生物降解与吸附作用协同去除卤乙酸生成势

评价了生物强化活性炭(BAC)的生物降解与吸附作用协同对消毒副产物前体物质(DBPFP)的控制效果.控制 BAC 的空床接触时间(EBCT)为 20min 时,BAC 对卤乙酸生成势(HAAFP)的去除率达到 59%,而相同条件下,普通颗粒炭(GAC)对其去除率只有 27%.BAC 工艺中微生物数量和微生物活性均明显高于 GAC 工艺.通过微生物降解作用和活性炭吸附作用的协同,BAC 对 HAAFP 的去除率与 EBCT 具有明显的线性相关性(R²=0.9069).BAC 出水中指标 UV254与 HAAFP 也表现出一定的线性相关性(R²=0.7702).     

Partitioning of water soluble organic carbon in three sediment size fractions： Effect of the humic substances

Water soluble organic carbon (WSOC) in sediments plays an important role in transference and transformation of aquatic pollutants. This article investigated the inherent mechanisms of how sediemnt grain size affect the partitioning coeffcient (k) of WSOC. Influences of NaOH extracted humic substances were particularly focused on. Sediments were sampled from two cross-sections of the middle Yellow River and sieved into three size fractions (< 63 μm, 63-100 μm, and 100--300 μm). The total concentration of WSOC in sediments (CWSOC) and k were estimated using multiple water-sediment ratio experiments. Results show that CWSOC ranges from 0.012 to 0.022 mg/g, while k ranges from 0.8 to 3.9 L/kg. Correlations between the spectrum characteristics of NaOH extracted humic substances and k were analyzed. Strong positive correlations are determined between k and the aromaticity indicators of NaOH extracted humic substances in different sediment size fractions. Comparing with finer fractions (< 63 μm), k is higher in larger size fractions (63--100 and 100--300 μm) related to higher aromaticity degree of NaOH extracted humic substances mostly. While negative relationship between k and the area ratio of fourier transform infrared spectroscopy (FT-IR) at 3400 and 1430 cm-1 implied that the lowest k was related to the highest concentration of the acidic humic groups in particles < 63 μm. WSOC in finer fractions (< 63 μm) is likely to enter into pore water, which may further accelerate the transportation of aquatic contaminants from sediment to water.     

Passive dosing: an approach to control mutagen exposure in the Ames fluctuation test

By using dialysis equilibrium experiments, the sorption of a branched nonylphenol isomer [4-(1-ethyl-1,3-dimethylpentyl)-phenol] (NP111) on various humic acids (HAs) isolated from river sediments and two reference HAs was studied. The HAs were characterized by solid-state ¹³C direct polarization/magic angle spinning nuclear magnetic resonance (¹³C DP/MAS NMR) spectroscopy. Sorption isotherms of NP111 on HAs were described by a linear model. The organic carbon-normalized sorption coefficient (K_OC) ranged from 2.3 × 10³ to 1.5 × 10⁴ L kg⁻¹. Interestingly, a clear correlation between K_OC value and alkyl C content was observed, indicating that the aliphaticity of HAs markedly dominates the sorption of NP111. These new mechanistic insights about the NP111 sorption indicate that the fate of nonylphenols in soil or sediment depends not only on the content of HA, but also on its structural composition.     

Characterization of fulvic acids during olive mill waste composting (Elemental, Thermal and fluorescence analyses)

Elemental analysis, fluorescence spectroscopy and differential scanning calorimetry (DSC) were applied to the study of fulvic acids isolated from different stages during olive mill waste composting. The fulvic extracted acids are characterized by a high nitrogen content and O/C ratio values that may result from the high degree of humification and the synthesis of more condensed humic complexes. This was confirmed by fluorescence spectroscopy in the synchronous-scan mode by the decrease of shoulder intensities at intermediate wavelengths indicating the increase of polycondensation and conjugation of unsaturated structures and the greater uniformity of fluorophores. Fluorescence spectra in the emission, excitation and synchronous modes became simpler with compost maturation. This was confirmed by DSC results which proved the high degree of polycondensation of aromatic nuclei of fulvic acid molecules during olive mill waste composting.     

Adsorption-desorption behavior of acetochlor to soils in the presence of some environmental substances

ＩｎｔｒｏｄｕｃｔｉｏｎＡｌｔｈｏｕｇｈｔｈｅｈｅｒｂｉｃｉｄｅａｃｅｔｏｃｈｌｏｒ [2 ｃｈｌｏｒｏ Ｎ (ｅｔｈｏｘｙｍｅｔｈｙｌ) Ｎ (2 ｅｔｈｙｌ 6 ｍｅｔｈｙｌｐｈｅｎｙｌ)ａｃｅｔａｍｉｄｅ]ｈａｓｂｅｅｎｕｓｅｄｆｏｒｔｅｎｙｅａｒｓｉｎＣｈｉｎａ,ｌｉｍｉｔｅｄｉｎｆｏｒｍａｔｉｏｎｈａｓｂｅｅｎｃｏｌｌｅｃｔｅｄｔｏｄｅｔｅｒｍｉｎｅｉｔｓｆａｔｅａｎｄｔｒａｎｓｐｏｒｔｉｎｔｈｅｅｎｖｉｒｏｎｍｅｎｔ.Ｆｏｒｍｕｌａｔｉｏｎｓａｒｅｇｅｎｅｒａｌｌｙｓｏｌｄａｓｅｍｕｌｓｉｆｉａｂｌ…     

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.     

饮用水致突变前体物水生腐殖酸研究进展

腐殖质是水体中常见的有机物，也是饮用水主要致突变前体物质之一。本文拟对水生腐殖酸的来源、分析方法、环境效应与健康效应以及去除方法作一简要介绍。     

Redox potential EH [Se(VI)/Se(IV)] of aqueous extractof soils from Yongshou Kaschin-Beck diseaseregion and the influence by humic acid

The relation between E_H [Se(VI)/Se(IV)] and pH of soil aqueous extract in Kaschin-Beck disease region and the effects of natural redox agents, namely humic substances, MnO₂ and Fe²⁺, on the redox property of the system were studied. The results indicated that both humic acid and Fe²⁺ could enhance the reducibility of Se(VI) and MnO₂, a limited oxidizability for Se(IV). Fe²⁺ showed a weak reducibility only at low pH value. The reducibilities of three sulfur-containing compounds for Se(VI) were in following order:thioglycollic acid > L-cysteine > sulfide     

腐殖酸与稀土元素的作用及体系稳定性

 用稀土元素（La³⁺，Ce³⁺，Ho³⁺，Yb³⁺）标准溶液对湖泊沉积物腐殖酸进行非连续滴定，研究二者之间的络合反应能力及其结合产物在水溶液体系的稳定性。结果表明，腐殖酸结构中的活性点位在与三价稀土离子作用时表现出两种不同类型，在机制上采取两级络合反应。体系中沉淀生成与否主要取决于腐殖酸对稀土离子的容纳能力。     

腐殖酸树脂处理含Pb^2＋、CU^2＋、Ni^2＋废水的研究

利用泥炭为原料制备腐殖酸树脂.在动态条件下,研究了腐殖酸树脂对重金属离子Pb^2＋、Cu^2＋和Ni^2＋的吸附效果及吸附条件.同时探讨了腐殖酸树脂对重金属离子Pb^2＋、Cu^2＋和Ni^2＋的吸附与解吸再生机理,吸附机理研究表明,腐殖酸树脂对重金属离子Pb^2＋、Cu^2＋和Ni^2＋的主要吸附形式为离子交换吸附和络合吸附.结果表明,在废水pH值为5.0～7.0,Pb^2＋、Cu^2＋和Ni^2＋浓度分别为50 mg/L,经腐殖酸树脂处理,Pb^2＋、Cu^2＋和Ni^2＋去除率可达98%以上,且处理后废水近中性.含Pb^2＋、Cu^2＋和Ni^2＋电镀废水经腐殖酸树脂处理后,废水中Pb^2＋、Cu^2＋和Ni^2＋含量显著低于国家排放标准.