A theoretical study of hydrogen-bonded molecular clusters of sulfuric acid and organic acids with amides

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.     

The oxidation of octanoic acid by cultured amniotic fluid cells: The effect of cell type and passage number

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.     

大孔树脂对邻苯二甲酸的吸附研究

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。     

利用糠醛渣生产高吸附性粉状活性炭

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     

RAINS-ASIA模型及上海市、浙江省的应用

ＲＡＩＮＳ是欧洲开发的关于酸雨污染综合分析的计算机模型。模型参数根据亚洲情况进行调整后，称为ＲＡＩＮＳ－ＡＳＩＡ。该模型能根据国家和地区的经济、行业、能耗状况，及污染控制技术，计算ＳＯ２的排放量分布和酸性污染物的输送沉积，结合各地临界负荷，建议控制对策。以上海市和浙江省为对象，采纳两地经济年鉴公布的数据，模型运行结果表明，其结论与其他研究成果相符，模型有良好的应用与开发前景。     

硫铁矿生产硫酸的废水治理

电石渣中和－精密微孔过滤技术治理硫酸废水的工艺简洁、可靠，占地面积小，运行费用低，出水优于国家二级排放标准。     

上海市嘉定县的酸雨现状

叙述了嘉定县1989～1991年酸雨的发展趋势及现状,并扼要分析了成因。     

Metagenomic insights into responses of microbial population and key functional genes to fulvic acid during partial nitritation

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.     

降雨氢离子浓度的参数化研究

对酸雨模式中降雨的物理过程进行了简化假设，在此基础上研究了大气中影响降雨氢离子浓度的几种主要污染物（ＳＯ２ ，ＶＯＣｓ ，ＮＨ３ ，ＮＯｘ） 及温度、天顶角、雨强等因素同降雨氢离子浓度的参数关系