Adsorption Performance and Mechanism in Binding of Azo Dye by Raw Bentonite

The adsorption behavior of methyl orange (MO) from aqueous solution onto raw bentonite (RB) sample was investigated as a function of parameters such as pH, inorganic anion, contact time, and temperature. The Langmuir and Freundlich adsorption models were applied to describe the equilibrium isotherms. Langmuir adsorption capacity was found to be 34.34 mg/g at pH 4.0. The pseudo‐first‐order, pseudo‐second‐order kinetic, and the intra‐particle diffusion models were used to describe the kinetic data. The values of the energy (E_a), enthalpy (ΔH^≠), and entropy of activation (ΔS^≠) were calculated as 38.62 kJ/mol, 36.04 kJ/mol, and ?150.05 J/mol K, respectively, at pH 4.0.     

Determination of experimentally enriched15N in nitrate nitrogen based on an improved method of azo dye formation

A method has been developed for determination of¹⁵N isotope ratio in nitrate nitrogen, which is a major analytical step in tracer experiments for studies of nitrate metabolism in the marine environment. The method is based on diazotization of nitrite with sulfanilic acid following reduction of nitrate to nitrite by a cadmium-copper column. The diazonium compound is then subject to the azo coupling reaction with 2-naphthol, and the azo dye formed is extracted by a solid phase extraction column. The dye eluted from the column is collected, and total nitrogen and¹⁵N content of the dye are determined by mass spectrometry. Sulfanilic acid can also remove preexisting nitrite by heating the sample under acidic conditions before passing through the cadmium-copper reduction column. The average recovery of nitrate nitrogen was 86%. A procedure for reducing the background nitrogen that derives from the analytical operations has been developed; background nitrogen was limited to about 0.25 μg-atomN. The variation in the background nitrogen levels reflects the range of error in¹⁵N determination of nitrate nitrogen by this method. Application of the present method to a¹⁵NO₃ ⁻ isotope dilution experiment for determination of nitrification rate in sea water is demonstrated.     

江蓠属藻胆体的研究 Ⅱ.藻胆体的荧光光谱特性

报道以青岛野生型龙须菜（ｗｔ）、黄色突变体（ｙｅ１００）、４株绿色突变体（ｇｒ１８０、ｇｒ１８４、ｇｒ１８６、ｇｒ１８８）、委内瑞拉野生型龙须菜（ｌｖ）、南非野生型龙须菜（ｓａ）及真江蓠（ｇａ）为材料,用蔗糖密度梯度离心法得到完整的藻胆体。用５４０ｎｍ激发,野生型的荧光发射峰位于５７８ｎｍ和６７０ｎｍ,相对荧光强度ＦＡＰＢ／ＦＰＥ的比值为１．５０。几种材料的ＰＥ和ＡＰＢ荧光发射峰没有明显区别（不超过２ｎｍ）,但两峰荧光强度比值显著差异。结果显示ｌｖ的ＦＡＰＢ／ＦＰＥ比值最低,只有１．２０,ｇｒ１８６的比值最高,为５．６７,野生型中ｓａ也比较高,为４．７９。用６７０ｎｍ激发,野生型龙须菜的荧光社发光谱有５个峰,分别为４９９ｎｍ、５４０ｎｍ、５６８ｎｍ、６１４ｎｍ、６５０ｎｍ,与其吸收光谱一一对应。野生型和突变体、不同产地龙须菜及真江蓠的荧光发射峰的波长都与其吸收光谱相对应。     

贝类精子质量检测与评价方法的研究Ⅴ:栉江珧精子线粒体活性的荧光检测

采用罗丹明123(Rh123)和碘化丙啶(PI)两种荧光染料对栉江珧(Atrina pectinata)精子线粒体活性进行检测,比较不同染液浓度和染色时间的检测效果,并用该方法检测和比较超低温冷冻保存对线粒体活性的影响。结果显示:Rh123和PI染色的最适染液浓度均为10μg/mL,染色时间控制在10 min之内;染色后具有线粒体活性的精子发出绿色荧光,死精子发出红色荧光,质膜受损但线粒体还未受损的精子发出红绿色荧光,表明Rh123和PI双荧光染色检测栉江珧精子线粒体活性是可行的;精液经冷冻后,线粒体活性为61.9%、质膜完整率56.8%,显著低于新鲜精液组(95.3%、93.5%),表明冷冻对精子结构会造成不同程度的损伤,Rh123和PI双荧光染色法可用来检测栉江珧精子质量。     

荧光示踪剂的干扰实验研究

通过在室内无光照条件下开展干扰实验,探究了荧光素钠、罗丹明和荧光增白剂三种示踪剂之间的干扰规律,并应用于野外地下水二元示踪试验实例,说明了校正荧光示踪仪检测浓度(ΔC)的方法。结果表明:（1）在实验室条件下,荧光素钠的抗干扰性最强,罗丹明次之,荧光增白剂易受到干扰产生检测浓度增大的假象,这种假象服从线性变化规律;（2）当使用罗丹明作为示踪剂时,ΔC钠=0.052C罗、ΔC白=0.012C罗;当使用荧光素钠时,ΔC罗=0.507C钠、ΔC白=0.323C钠。在野外开展二元示踪试验时,建议尽量选用相互之间干扰较小的罗丹明和荧光增白剂进行组合投放,或利用本实验得到的不同示踪剂之间的干扰规律对荧光示踪仪的检测浓度进行校正。      

水溶液中有机染料分子在甲基（苯乙基）键合硅胶上的吸附

本文研究了０．２Ｍ ＮａＣｌ水溶液中亚甲兰,亮绿,中性红,品红和孔雀石绿在甲基（苯乙基）键合硅胶上的吸附速率曲线和等温线,结果表明,５种有机染料分子在键合硅胶上的平衡时间小于１ｈ,其吸附等温线符合改进ＢＥＴ方程,而且推测其吸附过程是一个开始在键合硅胶表面发生单分子层吸附,然后在微孔“凝聚”的过程。     

Direct examination of the dietary preference of the copepod<Emphasis Type="Italic">calanus helgolandicus</Emphasis> using the colorimetric approach

The food selectivity of tethered females of the copepodCalanus helgolandicus was examined by using the colorimetric approach. First, feeding behavior of the copepod did not show any differences between the red-color stained with neutral red and non-stained diets using the diatomCoscinodiscus curvatulus. Then, the copepods were fed a mixtures of two diets, the diatomC. curvatulus, stained with neutral red, and the dinoflagellateGymnodinium sanguineum for 14~60 minutes of feeding duration. The foregut colors of females were examined using a stereo-microscope and a video monitor. The foreguts of animals fed with a high density of diatoms in mixed diets showed a dark red color, whereas those fed with a high density of dinoflagellate in mixed diets were a dark yellow. The results suggest that this species of copepod may not selectively feed either one of the diets used for this study. Their feeding activity may be more likely related to the density of available prey in their environment. Therefore, this quick and easy colorimetric approach could provide very useful information, like the pre-screening procedure before designing and conducting the time-consuming and complex feeding experiments to understand the feeding ecology of copepods.     

江蓠属藻胆蛋白的研究──Ⅰ 诱变、突变体筛选及藻胆蛋白的光谱特性

用N-甲基-N′-硝基-N-亚硝基胍（MNNG）对龙须菜配子体进行诱变处理，并筛选出色素突变体。又以真江蓠、细基江篱繁枝变型、龙须菜及其突变体为材料进行了藻胞蛋白的提取、纯化及藻胆蛋白光谱特性的研究。结果表明，江蓠属三个物种藻胆蛋白的含量有明显差异，龙须菜的野生型藻体与突变体之间藻胆蛋白含量的差异比不同物种之间的差异更为显著。江蓠属三个物种中藻胆蛋白的吸收光谱中以藻红蛋白（PE）变化最大：细基江蓠繁枝变型PE的吸收光谱有二峰一肩，属Ⅰ型R-PE，而真江蓠和龙须菜的PE的吸收光谱有三个峰，属Ⅱ型R－PE：龙须菜的不同突变型藻体的吸收光谱也有Ⅰ型和Ⅱ型R－PE之分。不同物种藻蓝蛋白也有R－PC和C－PC的差异，异藻蓝蛋白的吸收光谱及三种藻胆蛋白的荧光发射光谱也略有变化。并以光合进化的观点分析了本文的实验结果。     

Comparison of Methods for Determining Specific-surface Area of Fine-grained Soils

Characteristics of fine-grained soils primarily depend on their specific-surface area and hence, reliable determination of this parameter is essential. In this context, researchers have employed quite sophisticated instruments (viz., a BET surface area analyzer, the mercury intrusion porosimetry, internal reflectance spectroscopy, X-Ray diffraction and gas pycnometer etc.) and methodologies (viz., sorption of Methylene Blue dye, Ethylene Glycol Monoethyl Ether and p-Nitrophenol) to determine specific-surface area of these soils. However, most of these methodologies are found to be quite tedious, cost and time intensive. Apart from this, the results obtained are contentious due to the inherent limitations associated with either the instruments employed or the basic assumptions made for computing the specific-surface area of the soil. Hence, it becomes mandatory to evaluate the efficiency of these methodologies for determining specific-surface area of fine-grained soils. With this in view, different types of soils were considered in this study and their specific-surface area was determined, by following different methodologies, and the results were evaluated critically. In addition, attempts were made to develop relationships between the basic properties of fine-grained soils (viz., liquid limit, cation-exchange capacity, activity, and free swell index) and the specific-surface area. These relationships will be of immense help to the practicing engineers and research fraternity.     

Hydrologic connectivity at the hillslope scale through intra-snowpack flow paths during snowmelt

The seasonal snowmelt period is a critical component of the hydrologic cycle for many mountainous areas. Changes in the timing and rate of snowmelt as a result of physical hydrologic flow paths, such as longitudinal intra-snowpack flow paths, can have strong implications on the partitioning of meltwater amongst streamflow, groundwater recharge, and soil moisture storage. However, intra-snowpack flow paths are highly spatially and temporally variable and thus difficult to observe. This study utilizes new methods to non-destructively observe spatio-temporal changes in the liquid water content of snow in combination with plot experiments to address the research question: What is the scale of influence that intra-snowpack flow paths have on the downslope movement of liquid water during snowmelt across an elevational gradient? This research took place in northern Colorado with study plots spanning from the rain-snow transition zone up to the high alpine. Results indicate an increasing scale of influence from intra-snowpack flow paths with elevation, showing higher hillslope connectivity producing larger intra-snowpack contributing areas for meltwater accumulation, quantified as the upslope contributing area required to produce observed changes in liquid water content from melt rate estimates. The total effective intra-snowpack contributing area of accumulating liquid water was found to be 17, 6, and 0 m² for the above tree line, near tree line, and below tree line plots, respectively. Dye tracer experiments show capillary and permeability barriers result in increased number and thickness of intra-snowpack flow paths at higher elevations. We additionally utilized aerial photogrammetry in combination with ground penetrating radar surveys to investigate the role of this hydrologic process at the small watershed scale. Results here indicate that intra-snowpack flow paths have influence beyond the plot scale, impacting the storage and transmission of liquid water within the snowpack at the small watershed scale.