Effect of a sulfonated azo dye and sulfanilic acid on nitrogen transformation processes in soil

Introduction of organic dyes into soil via wastewater and sludge applications has been of increasing concern especially in developing or under-developed countries where appropriate management strategies are scarce. Assessing the response of terrestrial ecosystems to organic dyes and estimating the inhibition concentrations will probably contribute to soil remediation studies in regions affected by the same problem. Hence, an incubation study was conducted in order to investigate the impact of a sulfonated azo dye, Reactive Black 5 (RB5) and sulfanilic acid (SA), a typical representative of aromatic sulfonated amines, on soil nitrogen transformation processes. The results apparently showed that nitrogen related processes in soil can be used as bioindicators of anthropogenic stress caused by organic dyes. It was found that urease activity, arginine ammonification rate, nitrification potential and ammonium oxidising bacteria numbers decreased by 10–20% and 7–28% in the presence of RB5 (>20 mg/kg dry soil) and SA (>8 mg/kg dry soil), respectively. Accordingly, it was concluded that organic dye pollution may restrict the nitrogen-use-efficiency of plants, thus further reducing the productivity of terrestrial ecosystems. Furthermore, the response of soil microbiota to SA suggested that inhibition effects of the organic dye may continue after the possible reduction of the parent dye to associated aromatic amines.     

Predicting N mineralized in a Georgia Coastal Plain field

The N mineralized from soil organic matter provides an important portion of N available for crop production. The objective of this study was to determine the amount of spatial variability in N mineralization potential in a field and to evaluate three different methods that might be used to estimate this variability. The three methods tested included predicting the N mineralized from surface soil properties as well as from a biological and a chemical procedure. Three soils varying in N mineralization potential were selected for the study from a field in the Georgia Coastal Plain. The N mineralized from these soils was determined by an N balance of unfertilized and cropped plots. The amount of N mineralized could not be reliably predicted from surface soil organic C, although surface soil clay concentration was positively correlated with the N mineralized. The N mineralized that was predicted using mineralization parameters determined by aerobic incubation, adjusted daily for soil water content and temperature, was approximately 50% of the field measurements of N mineralized. The values of NH₄-N extracted with hot 2 M KCl were related significantly to N mineralized in the field (r²= 0.60) and also to the zero order rate constant of mineralization, k₀ (r²= 0.77), determined from the N mineralized in the aerobic laboratory incubation.     

电纺丝方法制备GaN：Eu2+ 纳米纤维与发光特征

通过结合静电纺丝和氨化技术方法合成了Eu2 掺杂的GaN（GaN：Eu2 ）纳米纤维。SEM和TEM图像显示纳米纤维由尺寸均匀分布的GaN纳米颗粒组成。XRD测试结果表明GaN：Eu2 样品主要为六方相GaN（h-GaN）,其平均粒径为7.3 nm。进一步的拉曼测试结果显示出现了两个额外的GaN拉曼位移,波数分别位于252和422 cm-1。室温光致发光谱表明GaN基质中的Eu 2 在407 nm处产生了强烈的特征蓝色发光峰。     

草浆木质素化学加氨

研究了草浆木质素化学加氨的影响因素和原料配比及氨化反应过程中活性基团的变化情况,确定出氨化反应最佳反应条件为：温度 １４０℃,氧压 １．２５ ＭＰａ,时间 １２０ ｍｉｎ。反应终结 ｐＨ值 ６．０,原料配比为木质素（纯度 ４８．９９％）：氨：水＝１ｋｇ：３０ ｍｏｌ： ４ Ｌ．氨化反应与木质素分子中羧基和基的含量密切相关。     

工业聚磷酸铵的简易制备

叙述了一种制备工业聚磷酸铵的简易方法，并就反应条件对产品质量的影响进行了详细讨论。