Gas chromatography-high resolution mass spectrometry (GC-HRMS), with its superior qualitative capability, has become a powerful tool for non-targeted screening (NTS) of volatile and semi-volatile organic contaminants in complex water matrices. However, conventional workflows rely heavily on reference standards, limiting their ability to capture the chemical diversity present in real samples. This study proposes an alternative three-stage strategy that prioritizes real sample data for method development prior to standard-based validation. Using liquid-liquid extraction (LLE), the extraction efficiency of four common solvents-dichloromethane (DCM), ethyl acetate (EAC), n-hexane (HEX), and methyl tert-butyl ether (MTBE)-was systematically evaluated across five representative water types according to this strategy. Multidimensional data analysis revealed that the DCM-MTBE solvent combination achieved the highest average chemical space coverage and satisfactory extraction efficiency across different matrices. Validation with 152 reference compounds confirmed 100 % detection accuracy and an average recovery of 92.38 %. The study highlights the value of integrating real sample data into NTS workflow development and provides a practical, extensible solution for enhancing the detection of unknown pollutants in aquatic environments. This work also offers a generalizable framework that can guide future pretreatment optimization in non-targeted analysis and support more reliable environmental risk assessments.

Since the variation of dissolved organic matter (DOM) is complicated in the aquatic environment and water treatment processes, adverse effects on human and water quality may be triggered. Nowadays, more drinking water treatment plants (DWTPs) begin using pretreatment and advanced treatment processes for removing refractory DOM to pursue high-quality drinking water, including preozonation, and combined ozonation and biological activated carbon (BAC) treatment. The combination of Fourier transform ion cyclotron resonance mass spectrometer and fluorescence spectroscopy could comprehensively unveil the DOM composition and characteristics in water treatments. This study aims to provide information on the molecular and spectroscopic characteristics of DOM in a DWTP with pretreatments and advanced treatment processes and summarize the removal efficiency of different treatment processes on DOM. Results showed that the removal rate of low-molecular weight acids (LMW-acids) by BAC was as high as 98 %, reflecting the synergistic effect of ozonation/BAC unit. Pre-ozonation enhanced coagulation process had a good removal effect on CHONS. The diversity of DOM increased and the relative abundance of DOM intensity was reduced in preozonation/coagulation/sedimentation and O3/BAC units. The preozonation-coagulation/sedimentation unit reduced the aromaticity or unsaturation of DOM while the advanced treatment process had a higher removal rate of fluorescent components.

Prechlorination routinely applied for the treatment of algae-laden raw water has received extensive attention due to its influence on water quality and aquatic microbes. In this study, prechlorination experiments with different doses were conducted in sets of model raw water distribution systems. With the elevated dose of chlorine and prolonged hydraulic retention time (HRT), the ratio of intact algal cells decreased, and the stability of water enhanced. Dissolved organic carbon (DOC) and nitrogen (DON) increased when chlorine dose elevated from 0 to 0.5 mg/L but decreased with elevations from 0.5 to 2.0 mg/L, while UV254 showed a monotonically increasing tendency. DOC, DON and extracellular microcystin-LR increase initially and decrease thereafter with the pro-longed HRT. Notably, the effects of prechlorination on extracellular polymeric substances aggregation behavior on pipe walls and microbial community composition was revealed, providing more profound understanding of the community dynamics in this engineered system. This study helped optimize strategies to improve the stability and efficiency of pretreatment of algae-laden water.

备用水源原水管道较为封闭,原水停留时间过长会导致溶解氧(DO)浓度降低,管道环境由好氧变为缺氧甚至厌氧,从而引起水质恶化.实验室模拟M、N两种不同水源条件在原水管道的备用状态,以DO降至2 mg/L确定停留时间,探究相应的水质变化以及原水的化学稳定性和管壁微生物群落多样性.结果表明,DO在水质较差水源条件下的衰减时间明显短于水质较好的水源.两种水源水都具有严重腐蚀性,出水pH、总碱度和钙硬度均显著升高.M装置进水水质相对较差,微生物存在水平高,对有机物的去除率更高,CODMn和UV254的去除率分别为27.8％和22.9％,而N装置分别为24.6％和21.4％;M装置中的硝化作用更强,NO3--N生成率为23.4％,而N装置为16.2％.两组装置管壁生物膜中的优势菌门基本相同,但丰度较高的菌门差异较大,而丰度较低的菌门差异不明显.较高的NH4+-N浓度有利于增加硝化螺旋菌门的丰度,从而促进硝化作用.良好的水质可以增加管道内的微生物多样性,更有利于管道内生态系统的稳定.

考察了臭氧强化混凝沉淀对溶解性有机物(DOM)去除的影响,针对长荡湖原水、直接沉后水、预臭氧出水和臭氧沉后水四种水样,利用液相色谱-有机碳检测仪(LC-OCD)和傅里叶变换离子回旋共振质谱仪(FT-ICR MS)等从不同层面探究DOM的演变.经试验确定,预臭氧和聚合氯化铝(PAC)的最佳投加量分别为1.0、30mg/L,并在此工况下进行研究.原水中主要存在类色氨酸和类富里酸两种有机物,臭氧强化混凝沉淀对有机物的去除效果最好,对类色氨酸、类富里酸和类腐殖酸类物质的去除率分别为80.75％、77.39％、80.28％.经LC-OCD分析,原水中亲水性有机物总浓度最高为3 776.74 μg/L.臭氧沉后水中腐殖质降解产物增多,其他几类有机物均减少.在小分子DOM中,CHOSP-DOM占比最大,CHOP-DOM占比最小.臭氧强化混凝沉淀对各类分子相对丰度的分布影响最大,峰值出现在C10H10O3(177.06u)、C13H18O6(269.10u)和C15H20O7(311.11u),且质荷比＞680的分子分布明显减少.原水经不同工艺处理后,小分子DOM分布范围均变广,并逐渐向高H/C、低O/C转移,各水样中碳水化合物类、不饱和碳氢化合物、单宁酸类和稠环化合物类占比很少,总占比为10.90％～18.25％.四种水样中小分子DOM的DBE平均值分别为6.6、6.5、6.3和6.1,可以看出臭氧对芳香性或不饱和度的降低起关键作用.总体来看,臭氧强化混凝沉淀工艺的处理效果最好,可以降低水厂后续工艺对有机物的处理难度.

文章利用傅里叶变换离子回旋共振质谱法深入探究某浅水型湖泊为水源的水厂中原水、混凝沉淀出水、臭氧活性炭出水、砂滤池出水和出厂水中小分子溶解性有机物(DOM)的分子组成、质荷比、芳香性等变化.研究表明小分子DOM中CHOSP(含有C、H、O、S、P元素的小分子DOM,15.99％～25.99％)占主导地位,CHOP(2.26％～5.30％)占比最小.加氯消毒工艺对小分子DOM影响最大,CHONSP和CHOP分子式种类分别增加183.59％和141.91％,各类小分子DOM相对丰度均明显增加,芳香性及不饱和度趋于降低.总体上小分子DOM逐渐向低H/C、高O/C转移,出水中碳水化合物类、稠环化合物类和单宁酸类增加较为显著,类蛋白类也有所增加,脂质类、不饱和碳氢化合物类和木质素/CRAM类减少,小分子DOM的芳香性或不饱和度在动态变化中没有明显规律.

Higher initial DO concentrations could enhance the nitrification reaction and purification process of the raw water.

Graphene oxide lamellar 2D membranes are widely researched for ion separation and molecular sieving in aqueous solution. Extension of the research of GO-based membranes for organic solvent nanofiltration has drawn much attention but is still in its infancy. The relatively low solvent permeability remains a difficult problem to overcome. Inspired by the shell of the Namib Desert beetle, a heterostructured lamellar membrane was prepared by incorporating MoS2 quantum dots (MQDs) into the graphene oxide membrane. A dual-functional zone was formed, where hydrophilic areas exhibited excellent absorption performance for polar solvents and hydrophobic regions were propitious to the discharge of polar solvents when incorporating a moderate amount (10%) MQDs, denoted as GM-10 (nonpolar solvents presented the opposite performance). The synergistic effects of the dual-functional zone successfully improved the transport efficiency for various solvents, and the flux of various solvents for GM-10 was over three times higher than that of the pure GO membrane. Simultaneously, the composite biomimetic membrane showed excellent stability. This paper provides a novel strategy for constructing a heterostructured dual-functional zone for 2D lamellar membrane modification without the sacrifice of rejection, revealing the potential for further optimization of separation performance and membrane stability.

蓝藻水华暴发时原水管道可能混入大量藻细胞,威胁饮用水安全.研究采用BAR模拟管道装置,对比探究105 cell/mL、106 cell/mL两种不同浓度含藻原水在长距离输送过程中的水质变化.以无藻原水作为对照,采用高通量测序研究管壁生物膜群落结构多样性,以探究原水管道中藻类浓度对水质及管壁生物膜的影响.结果表明,两种藻类浓度下原水pH略微上升,溶解氧和浊度逐渐降低,UV254和总磷呈下降趋势,而溶解性有机碳在高藻水中先上升后下降.胞外有机物在低藻水中变化不大,在高藻水中波动上升,而胞内有机物均不断增加.高藻水可能存在藻毒素超标风险.原水中藻类浓度增加有利于管壁生物膜群落多样性的提高,其对管壁生物膜影响不大,优势菌门均为变形菌门和拟杆菌门.

Construction of nanosized pore and heterointerface provides an efficient way to enhance the electrocatalytic activity of hydrogen evolution reaction (HER). However, the exploration to tailor these structures is still insufficient for two-dimensional (2D) catalysts. Herein, a facile phosphine (PH3) and hydrogen (H-2) vapor-assisted phase engineering strategy is proposed to successfully achieve the controllable conversion of 2D MoO2 nanosheet precursor into 2D porous MoP/MoO2 heterojunction nanosheets for HER. The holey lamellar properties and plentiful interfaces between 2D MoP and MoO2 domains are intuitively confirmed by high-resolution transmission electron microscopy images. The porous MoP/MoO2 nanosheets exhibit outstanding HER activity with low overpotentials of 90 +/- 1 and 79 +/- 1 mV to drive a current density of 10 mA cm(-2) in acidic and alkaline electrolytes, respectively. Density functional theory calculations reveal that both P and Mo sites located on the wall of the nanopores at the interface region optimize the hydrogen binding energy, thereby accelerating the HER kinetics.

研究了溶解性有机物(DOM)在水厂全流程处理工艺中的演变,并利用FT-ICR MS技术深入分子层面探究小分子DOM的分子组成、质荷比、芳香性等变化.结果 表明,DOM总浓度呈下降趋势,小分子DOM(分子质量＜1 ku)在水厂中占比最大且去除效果最差.小分子DOM中CHO-DOM(仪含C、H、O,占比为48.75％ ～53.13％)的多样性和相对丰度占主导地位,木质素/CRAM类化合物(68.12％ ～72.05％)占显著优势.预氯化对小分子DOM的去除量低、生成量高,混凝沉淀对CHO-DOM和CHON-DOM(仅含C、H、O、N)有较好的去除效果,普通砂滤和生物活性炭过滤对DOM的影响较小,加氯消毒工艺影响最大,去除了大量芳香性/不饱和度高的小分子DOM,CHO-DOM的相对丰度趋于平缓,CHON-DOM中C13H20NO9跃升至最大丰度,CHOS-DOM(仅含C、H、O、S)的相对丰度明显增加,出现多个突出的高H/C化合物.总体上小分子DOM向高H/C、低O/C转移,出水中碳水化合物类、单宁酸类占比下降,稠环化合物类基本被去除,脂质类、类蛋白类和木质素/CRAM类占比增加,小分子DOM的芳香性或不饱和度大大降低.

The raw water distribution systems (RWDSs) play key roles in urban water supply systems. The changes of disinfection byproducts (DBPs) precursors of trihalomethanes (THMs), haloacetic acids (HAAs) and halogenated acetaldehydes (HALs) in the RWDS in Taihu Basin were investigated by formation potentials. Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR MS) method and 454-pyrosequencing were employed to study the variation of molecular characteristics of low molecular weight-dissolved organic matter (LMW-DOM) and microbial communities of pipeline biofilms respectively, which played crucial roles in the variation of DBPs precursors. The results showed that both DBPs precursors and the molecular characteristics of LMW-DOM in the RWDS had changed. Moreover, the LMW-DOM could be an indicator due to the good positive correlation with precursors of HAAs and HALs. Specifically, the LMW-DOM showed continuous accumulation in the RWDS. The LMW-DOM tended to possess higher m/z and more CH2 or long alkyl chains while pre-chlorination controlled this trend. The LMW-DOM in the pre-chlorinated pipe section also possessed higher saturation. Additionally, lignins served as an important part of DBPs precursors and dominated the LMW-DOM. The microbial diversity decreased in the RWDS, and the abundance and diversity of the microbial community in the pre-chlorinated section were significantly lower than those in the no-chlorinated section. Finally, most DBPs precursors had positive correlation with dominant phylum and genus in RWDS. This study reveals variation of DBPs precursors, LMW-DOM and microbial pipeline biofilms as well, and provide important data for further research on raw water safety and stability in RWDSs.

Downsizing the catalyst to atom scale offers an effective way to maximize the atom utilization efficiency for electrocatalytic nitrogen reduction reaction (NRR). Herein, single-atomic ruthenium (Ru) anchored on a chemically activated Ti3 C2 with O-terminated groups (Ti3 C2 O) was designed to catalyze the NRR process. The catalyst achieved a superior activity and selectivity with ammonia yield rate of 27.56 μg h-1  mg-1 and faradaic efficiency of 23.3 % at a low potential of -0.20 V versus the reversible hydrogen electrode. According to the atomic resolution images from aberration-corrected scanning transmission electron microscopy, Ru sites on Ti3 C2 O achieved good dispersion on atomic scale. X-ray photoelectron spectroscopy analysis further demonstrated that the O-termination groups were successfully activated. Density functional theory calculations combined with experiments revealed that single Ru sites binding to four oxygen were the main reaction centers that permitted the hydrogenation of *NNH2 to *NHNH2 in a novel distal/alternating hybrid path while reducing the energy barrier of the potential-limiting step to 0.78 eV from 0.96 eV in the distal path alone or 1.18 eV in the alternating path alone, thereby significantly promoting the NRR dynamics.

Understanding the transformation pattern of nitrogen (N) pollutants and its pathways in the prechlorinated raw water distribution system (PRWDS) is vital for controlling the stablitiy and safety of raw water qulity. This study investigated the N transformation, N functional genes and their correlations to find the N transformation pathways along the PRWDS. Results suggested that simultaneous nitrification, anaerobic ammonium oxidation and denitrification (SNAD) contribute to the N transformationin the PRWDS. Along the pipeline, anammox 16S rRNA (9.18 x 10(7)-8.41 x 10(8) copies/g), limited by prechlorination, was the most abundant N functional genes and anammox process was the main pathway of ammonia nitrogen (NH4+-N). The decreasing NH4+-N was connected with Planctomycetes, Nitrospira and abundance of nxrA attributing to the joint effort of anammox and declined nitrification. The concentration of nitrate (NO3--N) increasing at first and then decreasing, was correlated positively with Sphingomonas. because of the declined nitritication and increased denitrification. Besides, the NO3--N -> NO2--N process was considered to be primary NO3--N transformation pathways. Increases in the concentration of dissolved organic nitrogen (DON) and nitrite (NO2--N) observed in the PRWDS had positive correlation with relative abundance of Pseudomonas. We believe that prechlorination shaped the particular bacterialcharacteristics in biofllms and influenced the N transformation pathways indirectly, resulting in the varying N transformation rules in PRWDSs. Moreover, systematic and extended research is particularly vital for determining the effects of changes in source water quality and environmental conditions on bacterial community structure and N conversion along PRWDSs. (C) 2020 Published by Elsevier Ltd.

研究太湖流域某水厂原水输送管道沿程消毒副产物的生成势变化,并利用皮尔逊相关性分析其影响因素.结果 表明:三氯甲烷生成势最高,二氯乙醛生成势最低;总生成势由高到低依次为三卤甲烷类、卤乙酸类、卤乙醛类;氯代副产物生成势的质量浓度约为溴代副产物的6.25倍;除二氯乙酸外的消毒副产物生成势出水相较于进水升高了18.61％～664.22％.此外,预氯化管段中各类副产物生成势及沿程升高比例基本高于未加氯管段,两管段变化趋势基本一致.温度与除一氯二溴甲烷外的三类甲烷类副产物生成势呈正相关;氨氮与各类副产物总生成势呈负相关;DOC与三卤甲烷类副产物生成势呈良好正相关,但与卤乙酸和卤乙醛类副产物生成势相关性不强,因而其可能适宜作为三卤甲烷生成势的指标;管道停留时间与大多数消毒副产物生成势正相关性良好.

研究不同管材(水泥内衬管、油漆内衬管)原水管道模拟装置中成熟生物膜的微生物群落结构及含氮污染物转化规律,并利用冗余分析阐明微生物与氮转化之间的关系.结果表明:不同管材的模拟管道内含氮污染物转化存在差异,油漆内衬管中硝化反应更为明显;粗糙度高的油漆内衬管中HPC稳定在1.89× 106 ～ 2.45× 106 CFU/cm2,高于水泥内衬管的2.60×105～4.00× 105 CFU/cm2;不同管材管道内壁生物膜中优势菌门种类基本一致但丰度不同.优势菌门与含氮污染物转化关系密切,NH4+-N、NO-2-N的转化率与硝化螺旋菌门、拟杆菌门相对丰度呈显著正相关,而与绿弯菌门、酸杆菌门呈负相关关系.NO3-N的转化率与厚壁菌门相对丰度正相关,与浮霉菌门、放线菌门表现出负相关性.同时,管材表面粗糙度越大,管道内的生物多样性也越大.油漆内衬管中硝化螺旋菌门、放线菌门、拟杆菌门相对丰度略高,因此硝化反应更明显,出水中出现更多的小分子DON,而管材对管道出水中DON的亲疏水性的影响不明显.

Raw water transportation pipelines are vital in an urban water supply system for transporting raw water to drinking water treatment plants. This study investigated the effects of pipe material on nitrogen transformation, microbial communities and characteristics of related function genes in paint-lined steel pipe (PLSP) and cement-lined steel pipe (CLSP) raw water model systems. We established quantitative relationships between specific functional genes and change rates of nitrogen pollutants, which were verified by field investigation on nitrogen pollutant transformations in real raw water transportation systems. The results showed that the CLSP produced higher ammonia nitrogen (NH4+-N) transformation rates and higher effluent concentrations of nitrate nitrogen (NO3−-N) and dissolved organic nitrogen (DON) than the PLSP. Both pipes achieved high and stable nitrite nitrogen (NO2−-N) and low total nitrogen (TN) removal efficiency. Nitrification was found to be the dominant process in both model systems, especially in the CLSP. Characteristics of microbial communities and nitrogen functional genes, which were analysed by high-throughput pyrosequencing and quantitative polymerase chain reaction (qPCR), respectively, varied between the two pipe systems. Nitrogen transformation pathways, identified by path analysis, were also different between the PLSP and CLSP due to different microbial community characteristics and synergistic effects of nitrogen functional genes. In the CLSP, (NH4+-N→NO2−-N) with part denitrification, was the primary transformation pathway of ammonia nitrogen (NH4+-N), while only ammonia oxidization contributed to NH4+-N transformation in the PLSP. (NO2−-N→NO3−-N) was the main pathway involved in NO2−-N transformation and NO3−-N accumulation. The TN removal showed complex relationships with nitrification, denitrification and nitrogen fixation processes. These findings provided molecular-level insights into nitrogen pollutant transformations during the transportation of raw water through different types of pipes and technical support for the selection of raw water pipe materials. In our study area, the Taihu basin, China, PLSP was better than CLSP for distributing raw water in a short transportation distance, due to the lower effluent concentrations of DON and NO3−-N and less abundance of microorganisms.

利用原水输送管道模拟系统,考察了管壁生物膜在自然形成过程中的微生物种群分布和生物多样性变化,探讨了原水管道的运行时间对原水中硝化作用的影响.结果表明,在管壁生物膜自然形成过程中,微生物表现出明显的群落演替现象,微生物的生长经历了适应期、对数生长期、脱落期和稳定期四个阶段,原水中的硝化作用不断趋于彻底.随着运行时间的增加,微生物多样性逐渐降低,生物系统趋于稳定.运行75 d后,NH4+-N浓度的变化率稳定在-45％左右;125 d后,NO2--N浓度的变化率稳定在-90％左右,NO3--N浓度的变化率稳定在40％左右.

Visible-light-driven, graphene-like boron nitride (g-BN)-mediated graphitic carbon nitride (g-C3N4) photocatalysts were firstly synthesized via a facile and green method. The as-prepared catalyst samples were characterized by their morphology, optical and electrochemical performance. The photocatalytic activity of the g-BN/g-C3N4 composites was evaluated by bisphenol A photodegradation and H2 evolution under visible-light irradiation. The results indicated that 0.9% g-BN/g-C3N4 exhibited the best photocatalytic activity amongst the hybrid photocatalysts. The enhanced photocatalytic activity was ascribed to excellent surface properties, an enhanced visible-light harvesting capability, a stable structure and a high-efficiency separation rate of photoinduced electron–hole pairs. This work will support the rational design of g-BN-based photocatalytic materials for use in energy conversion and environmental preservation.

The use of fourier transform ion cyclotron resonance mass spectrometer (FT-ICR MS) and fluorescence excitation-emission matrix (EEM) systematically provide more comprehensive information on the changes in dissolved organic matter (DOM) composition and characteristic in water treatments. Therefore, this study aims to provide information on the molecular and spectroscopic characteristics of DOM in a full-scale drinking water treatment plant (DWTP) and summarize the effects of different treatment processes on DOM. This study sheds light on the molecular transformation of DOM in conventional treatments and advanced treatments.