Characterization of extracellular polymeric substances in the biofilms of typical bacteria by the sulfur K-edge XANES spectroscopy

A combined approach of physicochemical extraction and sulfur K-edge X-ray absorption near-edge structure（XANES） spectroscopy was applied to characterize the extracellular polymeric substances（EPS） of typical bacterial biofilms in this study. Physicochemical analysis showed variation of the contents of DNA,polysaccharide and protein in different fractions of EPS in different mediums. The sulfur K-edge XANES analysis yielded a variety of spectra.Spectral fitting of the XANES spectra utilizing a large set of model compounds showed that there was more reduced sulfur in both LB-EPS（loosely bound EPS） and TB-EPS（tightly bound EPS） of all the biofilms in LB medium than in R2 A medium. More oxidized sulfur was identified in LB-EPS than that in TB-EPS,suggesting different niches and physiological heterogeneity in the biofilms. Our results suggested that the sulfur K-edge XANES can be a useful tool to analyze the sulfur speciation in EPS of biofilms.     

TR-01稠油乳化降粘剂研究

针对河南油田井楼区块稠油,自制TR-01乳化降粘剂,通过实验研究了其降粘性能、稳定性,确定了降粘剂TR-01最佳浓度为0.3%、最佳油水比为70∶30。实验结果表明:TR-01乳化降粘剂对井楼区块油井的普遍适用性较强,具有较好的乳化降粘作用(降粘率达到99%以上),地层水对其降粘效果影响不大。其中的纳米成分能增加对污水中悬浮物的吸附能力和絮凝能力,对油田污水处理起到积极作用。     

Product identification and toxicity change during oxidation of methotrexate by ferrate and permanganate in water

• Oxidation of methotrexate by high-valent metal-oxo species was first explored. • Fe(VI) presented a higher reactivity to MTX than Mn(VII) at pH 8.0. • Ketonization and cleavage of peptide bond were two initial reaction pathways. • Products of MTX were not genotoxic, neurotoxic, or endocrine-disrupting chemicals. • The less biodegradable products exhibited developmental and acute/chronic toxicity. Accompanying an annual increase in cancer incidence, the global use of anticancer drugs has remarkably increased with their worldwide environmental prevalence and ecological risks. In this study, the oxidation of methotrexate (MTX), a typical anticancer drug with ubiquitous occurrence and multi-endpoint toxicity, by ferrate(VI) (Fe(VI)) and permanganate (Mn(VII))) was investigated in water. Fe(VI) exhibited a higher reactivity with MTX (93.34 M⁻¹ s⁻¹) than Mn(VII) (3.01 M⁻¹ s⁻¹) at pH 8.0. The introduction of Cu(II) and Fe(III) at 1.0 mM improved the removal efficiency of 5.0 μM MTX by 100.0 μM Fe(VI) from 80% to 95% and 100% after 4 min, respectively. Seven oxidized products (OPs) were identified during oxidative treatments, while OP-191 and OP-205 were characterized as specific products for Fe(VI) oxidation. Initial ketonization of the L-glutamic acid moiety and cleavage of the peptide bond of MTX were proposed. Additionally, a multi-endpoint toxicity evaluation indicated no genotoxicity, neurotoxicity, or endocrine-disrupting effects of MTX and its OPs. Particularly, serious developmental toxicity in zebrafish larvae was observed in the treated MTX solutions. Based on the acute and chronic aquatic toxicity prediction, OP-190, OP-192, OP-206, and OP-208 were deemed toxic or very toxic compared to harmful MTX. Furthermore, the reduced biodegradability index from 0.15 (MTX) to −0.5 to −0.2 (OP-192, OP-206, and OP-468) indicated the formation of lower biodegradable OPs. Overall, this study suggests that Fe(VI) and Mn(VII) oxidation are promising treatments for remediating anticancer drug-contaminated water. However, the environmental risks associated with these treatments should be considered in the evaluation of water safety.     

炭砂滤池对农村饮用水中浊度及细菌的去除效果

粗滤-炭砂过滤是简单实用的农村水处理工艺。通过中试装置,检测了滤池对浊度、细菌总数和大肠杆菌的去除效果,研究了炭砂滤池出水安全性。结果表明：炭砂滤池能进一步降低粗滤池出水浊度,并将其控制在0.7~2.2 NTU;砂层作为保证出水浊度的屏障,其浊度去除率在炭层基础上可再增加11.1%;炭砂滤池对大肠杆菌的平均去除率随着滤速的降低而增大,且该差异主要是由炭层贡献的;当滤速为5 m·h⁻¹时,炭砂滤池对大肠杆菌平均对数去除率为0.79;但滤池运行过程中会产生微生物泄露的现象,对细菌总数基本无去除作用。因此,为保障出水的微生物安全性,炭砂滤工艺后须增加行之有效的消毒工艺。     

水传病原微生物PCR-纳米金显色快速检测方法

水传病原微生物是腹泻等肠胃疾病发病的主要原因,而发展快速、有效的检测方法对于控制和减少该类微生物的传播风险十分重要.因此,本文研究了PCR反应结合不修饰的纳米金颗粒(Gold nano-particles,AuNPs)显色检测方法的最佳盐浓度、探针含量、PCR反应条件等,并从纳米金制备、病原菌种类、检测特异性等方面进行考核,确定了最优检测条件为:10μL PCR扩增产物混合20 pmol探针,95℃反应5 min,55.5℃反应3 min后,40℃杂交10 min;此时,先后加入90μL实验用纳米金和一定浓度的PBS溶液,室温观察颜色变化.结果发现,纳米金溶液由红色变为紫色或近于无色为阳性结果,对应的吸光度值迁移出530 nm,以此可达到快速检测病原微生物的目的.     

抗生素药生产废水处理工艺改进研究

企业抗生素废水经原有工艺处理后污染物指标偏高,且不稳定。工艺通过采用增加初沉池和二沉池、污泥回用等改进措施,COD、氨氮等排放浓度下降且稳定排放,改进效果明显。     

煅烧菱铁矿制备纳米结构化α-Fe2O3及其NH3-SCR脱硝活性研究

利用菱铁矿的热分解特性,在空气中不同温度下(400、500、600、700、800℃)煅烧天然菱铁矿制备具有纳米尺寸形貌特征的α-Fe_2O_3,作为NH_3选择性催化还原(NH_3-SCR)脱硝的催化剂.采用X射线衍射(XRD)、程序升温脱附(NH_3-TPD)、X射线光电子能谱(XPS)、紫外-可见漫反射吸收光谱(UV-Vis DRS)等手段对催化剂结构进行表征,并利用气固相催化反应系统对催化剂的NH_3-SCR脱硝活性和N_2选择性进行评价,同时考察其抗水抗硫及稳定性.结果表明,天然菱铁矿于空气中500℃煅烧相变为α-Fe_2O_3,具有最低的晶体尺寸(约10 nm)、最高的比表面积(39.68 m~2·g~(-1))和最优的脱硝活性;500℃煅烧菱铁矿制备的催化剂在250~400℃温度窗口内脱硝效率达到100%,并能保持较高的N_2选择性,这主要归因于其具有的纳米多孔结构特性和较大的比表面积,以及表面丰富的酸性位点和吸附态氧.当同时存在5%H_2O和0.04%SO_2时,α-Fe_2O_3在250~400℃区间的脱硝效率高于88%,且在300℃下持续反应360 min,脱硝效率维持在75%以上,表明500℃煅烧菱铁矿制备的催化剂具有良好的抗水抗硫和稳定性.     

振动筒式压力传感器技术及其应用

振动筒式压力传感器是一种技术成熟的高精度纸对压力传感器，具有测量精度高，稳定性好，工作温度范围宽，功耗低，抗振动，耐冲击，可靠性高，频率输出以及易与计算机连接等特点，且汞柱测压设备的理想替代仪器之一，文章对振动筒式压力传感器的工作原理，产品分类和技术特点以及气象观测上的应用作了介绍。     

Assessment of antibiotic resistance genes in dialysis water treatment processes

• Quantitative global ARGs profile in dialysis water was investigated. • Totally 35 ARGs were found in the dialysis treatment train. • 29 ARGs (highest) were found in carbon filtration effluent. • erm and mtrD-02 occurred in the final effluent. • The effluent was associated with health risks even after RO treatment. Dialysis water is directly related to the safety of hemodialysis patients, thus its quality is generally ensured by a stepwise water purification cascade. To study the effect of water treatment on the presence of antibiotic resistance genes (ARGs) in dialysis water, this study used propidium monoazide (PMA) in conjunction with high throughput quantitative PCR to analyze the diversity and abundance of ARGs found in viable bacteria from water having undergone various water treatment processes. The results indicated the presence of 35 ARGs in the effluents from the different water treatment steps. Twenty-nine ARGs were found in viable bacteria from the effluent following carbon filtration, the highest among all of the treatment processes, and at 6.96 Log (copies/L) the absolute abundance of the cphA gene was the highest. Two resistance genes, erm (36) and mtrD-02, which belong to the resistance categories macrolides-lincosamides-streptogramin B (MLSB) and other/efflux pump, respectively, were detected in the effluent following reverse osmosis treatment. Both of these genes have demonstrated the potential for horizontal gene transfer. These results indicated that the treated effluent from reverse osmosis, the final treatment step in dialysis-water production, was associated with potential health risks.     

Intensified inactivation of model and environmental bacteria by an atmospheric-pressure air-liquid discharge plasma compared with chlorination

Water-borne pathogenic bacteria are always the top priority to be removed through disinfection process in water treatment due to their threat to human health. It was necessary to develop novel disinfection methods since the conventional chlorine disinfection was inefficient in inactivating chlorine-resistant bacteria, inducing the viable but non-culturable(VBNC) bacteria and forming disinfection by-products(DBPs). In this study, the inactivation of four model strains including Gram-negative(G