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。     

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.     

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。     

基于示波法的血压测量新方法

血压是反映人体生理状况的最重要指标之一,血压测量的准确性对疾病诊断,临床医疗具有重要的意义。为了提高电子血压计血压测量的准确性,采用基于幅度系数法和波形特征法的综合改进方法．通过将二者结合起来应用,在比较宽松的幅值范围内寻找突变点,从而获得收缩压和舒张压。经过大量的测试,新方法能可靠作为收缩压和舒张压的判据,具有工程实现的可行性和面对不同个体的普遍适用性。     

固体酸催化合成邻苯二甲酸二丁酯的研究

以苯酐和正丁醇为原料,用自制的SO4^2-/SiO2、SO4^2-/Fe2O3、SO4^2-/SnO2及固体铁系为催化剂,催化合成邻苯二甲酸二丁酯（DBP）,分别考察固体酸催化剂的种类、固体酸催化剂的用量、醇酐摩尔比和反应时间等因素对合成DBP产率的影响。试验结果表明,其中SO42-/SnO2催化剂催化活性高。在苯酐0.1 mol（14.8 g）、固体酸催化剂m（SO4^2-/SnO2）/n（苯酐）为16（g/mol）、醇酐摩尔比2.5、带水剂二甲苯200[mL/mol（苯酐）]、反应时间4.0 h的条件下,其产率达94.0%以上,寿命长、可多次重复使用、产物易纯化分离、且产品色泽浅等优点,可望代替传统浓硫酸作催化剂应用于DBP的合成。     

磁性多孔尖晶石铁氧体制备及催化臭氧性能

为了提高臭氧氧化水中难降解有机物性能,采用溶胶–凝胶法合成了磁性多孔尖晶石铁氧体NiFe2O4和MnFe2O4.通过SEM、XRD、VSM和XPS对其性能进行表征,对催化剂不同存在条件下催化臭氧降解水中邻苯二甲酸二丁酯(DBP)的效果、催化臭氧化机理及催化剂的稳定性进行了探讨.结果表明:两种催化剂均为磁性、多孔状、尖晶石结构铁氧体,NiFe2O4和MnFe2O4对催化臭氧化DBP具有良好的强化能力,比单独臭氧化体系对DBP去除率可分别提高54%和47%,NiFe2O4催化臭氧化能力强于MnFe2O4.两种催化剂催化臭氧降解DBP的反应均遵循羟基自由基机理,反应过程中水中金属离子溶出均低于0.06 mg/L,结构稳定,易于回收处理.     

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.     

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。