Effects of oxidizing environment on digestate humification and identification of substances governing the dissolved organic matter (DOM) transformation process

• Liquid digestate humification was investigated under different oxidizing environment. • Tryptophan-like substances dominated the transformation of the liquid digestate DOM. • The humification sequence of the liquid digestate DOM was identified. • UV₃₂₅ was first identified as a pre-humus intermediate during humification reaction. The formation of humic-like acids (HLAs) is an essential process for converting liquid digestate into organic soil amendments to enhance agricultural sustainability. The aim of this study was to investigate the impact of oxygen and/or MnO₂ on the production of HLAs. Herein, abiotic humification performance of the digestate dissolved organic matter (DOM) is investigated with fluxes of air and N₂ in the absence and presence of MnO₂. Our results demonstrated that the fate of digestate DOM greatly depends on the oxidizing environment, the MnO₂ enhanced nitrogen involved in the formation of HLAs. The synergistic effects of MnO₂ and oxygen effectively improved the production of HLAs, and the corresponding component evolution was analyzed using spectroscopic evidence. The two-dimensional correlation spectroscopy results demonstrated that the reaction sequence of digestate DOM followed the order of protein-like substances, substances with an absorbance at 325 nm, substances with UV absorbance at 254 nm and HLAs. Additionally, excitation emission matrix fluorescence combined with parallel factor analysis (EEM-PARAFAC) showed that tryptophan-like C3 was more prone to transformation than tyrosine-like C2 and was responsible for the humification process. The substance with an absorbance at 325 nm was a reaction intermediate in the transformation process of protein-like substances to HLAs. The above findings can be used to promote the production of liquid fertilizer associated with carbon sequestration as well as the sustainable development of biogas production.     

高效液相色谱及其联用技术在有机锡形态测定中的应用

本文对发展中高效液相色谱及其联用技术在有机锡形态测定的应用分两部分作了综述：第一部分,各类高效液相色谱分离有机锡：第二部分,从接口角度讨论高效液相色谱及其联用技术测定有机锡。共引３６ 篇文献。     

白腐真菌对活性艳红染料X-3B的脱色实验研究

探讨了白腐真菌对活性艳红染料X-3B废水的脱色效果。实验结果表明白腐真菌可以有效地对染料废水进行脱色。白腐真菌在空气曝气培养条件下,比在空气静置培养状态下具有更强的脱色降解能力;而且当在染料废水中加入一定量的碳源物质(葡萄糖)能提高白腐真菌脱色能力。最后,通过考察细胞外液对染料废水的脱色效果,表明白腐真菌对染料进行脱色的核心体系位于细胞体外。实验结果对白腐真菌在环境工程中的直接应用具有一定的价值。     

高效液相色谱法测定矿区塌陷区水体中多环芳烃

高效液相色谱法是目前多环芳烃(PAHs)测定最常用技术之一。针对EPA规定的16种优先控制PAHs污染物,采用高效液相色谱法进行矿区塌陷区水体样品的测试。通过紫外-荧光串联使用,紫外检测器变波扫描,荧光检测器波长切换,合理设定流动相梯度洗脱程序等手段优化分析条件,使16个组分在40min内获得良好的分离效果。并分别选取在紫外和荧光检测条件下各组分的最大响应进行定量,使各组分均具有更低的检出限。本方法精密度为0.98%～10.4%,加标回收率达72.4%～112%,可作为各种环境样品中PAHs分析检测的参考。     

液氦罐车碰撞仿真安全性研究

本文采用s0Mworks、ANSyS／Workbench、LS—DYNA等软件对常温裸形的液氨罐车进行了碰撞仿真研究,获得了多种情形下罐车的碰撞性能,为以后展开实车碰撞提供了重要的技术支撑。     

Characteristics and removal mechanism of the precursors of N-chloro-2,2-dichloroacetamide in a drinking water treatment process at Taihu Lake

• N-Cl-DCAM, an emerging N-DBP in drinking water was investigated. • A new BAC has a better removal efficiency for N-Cl-DCAM precursors than an old BAC. • N-Cl-DCAM precursors are more of low molecular weight and non-polar. • Adsorption of GAC plays a major role in removal of N-Cl-DCAM precursors by an O₃-BAC. N-chloro-2,2-dichloroacetamide (N-Cl-DCAM) is an emerging nitrogenous disinfection by-product (N-DBP) which can occur in drinking water. In this study, an analytical method based on liquid chromatography with tandem mass spectrometry (LC-MS/MS) was developed to validate the concentration of N-Cl-DCAM, which was found to be 1.5 mg/L in the effluent of a waterworks receiving raw water from Taihu Lake, China. The changes of N-Cl-DCAM formation potential (N-Cl-DCAMFP) in the drinking water treatment process and the removal efficiency of its precursors in each unit were evaluated. Non-polar organics accounted for the majority of N-Cl-DCAM precursors, accounting for 70% of the N-Cl-DCAM FP. The effect of conventional water treatment processes on the removal of N-Cl-DCAM precursors was found to be unsatisfactory due to their poor performance in the removal of low molecular weight (MW) or non-polar organics. In the ozonation integrated with biological activated carbon (O₃-BAC) process, the ozonation had little influence on the decrease of N-Cl-DCAM FP. The removal efficiency of precursors by a new BAC filter, in which the granular activated carbon (GAC) had only been used for four months was higher than that achieved by an old BAC filter in which the GAC had been used for two years. The different removal efficiencies of precursors were mainly due to the different adsorption capacities of GAC for individual precursors. Low MW or non-polar organics were predominantly removed by GAC, rather than biodegradation by microorganisms attached to GAC particles.     

LLE-GC-MS法测定水中27种有机农药

建立了同时测定水中27种有机农药的LLE-GC-MS法。该法前处理前需调节水样pH值2,不加甲醇作为改性剂,以1:1(V/V)正己烷-石油醚为萃取溶剂进行液液萃取,GC-MS法进行检测。方法在各目标化合物质量浓度0.010~0.500 mg/L范围内线性良好,相关系数R2均0.995,检出限为0.021~0.250μg/L,加标回收率为73.6%~113.6%,相对标准偏差RSD为4.0%~14.1%,适用于水中27种有机农药的检测。     

The effect of clay catalyst on the chemical composition of bio-oil obtained by co-pyrolysis of cellulose and polyethylene

Cellulose/polyethylene (CPE) mixture 3:1, w/w with and without three clay catalysts (K10 – montmorillonite K10, KSF – montmorillonite KSF, B – Bentonite) addition were subjected to pyrolysis at temperatures 400, 450 and 500 °C with heating rate of 100 °C/s to produce bio-oil with high yield. The pyrolytic oil yield was in the range of 41.3–79.5 wt% depending on the temperature, the type and the amount of catalyst. The non-catalytic fast pyrolysis at 500 °C gives the highest yield of bio-oil (79.5 wt%). The higher temperature of catalytic pyrolysis of cellulose/polyethylene mixture the higher yield of bio-oil is. Contrarily, increasing amount of montmorillonite results in significant, almost linear decrease in bio-oil yield followed by a significant increase of gas yield. The addition of clay catalysts to CPE mixture has a various influence on the distribution of bio-oil components. The addition of montmorillonite K10 to cellulose/polyethylene mixture promotes the deepest conversion of polyethylene and cellulose. Additionally, more saturated than unsaturated hydrocarbons are present in resultant bio-oils. The proportion of liquid hydrocarbons is the highest when a montmorillonite K10 is acting as a catalyst.     

液相微萃取技术及其在环境水样预处理中的应用

介绍了液相微萃取技术的基本原理、萃取过程与中空纤维的形式。分析了中空纤维、有机萃取剂、吸收液体积、样品搅动、无机盐类、pH值和萃取时间等因素对萃取效果的影响。综述了液相微萃取技术在环境水样预处理中的应用。     

超高效液相色谱三重四极杆质谱联用法测定水中的苯胺及联苯胺

将含有苯胺及联苯胺的水样过滤后加入乙腈(水样中乙腈比例为20%)直接进样,使用超高效液相色谱三重四极杆质谱联用法测定。通过选择离子反应监测,可实现定性和外标法定量分析。该法测定生活饮用水及其水源水中苯胺和联苯胺的最低检测浓度分别为2和0.2ng/mL,对实际样品的加标回收率为苯胺:112%～115%,联苯胺:84.5%～86.5%,该方法绿色环保、简单、具有较高的灵敏度和较低的检出限。