Calculations and Sensitivity Analysis of Chlorine-,NO_(x)-,and Bromine-Depleting Cycles of Stratospheric Ozone

This paper presents an engineering system approach using a 2D model of conservation of mass to study the dynamics of ozone and concerned chemical species in the stratosphere.By considering all fourteen photolysis,ozone-generating,and-depleting chemical reactions,the model calculated the transient,spatial changes of ozone under different physical-chemical-radiative conditions.Validation against the measured data demonstrated good accuracy,close match of our model with the observed ozone concentrations at both 20°S and 90°N locations.The deviation in the average concentration was less than 1% and in ozone profiles less than 17%.The impacts of various chlorine-(Cl),nitrogen oxides-(NO_(x)),and bromine-(Br)depleting cycles on ozone concentrations and distribution were investigated.The chlorine catalytic depleting cycle was found to exhibit the most significant impact on ozone dynamics,confirming the key role of chlorine in the problem of ozone depletion.Sensitivity analysis was conducted with levels of 25%,50%,100%,200%,and 400% of the baseline value.The combined cycles(Cl+NO_(x)+Br)showed the most significant influence on ozone behavior.The total ozone abundance above the South Pole could decrease by a small 3%,from 281 DU(Dubson Units)to 273 DU for the 25% level,or by a huge thinning of 60%to 114 DU for the 400% concentration level.When the level of chlorine gases increased beyond 200%,it would cause ozone depletion to a level of ozone hole(below 220 DU).The 2D Ozone Model presented in this paper demonstrates robustness,convenience,efficiency,and executability for analyzing complex ozone phenomena in the stratosphere.

EXAMINATION OF POLYCHLORINATED DIBENZO-P-DIOXINS AND POLYCHLORINATED DIBENZOFURANS INTO PROCESS WATER OF KRAFT PULP BLEACHING MILL FROM ASPECT OF ENVIRONMENTAL WATER QUALITY

Process water of a pulp mill with kraft cooking, oxygen delignification and chlorine bleaching or chlorine dioxide (ECF) bleaching was examined from an aspect of a new level for environmental water quality in Japan. According to the new level, a concentration of dioxins consisting of polychlorinated dibenzo-p-dioxins (PCDDs), polychlorinated dibenzofurans (PCDFs) and coplanar polychlorinated biphenyls (PCBs) in environmental water is restricted to less than 1 pg- TEQ/L. We clarified that the 2,3,7,8-tetrachlorodibenzofuran (TCDF) concentrations were 0.5 pg/L or less. In addition, a main source of 1,3,6,8- and 1,3,7,9-tetrachlorodibenzo-p-dioxins in the process water seemed to be an agrochemical in water supplied from a river.

Automatic Detection Instrument for the Ratio of Chlorine to Bromine in Oxidized Liquid of Bromine Production Based on Fuzzy Method

In the process of bromine production,because of lag adjustment methods,there are problems of adjusting delay,raw material wastage and low growth rate.By considering the nature of bromine production,with the help of fuzzy data processing method,computer detection and display technique,we designed an automatic detection instrument for the ratio of chlorine to bromine in oxidized liquid of bromine production.This instrument can be used to detect the different parameters of raw materials adjustment and control in real time,and afford assurance that raw materials will be adjusted in time.This paper briefly introduces the working mechanism,hardware and software design of the instrument.

Chlorination of water containing bromide and formation of the bromine－substituted trihalomethanes

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在线燃烧离子色谱法测定环氧树脂中的氯和溴

建立了在线燃烧离子色谱同时测定环氧树脂中氯和溴的分析方法.采用高温裂解炉与离子色谱的在线联用装置,通过对样品进行高温燃烧裂解和气化,以100 mg·L^(-1)过氧化氢为吸收液,将产生的卤化氢气体吸收并转化为无机阴离子,离子色谱法进行样品的测定,以氯和溴的峰面积外标法进行定量.对影响燃烧效果和测定结果准确度的因素如燃烧时间、燃烧温度、吸收液体积、称样量、氧气和氩气流速等条件进行了选择优化.在(0.10—2.50)mg·L^(-1)和(0.02—0.50)mg·L^(-1)范围内,氯和溴离子的线性相关系数(r^(2))大于0.999,该方法对于氯和溴的定量下限分别为0.55 mg·kg^(-1)和2.60 mg·kg^(-1).采用建立的方法分别对环氧树脂和EC680k低密度聚乙烯标准物质中的氯和溴进行测定,并与传统的氧弹燃烧-离子色谱法进行了比较.结果表明:在线燃烧离子色谱法对于环氧树脂中氯和溴测定结果的相对标准偏差分别为1.28%和2.29%,测定值与氧弹燃烧-离子色谱法基本一致,EC680k的测定结果与标准值符合,证明该方法具有良好的准确度和精密度.该方法准确度和灵敏度高、重复性较好,能够满足批量树脂类样品中氯和溴的含量筛查和多批次产品的质量控制.

氯/溴取代有机污染物在南瓜中的吸收、迁移和转化研究进展

氯/溴取代有机污染物具有持久性、毒性、蓄积性,对人类健康造成威胁,成为环境科学研究热点.以南瓜作为模型植物,通过土壤或水培培养及影响因素分析,探究氯/溴取代有机污染物在植物中的吸收、迁移和转化规律,对明晰其环境行为、生态风险评价等具有重要意义.本文在现有的研究基础上总结了模式植物的培养方案设置,氯/溴取代有机污染物在南瓜幼苗中的吸收途径、迁移形式、转化过程,分析了影响吸收和迁移速率的主要因素.氯/溴取代有机污染物的吸收途径包括:南瓜幼苗的根系从土壤或水中吸收有机污染物,南瓜幼苗的叶片从空气中吸收有机污染物;迁移形式包括:南瓜幼苗的根系吸收的有机污染物向上迁移至茎、叶,南瓜幼苗的叶片吸收的有机污染物向下迁移至茎、根;转化主要过程包括:脱卤反应、卤原子重排、裂解反应、羟基化反应、甲基化反应、去甲基化反应、糖基化反应、去糖基化反应.氯/溴取代有机污染物自身的物理化学性质是影响吸收和迁移速率的主要因素.本文对氯/溴取代有机污染物在南瓜中的环境行为进行总结,有助于明晰有机污染物在环境中的生物地球化学循环,为环境健康研究提供借鉴.

气相色谱法检测红树林湿地土壤中氯/溴代多环芳烃

建立了气相色谱-电子捕获检测器(GC-ECD)法检测红树林湿地土壤中18种氯/溴代多环芳烃(Cl/Br-PAHs)同类物,探究了土壤样品的前处理方法,并验证了方法的有效性.该方法的检出限和加标回收率分别为0.21~3.75ng/g dw和64.9%~106.4%,相对标准偏差为0.42%~14.13%.与GC-MS方法相比,GC-ECD方法对于多数Cl/Br-PAHs的准确度和灵敏度相当,且该方法稳定性更好,测定成本更低,可以满足湿地土壤中Cl/Br-PAHs的定性定量分析.采用所建立的方法对广西红树林湿地土壤样品进行了检测,结果显示,湿地土壤样品中Cl/Br-PAHs的总含量范围为163.24~244.45ng/g dw.

Health risk assessments of polycyclic aromatic hydrocarbons and chlorinated/brominated polycyclic aromatic hydrocarbons in urban air particles in a haze frequent area in China

The potential threats of polycyclic aromatic hydrocarbons(PAHs)and chlorinated/brominated PAHs(Cl/Br-PAHs)to human health from particulate matter in the urban ambient air were studied using human health risk assessments.The risk to human health caused by exposure to PAHs was evaluated in Shijiazhuang,China,from January to December 2018.The PAHs concentration range was 16.02e475.21 ng/m3 and the toxic equivalent was 13.605 ng/m3.For adults,the average carcinogenic risk caused by respiratory exposure was 5.163×10^-6 and the resulting loss of life expectancy was 32.10 min.The human health risks of respiratory exposure to Cl/Br-PAHs in atmospheric samples from the Haidian District,Beijing,China,were evaluated from November 2017 to July 2018.The concentration ranges for the Cl-and Br-PAHs were 60.38e482.17 pg/m3 and 1.32e25.35 pg/m3,respectively.The average carcinogenic equivalent concentrations were 0.3274 pg/m3 and 0.0061 pg/m3 for the Cl-and Br-PAHs,respectively.For adults the average carcinogenic risks caused by respiratory exposure were 1.243×10^-10 and 2.316×10^-12 for the Cl-and Br-PAHs,respectively.The resulting loss of life expectancy values were 0.001 min(Cl-PAHs)and 0.00 min(Br-PAHs).The pollution concentrations and toxic equivalents of the Cl/Br-PAHs in Beijing and of the PAHs in Shijiazhuang both showed toxicity was high in the winter.The average carcinogenic risk for exposure of adults to PAHs in Shijiazhuang was low with certain potential hazards.The concentration of Cl-PAHs in Beijing was higher than that of Br-PAHs,and the average carcinogenic risk for exposure of adults to Cl/Br-PAHs was very low with slight harm.

Importance of Bromine-Substituted DBP’s in Drinking Water

Significant fractions of bromine-substituted disinfection byproducts (DBPs)—particularly trihalomethanes (THMs)— have been observed to form during treatment of water from the Missouri River. THM speciation was also noted to follow a seasonal pattern during a 2.5-year period, during which samples were collected multiple times per month. Although some treatment processes were effective at reducing the chloroform formation potential, no treatment used at this utility significantly reduced the formation of the three bromine-substituted THM species. Using chloramination rather than free chlorination for secondary disinfection, however, was effective at limiting increases in the concentration of all four regulated THM species in the distribution system.

Unveiling the secondary pollution in the catalytic elimination of chlorinated organics: The formation of dioxins

Since the discovery of polychlorinated dibenzo-p-dioxins and dibenzofurans(PCDD/Fs)in the process of municipal solid waste incineration(MSWI),a large number of researches have been conducted to reveal their formation mechanisms and emission characteristics.As one of national priority control pollutants,chlorinated organics are inclined to transfer into PCDD/Fs in the heterogeneously catalyzed process,which has been considered to be one of great challenges in environmental catalysis.However,so far direct evidences to support such a conversion process are insufficient,and the reaction mechanisms are lack of exploration.This study investigated the catalytic elimination of chlorobenzene(CBz)over a range of industrially applied active species including Pt,Ru,V,Ce and Mn oxides,and explored their reaction byproducts,chlorine adsorption/desorption behaviors and PCDD/F formations.We found that all of these species could generate the PCDD/Fs,amongst which,Mn species were the most active for PCDD/F formation.Approximately 140 ng I-TEQg-1 PCDD/Fs were detected on the Mn-CNT surface after ageing at250℃for 30 h.Even using the dichloromethane(DCM)as a precursor,significant PCDD/Fs were still detected.The Ru and V species were shown to generate much less polychlorinated byproducts and PCDD/Fs,owning to their sufficiently high abilities in Cl desorption,which were through the semi-Deacon and Br(?)nsted H reactions,respectively.

管式炉燃烧-离子色谱法测定石墨烯粉体中氟、氯、溴、硫元素的含量

提出了管式炉燃烧-离子色谱法测定石墨烯粉体中氟、氯、溴、硫元素含量的方法。样品经冷冻研磨,分取5~10 mg置于燃烧舟中,选择自动推进模式,设置燃烧室温度为1 050℃,后燃烧时间为160 s。样品充分燃烧后,以30%(质量分数)过氧化氢溶液为吸收液,Metrosep A Supp5阴离子色谱柱为分析柱,含3.2 mmol·L^(-1)Na_(2)CO_(3)和1.0 mmol·L^(-1)NaHCO_(3)的混合溶液为淋洗液,采用电导检测器测定其中F^(-)、Cl^(-)、Br^(-)、SO_(4)^(2-)的含量,进而换算为氟、氯、溴、硫元素的含量。结果显示:F^(-)、Cl^(-)、Br^(-)、SO_(4)^(2-)的质量浓度在一定范围内与其对应的峰面积呈线性关系,检出限(3S/N)为0.05~0.10 mg·L^(-1);方法用于测定标准物质ERM-EC-680K中氯、溴、硫的含量,所得测定值均在认定值的不确定度范围内;方法用于实际样品分析,未检出溴元素,并且氯、氟、硫元素的测定值与另外6家实验室的基本一致。

Monthly variations of unregulated brominated disinfection by-products in chlorinated water are correlated with total bromine

Brominated disinfection by-products(Br-DBPs)can form during the chlorination of drinking water in treatment plants(DWTP).Regulations exist for a small subset of Br-DBPs;however,hundreds of unregulated Br-DBPs have been detected,and limited information exists on their occurrence,concentrations,and seasonal trends.Here,a data-independent precursor isolation and characteristic fragment(DIPIC-Frag)method were optimized to screen chlorinated waters for Br-DBPs.There were 553 Br-DBPs detected with m/z values ranging from 170.884 to 497.0278 and chromatographic retention times from 2.4 to 26.2 min.With MS2 information,structures for 40 of the 54 most abundant Br-DBPs were predicted.The method was then applied to a year-long study in which raw,clear well,and finished water were analyzed monthly.The 54 most abundant unregulated Br-DBPs were subjected to trend analysis.Br-DBPs with higher oxygen-to-carbon(O/C)and bromine-to-carbon(Br/C)ratios increased as water moved from the clear well to the finished stage,which indicated the dynamic formation of Br-DBPs.Monthly trends of unregulated Br-DBPs were compared to raw water parameters,such as natural organic matter,temperature,and total bromine,but no correlations were observed.It was found that total concentrations of bromine(TBr)in finished water(0.04–0.12 mg/L)were consistently and significantly greater than in raw water(0.013–0.038 mg/L,P<0.001),suggesting the introduction of bromine during the disinfection process.Concentrations of TBr in treatment units,rather than raw water,were significantly correlated to 34 of the Br-DBPs atα?0.05.This study provides the first evidence that monthly trends of unregulated Br-DBPs can be associated with the concentration of TBr in treated waters.

海水基质成分对紫外线去除游离氯和游离溴的影响

紫外线照射可以去除反渗透工艺中的游离氯和游离溴,但是海水基质成分对于去除效果的影响尚不清晰.为解决上述问题,在低压紫外照射下测定了游离氯和游离溴的浓度变化,计算了分解速率常数,分析了水中pH、无机阴离子和腐殖酸对其分解速率的影响.结果表明,随着pH的降低,游离氯和游离溴的分解速率均升高,且pH对游离溴分解速率的影响更大;无机阴离子中Cl^(−)能够抑制游离氯的分解而促进游离溴的分解,NO_(3)^(-)能够促进游离氯的分解而抑制游离溴的分解;水中腐殖酸在低浓度时抑制游离氯和游离溴的分解,在高浓度时促进分解,对游离溴的促进作用更强.研究结果可以为反渗透系统中紫外线去除游离氯和游离溴的工艺优化提供数据参考.

Formation pathways of brominated products from benzophenone-4 chlorination in the presence of bromide ions

The brominated products, formed in chlorination treatment of benzophenone-4 in the presence of bromide ions, were identified, and the formation pathways were proposed.Under disinfection conditions, benzophenone-4 would undertake electrophilic substitution generating mono- or di-halogenated products, which would be oxidized to esters and further hydrolyzed to phenol derivatives. The generated catechol intermediate would be transformed into furan-like heterocyclic product. The product species were p H-dependent,while benzophenone-4 elimination was chlorine dose-dependent. When the chlorination treatment was performed on ambient water spiked with benzophenone-4 and bromide ions, most of brominated byproducts could be detected, and the acute toxicity significantly increased as well.

工业液氯中溴含量分析方法的研究

介绍分光光度法测量工业液氯中的溴含量。给出试验试剂、仪器、试验方法。对试验结果进行讨论,分光光度法测定液氯中溴含量加标回收率为97.9%~101.8%,有较高的准确度,完全可以满足液氯中溴含量的检测要求。

溴系阻燃剂与CPE对阻燃ABS的水煮老化性能的影响

以溴化环氧树脂(BEO)、溴代三嗪(BrN)、复配溴代三嗪/四溴双酚A(BrN/TBBA)为阻燃剂,三氧化二锑(Sb_(2)O_(3))为阻燃协效剂,氯化聚乙烯(CPE)为增韧剂,对丙烯腈-丁二烯-苯乙烯(ABS)进行增韧阻燃改性,并对阻燃ABS进行水煮老化试验。结果表明,3种阻燃体系对ABS都有优异的阻燃效果:BrN阻燃ABS具有最佳的缺口冲击强度;CPE不仅具有优异的增韧效果,也有协效阻燃的作用,添加CPE后,阻燃ABS的韧性和阻燃性均有提高;BrN阻燃体系也具有良好的耐水煮性能,水煮后色差和力学性能变化最小。CPE的加入增加了材料的吸水性,使得阻燃ABS的颜色变化加剧,但缺口冲击强度明显提升,3种阻燃体系的缺口冲击强度分别提升39.5%、18.7%和14.0%,且阻燃性能仍能保持良好。

Factors influencing the formation of chlorination brominated trihalomethanes in drinking water

The formation of brominated trihalomethanes (THMs-Br) which is proved more carcinogenic than their chlorinated analogues reported was very different at various water qualities.This study was performed to assess the effects of water quality parameters (bromide concentration,pH value and ammonia concentration),chlorination conditions (chlorine dose,reaction time) and ratios of Br-/DOC and Br-/Cl2 consumption on the formation and distribution of THMs-Br in chlorination.The results showed good correlation between the bromine incorporation factor (BIF) n(Br) and Br-/Cl2 consumption ratio.The formation of total THM (TTHM) was found to decrease with increasing ammonia concentration but to increase with bromide concentration and pH value.The n(Br) trends were significantly affected by the presence of bromide concentration.The effects on the molar yields of THMs were more strongly influenced by bromide concentration and dissolved organic carbon (DOC) concentration than pH value and natural organic matter (NOM) source.High Br-/DOC and Br-/Cl2 favor the formation of THMs-Br over chlorinated THMs (THMs-Cl).The experimental data including the main parameters such as bromide,DOC,ammonia,pH and reaction time were used for developing the predictive model for THMs-Br.

二氧化钛催化下的氯代二苯并-对-二恶英光解反应

本文利用中压汞灯作光源,研究了氯代二苯并-对-二恶英(CDDs,包括CDD,DCDD,PeCDD和OCDD)在二氧化钛催化下的光解反应,并讨论了二氧化钛浓度、pH值、反应温度以及取代氯原子数目等对反应速率的影响.结果表明,二氧化钛能有效地催化CDDs的光降解,在室温下,4h内DCDD,PeCDD,OCDD分别降解了87.2%,84.6%,91.2%,反应温度和二氧化钛浓度是控制该反应的主要因素.

煤中氯对多环芳烃生成的影响研究

本文在管式炉上研究了煤中氯对多环芳烃生成的影响,测定了煤中氯含量不同时多环芳烃生成量的变化,并分析了在不同气氛下不同含氯量的煤燃烧时多环芳烃与二(?)英生成的相互关系.实验结果表明,在空气中燃烧及氮气气氛热解条件下,随着氯含量的增加,多环芳烃呈减少趋势;氯代反应是导致多环芳烃生成量减少的一个主要原因.

地质样品中痕量氯溴和硫的X射线荧光光谱法测定

报道了粉末压样 -X射线荧光光谱法测定地质样品中痕量Cl、Br、S的分析方法。采用水系沉积物、岩石和土壤等国家一级标准物质进行校准。实验表明 ,对于不同岩性样品中Br的分析 ,特别是当Br的含量低于 2 μg/g时 ,采用谱峰强度 (未扣除背景 )与背景强度的比进行校准所得到的结果 ,明显优于铑靶线的Compton散射线内标法 ,分析精度 (RSD ,n =6 )为 2 .4%～1 5 .3 % ,大多数优于 1 0 % ;平均值的相对误差低于 2 4 %。对于Cl的分析 ,只需对Ca的影响加以校正即可得到非常好的结果 ;不同样品中Cl的分析精度 (RSD ,n =6 )为 2 .1 %～ 1 3 .6 % ,大多数优于 5 % ;平均值的相对误差不大于 2 5 % ,多数优于 1 0 %。S的校准曲线的离散性较大 ,矿物学效应是影响S分析准确度的主要因素 ,其分析精度 (RSD ,n =6 )为 0 .87%～ 5 .6 % ,除个别样品外 ,平均值的相对误差优于 3 6 %。Cl和S均存在分析结果随测量时间 (次数 )的增加而增高的现象 ,必须在制样后立即测量。方法的检出限 (μg/g)Br、Cl、S分别为 0 .43、5 .8和 2 .2。