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161.
青岛大气气溶胶中氨基化合物的分布特征 总被引:2,自引:1,他引:1
氨基化合物是大气气溶胶和雨水中常被检出的一类有机氮化合物,由于其可作为生物生长直接的氮源,因此可能对海洋生态系统产生直接作用.利用2008年1~12月在青岛采集的66个总悬浮颗粒物样品,采用邻苯二甲醛/N-乙酰-L-半胱氨酸柱前衍生高效液相色谱法,分析了其中溶解态(DAC)和颗粒态氨基化合物(PAC)的浓度.气溶胶中DAC浓度为2.4~40.9nmol·m-3,在春季最高,夏季次之,秋季、冬季最低.PAC浓度为0.7~76.1nmol·m-3,呈现春季冬季秋季夏季的变化趋势.不同季节氨基化合物的组成不同.依据气团的后向轨迹,气溶胶样品可分为受北方陆源、南方陆源和海洋源影响,DAC和PAC在受南方陆源影响的气溶胶中浓度最高,北方陆源次之,海洋源气溶胶中最低.不同来源的气溶胶中氨基化合物的组成不同,蛋白质类氨基化合物对总氨基化合物的贡献在海洋源气溶胶中最高,在南方源气溶胶中最低. 相似文献
162.
Removal of phosphate by Fe-coordinated amino-functionalized 3D mesoporous
silicates hybrid materials
Phosphate removal from aqueous waste streams is an important approach to control the eutrophication downstream bodies of water.
A Fe(III) coordinated amino-functionalized silicate adsorbent for phosphate adsorption was synthesized by a post-grafting and metal
cation incorporation process. The surface structure of the adsorbent was characterized by X-ray di raction, N2 adsoropion/desoprotion
technique, and Fourier transform infrared spectroscopy. The experimental results showed that the adsorption equilibrium data were well
fitted to the Langmuir equation. The maximum adsorption capacity of the modified silicate material was 51.8 mg/g. The kinetic data
from the adsorption of phosphate were fitted to pseudo second-order model. The phosphate adsorption was highly pH dependent and
the relatively high removal of phosphate fell within the pH range 3.0–6.0. The coexistence of other anions in solutions has an adverse
e ect on phosphate adsorption; a decrease in adsorption capacity followed the order of exogenous anions: F?? > SO2?? 4 > NO??3 > Cl??. In
addition, the adsorbed phosphate could be desorbed by NaOH solutions. This silicate adsorbent with a large adsorption capacity and
relatively high selectivity could be utilized for the removal of phosphate from aqueous waste streams or in aquatic environment. 相似文献
163.
Yusheng Wang Zhiguo Pei Xiaoquan Shan Guangcai Chen Jing Zhang Yaning Xie Lirong Zheng 《环境科学学报(英文版)》2011,23(1):112-118
The mutual e ects of metal cations (Cu2+, Pb2+, Zn2+, and Cd2+) and p-nitrophenol (NP) on their adsorption desorption behavior
onto wheat ash were studied. Results suggested that Cu2+, Pb2+, and Zn2+ diminished the adsorption and increased the desorption of
NP remarkably, while Cd2+ had no such e ect. In contrast, NP diminished the adsorption of Cu2+, Pb2+, and Zn2+ onto ash, however,
this suppression e ect depended on the initial concentrations of metal cations. NP had no e ect on Cd2+ adsorption on ash. Fourier
transform infrared (FT-IR) and X-ray absorption spectroscopic (XAS) studies suggested the following mechanisms responsible for the
metal suppression e ect on NP adsorption: (1) large hydrated Cu2+, Pb2+, and Zn2+ shells occupied the surface of ash and prevent
nonspecific adsorption of NP onto ash surface; (2) Cu2+, Pb2+, and Zn2+ may block the micropores of ash, resulting in decreased
adsorption of NP; (3) complexation of Cu2+, Pb2+, and Zn2+ was likely via carboxyl, hydroxylic and phenolic groups of wheat ash and
these same groups may also react with NP during adsorption. As a “soft acid”, Cd2+ is less e cient in the complexation of oxygencontaining
acid groups than Cu2+, Pb2+, and Zn2+. Thus, Cd2+ had no e ect on the adsorption of NP on wheat ash. 相似文献
164.
F. Olcay Topac Sagban 《环境科学学报(英文版)》2011,23(4):616-623
The possible impacts on nitrogen-cycle in a p-nitrophenol (PNP) polluted soil and the e ectiveness of wastewater sludge amendments
in restoring nitrification potential and urease activity were evaluated by an incubation study. The results indicated that PNP at 250 mg/kg
soil inhibited urease activity, nitrification potential, arginine ammonification rate and heterotrophic bacteria counts to some extents.
After exposure to PNP, the nitrification potential of the tested soil was dramatically reduced to zero over a period of 30 days. Based
on the findings, nitrification potential was postulated as a simple biochemical indicator for PNP pollution in soils. Nitrogen-cycling
processes in soils responded positively to the applications of wastewater sludges. A sludge application rate of 200 tons/ha was su cient
for successful biostimulation of these nitrogen processes. The microbial activities in sludge-amended, heavy PNP-polluted soils seemed
to recover after 30–45 days, indicating the e ectiveness of sludge as a useful soil amendment. 相似文献
165.
Application of magnetic particles modified with amino groups to adsorb
copper ions in aqueous solution 总被引:1,自引:1,他引:0
A magnetic adsorbent can be easily recovered from treated water by magnetic force,without requiring further downstream treatment.In this research,amine-functionalized silica magnetite has been synthesized using N-[3-(trimethoxysilyl)propyl]-ethylenediamine(TPED) as a surface modification agent.The synthesized magnetic amine adsorbents were used to adsorb copper ions in an aqueous solution in a batch system,and the maximum adsorption was found to occur at pH 5.5 ± 0.1.The adsorption equilibrium data fitted t... 相似文献
166.
Carbonyl sulfide (COS) and dimethyl sulfide (DMS) fluxes from an urban Cynodon dactylon lawn and adjacent bare soil were
measured during April–July 2005 in Guangzhou, China. Both the lawn and bare soil acted as sinks for COS and sources for DMS.
The mean fluxes of COS and DMS in the lawn (–19.27 and 18.16 pmol/(m2 sec), respectively) were significantly higher than those
in the bare soil (–9.89 and 9.35 pmol/(m2 sec), respectively). Fluxes of COS and DMS in mowed lawn were also higher than those
in bare soils. Both COS and DMS fluxes showed diurnal variation with detectable but much lower values in the nighttime than in the
daytime. COS fluxes were related significantly to temperature and the optimal temperature for COS uptake was 29°C. While positive
linear correlations were found between DMS fluxes and temperature. COS fluxes increased linearly with ambient COS mixing ratios,
and had a compensation point of 336 ppt. 相似文献
167.
Visible light responsive N-F-codoped TiO2 photocatalysts exhibit a higher catalytic activity than N-doped TiO2 for the degradation of 4-chlorophenol due to the synergistic effect of nonmetal elements. 相似文献
168.
169.
170.
Qiushi Shen Qilin Zhou Jingge Shang Shiguang Shao Lei Zhang Chengxin Fan 《环境科学学报(英文版)》2014,26(2):281-288
Organic matter-induced black blooms(hypoxia and an offensive odor) are a serious ecosystem disasters that have occurred in some large eutrophic shallow lakes in China. In this study, we investigated two separate black blooms that were induced by Potamogeton crispus in Lake Taihu, China. The main physical and chemical characteristics, including color- and odor-related substances, of the black blooms were analyzed. The black blooms were characterized by low dissolved oxygen concentration(close to 0 mg/L), low oxidation-reduction potential, and relatively low pH of overlying water. Notably higher Fe2+and∑S2-were found in the black-bloom waters than in waters not affected by black blooms. The black color of the water may be attributable to the high concentration of these elements, as black FeS was considered to be the main substance causing the black color of blooms in freshwater lakes. Volatile organic sulfur compounds, including dimethyl sulfide, dimethyl disulfide, and dimethyl trisulfide, were very abundant in the black-bloom waters. The massive anoxic degradation of dead Potamogeton crispus plants released dimethyl sulfide, dimethyl disulfide, and dimethyl trisulfide, which were the main odor-causing compounds in the black blooms. The black blooms also induced an increase in ammonium nitrogen and soluble reactive phosphorus levels in the overlying waters. This extreme phenomenon not only heavily influenced the original lake ecosystem but also greatly changed the cycling of Fe, S, and nutrients in the water column. 相似文献