氢化物发生-原子荧光法测定污泥中的痕量汞

针对污泥中复杂基质的特点,进行了三种样品湿法消解体系、还原剂、载流等实验条件的研究,确定了HNO₃-HClO₄湿法消解体系、5%硝酸载流和0.1%硼氢化钠还原剂、以及标准和样品中5％硝酸+0.05%重铬酸钾混合溶液的酸度介质等,用以测试污泥中痕量Hg的实验条件。该方法快速、准确,易操作,检出限为0.06 μg·L-1,连续11次测定4.0 μg·L-1Hg标准溶液相对标准偏差为2.0%,实验建立的氢化物原子荧光(HG-AFS)测定污泥中痕量Hg的测试方法具有较好的应用前景。     

微波消解-石墨炉原子吸收法测定活性污泥中的钴

建立了一种微波消解样品 ,石墨炉原子吸收法测定活性污泥中钴含量的方法。实验选用不同的消解体系及不同基体改进剂 ,进行了对比实验 ,在优化实验条件下 ,测定了 3个经中温 (33— 35℃ )厌氧微生物消化后的剩余活性污泥样品 ,并做了常压消解对比实验 ,空白和加标回收率实验。样品中钴加标回收率>90 % ,相对标准偏差 <6 % ,检出限为 (3s) 0 .0 5 31ng· g-1,该法具有简便、快速、准确、空白值低、重现性好等优点     

紫外光引发模板聚合阳离子聚丙烯酰胺及其污泥脱水应用

阳离子聚丙烯酰胺是污水和污泥处理中常用的一种絮凝剂,传统方法制备的阳离子聚丙烯酰胺因阳离子单体随机分布, 电荷过于分散, 导致其在絮凝时不能充分发挥阳离子单体的电中和作用,为此本研究尝试使用一种新型方法制备阳离子聚丙烯酰胺,即以二甲基二烯丙基氯化铵(DMDAAC)和丙烯酰胺(AM)为单体,分别以两种不同分子量的聚丙烯酸钠(PAAS)为模板,使用紫外光引发模板聚合法制得模板聚合物TPDA1和TPDA2,同时使用紫外光引发聚合法制得非模板聚合物(NTPDA)作为对比。使用红外光谱(FTIR)、氢核磁共振图谱(1H NMR)、扫描电镜(SEM)等方法对制得的聚合物进行表征,并通过污泥脱水试验研究其污泥脱水效率。波谱分析结果表明,添加模板提高了DMDAAC单体的活性,促使聚合物分子中形成DMDAAC连续分布的阳离子单体嵌段结构,从而提高了聚合物的絮凝性能,尤其是电中和作用;SEM扫描显示模板聚合物的具有较大的比表面积和分形维数;污泥脱水试验表明,模板聚合物具有较好的污泥脱水性能和较宽pH应用条件,当模板聚合物TPDA1投加量为50 mg·L-1,污泥pH为8时,其具有最佳污泥脱水效率,污泥含水率降至最低值72.5%。模板分子量对聚合物属性也存在影响,分子量较低的模板制得的聚合物具有相对较好的污泥脱水效率。     

Changes in pore size distribution inside sludge under various ultrasonic conditions

The pore size distribution is quite significant for determining the transport capacity of heat and moisture in sludge during the drying process. It is crucial to investigate the transformation of the pore size in sludge under sonication. In this paper, the microstructures of pores inside sludge before and after ultrasonic treatment with various ultrasonic conditions were observed using a microscope. Fractal geometry and image analysis were combined to quantitatively identify the evolution of pore size in sludge undergoing various acoustic energy densities and treatment times. The surface fractal dimension (d_f) was applied to characterize the pore size distribution of sludge. The results confirmed that sonication has a positive influence on the characteristics of pore structure inside the sludge and that the average pore size increases with increasing ultrasonic energy level, as determined by both acoustic energy density and treatment time. The d_f appropriately characterizes and quantifies the evolution of the pore size distribution of sludge under various ultrasonic conditions. This work is quite valuable for further investigating and evaluating moisture removal in the sludge drying process assisted by ultrasonic treatment.     

Recovering platinum from wastewater by charring biofilm of microbial fuel cells (MFCs)

Reduction in and recovery of precious metals are research hotspots in the environmental engineering field. In this study, we investigated the transformation and distribution of platinum in microbial fuel cells (MFCs) and demonstrated a feasible approach to recover platinum (Pt) from wastewater with less than 16.88?mg/L platinum through charring biofilms in MFCs and generate Pt/C catalyst. The optimal reaction condition was identified, and charred biofilms were analyzed via SEM-EDS, XRD and XPS. Results showed that less than 10% of Pt was in MFC effluents, and less than 0.5% was in the cathode chamber when the influent concentration was below 16.88?mg/L. Close to 40% of Pt could be recovered. The recovery efficiency could be higher should the reactions run longer. SEM-EDS and XRD results indicated that the metallic form Pt⁰ is one of the reduction products in MFCs. XPS results induced that Pt (IV) was reduced to Pt (II) and Pt⁰.     

污泥厌氧水解/酸化的影响因素及研究进展

污泥厌氧水解/酸化作为一种新型的污泥处置技术,由于具有较好的处理效果,已逐渐成为环境化学研究领域的热点。本文综述了国内外污泥厌氧水解/酸化产酸的研究现状,重点阐述了营养物质在厌氧条件下的化学变化以及pH、温度、氧化还原电位、碳氮比(C/N)、泥龄(SRT)及表面活性剂等对污泥厌氧酸化的影响,对其研究进展进行综述,并指出了污泥厌氧水解/酸化产酸在污泥处置方向的可行性和应用前景。     

基于非线性拟合的污泥衍生吸附剂对铅子等温吸附特性研究

利用城市污水厂污泥制取污泥衍生吸附剂，对溶液中铅离子进行吸附实验，研究一定条件下的等温吸附特性。利用线性拟合和非线性拟合两种方法对等温吸附方程进行模拟，得到非线性拟合求得的模型参数比较可靠，同时得到Langmuir模型比Freundlich方程更适合于描述铅离子在污泥衍生吸附剂表面上的吸附行为。     

Multi‐residue method for the analysis of pharmaceutical compounds in sewage sludge,compost and sediments by sonication‐assisted extraction and LC determination

A method for the simultaneous determination of 16 pharmaceutical compounds in three types of sewage sludge (primary, secondary and anaerobically digested dehydrated sludge), compost and sediment samples is described. Pharmaceutical compounds evaluated were nonsteroidal anti‐inflammatory drugs (acetaminophen, diclofenac, ibuprofen, ketoprofen, naproxen and salicylic acid), antibiotics (sulfamethoxazole and trimethoprim), an anti‐epileptic drug (carbamazepine), a β‐blocker (propranolol), a nervous stimulant (caffeine), estrogens (17α‐ethinylestradiol, 17β‐estradiol, estriol and estrone) and lipid regulators (clofibric acid, metabolite of clofibrate and gemfibrozil). The method is based on the ultrasonic‐assisted extraction, clean‐up by SPE and analytical determination by HPLC with diode array and fluorescence detectors. The best extraction recoveries were achieved in a three‐step extraction procedure with methanol and acetone as extraction solvents. Extraction recoveries of several pharmaceutical compounds as caffeine were highly dependent on the type of sample evaluated. The applicability of the method was tested by analyzing primary, secondary and anaerobically digested dehydrated sludge, compost and sediment samples from Seville (Southern Spain). Ten of the sixteen pharmaceutical compounds were detected in sludge samples and five in compost and sediment samples. The highest concentration levels were recorded for ibuprofen in sewage samples, whereas salicylic acid and 17α‐ethinylestradiol were detected in all of the samples analyzed.     

Determination of chiral pharmaceuticals and illicit drugs in wastewater and sludge using microwave assisted extraction,solid-phase extraction and chiral liquid chromatography coupled with tandem mass spectrometry

This is the first study presenting a multi-residue method allowing for comprehensive analysis of several chiral pharmacologically active compounds (cPACs) including beta-blockers, antidepressants and amphetamines in wastewater and digested sludge at the enantiomeric level. Analysis of both the liquid and solid matrices within wastewater treatment is crucial to being able to carry out mass balance within these systems. The method developed comprises filtration, microwave assisted extraction and solid phase extraction followed by chiral liquid chromatography coupled with tandem mass spectrometry to analyse the enantiomers of 18 compounds within all three matrices. The method was successfully validated for 10 compounds within all three matrices (amphetamine, methamphetamine, MDMA, MDA, venlafaxine, desmethylvenlafaxine, citalopram, metoprolol, propranolol and sotalol), 7 compounds validated for the liquid matrices only (mirtazapine, salbutamol, fluoxetine, desmethylcitalopram, atenolol, ephedrine and pseudoephedrine) and 1 compound (alprenolol) passing the criteria for solid samples only. The method was then applied to wastewater samples; cPACs were found at concentration ranges in liquid matrices of: 1.7 ng L⁻¹ (metoprolol) – 1321 ng L⁻¹ (tramadol) in influent, <LOD (desmethylcitalopram and metoprolol) – 506 ng L⁻¹ in effluent, and in solid matrix digested sludge: 0.4 ng g⁻¹ (metoprolol) – 275 ng g⁻¹ (citalopram). Enantiomeric profiling revealed that studied compounds were present in analysed samples in non-racemic composition. Furthermore, enantiomeric composition of studied analytes differed in liquid and solid matrices. This demonstrates that not analysing the solid fraction of wastewater may lead to over-estimation of the removal rates of cPACs as well as possible misrepresentation of the enantiomeric fraction of the compounds as they leave the wastewater treatment plant. Consequently risks from cPACs entering the environment might be higher than anticipated.