Degradation of phthalate esters in an activated sludge wastewater treatment plant

Efficient removal of phthalate esters (PE) in wastewater treatment plants (WWTP) is becoming an increasing priority in many countries. In this study, we examined the fate of dimethyl phthalate (DMP), dibutyl phthalate (DBP), butylbenzyl phthalate (BBP), and di-(2-ethylhexyl) phthalate (DEHP) in a full scale activated sludge WWTP with biological removal of nitrogen and phosphorus. The mean concentrations of DMP, DBP, BBP, and DEHP at the WWTP inlet were 1.9, 20.5, 37.9, and 71.9 μg/L, respectively. Less than 0.1%, 42%, 35%, and 96% of DMP, DBP, BBP, and DEHP was associated with suspended solids, respectively. The overall microbial degradation of DMP, DBP, BBP, and DEHP in the WWTP was estimated to be 93%, 91%, 90%, and 81%, respectively. Seven to nine percent of the incoming PE were recovered in the WWTP effluent. Factors affecting microbial degradation of DEHP in activated sludge were studied using [U-¹⁴C-ring] DEHP as tracer. First order rate coefficients for aerobic DEHP degradation were 1.0×10⁻², 1.4×10⁻², and 1.3×10⁻³ at 20, 32, and 43 °C, respectively. Aerobic degradation rates decreased dramatically under aerobic thermophilic conditions (<0.1×10⁻² h⁻¹ at 60 °C). The degradation rate under anoxic denitrifying conditions was 0.3×10⁻² h⁻¹, whereas the rate under alternating conditions (aerobic-anoxic) was 0.8×10⁻² h⁻¹. Aerobic DEHP degradation in activated sludge samples was stimulated 5-9 times by addition of a phthalate degrading bacterium. The phthalate degrading bacterium was isolated from activated sludge, and maintained a capacity for DEHP degradation while growing on vegetable oil. Collectively, the results of the study identified several controls of microbial PE degradation in activated sludge. These controls may be considered to enhance PE degradation in activated sludge WWTP with biological removal of nitrogen and phosphorus.     

Biosynthesis of di-(2-ethylhexyl) phthalate (DEHP) and di-n-butyl phthalate (DBP) from red alga--Bangia atropurpurea

The contents of di-(2-ethylhexyl) phthalate (DEHP) and di-n-butyl phthalate (DBP) of red alga, Bangia atropurpurea, filaments cultured in artificial sea water medium were similar to those cultured in natural sea water medium. In the culture experiment, B. atropurpurea filaments were found to synthesize de novo phthalate esters. Additionally, DEHP and DBP contents in different species of algae grown in the same environment were different significantly, suggesting that it was due to the intrinsic nature of algae.     

增韧剂对环氧树脂玻璃钢性能影响的研究

分别采用邻苯二甲酸二丁酯(DBP)和苯乙烯-丁二烯-苯乙烯(SBS)来增韧环氧树脂玻璃钢(EPFRP),探讨增韧剂对EP FRP的拉伸性能、冲击性能以及硬度的影响。结果表明:DBP和SBS的质量分数为7%左右时,经两种增韧剂改性的EP FRP的性能相当;而当质量分数大于7%时,DBP的增韧效果随用量的增大进一步增强,而SBS的增韧效果则呈减弱趋势。从断口的微观形貌来看,是由于DBP和SBS分散状况不同,导致了两者增韧机理和增韧效果的差异。     

Hydrodehalogenation of 2,4-dibromophenol by electrochemical reduction

The electrochemical hydrodehalogenation (HDH) of 2,4-dibromophenol (DBP) has been carried out by electrochemical reduction in H-cells and solid polymer electrolyte (SPE) cells using catalysed cathodes. The electrochemical process gave high conversions of up to 95%, high selectivities of up to 98%, high current efficiencies of up to 98.5% and energy consumption as low as 2.2 kW h (kg DBP)^–1. The type of the catalyst plays a decisive role in the efficiency of the HDH of DBP, with palladium being an attractive material. The effect of current density, DBP concentration, supporting electrolyte and temperature, on the HDH is reported.     

气相色谱-质谱法测定葡萄酒中邻苯二甲酸 二丁酯含量的不确定度评定

依据GB/T 21911-2008《食品中邻苯二甲酸酯的测定》,采用正己烷提取、气相色谱-质谱法测定酒中的邻苯二甲酸酯类增塑剂。参照JJF1059-1999《测量不确定度的评定与表示》,以测定红酒中邻苯二甲酸二丁酯DBP为例,对整个过程中不确定度的来源进行了分析,结果表明：气相色谱-质谱法测定红酒中DBP过程中的扩展不确定为0.01135 mg/kg。     

Feasibility study of electrochemical hydrodehalogenation of 2,4-dibromophenol in a paraffin oil

The feasibility of electrochemical hydrodehalogenation (HDH) of 2,4-dibromophenol (DBP) in paraffin oil has been evaluated for short or long operation periods of up to 170 h. HDH has been performed successfully using a solid polymer electrolyte reactor in a batch recycle mode with a dilute H₂SO₄ aqueous solution as the anode feed and source of protons. The work reported in this paper expands the application of electrochemical HDH from aqueous systems to non-conductive media. The effect of the operating conditions, including current density, reactant concentration and temperature, is evaluated. The results are compared with those achieved in the aqueous solutions.     

DBP对聚醋酸乙烯酯乳液性能的影响

讨论了邻苯二甲酸二丁酯(DBP)对聚醋酸乙烯酯(PVAcEm)胶膜的柔韧性、最低成膜温度(FMT)、黏度、粘接强度及稳定性的影响.     

PVC玩具中邻苯二甲酸酯类增塑剂分析方法初探

在PVC玩具中通常添加一些增塑剂，来增加玩具的弹性和韧性。邻苯二甲酸酯类物质就是增塑剂中的一类。这类物质具有毒性，会诱导癌症。欧盟指令中规定PVC塑料玩具中邻苯二甲酸酯类物质的总含量不超过0．1％。因此确立一种准确、有效的检测方法十分有必要。本文先将塑料样品进行粉碎、用正己烷溶剂抽提，然后采用气相色谱法（GC），选用氢火焰电离检测器（FID），采取程序升温进行检测，用内标法对其进行定量分析。测定的结果精密度较好。变异系数为4．2％，回收率在52％到69％之间。     

基于动态BP网络的实验电炉温度控制系统

针对一类不允许出现超调的工艺参数,提出了采用动态BP网络对工艺参数进行控制,可以达到良好的效果。并以实验电炉为对象,用工控机对其炉温进行控制,结果表明,采用动态BP网络进行控制,可以无超调地无限逼近给定值,控制精度高,控制时间较短。因此可以认为,用动态BP网络对这一类工艺参数的控制是有效的。     

Selection of NF membrane to improve quality of chemically treated surface water

The requirement for higher quality drinking water necessitates the application of more efficient water treatment techniques. Nanofiltration is one promising option for enhanced water treatment, for example, in enhanced organic matter removal. The characteristics of different nanofiltration membranes vary remarkably, and the selection of a membrane has to be made according to the requirements of an application. In this study six nanofiltration membranes (NF70, NF255, NTR-7450, NTR-7410, Desal-5 and TFC-S) were evaluated in improving the quality of chemically pre-treated surface water in a pilot-scale process. The results indicate that the membrane with high organics removal and slightly reduced ion removal characteristics (NF255) performed best in terms of product water quality as well as membrane productivity and fouling. The most permeable membrane (NTR-7410) suffered intensive fouling and insufficient product water quality. An interesting finding was that the permeates of all the tested membranes possessed a significant potential for microbial growth, despite the low nutrient contents.