离子交联体系在纯棉织物免烫整理中的应用

采用阳离子化降解壳聚糖(CC)/氯乙基磺酸钠(CESA)离子交联技术,对离子交联无甲醛免烫整理技术进行了研究.结果表明,离子交联法可以明显提高织物的抗皱性,整理后织物的强力保持良好.经过离子交联整理,织物折皱回复角可提高40%以上,强力下降不大.     

氯乙酸/阳离子丙三醇离子交联抗皱整理

采用氯乙酸(CAA)处理棉织物使之阴离子化,然后与阳离子丙三醇(CG)交联,以赋予棉织物抗皱性.确定了棉织物的阴离子化工艺:浸轧→烘干→冷轧堆;研究了CAA浓度、CG浓度对离子交联棉织物折皱回复角、断裂强力和白度的影响.结果表明,离子交联织物的抗皱性明显提高,干折皱回复角提高到220°左右,湿折皱回复角高达240°;整理织物的断裂强力保留率随CG浓度的增加先增大后减小,自度逐渐降低,但均高于经2D树脂整理棉织物的断裂强力和白度.     

离子交联法对棉织物的抗皱整理

采用CAA/CHTAC、CAA/CG及CHTAC/BTCA等离子交联法对棉织物进行抗皱整理.整理后棉织物的抗皱性明显提高,强度损伤降低,无甲醛释放,但白度降低.研究发现,以CHTAC/BTCA离子交联整理的效果最好.     

中心旋转法优化离子交联提高棉织物抗皱性的工艺

棉织物阳离子化后与BTCA进行离子交联,能提高棉织物的抗皱性.采用中心旋转法优化了BTCA用量、培烘温度、焙烘时间的工艺参数.确定了离子交联整理工艺:BTCA用量90～110 g/L,145～155℃焙烘120～150 s.整理织物的千,湿折皱回复角可达220°/240°,断裂强力保留率>75%,白度>80%.     

离子交联无甲醛免烫整理工艺研究

采用CHTAC/BTCA离子交联技术对无甲醛免烫整理工艺进行研究,结合化学和红外光谱分析,提出了阳离子醚化剂CHTAC在碱性条件下的反应机理.介绍了用于离子交联免烫整理工艺的环保型催化剂硝酸钠(SN).正交试验表明,棉织物经CHTAC阳离子醚化后,质量分数为5%的NaN03用于6%的BTCA整理液中,经180℃焙烘120 s后效果最佳,整理后的织物折皱回复角可达到217°,比原布提高36%,断裂强力保留率(纬)65.9%,白度为82.7%.     

铜氨改性柠檬酸交联棉织物的研究

采用柠檬酸交联棉织物,在此基础上,配制铜氨溶液对其进行整理,生成铜氨络合的柠檬酸交联棉织物。通过红外光谱分析其结构,并通过扫描电镜观察表面形态,对其抗菌性能、耐水洗性能、铜溶出含量进行了研究。结果表明,铜氨络合的柠檬酸交联棉织物具有良好的抗菌性、耐水洗性,而且铜离子溶出含量并不高。     

棉织物的低用量BTCA/免烫树脂复合抗皱整理

采用低用量丁烷四羧酸(BTCA)和免烫树脂对纯棉织物进行复合抗皱整理。研究了免烫树脂用量和不同整理工艺对棉织物抗皱性能的影响,探讨了不同整理工艺对BTCA与棉织物酯交联度和整理织物甲醛释放量的影响。结果表明:采用BTCA和免烫树脂对棉织物两步法抗皱整理时,BTCA的酯交联度高,整理织物具有较好的抗皱性,折皱回复角(WRA)由原布的128°提高至250°,纬向撕破强力保留率为63.3%,同时整理织物的甲醛释放量比单独用免烫树脂降低了近一半。     

聚丙烯酸钠在棉织物丝素防皱整理中的应用

研究了以丝素蛋白与聚丙烯酸钠作为抗皱整理液的工艺条件(丝素含量、交联剂用量、焙烘条件等)对棉织物防皱效果的影响.结果表明,聚丙烯酸钠能使丝素大分子更好地与棉纤维共价交联,改善棉织物的抗皱性,抑制棉织物强力下降,且整理后织物白度变化不大.     

多元羧酸分子结构对交联反应的影响

采用4种分子结构不同的多元羧酸,以相同的工艺对棉织物进行免烫整理。通过红外光谱分析以及分子模拟,依据多元羧酸与棉织物的反应机理,探讨了影响棉织物折皱回复性能的多元羧酸分子结构因素。结果表明,尽管交联度比丁烷四羧酸(BTCA)低,但是环戊烷四羧酸(cis-CPTA)和环己烷六羧酸(cis-CHHA)的刚性结构能赋予棉织物更好的免烫整理效果。丙三酸(PCA)虽然分子体积小,易于向纤维内部扩散,但由于交联尺度不及丁烷四羧酸,因而难以赋予棉织物良好的折皱回复性能。因此,分子体积大小适中、交联尺度合适且具备一定的刚性,是高性能多元羧酸类交联剂的必备条件。     

潮交联整理棉织物性能与衬衫门襟缝线平整度关系

为提高潮交联整理棉织物制作衬衫时的缝线平整度,通过大量试验分析潮交联整理棉织物性能与门襟缝线平整度之间的关系,明显看出潮交联整理棉织物外观平整度、缩水、纬向弹性与门襟缝线平整度弱相关,经向弹性与门襟缝线平整度之间存在很强的正相关性,因此可通过改善潮交联整理棉织物的经向弹性,提高门襟缝线平整度。     

Arsenic(III) oxidation by iron(VI) (ferrate) and subsequent removal of arsenic(V) by iron(III) coagulation

We investigated the stoichiometry, kinetics, and mechanism of arsenite [As(III)] oxidation by ferrate [Fe(VI)] and performed arsenic removal tests using Fe(VI) as both an oxidant and a coagulant. As(III) was oxidized to As(V) (arsenate) by Fe(VI), with a stoichiometry of 3:2 [As(III):Fe(VI)]. Kinetic studies showed that the reaction of As(III) with Fe(VI) was first-order with respect to both reactants, and its observed second-order rate constant at 25 degrees C decreased nonlinearly from (3.54 +/- 0.24) x 10(5) to (1.23 +/- 0.01) x 10(3) M(-1) s(-1) with an increase of pH from 8.4 to 12.9. A reaction mechanism by oxygen transfer has been proposed for the oxidation of As(III) by Fe(VI). Arsenic removal tests with river water showed that, with minimum 2.0 mg L(-1) Fe(VI), the arsenic concentration can be lowered from an initial 517 to below 50 microg L(-1), which is the regulation level for As in Bangladesh. From this result, Fe(VI) was demonstrated to be very effective in the removal of arsenic species from water at a relatively low dose level (2.0 mg L(-1)). In addition, the combined use of a small amount of Fe(VI) (below 0.5 mg L(-1)) and Fe(III) as a major coagulant was found to be a practical and effective method for arsenic removal.     

Iron(VI) and iron(V) oxidation of copper(I) cyanide

Copper(Il) cyanide (Cu(CN)4(3-)) in the gold mine industry presentsthe biggest concern in cyanide management because it is much more stable than free cyanide. Cu(CN)4(3-) is highlytoxic to aquatic life; therefore, environmentally friendly techniques are required for the removal of Cu(CN)4(3-) from gold mine effluent. The oxidation of Cu(CN)4(3-) by iron-(VI) (FeVIO4(2-), Fe(VI)) and iron(V) (FeVO4(3-), Fe(V)) was studied using stopped-flow and premix pulse radiolysis techniques. The stoichiometry with Fe(VI) was determined to be 5HFeO(4-) + Cu(CN)4(3-) + 8H2O - > 5Fe(OH)3 + Cu2+ + 4CNO- +3/202 + 6OH-. The rate law for the oxidation of Cu(CN)4(3-) by Fe(VI) was found to be first-order with each reactant. The rates decreased with increasing pH and were mostly related to a decrease in concentration of reactive protonated Fe(VI) species, HFeO4-. A mechanism is proposed that agrees with the observed reaction stoichiometry and rate law. The rate constant for the oxidation of Cu(CN)4(3-) by Fe(V) was determined at pH 12.0 as 1.35 +/- 0.02 x 10(7) M(-1) s(-1), which is approximately 3 orders of magnitude larger than Fe(VI). Results indicate that Fe(VI) is highly efficient for removal of cyanides in gold mill effluent.     

Mind the (yield) gap(s)

This paper explores the origin of the notion of ??yield gap?? and its use as a framing device for agricultural policy in sub-Saharan Africa. The argument is that while the yield gap of policy discourse provides a simple and powerful framing device, it is most often used without the discipline or caveats associated with the best examples of its use in crop production ecology and microeconomics. This argument is developed by examining how yield gap is used in a selection of recent and influential agricultural policy documents. The message for policy makers and others is clear: ??mind the (yield) gap(s)??, for they are seldom what they appear.     

Supercritical fluid extraction (SFE) of 4(5)-methylimidazole (4-MeI) and 2-acetyl-4(5)-(1,2,3,4)-tetrahydroxybutyl-imidazole (THI) from ground-coffee with high-performance liquid chromatographic-electrospray mass spectrometric quantification (HPLC/ESI-MS).

Two polar analytes, 4(5)-methylimidazole (4-MeI) and 2-acetyl-4(5)-(1,2,3,4)-tetrahydroxybutyl-imidazole (THI), were extracted with supercritical carbon dioxide (CO2) modified with aqueous methanol. The method was applied to a roasted coffee powder with good recovery rates. Method efficiency was compared with that of solid-phase extraction using SCX Disc cartridges and validated for spiked solid matrix. The analytes were determined using isocratic liquid chromatography-mass spectrometry (LC/MS) on an Atlantis HILIC Silica column (150 x 2.1 mm, 3 microm) with 80% methanol and 20% 0.01 mol l-1 ammonium formate as the mobile phase. The limit of quantification was around 1.5 pg for 4-MeI and 2.0 pg for THI. The linearity of the calibration curves was satisfactory as indicated by correlation coefficients of >0.999. The coefficient of variation for the intra-day and inter-day precisions was <4% (n = 6). Accuracy was in the range 98-101%; recovery rates were > or = 98 and > or = 99% for THI and 4-MeI, respectively. Several samples of Arabica coffee from various locations and commercially available 'off-the-shelf' coffee products (Arabica/Robusta mixtures) were analysed to test the method.     

Reduction of Tc(VII) by Fe(II) sorbed on Al (hydr)oxides

Under oxic conditions, Tc exists as the soluble, weakly sorbing pertechnetate [TcO4-] anion. The reduced form of technetium, Tc(IV), is stable in anoxic environments and is sparingly soluble as TcO2 x nH2O(s). Here we investigate the heterogeneous reduction of Tc(VII) by Fe(II) adsorbed on Al (hydr)oxides [diaspore (alpha-AlOOH) and corundum (alpha-Al2O3)]. Experiments were performed to study the kinetics of Tc(VII) reduction, examine changes in Fe surface speciation during Tc(VII) reduction (M?ssbauer spectroscopy), and identify the nature of Tc(IV)-containing reaction products (X-ray absorption spectroscopy). We found that Tc(VII) was completely reduced by adsorbed Fe(II) within 11 (diaspore suspension) and 4 days (corundum suspension). M?ssbauer measurements revealed thatthe Fe(II) signal became less intense with Tc(VII) reduction and was accompanied by an increase in the intensity of the Fe(III) doublet and magnetically ordered Fe(III) sextet signals. Tc-EXAFS spectroscopy revealed that the final heterogeneous redox product on corundum was similar to Tc(IV) oxyhydroxide, TcO2 x nH2O.     

优质农业生产管理指导手册

优质农业生产管理体系(GAP)概念提出的目的在于确保烟叶生产的持续、健康发展,可以将GAP定义为:在保护、维持或增强土壤、水源、空气、动植物生命和环境的同时,在确保农业生产可持续发展的条件下,推行一系列农业措施,生产出一定产量和质量的优质农作物.     

优质农业生产管理指导手册(二)

4病虫害综合防治 病虫害综合防治(IPM)是烟叶生产的一项系统体系,利用病虫害预测预报系统,提供最好的病虫害综合防治决策,重点是协调应用一切可行的办法.病虫害综合防治并不意味着完全排除使用农药,而是在使用其它办法不能使病虫害的种群数保持在可接受的范围时适当使用农药.施用农药的地方应确保安全,并遵守一切法律法规.     

优质农业生产管理指导手册(三)

7 烘烤（调制）和烤房管理 烟叶的正确烘烤和烤房管理对优化烟叶的产量、质量和产值来说是非常关键的因素。烟叶烘烤是保持烟叶产量、质量的最后一道环节。烟叶质量会因烘烤不当而降低，而正确进行烘烤能确保烟叶质量的稳定。然而，若将劣质的鲜烟叶或烟株放入烤房，则不可能提高最终的烟叶质量。     

Reactivity of Pb(II) at the Mn(III,IV) (oxyhydr)oxide--water interface

In this study, the reactivity of lead (Pb(II)) on naturally occurring Mn(III,IV) (oxyhydr)oxide minerals was evaluated using kinetic, thermodynamic, and spectroscopic investigations. Aqueous Pb(II) was more strongly adsorbed to birnessite (delta-MnO1.7) than to manganite (gamma-MnOOH) under all experimental conditions. The isoteric heat of Pb adsorption (delta HT) or birnessite was 94 kJ mol-1 at a surface loading of 1.1 mmol g-1, and decreased with increasing adsorption density. This indicated that adsorption was an endothermic process and that birnessite possessed heterogeneous sites of reactivity for Pb. X-ray absorption fine structure (XAFS) spectra revealed that Pb was adsorbed as inner-sphere complexes on both birnessite and manganite with no evidence to suggest oxidation as an operative sorption mechanism. Lead appeared to coordinate to vacancy sites in the birnessite layer structure with concurrent release of Mn to solution, which resulted in a greater number of second shell Mn scatterers in Pb-birnessite when compared to Pb-manganite samples. The difference in Pb coordination apparently explained the contrasting desorption behavior between the two Mn minerals. These results have significant implications for Pb partitioning in soil environments containing solid-phase Mn(III,IV) (oxyhydr)oxides.