土壤氟化物(全量)的分析与测定

离子选择电极法测定氟化物作为一种成熟的测定方法被广泛应用环境监测等领域.本实验采用离子选择电极法测定土壤中氟含量.但样品前处理过程较复杂,极易造成测定结果的偏离.通过反复实验和比较我们对实验条件进行了优化,同时通过对该方法的准确度和精密度的测试,得到了较好的结果,适合且能满足土壤调查等样品量较大的测定工作要求.     

Efficient nitrogen doped porous carbonaceous CO2 adsorbents based on lotus leaf

In this work, the waste biomass lotus leaf was converted into N-doped porous carbonaceous CO₂ adsorbents. The synthesis process includes carbonization of lotus leaf, melamine post-treatment and KOH activation. For the resultant sorbents, high nitrogen content can be contained due to the melamine modification and advanced porous structure were formed by KOH etching. These samples were carefully characterized by different techniques and their CO₂ adsorption properties were investigated in detail. These sorbents hold good CO₂ adsorption abilities, up to 3.87 and 5.89 mmol/g at 25 and 0°C under 1 bar, respectively. By thorough investigation, the combined interplay of N content and narrow microporous volume was found to be responsible for the CO₂ uptake for this series of sorbents. Together with the high CO₂ adsorption abilities, these carbons also display excellent reversibility, high CO₂/N₂ selectivity, applicable heat of adsorption, fast CO₂ adsorption kinetics and good dynamic CO₂ adsorption capacity. This study reveals a universal method of obtaining N-doped porous carbonaceous sorbents from leaves. The low cost of raw materials accompanied by easy synthesis procedure disclose the enormous potential of leaves-based carbons in CO₂ capture as well as many other applications.     

Urinary analysis reveals high Alternaria mycotoxins exposure in the general population from Beijing, China

Alternaria mycotoxins are of concern due to its adverse health effect, they affect various cereal crops and grain-based food along with modified forms that contribute to overall exposure. This study aimed to determine the frequency and level of exposure to Alternaria mycotoxins (tenuazonic acid, TeA; alternariol, AOH; alternariol monomethyl ether, AME; tentoxin, TEN; and altenuene, ALT) in human urine from Beijing adults. A total of 2212 urine samples were collected and analyzed for five mycotoxins using LC–ESI–MS/MS. More than 98% of the samples had at least one Alternaria mycotoxin detected. Among the mycotoxins, AME had the highest detection rate (96.0%), followed by TeA (70.5%). The calculated average daily intake values of AME (12.5 ng/kg b.w.) was 5 times the TTC value (2.5 ng/kg b.w.) set by the EFSA, indicating the potential health risks associated with mycotoxins. Immediate attention and subsequent actions should be taken to identify the sources of mycotoxins and the corresponding exposure pathways to humans in the investigated regions.     

Migration and transformation of Sb are affected by Mn(III/IV) associated with lepidocrocite originating from Fe(II) oxidation

Antimony (Sb) is a recognized priority pollutant with toxicity that is influenced by its migration and transformation processes. Oxidation of Fe(II) to Fe(III) oxides, which is a common phenomenon in the environment, is often accompanied by the formation of Mn(III/IV) and might affect the fate of Sb. In this study, incorporated Mn(III) and sorbed/precipitated Mn(III/IV) associated with lepidocrocite were prepared by adding Mn(II) during and after Fe(II) oxidation, respectively, and the effects of these Mn species on Sb fate were investigated. Our results indicated that the association of these Mn species with lepidocrocite obviously enhanced Sb(III) oxidation to Sb(V), while concomitantly inhibiting Sb sorption due to the lower sorption capacity of lepidocrocite for Sb(V) than Sb(III). Additionally, Mn oxide equivalents increased in the presence of Sb, indicating that Sb oxidation by Mn(III/IV) associated with lepidocrocite was a continuous recycling process in which Mn(II) released from Mn(III/IV) reduction by Sb(III) could be oxidized to Mn(III/IV) again. This recycling process was favorable for effective Sb(III) oxidation. Moreover, Sb(V) generated from Sb(III) oxidation by Mn(III/IV) enhanced Mn(II) sorption at the beginning of the process, and thus favored Mn(III/IV) formation, which could further promote Sb(III) oxidation to Sb(V). Overall, this study elucidated the effects of Mn(III/IV) associated with lepidocrocite arisen from Fe(II) oxidation on Sb migration and transformation and revealed the underlying reaction mechanisms, contributing to a better understanding of the geochemical dynamics of Sb.     

活性炭纤维负载柠檬酸铁活化过硫酸氢钾降解罗丹明B的研究

以ACF（活性炭纤维）为载体,制备出一种新的非均相催化剂ACF@Cit-Fe/S〔将Cit-Fe（柠檬酸铁）负载在ACF表面并引入S元素〕,并采用SEM-EDS（电镜-能谱）、XPS（X射线光电子能谱）对其进行表征,研究其活化PMS（过硫酸氢钾）降解染料RhB（罗丹明B）的降解效果.结果表明:①ACF表面成功负载了Cit-Fe和S元素,Cit-Fe和S元素的掺杂增强了ACF催化PMS的性能,能有效降解染料RhB,反应120 min时RhB的脱色率达98%.②ρ（ACF@Cit-Fe/S）、c（PMS）对RhB降解有一定的影响,ρ（ACF@Cit-Fe/S）为0.5 g/L、c（PMS）为6 mmol/L是降解RhB（10 mg/L）的最佳投加量.③温度对RhB降解速率的影响符合阿伦尼乌斯模型,通过计算得出活化能为39.47 kJ/mol,降解过程是一个表面反应控制过程.④以叔丁醇、甲醇、苯酚为分子探针的自由基清除试验显示,SO₄-·（硫酸根自由基）和HO·（羟基自由基）是降解反应过程中主要的自由基,其主要存在于催化剂表面及其周围.研究显示,ACF@Cit-Fe/S能用于活化PMS的高级氧化体系中,ACF@Cit-Fe/S表面丰富的电子转移过程导致其活化PMS的能力增强,从而促进SO₄-·和HO·的产生,提高RhB的降解效率.      

HAZOP分析在安全管理应用中的问题分析及对策探讨

介绍了HAZOP分析在高含硫气田开发生产中的应用情况,探讨了HAZOP分析方法在应用过程中存在的问题,提出了对策措施和建议。     

污水处理厂污泥土地利用的现状与发展趋势

污水处理厂剩余污泥含有大量的有机质和矿质元素,可以显著提高土壤肥力,将其进行土地利用是一种既经济又有效的污泥处置方式。本文介绍了国内外污泥土地利用的概况,以及污泥在农业、园林绿化和土地修复等方面的利用现状,并分析了污泥土地利用在未来的发展趋势。     

输水水质保障下南四湖流域产业结构优化调整研究

通过对南四湖流域产业结构现状、水污染现状以及两者动态演化趋势的解析,结合对流域经济与环保政策导向的梳理,综合权衡三次产业发展对流域经济支撑度、水污染影响潜在威胁与现实效应,汇总形成了南四湖流域三次产业结构优化调整分析矩阵。在此基础上,探讨了不同产业结构优化调整的方案模式,提出南四湖流域三次产业中不同行业的结构优化方案。     

河口区有色溶解有机物(CDOM)三维荧光光谱的影响因素

结合在厦门湾九龙江口的现场调查与实验室分析,对目前河口区CDOM三维荧光光谱(excitation-emission matrix spectroscopy,EEMS)分析的一些影响因素(主要是离子强度、浓度效应、不同孔径滤膜过滤)进行了探讨.结果表明,CDOM的EEMS与样品中离子强度关系不大,说明在河口区河海水混合过程中,仅仅由于水体盐度的变化不会造成CDOM光学特征的明显变化.河端CDOM的荧光强度随物理稀释倍数的增大成相应比例的减小,稀释对EEMS的影响仅仅体现在荧光强度上,显示河口区的CDOM样品不存在荧光淬灭效应.九龙江口河流端样品中共含有类腐殖质(C、A)及类蛋白质(T1、T2)4种荧光团,随着混合样品中海水体积分数的增大,样品荧光强度逐渐降低,代表海洋来源的类腐殖质荧光峰M逐渐显露,T1峰逐渐高于A峰.这说明从河端至外海CDOM的组成结构发生了一系列的变化,来源上逐渐完成了以陆源为主到海源为主的转变;性质上逐渐完成了以类腐殖质荧光团为主到类蛋白质荧光团为主的转变.在中、高盐度区,0.2μm的Millipore聚碳酸酯滤膜可以很好地去除水体散射对EEMS的干扰,EEMS(0.2μm)比EEMS(0.7μm)更为规则,各峰的显示更加清晰.不同荧光基团的划分更加容易.无论高、中、低盐度站位,0.7μm滤膜过滤的样品,其CDOM荧光强度都要略高于0.2μm滤膜过滤的样品,2种不同孔径滤膜过滤对CDOM荧光测定带来的差异不可忽略.     

沿海城市自然灾害脆弱性评价研究——以天津滨海新区为例

从脆弱性和风险内涵比较出发,基于灾害学理论及脆弱性概念模型,从区域自然地理环境和社会经济状况构建自然灾害脆弱性评价指标体系。选择天津市滨海新区各区县为研究对象,收集指标数据,应用层次分析法（AHP）确定指标权重。采用两种评价方法进行脆弱性评价：一是应用脆弱性模型评价天津滨海新区自然灾害综合脆弱性;二是选取地面沉降灾害脆弱性指标,应用模糊综合评判评价地面沉降灾害脆弱性。评价结果表明：葛沽镇和塘沽区自然灾害综合脆弱度相对较大,大港区最小;就地面沉降灾害脆弱性而言,塘沽区最大,大港和东丽区的部分相对较小。两种评价结果具有一致性。