the presence of ??-CD leads to higher concentration of BHA in the organic phase.     

The effect of solvents and organic acids on the p-doping behaviors of poly(3′,4′-Ethylenedioxy-2,2′:5′,2″-terthiophene)

Poly(3??,4??-Ethylenedioxy-2,2??:5??,2??-terthiophene) was synthesized by chemical oxidative polymerization of 3??,4??-Ethylenedioxy-2,2??:5??,2??-terthiophene using FeCl₃ as an oxidant. The resulting polymer was characterized by FTIR and ¹H NMR. p-doping behaviors of substituted polyterthiophene with different organic sulfonic acids (methanesulfonic acid, p-toluene sulfonic acid, and ??-naphthalene sulfonic acid) in different solvents (CH₃CN, CHCl₃, THF and DMF) were studied by UV-VIS spectroscopy. The results from structural characterizations showed that the ??,????-bonding predominates in polyterthiophene. The spectroscopic changes in UV-VIS showed that ??-naphthalene sulfonic acid was an efficient doping acid for polymer while varying the solvents. Meanwhile, CH₃CN showed a high efficiency for p-doping of polyterthiophene while varying the doping acids.     

Photoluminescent phenylated polyfluorenes synthesized in an organic solvent and supercritical carbon dioxide

A number of new phenylated polyfluorenes with blue emission are synthesized via the Diels-Alder reaction in chloronaphthalene and supercritical carbon dioxide. It is shown that these polymers are thermally stable. A comparative analysis of their properties shows that a ??green?? solvent is a suitable alternative to organic solvents for obtaining phenyl-substituted polyfluorenes via the Diels-Alder reaction.     

Nitration of Mechanically Activated Sunflower Shells

Oxidative nitration of mechanically activated sunflower shells produces high-molecular-weight products containing 2.1-10.1% organically bound nitrogen and 3.6-13.7% carboxylic and 1.5-3.2% methoxyl groups. The products are proposed for using as N-containing organic fertilizers.     

Role of ligand softness and diluent on the separation behaviour of Am(III) and Eu(III)

Separation of trivalent actinides (An(III)) and lanthanides (Ln(III)) is a challenging task in the nuclear fuel cycle due to their similar charge and chemical behaviour. Some soft donor ligands show selectivity for An(III) over Ln(III) due to the formation of stronger covalent bonds with the former. The extraction behaviour of Am(III) and Eu(III) is studied in the present work with a mixture of Cyanex-301 (bis(2,4,4-trimethylpentyl)di-thiophosphinic acid) with several various ??N??, ??O?? or ??S?? donor neutral ligands. Comparison of the data was done with that of the oxygen donor analogue of Cyanex-301, i.e. Cyanex-272 (bis(2,4,4-trimethylpentyl)phosphinic acid). Effect of the organic diluent on the extraction behaviour of Am(III) using Cyanex-301 in presence of ??N?? donor synergists was also studied. Ab initio molecular orbital calculations were carried out using GAMESS software and charges on the donor atoms were calculated which helped in understanding the co-ordination chemistry of the ligands and explained the separation behaviour.     

天然螯合微肥增效作用及机理的研究

目前由人工合成的有机螯合微量元素肥料，因价格昂贵不能在农业生产中广泛应用。本研究采用丰富廉价的有机肥料，经转化提取的天然螯合剂与微量元素螯合研制的天然螯合微肥，在多种作物上施用，证明能促进作物对Ｎ、Ｐ、Ｋ和Ｆｅ、Ｍｎ、Ｚｎ、Ｃｕ等微量元素的吸收。明显提高作物的产量，改善品质，并不同程度地提高作物的抗病能力．     

Solvent extraction of dopamine by heptakis (2,3,6-tri-O-acetyl)-��-cyclodextrin

The possibility of modified cyclodextrin, heptakis (2,3,6-tri-O-acetyl)-??-cyclodextrin (TA-??-CD) to act as extracting agent for dopamine from aqueous phase into the organic phase has been investigated. Thus, by means of an ion-pairing mechanism, dopamine was extracted by modified cyclodextrin in the presence of counter ions such as picrate and tropaeolin 00. The results showed that the modified cyclodextrin can be used as extractant for dopamine. Some aspects of dopamine extractability concerning the pH and the nature of anion used as counter ion have been studied.     

QuEChERS-高效液相色谱-串联质谱法同时测定有机肥料中10种氟喹诺酮类药物残留

分析检测有机肥料中的兽药残留对于评价土壤微生物群落和人类健康的潜在风险至关重要。该文建立了一种QuEChERS联用高效液相色谱-串联质谱（HPLC-MS/MS）同时检测有机肥料中10种氟喹诺酮类药物残留的分析方法。样品经乙二胺四乙酸二钠（Na₂EDTA）-Mcllvaine缓冲溶液（pH=4.0）和乙腈提取，采用Atlantis T3 C₁₈色谱柱（250 mm×4.6 mm，5 μm），以0.2%（体积分数）甲酸水溶液和乙腈为梯度洗脱的流动相，采用电喷雾离子（ESI）源，在多反应监测（MRM）扫描模式下进行检测。10种氟喹诺酮类药物用内标法定量。结果表明，10种氟喹诺酮类药物在10~500 μg/kg范围内线性关系良好，相关系数均大于0.9930。方法检出限为0.5~2.5 μg/kg，定量限为1.7~8.3 μg/kg。该分析方法成功应用于9个有机肥样品的兽药污染调查。结果显示，样品的平均加标回收率为82.5%~117.1%，相对标准偏差为3.4%~10.2%。该方法准确可靠、灵敏度高，能够满足多种兽药残留的同时检测，该方法有望为有机肥料兽药风险评估提供依据。     

Thermal analysis of tetraethylammonium and benzyltrimethylammonium montmorillonites

Na-montmorillonite was loaded with tetraethylammonium cations (TEA) or with benzyltrimethylammonium cations (BTMA) by replacing 77 and 81% of the exchangeable Na with TEA or BTMA, labeled TEA-MONT and BTMA-MONT, respectively. TEA- and BTMA-MONT were heated in air up to 900?°C. Thermally treated organoclays are used in our laboratory as sorbents of organic compounds from water. The two organoclays were studied by TG and DTG in air and under nitrogen. Carbon content in each of the heated sample was determined. They were diffracted by X-ray, and fitting calculations of d(001) peaks were performed on each diffractogram. TG and thermo-C analysis showed that at 150 and 250?°C both organoclays lost water but not intercalated ammonium cations. DTG peak of the first oxidation step of the organic cation with the formation of low-temperature stable charcoal (LTSC) appeared at 364 and 313?°C for TEA- and BTMA-MONT, respectively. The charcoal was gradually oxidized by air with further rise in temperature. DTG peak of the second oxidation step with the formation of high-temperature stable charcoal (HTSC) appeared at 397 and 380?°C for TEA- and BTMA-MONT, respectively. DTG peak of the final oxidation step of the organic matter appeared at 694 and 705?°C for TEA- and BTMA-MONT, respectively, after the dehydroxylation of the clay. Thermo-XRD analysis detected TEA-MONT tactoids with spacing 1.40 and 1.46?nm up to 300?°C. At 300 and 360?°C, LTSC-MONT tactoids were detected with spacing of 1.29?nm. At higher temperatures, HTSC-MONT-?? and -?? tactoids were detected with spacings of 1.28 and 1.13?nm, respectively. BTMA-MONT tactoids with spacings 1.46 and 1.53?nm were detected up to 250?°C. At 300 and 360?°C, LTSC-MONT tactoids were detected with a spacing of 1.38?nm. At higher temperatures, HTSC-MONT-?? and -?? tactoids were detected with spacings of 1.28 and 1.17?nm, respectively. At 650?°C, both clays were collapsed. HTSC-??-MONT differs from HTSC-??-MONT by having carbon atoms keying into the ditrigonal holes of the clay-O-planes. At 900?°C, the clay fraction is amorphous. Trace amounts of spinel and cristobalite are obtained from thermal recrystallization of amorphous meta-MONT.