UV254与COD、TOC相关分析及氯离子对测定UV254的影响

[目的]研究UV254与COD、TOC相关性及氯离子对测定UV254的影响.[方法]通过对不同浓度的邻苯二甲酸氢钾标准溶液和青岛市某污水处理厂二级出水UV254、TOC、COD进行测定分析其相关性,并分别在溶液中加入一定量的氯化钠,分析氯离子对UV254测定的影响.[结果]在试验条件下,不同浓度的邻苯二甲酸氢钾标准溶液和青岛市某污水处理厂二级出水中UV254与TOC、COD具有很好的相关性,可以作为评价水中的有机物指标;在邻苯二甲酸氢钾标准溶液中不同含量氯离子对UV254与COD、TOC相关性分析影响很小,基本可以忽略;氯离子的存在使污水厂二级出水COD/UV254、TOC/UV254值减小.[结论]用UV254替代COD、TOC评价溶液中有机物含量时,必须与具体水质相结合,才能准确表达有机物含量.     

Specific ion effect on the accumulation of abscisic acid in wheat

Studies were carried out in the glass house using sand culture to find out the specific ion effect on the accumulation of abscisic acid in wheat. Seeds were sown in sixteen different solutions of chloride, sulphate, nitrate, carbonate salts of sodium, potassium, calcium and magnesium used each at ‐2 bar osmotic potential. The leaf samples taken after 25 days of sowing indicated that osmotic as well as salt stress increased significantly the accumulation of abscisic acid. The accumulation of abscisic acid was significantly less under potassium and calcium salt ions as compared to that under sodium and magnesium salts ions. Overall effect of anions showed that accumulation of abscisic acid was more under PEG (osmotic stress and chloride salts but it was less under sulphate and nitrate salts and was the least under carbonate salts. The accumulation of abscisic acid was exceptionally high under potassium dihydrogen phosphate. In general, the accumulation of abscisic acid‐a growth inhibitor varied not only with the type of the cation but also depended on the accompanying anion indicating differential growth response of plants under different types of saline conditions having dominance of different salt ion(s).     

Is Nutrient Contamination of Groundwater Causing Eutrophication of Groundwater-Fed Meadows?

There is an ongoing debate as to whether nutrient contamination of groundwater under agricultural fields may cause nutrient-enrichment and subsequent eutrophication in discharge areas. Often, there is only circumstantial evidence to support this supposition (proximity of agricultural fields, direction of water flow, highly productive vegetation). Research on solute transport along a flow path is necessary to evaluate the risk for eutrophication. In this paper we present results of such a study. Two transects were established in a discharge meadow, a few meters downstream from fertilized cornfields. Highly productive vegetation in parts of the meadow suggested nutrient-enrichment caused by inflow of contaminated groundwater. This supposition was supported by an analysis of groundwater flow paths, residence times and chloride as tracer for pollution. However, the fate of nutrients along the flow path indicated otherwise. While we found high concentrations of DIN (dissolved inorganic nitrogen), P and K under the cornfields, DIN and P concentrations drop below detection limit when groundwater enters the meadow. Only K progressed into the meadow but did not enter the root zone. We conclude that (1) polluted groundwater from the cornfields did not cause the nutrient-enrichment, as indicated by the highly productive vegetation. Restoration projects in discharge areas should not focus upon measures in upstream areas if only circumstantial evidence is available. Solute transport should be considered as well. (2) Because K clearly showed to be the most mobile nutrient, its importance for nutrient-enrichment in discharge wetlands merits more attention in future research.     

风化煤改变黄河三角洲盐渍化土壤溶液组分的过程

黄河三角洲盐渍土改良具有重要的经济和社会意义。风化煤(0%、1%、3%、5%)添加到不同含盐量(1.0 mg·g~(-1)、7.5 mg·g~(-1)、35.3 mg·g~(-1))的滨海盐渍化土壤后,可降低土壤浸提液的钠吸附比(Sodium adsorption ratio,SAR)及Cl~-/SO_4~(2-)比,有助于减轻盐渍危害。7.5 mg·g~(-1)含盐量土壤在5%添加下SAR由7.81降为6.61,Cl~-/SO_4~(2-)由10.20降为8.25。风化煤中丰富的羧基等表面官能团及Ca~(2+),可通过三个作用过程改变盐渍化土壤溶液的离子组成,涉及:(1)风化煤固相Ca~(2+)与溶液Na~+离子的交换,从而降低土壤溶液中Na~+的浓度和危害;(2)溶液中Ca~(2+)与土壤交换性Na~+的置换,有助于土壤团聚体的形成和Na~+的淋洗;(3)溶液中的Na~+与风化煤中的溶解性有机质形成络合物,使Na~+的活度和植物有效性降低,间接起到减害作用。此外,钠吸附比和氯硫比可用于在实验室初步判断风化煤等物料用于盐渍土改良的潜力和效果。     

运城盐湖卤水化学需氧量的测定

[目的]探索氯耗氧曲线校正法测定盐湖卤水中的COD值的效果。[方法]用氯耗氧曲线校正法测定运城市盐湖卤水的化学需氧量,并与其他的一些化学分析方法进行比较。[结果]在测定条件下,氯离子极易被重铬酸钾氧化,氯离子完全氧化时间为30min。CODCr（C1）与氯离子浓度之间有较好的线性关系,线性回归方程为Y=0．2224x-0．519,相关系数r=0．9876。通过测定得知,水样中氯离子的浓度为3503．85mg／L,通过耗氧曲线及方程得出运城市盐湖卤水中的CODCr的值为438．18mg／L,显示其污染较严重,需要进一步保护。[结论]用氯耗氧曲线校正法测定盐湖卤水COD值操作简单、简便、准确度高、精密性好,同时还可避免汞盐污染环境。     

混凝土冻融损伤后的氯离子浓度分布预测

引入损伤因子对氯离子扩散系数加以修正,进而得到了同时考虑混凝土质量损失和内部损伤累积的冻融循环后混凝土中氯离子浓度分布的预测方法,通过与实验结果比较初步证明了该方法的有效性．     

二甲基二烯丙基氯化铵-镁盐改性甘蔗渣对染料废水脱色研究

为研究改性甘蔗渣在处理印染废水脱色中的实际效果,以刚果红和亚甲基蓝模拟废水为研究对象,探讨了二甲基二烯丙基氯化铵(DMDAAC)-镁盐改性甘蔗渣在吸附剂不同投加量、pH值、反应时间、初始染料浓度、温度等实验条件下对刚果红和亚甲基蓝的吸附脱色效果。结果表明,DMDAAC-Mg~(2+)改性甘蔗渣对溶液中刚果红和亚甲基蓝均具有良好的脱色作用。吸附剂投加量、pH、反应时间是影响改性甘蔗渣脱色性能的主要因素。正交实验结果显示,DMDAAC-Mg~(2+)改性甘蔗渣对刚果红和亚甲基蓝脱色率分别达到97.96%和91.89%,在相同脱色条件下,与单因素改性甘蔗渣及原材料相比,DMDAAC-Mg~(2+)改性甘蔗渣脱色效果最佳。     

离子色谱法测定蔬菜水果中氯离子、亚硫酸盐、硫酸盐含量

确立离子色谱法同时检测蔬菜水果中氯离子、亚硫酸盐、硫酸盐含量的样品处理方法和检测条件。在2%甲醛溶液SO32-的稳定剂的作用下,样品用10 mmol/L氢氧化钠溶液提取后,用IonPacAS9-HC型色谱柱为分离柱和9 mmol/L的碳酸钠淋洗液为流动相,电导检测器进行分析。结果表明,Cl-、SO32-、SO42-在2～10μg/mL浓度范围内线性良好(其相关系数分别为0.9973、0.9999、0.9991),样品中Cl-、SO32-、SO42-的加标回收率分别为83.7%～99.2%、80.6%～98.4%、81.0%～100.4%,检出限分别为0.005、0.05、0.01 mg/kg。     

Effect of substrate,medium composition,irradiance and ventilation on jojoba plantlets at the rooting stage of micropropagation

The effect of substrate, medium composition, irradiance and ventilation on rooting percentage, and root morphology and functioning with respect to mineral uptake was investigated in jojoba [Simmondsia chinensis (Link) Schneider]. Plantlets grown on Sorbarod plugs embedded in perlite accumulated more biomass and showed better rooting than plantlets grown on Sorbarod plugs embedded in agar. In plants grown on the latter substrate, the addition of sucrose to water or salts media promoted rooting and accumulation of shoot and root biomass. On perlite, rooting was high in all treatments, while root growth was enhanced only by 2% sucrose. Sucrose and irradiance had a positive synergistic effect on plantlet growth. Doubling the irradiance from 58 to 116 μE m⁻² s⁻¹ and using high ventilation (22-mm membrane) failed to improve rooting but promoted the ability of the stomata to close, thereby reducing water loss under ambient conditions. High irradiance and ventilation lowered the chlorophyll content, but without impairing biomass accumulation. Plantlets grown under enhanced ventilation and 0.5% sucrose formed fine roots within the cellulose plug and thick roots on the vessel floor. With the 2% sucrose supplementation, the roots were generally thicker, with very few thin roots being formed. ³⁶Cl uptake into plantlets and transport to the leaves decreased in plants exposed to a high sucrose concentration. Acclimatization of jojoba plantlets was improved by enhancing ventilation.