以聚己内酯作为生物反硝化固体碳源的研究

为解决水体因低碳氮比而导致脱氮效率差的问题,将颗粒聚己内酯(PCL)重新塑形为阶梯环状,研究其作为反硝化过程的生物膜载体与固相碳源的反硝化性能。结果表明,在静态实验中,平均反硝化速率为8.57 mg NO3-N/(L·h);反硝化过程为零级反应。连续填充床实验中,超过90%的硝酸盐可被去除,出水NO2-N质量浓度低于0.20 mg/L;出水NH3-N质量浓度略有上升;出水溶解性有机碳(DOC)先上升后降低至1 mg/L左右。电子扫描显微镜扫描显示,PCL阶梯环反应表面空隙率较高,表面生物膜以杆菌为主,反应后被明显腐蚀;液相色谱检测显示PCL阶梯环分子量反应前后略有下降,其结构未受到破坏;表明该材料适合作为反硝化反应的碳源的同时,又可以作为载体供微生物附着生长。     

Effect of alginate on the aggregation kinetics of copper oxide nanoparticles (CuO NPs): bridging interaction and hetero-aggregation induced by Ca<Superscript>2+</Superscript>

The stability of CuO nanoparticles (NPs) is expected to play a key role in the environmental risk assessment of nanotoxicity in aquatic systems. In this study, the effect of alginate (model polysaccharides) on the stability of CuO NPs in various environmentally relevant ionic strength conditions was investigated by using time-resolved dynamic light scattering. Significant aggregation of CuO NPs was observed in the presence of both monovalent and divalent cations. The critical coagulation concentrations (CCC) were 54.5 and 2.9 mM for NaNO₃ and Ca(NO₃)₂, respectively. The presence of alginate slowed nano-CuO aggregation rates over the entire NaNO₃ concentration range due to the combined electrostatic and steric effect. High concentrations of Ca²⁺ (>6 mM) resulted in stronger adsorption of alginate onto CuO NPs; however, enhanced aggregation of CuO NPs occurred simultaneously under the same conditions. Spectroscopic analysis revealed that the bridging interaction of alginate with Ca²⁺ might be an important mechanism for the enhanced aggregation. Furthermore, significant coagulation of the alginate molecules was observed in solutions of high Ca²⁺ concentrations, indicating a hetero-aggregation mechanism between the alginate-covered CuO NPs and the unabsorbed alginate. These results suggested a different aggregation mechanism of NPs might co-exist in aqueous systems enriched with natural organic matter, which should be taken into consideration in future studies.

Open image in new window

Graphical abstract Hetero-aggregation mechanism of CuO nanoparticles and alginate under high concentration of Ca²⁺

     

应用带电检测技术对开关柜早期缺陷的诊断

针对高压开关柜早期局部放电缺陷发现率低,故障信号源定性困难,定位准确率差的问题,结合现场实际案例进行分析,提出了基于暂态低电压、特高频和超声波的带电检测方法及幅值定位法和时差定位法的定位技术。应用结果表明:带电检测技术能够在开关柜早期缺陷诊断中发挥重大作用,并有利于设备状态评价与检修工作的开展。     

Effect of electrokinetic property of charged polyether sulfone membrane on bovine serum albumin fouling behavior

Negatively charged carboxymethylated polyethersulfone (CMPES) and positively charged quaternized polyethersulfone (QAPES) ultrafiltration (UF) membranes were prepared by bulk chemical modification and non-solvent induced phase separation method. The effects of PES membrane interfacial electrokinetic property on the bovine serum albumin (BSA) membrane fouling behavior were studied with the aid of the membrane-modified colloidal atomic force microscopy (AFM) probe. Electrokinetic test results indicated that the streaming potential (ΔE) of QAPES membrane was not consistent with its expected IEC value, however, within the pH range of 3–10, the ζ potentials of two charged-modified PES membranes were more stable than the unmodified membrane. When pH value was 3, 4.7 or 9, the interaction behavior between charged PES membrane and BSA showed that there was significant linear correlation between the jump distance r ₀ of membrane-BSA adhesion force (F/R) and the ζ potential absolute value. Charged modification significantly reduced the adhesion of PES membrane-BSA, and the adhesion data was good linear correlated with the flux decline rate in BSA filtration process, especially reflected in the CMPES membrane. The above experimental facts proved that the charged membrane interfacial electric double layer structure and its electrokinetic property had strong ties with the protein membrane fouling behavior.

Open image in new window

     

企业环境管理制度优化及其信息系统框架设计研究

污染源大数据是环保大数据的重要组成部分,然而在以环境管理制度为基础的污染源数据管理过程中,一直存在制度衔接不流畅、数据不共享等诸多问题。本文调研考察了现有各项环境管理制度的衔接情况,提出以排污许可制度为核心,通过与其他环境管理制度有效衔接,实现环境管理的各个环节的有效覆盖。通过SWOT分析法对基于"一证式"改革的环境管理制度优化方案的可行性和必要性进行了深入分析,并以排污许可证为核心,设计企业环境管理信息系统框架。试生产与竣工环保验收实效不足,可转为企业自行备案;将环评审批结论纳入排污许可证,可大幅度减轻企业相关环境管理业务人员的负担。环境管理制度的优化必须建立在部门职能转变与整合之上;同时,还必须获得国家层面的立法与行政的支持;社会舆论的关注与支持也将推动环境管理制度优化的进程。以排污许可证管理为核心的信息系统框架可以有效实现污染源排放信息整合共享。     

Effect of heavy metals (Cu, Pb, and As) on the ultrastructure of Sargassum pallidum in Daya Bay, China

Concentrations of Cu, Pb, and As were determined in seawater, surface sediment, Sargassum pallidum collected from the Daya Bay, China. The influence of metal contamination on the marine alga was investigated at chemical and ultrastructural level. Mean concentrations of Cu (19.44 mg kg^?1) and Pb (33.99 mg kg^?1) were found to be high in sediment, whereas concentration of As (122.29 mg kg^?1) in S. pallidum was higher than that in water and sediment. The ultrastructure of S. pallidum cells was anomalous and aberrant. Energy-dispersive x-ray spectroscopic analysis revealed that the nanometal particles in the form of comparatively high-electron density substance diffused in the cell structures constituted by Cu, Pb, As, etc. There is a remarkable similarity or correspondence in the anomalous elements between the geochemistry and the botanic cell, and the heavy metals have potential hazardous effect on the ocean ecology system in Daya Bay.     

生物滴滤塔处理氯苯废气的工艺性能

将活性污泥培养及驯化后接种于生物滴滤塔中，挂膜启动后处理模拟氯苯废气（简称氯苯废气），考察了生物滴滤塔在挂膜启动阶段及稳定运行阶段的性能。实验结果表明：接种41 d后生物滴滤塔成功挂膜，此时氯苯去除率稳定在90%以上；生物滴滤塔稳定运行阶段，随着进气中氯苯质量浓度由303.82 mg/m³逐渐增至1 489.05 mg/m³，氯苯去除率从85.1%降至70.1%。处理氯苯废气适宜的工艺条件为：空塔停留时间超过45 s，喷淋液流量31.8 mL/min，氯苯负荷23.97~128.01 g/（m³·h）。生物滴滤塔对喷淋液的酸性环境有较好的适应性，喷淋液pH的变化对氯苯去除率无显著影响。     

改性丝瓜络纤维对水体日落黄的吸附特性

采用化学改性的方法将丝瓜络制备为阴离子吸附剂,并将其用于水体日落黄(SY)染料的吸附,分别考察了吸附剂的用量、日落黄染料的初始浓度(C0)、p H值、温度(K)、时间(T)5个因素对吸附效果的影响。通过模拟吸附等温曲线、吸附动力学以及热力学方程并通过比表面积(BET)和红外光谱(FTIR)分析改性丝瓜络吸附染料前后和丝瓜络改性前后的变化情况以此探究其吸附机理。结果表明,p H对吸附效果影响不明显;最大吸附量随温度升高而增大,在298 K温度时最大吸附量达到137 mg/g,是未改性丝瓜络的9.78倍。Langmuir方程拟合吸附过程描述最好,吸附类别为化学吸附。吸附过程符合伪二级动力学,是一个自发和吸热的过程。改性丝瓜络可以有效去除水体中的日落黄染料。     

共代谢膜生物反应器法处理二甲基亚砜废水

采用蔗糖作为共代谢基质与一体式好氧膜生物反应器（MBR）工艺相结合处理二甲基亚砜（DMSO）废水。考察了装置的污泥驯化效果、DMSO去除率、污泥的性能、HRT和冲击负荷对DMSO去除率的影响。试验结果表明：驯化第29天，DMSO去除率达98.5%，表明MBR内的污泥已驯化成功；在MBR运行的正式期，当DMSO处于高负荷状态时，DMSO去除率较低；随蔗糖加入量的增加，DMSO去除率逐渐提高，最终恢复到DMSO高负荷冲击前的DMSO去除效果；正常运行时，装置进水ρ（DMSO）=257~1 448 mg/L（平均值为718 mg/L）、出水ρ（DMSO）=6~22 mg/L（平均值为7 mg/L），DMSO去除率为96.4%~99.6%（平均值为98.9%）；在MBR运行的正式期，污泥体积指数小于100 mL/g，表明污泥的沉降性能较好，MLVSS/MLSS较高，表明污泥的活性高，MBR内MLSS的平均值为5.52 g/L，MLVSS的平均值为4.78 g/L；MBR适宜的HRT为12 h。     

化学消毒的中和剂对水中内毒素活性检测的影响

本研究选取化学消毒的常用6种中和剂组氨酸、甘氨酸、抗坏血酸、吐温80、亚硫酸钠和硫代硫酸钠,采用动态浊度鲎试验定量检测样品中内毒素活性,研究中和剂在不同浓度范围内单独使用对内毒素活性检测的影响,旨在优选出适于鲎法检测细菌内毒素的中和剂种类,确定合适的浓度范围.结果表明在0~1.0%浓度范围内,除了甘氨酸和硫代硫酸钠之外,组氨酸、抗坏血酸、吐温80、亚硫酸钠(碱性和中性)均对鲎试验结果有不同程度的干扰,都不能在鲎试验之前作为化学消毒的中和剂.虽然0~1.0%浓度的甘氨酸对鲎试验结果基本无明显影响,但是甘氨酸和戊二醛的中和产物显黄色,所以不适于在光度法鲎试验中用作戊二醛的中和剂.0~1.0%浓度的硫代硫酸钠对鲎试验结果基本无明显干扰,但是当浓度升高至1.0%~5.0%时会对鲎试验结果有一定的抑制作用.与组氨酸、甘氨酸、抗坏血酸、吐温80和亚硫酸钠相比,硫代硫酸钠更适于在内毒素活性检测之前用作消毒剂的中和剂,但是浓度应控制在0.5%范围以内.