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951.
酸性溶液中铝-氟反应动力学 总被引:3,自引:0,他引:3
研究了酸性溶液中铝氟反应的动力学,结果表明,铝氟之间的反应速率随温度和pH的升高而增加.低pH下以Al3++F-=AlF2+反应为主,较高pH下由于AlOH2+参与反应及OH-的催化作用,反应速率加快.在铝的浓度比氟过量10倍的情况下,铝氟之间的反应可以用一级反应动力学方程来拟合,即为假一级反应.当pH<38时,柠檬酸和草酸的存在使反应速度加快,而当pH>38时,有机酸使铝氟反应速度变慢.有机酸在不同的pH下存在不同的作用机制. 相似文献
952.
EfectsofsimulatedacidrainoncationreleasinginsoilsofSouthChinaWuQing,QiuRongliang,LuYuenaDepartmentofEnvironmentalScience,Z... 相似文献
953.
Adsorption-desorption behavior of acetochlor to soils in the presence of some environmental substances 总被引:5,自引:0,他引:5
IntroductionAlthoughtheherbicideacetochlor [2 chloro N (ethoxymethyl) N (2 ethyl 6 methylphenyl)acetamide]hasbeenusedfortenyearsinChina,limitedinformationhasbeencollectedtodetermineitsfateandtransportintheenvironment.Formulationsaregenerallysoldasemulsifiabl… 相似文献
954.
Chenpeng Zuo Xianwei Zhao Hetong Wang Xiaohui M Siyuan Zheng Fei Xu Qingzhu Zhang 《环境科学学报(英文版)》2021,33(2):328-339
Amides, a series of significant atmospheric nitrogen-containing volatile organic compounds (VOCs), can participate in new particle formation (NPF) throught interacting with sulfuric acid (SA) and organic acids. In this study, we investigated the molecular interactions of formamide (FA), acetamide (AA), N-methylformamide (MF), propanamide (PA), N-methylacetamide (MA), and N,N-dimethylformamide (DMF) with SA, acetic acid (HAC), propanoic acid (PAC), oxalic acid (OA), and malonic acid (MOA). Global minimum of clusters were obtained through the association of the artificial bee colony (ABC) algorithm and density functional theory (DFT) calculations. The conformational analysis, thermochemical analysis, frequency analysis, and topological analysis were conducted to determine the interactions of hydrogen-bonded molecular clusters. The heterodimers formed a hepta or octa membered ring through four different types of hydrogen bonds, and the strength of the bonds are ranked in the following order: SOH???O > COH???O > NH???O > CH???O. We also evaluated the stability of the clusters and found that the stabilization effect of amides with SA is weaker than that of amines with SA but stronger than that of ammonia (NH3) with SA in the dimer formation of nucleation process. Additionally, the nucleation capacity of SA with amides is greater than that of organic acids with amides. 相似文献
955.
We have measured the rate of oxidation of [1−14C]octanoate in cultured amniotic fluid (AF) cells at various passages and in AF cell lines with different clonal morphology. It is possible that both the passage number and the cell type may influence the outcome of prenatal diagnosis of fatty acid oxidation defects using this technique. We found that there was no significant difference between the three major AF cell types (epithelial, large epithelial, and fibroblast) when analysed at identical passage number but there was a significant reduction in octanoate oxidation in all cell types with increasing passage. For reliable prenatal diagnosis, cell lines of similar low passage number should be used. 相似文献
956.
研究了XDA-200大孔树脂对水溶液中邻苯二甲酸的吸附。结果表明XDA-200树脂对水溶液中的邻苯二甲酸吸附速度很快,30min内基本达到平衡,其后达到完全平衡的吸附进程非常缓慢。树脂对邻苯二甲酸的吸附量随质量浓度增加而增加。pH值降低,有利于邻苯二甲酸在溶液中以分子态存在,易于树脂吸附。邻苯二甲酸的吸附均满足Freundlich和Langmiur等温吸附方程。泄漏点与进水浓度和流速均有很大关系。 相似文献
957.
介绍了采用磷酸作活化剂,将糠醛渣制成活性炭的最佳工艺条件。产品活性炭的脱色力及磷酸消耗成本等指标均达到预期理想目标 相似文献
958.
959.
960.
Jiachun Yang Li Zhang Shuang Lan Quanhao Dou Shiwei Hao Yueping Wang Xiaoxuan Wang Ruoyan Zhang Yongzhen Peng 《环境科学学报(英文版)》2023,35(2):952-962
The long-term impact of fulvic acid (FA) on partial nitritation (PN) system was initially examined in this study. The obtained results revealed that the FA lower than 50 mg/L had negligible effect on the nitrite accumulation rate (NAR nearly 100%) and ammonium removal rate (ARR 56.85%), while FA over 50 mg/L decreased ARR from 56.85% to 0.7%. Sludge characteristics analysis found that appropriate FA (<50 mg/L) exposure promoted the settling performance and granulation of PN sludge by removing Bacteroidetes and accumulating Chloroflexi. The analysis of metagenomics suggested that the presence of limited FA (0-50 mg/L) stimulated the generation of NADH, which favors the denitrification and nitrite reduction. The negative impact of FA on the PN system could be divided into two stages. Initially, limited FA (50-120 mg/L) was decomposed by Anaerolineae to stimulate the growth and propagation of heterotrophic bacteria (Thauera). Increasing heterotrophs competed with AOB (Nitrosomonas) for dissolved oxygen, causing AOB to be eliminated and ARR to declined. Subsequently, when FA dosage was over 120 mg/L, Anaerolineae were inhibited and heterotrophic bacteria reduced, resulting in the abundance of AOB recovered. Nevertheless, the ammonium transformation pathway was suppressed because genes amoABC and hao were obviously reduced, leading to the deterioration of reactor performance. Overall, these results provide theoretical guidance for the practical application of PN for the treatment of FA-containing sewage. 相似文献