Determination of alkylphenols and alkylphenol ethoxylates in sewage sludge: effect of sample pre-treatment

A complete characterization of sewage sludge collected from five biological waste water treatment plants was done to determine physico-chemical parameters, heavy metals and alkylphenols, making special emphasis on sampling, homogenization, and sample pre-treatment. Ultrasonic extraction followed by gas chromatrography coupled with mass spectrometry was used to evaluate the effect of sample pre-treatment (untreated sample, freeze-drying, drying at 40 °C or drying at 100 °C) on the concentration of octylphenol (OP), nonylphenol (NP) and nonylphenol ethoxylates (NP₁EO, NP₂EO). Untreated samples and samples dried at 100 oC gave concentration levels up to 62% and 89% lower, respectively, than freeze-dried samples. In 50% of cases, freeze-dried samples led to significantly higher concentrations than those obtained by drying at 40 °C. Thus, freeze-drying is the recommended sample pre-treatment to prevent possible losses of OP, NP, and NP₁EO. Using this methodology, concentrations detected were from 3.2 to 199 mg kg⁻¹ being NP followed by NP₁EO found in highest concentration. The total concentration of NP and NP₁EO exceeded the limit of 50 mg kg⁻¹ proposed by the draft European directive on sewage sludge in three out of five samples studied. Contrarily, heavy metals were below the legislated values.     

Comparison of Methods for the Preparation of Sewage Sludge Samples Prior to the Spectrophotometric Determination of Phosphorus

Abstract

Three procedures for the preparation of sewage sludge samples prior to the colorimetric determination of phosphorus as “molybdenum blue” were evaluated. Using samples of the US EPA's municipal digested sludge as a reference material, sulfuric acid/ammonium persulfate digestion, muffle furnace ignition followed by extraction of the ash with hydrochloric acid, and direct extraction of the sewage sludge with sodium bicarbonate solution were compared in terms of phosphorus recovery as determined by colorimetric measurements. On the basisof phosphorus recovery, the samples prepared by muffle furnace ignition/hydrochloric acid extraction of the ash showed the best accuracy and precision. This procedure was also superior in terms of the time and effort expended in the preparation of the sewage sludge samples.     

三维荧光光谱法表征污水中溶解性有机污染物

采用三维荧光光谱法研究了生活污水中溶解性有机物的荧光特性.基于对污水中腐殖酸类、蛋白质类、表面活性剂类、植物油类等有机物三维荧光特性研究结果,提出了表征污水中有机物种类、组成和含量的三维特征荧光参数:(1)特征荧光强度(Fex/em)表征污水中某一类溶解性有机物含量;(2)特征荧光强度综合指标(各类有机物的特征荧光强度之和,∑Fex/em)表示有机物的综合含量;(3)Fex/em/∑Fex/em表示不同种类有机物所占的比值.与传统有机物综合指标相比,三维特征荧光参数信息丰富、测定迅速、灵敏度高,能够方便地实现对水质的实时在线监测,从而更好地指导污水处理工艺运行、管理和控制,保证处理效果.     

超高含量氯离子基体下痕量亚硝酸盐的检测

介绍了一种无需对样品进行除氯处理,采用全新的离子色谱柱,抑制型电导离子色谱法检测,测定超高Cl-基体下痕量亚硝酸盐及其它常见阴离子的方法.其中Cl-浓度与亚硝酸盐浓度比可达到50000:1甚至100000:1,实现良好分离.选择色谱条件为:IonPac AS23阴离子交换柱,手工配制碳酸盐淋洗液等度淋洗,抑制型电导检测.污水样品通过Dionex OnGuardⅡRP柱和0.22 μm微孔尼龙膜处理.该方法采用25 μL进样,8种常见阴离子的检出限为0.2～5.8μg/L,线性范围均超过2个数量级,相关系数r在0.9996～0.9999的范围内,连续11次进样检出所有阴离子的RSD均小于5%,加标回收率结果在93%～106%之间.该方法具有选择性好,灵敏度高,操作简单等特点,从根本上解决了高氯离子基体中痕量亚硝酸盐及其它常见阴离子检测的问题,用于实际污水样品的检测.     

Matrix effect in high‐performance liquid chromatography‐tandem mass spectrometry analysis of antibiotics in environmental water samples

This paper describes the matrix effect during the analysis of ten antibiotic compounds in water by SPE followed by HPLC‐ESI‐MS/MS. The target analytes were tetracycline, oxytetracycline (tetracyclines), sulfathiazole, sulfamethazine, sulfadiazine (sulfonamides), erythromycin‐H₂O, roxithromycine, spiramycin (macrolides), ofloxacin, and norfloxacin (quinolones). The matrix effect was examined for internal standards and the target analytes in five different water matrixes, with signal suppression being increased in the order: ultrapure water, tap water, river water, sewage effluent, and sewage influent. A combined application of the internal standards and matrix‐matched extract calibration was shown to be successful in compensating the matrix effect for the analytes. The procedural recovery of the target compounds in sewage effluents and influents was higher than in river water samples, which was further enhanced by sample acidification to pH 2. The validity of the internal standard based matrix‐matched calibration approach was verified by the standard addition method.     

冷原子吸收光谱法测定污水中总汞的两种消解方法比较

研究了用王水(1+1)及KMnO4 K2S2O8 消解污水,冷原子吸收光谱法测定总汞的两种方法。试验证明王水(1+1)消解水样测定污水中总汞具有较高的灵敏度和精密度,方法的线性范围为0~10.0μg·L-1,检出限为0.22μg·L-1,相对标准偏差小于 3%,加标回收率为 98.5%~101.2%。与KMnO4 K2S2O8 消解法相比,具有操作简单、所需试剂较少、结果稳定等特点。     

固相萃取-高效液相色谱测定污水中的地塞米松

建立固相萃取-高效液相色谱法测定污水中地塞米松含量的方法。水样经固相萃取柱萃取富集后进行HPLC分析,以甲醇:水=65:35(V/V)为流动相,色谱柱为Agilent C18柱(5μm,4.6mm×150mm),柱温30℃;流速为1mL/min;紫外检测波长为240nm。地塞米松在25—300ng/mL范围内线性关系良好(n=5,R2=0.9992),最低检测浓度为25ng/mL(S/N>10),回收率为98.36%,地塞米松的低、中、高的日内精密度与日间精密度RSD均小于3%。本法准确、灵敏,能较好的应用于污水中地塞米松的测定。     

利用柠檬酸去除污泥中重金属的新工艺

经柠檬酸络合后采用离子交换法处理污泥中的重金属,该方法包括3个步骤:浸提过程、固液分离、浸提液的净化和循环。对影响浸提液的净化和循环步骤中的主要影响因素进行了研究。结果表明,732型阳离子交换树脂性能优异,对重金属的离子交换率接近100%;以5%HCl溶液为洗脱剂,动态逆流操作条件下,Cu、Ni和Zn的洗脱率分别达到88.85%、86.15%和88.40%;以铝片为置换剂,对重金属Pb、Cd、Cu、Ni都能得到90%以上的置换率。循环实验表明,处理后污泥中的重金属含量符合《农用污泥中污染物控制标准》(GB4284-84),柠檬酸可以实现循环使用。     

同时吸附油和六价铬离子复合材料的制备及性能

以亲油疏水型三元乙丙橡胶(EPDM)作为基体, 焙烧Fe2O3和阴离子交换树脂201Х7作为填料, 利用熔融共混的方法, 制备一种可以同时吸附油和六价铬离子的用于污水处理的复合材料, 这种材料能够悬浮于油水界面处. 当焙烧Fe2O3和阴离子交换树脂的用量比例不同时, 材料吸附性能变化很大. 实验结果表明, 在保证复合材料密度介于油水密度之间的前提下, 随着焙烧Fe2O3含量的增加, 材料的吸油性能不断增大; 随着阴离子交换树脂含量的增加, 材料对六价铬的吸附性能不断增加. 在油水共存体系中, 复合材料对两种污染物的吸附率同时达到最佳时, 两种填料的比例可以确定, 因油品的不同而不同. 在油水共存体系中, 复合材料对油和六价铬的总吸附能力要远大于复合材料分别在单一吸附介质中的吸附能力.     

On-line microwave oven digestion flame atomic absorption analysis of solid samples

A manifold has been developed for on-line microwave oven digestion and flame atomic absorption spectrometric (FAAS) determination of metallic elements in solid samples. The use of a closed flow system permits sample treatment before analysis by FAAS, the direct injection of slurries avoids a filtration step and the interconnection of two conventional rotary injection valves allows the rapid introduction of samples and standards. The determination of lead in sewage sludge was employed as a test system for the proposed on-line sample digestion manifold. The procedure has a limit of detection of 0.2 μg Pb g^?1.