A study of the Fe(III)/Fe(II)-triethanolamine complex redox couple for redox flow battery application

The electrochemical behavior of the Fe(III)/Fe(II)-triethanolamine(TEA) complex redox couple in alkaline medium and influence of the concentration of TEA were investigated. A change of the concentration of TEA mainly produces the following two results. (1) With an increase of the concentration of TEA, the solubility of the Fe(III)-TEA can be increased to 0.6 M, and the solubility of the Fe(II)-TEA is up to 0.4 M. (2) In high concentration of TEA with the ratio of TEA to NaOH ranging from 1 to 6, side reaction peaks on the cathodic main reaction of the Fe(III)-TEA complex at low scan rate can be minimized. The electrode process of Fe(III)-TEA/Fe(II)-TEA is electrochemically reversible with higher reaction rate constant than the uncomplexed species. Constant current charge-discharge shows that applying anodic active materials of relatively high concentrations facilitates the improvement of cell performance. The open-circuit voltage of the Fe-TEA/Br₂ cell with the Fe(III)-TEA of 0.4 M, after full charging, is nearly 2.0 V and is about 32% higher than that of the all-vanadium batteries, together with the energy efficiency of approximately 70%. The preliminary exploration shows that the Fe(III)-TEA/Fe(II)-TEA couple is electrochemically promising as negative redox couple for redox flow battery (RFB) application.     

金矿的溴氧化浸出工艺试验

在实验室条件下,详细考察了溴氧化浸出金的各项条件。结果表明,对含金量为55 5g/t的广东某硫化矿,经破碎至-0 147mm,600℃焙烧后,在常温、试剂浓度2%NaCl-0 1%Br2,液固比1∶1,浸出时间1h的条件下,金的平均浸出率达97 2%。     

1,2-Dimethylimidazole based bromine complexing agents for vanadium bromine redox flow batteries

To stabilize bromine produced during a vanadium-bromine redox flow batteries (VBr RFBs) charging, a bromine complexing agent (BCA) should be effectively used as a supporting material in VBr electrolyte. However, there remains a problem of improving the unstable reversibility between V²⁺ and V³⁺ in electrolyte including halogen elements (Br and Cl). This paper describes two imidazole-based BCAs, which are 1,2-dimethyl-3-ethylimidazolium bromide (DMEIm: C₇H₁₃BrN₂) and 1,2-dimethyl-3-propylimidazolium bromide (DMPIm: C₈H₁₅BrN₂), for not only confirming the capture of bromine but also improving the redox reaction of vanadium ions in VBr electrolyte. The effectiveness of the proposed two imidazole-based BCAs is demonstrated through the following experiments: cyclic voltammetry (CV), nuclear magnetic resonance analysis (NMR), scanning electron microscopy (SEM) analysis and cyclic cell operation test. Experimental results show that both the diffusion coefficient and the peak currents of each electrolyte using the proposed imidazole-based BCAs increases linearly with the rise of scan rate on the recorded CV curves, providing improved reversible reaction of V²⁺/V³⁺ in negative electrolyte. It also exhibits that the electrolytes using the DMEIm and DMPIm provide significantly improved charge (discharge) capacities which are 9.38 (31.01) % and 11.8 (35.66) % higher than the pristine one, respectively, resulting in 13.27% and 14.36% higher current efficiencies. In addition, corrosion cracks on the separator surface due to bromine attack are not observed after the cyclic cell operation. Consequently, these results indicate that the proposed two imidazole-based BCAs can not only sequester bromine during the VBr RFB charging, but also enhance electrochemical reversibility caused by improving diffusion coefficient of vanadium.     

Interpreting enhanced Hg oxidation with Br addition at Plant Miller

This paper introduces the first detailed reaction mechanisms for Br/Hg chemistry in flue gas, and interprets the Hg oxidation performance across a broad range of Br injection rates in recent field tests at Plant Miller. Homogeneous chemistry with Br species is much faster than with Cl species because the Br atom concentrations at the furnace exit are three to four orders of magnitude greater. The dominant channels with Br are analogous to those for Cl, whereby a Br atom partially oxidizes Hg⁰ into HgBr which is then oxidized into HgBr₂ by Br₂. Mercury also oxidizes heterogeneously on unburned carbon (UBC) with Br species. This mechanism is also analogous to the surface mechanism for Cl species, except that (i) Hg⁰ adsorption is faster on brominated sites and (ii) the high Br atom concentrations promote recombination reactions which maintain very low surface coverages of Hg/Br species. Hence, Br addition does not promote the production of particulate-Hg. Catalytic Hg⁰ oxidation on SCR monoliths by Br species is more than 40 times faster than by Cl species and follows a similar mechanism. For all Br loadings over 10 ppmw in the field tests, essentially all Hg⁰ entering the SCR was oxidized.     

Ozone-Bromine Treatment – Water Treatment in Public Pools without Chlorine: A New Standard?

The central task of the rules and regulations governing water treatment in public swimming pools is to provide guidelines, the compliance with which leads to completely hygienic water. For this purpose, DIN 19643 “Treatment of Water of Swimming Pools and Baths” applies in Germany. To date, this standard has prescribed the chlorination of water. In a therapeutic pool introduced here, water was treated without chlorine. The water quality was observed as part of a long-term study over the course of three years. During the entire period, no germs were detected in the filtrate of the system, not even unspecific CFU germs. The treatment presented here is detailed from both theoretical and practical viewpoints. The treatment uses the oxidation power of ozone to form hypobromous acid as a disinfectant in water containing bromide. A crucial aspect of the treatment is the possible formation of bromate. It is shown that the formation of bromate can be suppressed very effectively. Further bromine-based by-products were monitored. Unpleasant by-products as known from the chlorination were not found. The treatment, known as ozone-bromine Treatment, demonstrates new ways to treat water in public swimming pools and should now be incorporated into the German DIN 19643. It is to be expected that this will also be reflected in the national standards of other countries.     

Frequency of use controls chemical leaching from drinking-water containers subject to disinfection

Microbial-, and chemical-based burden of disease associated with lack of access to safe water continues to primarily impact developing countries. Cost-effective health risk-mitigating measures, such as of solar disinfection applied to microbial-contaminated water stored in plastic bottles have been increasingly tested in developing countries adversely impacted by epidemic water-borne diseases. Public health concerns associated with chemical leaching from water packaging materials led us to investigate the magnitude and variability of antimony (Sb) and bromine (Br) leaching from reused plastic containers (polyethylene terephthalate, PET; and polycarbonate, PC) subject to UV and/or temperature-driven disinfection. The overall objective of this study was to determine the main and interactive effects of temperature, UV exposure duration, and frequency of bottle reuse on the extent of leaching of Sb and Br from plastic bottles into water. Regardless of UV exposure duration, frequency of reuse (up to 27 times) was the major factor that linearly increased Sb leaching from PET bottles at all temperatures tested (13-47 °C). Leached Sb concentrations (∼360 ng L⁻¹) from the highly reused (27 times) PET bottles (minimal Sb leaching from PC bottles, <15 ng L⁻¹) did not pose a serious risk to human health according to current daily Sb acceptable intake estimates. Leached Br concentrations from both PET and PC containers (up to ∼15 μg L⁻¹) did not pose a consumer health risk either, however, no acceptable daily dose estimates exist for oral ingestion of organo-brominated, or other plasticizers/additives compounds if they were to be found in bottled water at much lower concentrations. Additional research on potential leaching of organic chemicals from water packaging materials is deemed necessary under relevant environmental conditions.     

卤代双磷酸酯阻燃剂的合成研究

以PCl3、季戊四醇、溴水及环氧乙烷为原料，四氯化钛为催化剂，合成了一种新型卤代双磷酸酯阻燃剂——2，2-二溴甲基-1，3-亚丙基双(2-氯乙基2-溴乙基磷酸酯)；用IR、元素分析对其进行了表征。结果表明：在各步反应过程中分别按照各步反应的量的比、温度、时间等最佳反应条件进行反应，产物的收率可达92％。     

分别测定双磷酸酯阻燃增塑剂中氯和溴含量的方法

介绍利用Ｂｒ的特征反应使系统中的Ｂｒ全部转化后，分别测定阻燃增塑剂中氯与溴含量的一种新方法。该方法分析速度快，操作简单，测定结果准确，重现性好，可应用于生产中的控制分析。     

国产溴化丁基橡胶BIIR2032微观结构对比研究

采用了核磁H谱、凝胶渗透色谱仪、傅里叶变换红外光谱、差示扫描量热仪、热失重分析仪等分析方法,研究国产溴化丁基橡胶的微观结构,并与BIIR2030、BIIR2222进行对比。结果表明：1H NMR测得的溴含量大小顺序为：BIIR2030相似文献   

波长色散X荧光测定石油及其产品中氯和溴的影响因素分析

采用荧光波长色散法测定石油及其产品中氯和溴,通过建立标准曲线,测量几种样品中氯和溴含量。方法的精密度RSD1%,在样品浓度氯和溴含量很低的情况下,氯元素的回收率仍达76.72%~104.78%,溴元素的回收率高达84.22%~101.32%。所以该法可直接取样测定,影响因素较少,适合于快速、准确测定石油及其产品中氯和溴。