Effects of Chlorine and Chlorine Monoxide on Stratospheric Ozone Depletion

This paper presents a system approach of mass balance calculations of ozone and other species under diffusion-convection-reaction processes to study the impacts of major ozone-depleting chemicals, chlorine (Cl) and chlorine monoxide (ClO), and the effect of photolysis on ozone concentrations, ozone depletion, total ozone abundance, and ozone layer along the altitude in the stratosphere. The calculated ozone concentrations and profile of the layer followed a similar trend and were generally in good agreement with the measurements above the tropical area. The calculated peak of the layer was at the same mid-stratosphere at Z = 30 km with a peak concentration and total ozone abundance about 20% higher than the measured peak concentration of 8.0 ppm and total abundance of 399 DU. In the presence of Cl and ClO, the calculated ozone concentrations and total abundance were substantially reduced. Cl generally depleted more uniformly of ozone across the altitude, while ClO reduced substantially the ozone in the upper stratosphere and thus shifted the peak of the layer to a much lower elevation at Z = 14 km. Although both ClO and Cl are active ozone-depleting chemicals, ClO was found to have a more pronounced impact on ozone depletion and distribution than Cl. The possible explanations of these interesting phenomena were discussed and elaborated. The approach and calculations in this paper were shown to be useful in providing an initial insight into the structure and behavior of the complex ozone layer.

Unveiling the geometric site dependent activity of spinel Co_(3)O_(4)for electrocatalytic chlorine evolution reaction

Spinel cobalt oxide(Co_(3)O_(4)),consisting of tetrahedral Co^(2+)(CoTd)and octahedral Co^(3+)(CoOh),is considered as promising earth-abundant electrocatalyst for chlorine evolution reaction(CER).Identifying the catalytic contribution of geometric Co site in the electrocatalytic CER plays a pivotal role to precisely modulate electronic configuration of active Co sites to boost CER.Herein,combining density functional theory calculations and experiment results assisted with operando analysis,we found that the Co_(Oh) site acts as the main active site for CER in spinel Co_(3)O_(4),which shows better Cl^(-)adsorption and more moderate intermediate adsorption toward CER than CoTd site,and does not undergo redox transition under CER condition at applied potentials.Guided by above findings,the oxygen vacancies were further introduced into the Co_(3)O_(4) to precisely manipulate the electronic configuration of Co_(Oh) to boost Cl^(-)adsorption and optimize the reaction path of CER and thus to enhance the intrinsic CER activity significantly.Our work figures out the importance of geometric configuration dependent CER activity,shedding light on the rational design of advanced electrocatalysts from geometric configuration optimization at the atomic level.

One-Step Scalable Fabrication of Nitrogen and Chlorine Co-doped Graphene by Electrochemical Exfoliation for High-Performance Supercapacitors

The stacking and aggregation of graphene nanosheets have been obstacles to their application as electrode materials for microelectronic devices.This study deploys a one-step,scalable,facile electrochemical exfoliation technique to fabricate nitrogen(N)and chlorine(Cl)co-doped graphene nanosheets(i.e.,N-Cl-G)via the application of constant voltage on graphite in a mixture of 0.1 mol/L H_(2)SO_(4)and 0.1 mol/L NH_(4)Cl without using dangerous and exhaustive operation.The introduction of Cl(with its large radius)and N,both with high electrical negativity,facilitates the modulation of the electronic structure of graphene and creation of rich structural defects in it.Consequently,in the as-constructed supercapacitors,N-Cl-G exhibits a high specific capacitance of 77 F/g at 0.2 A/g and remarkable cycling stability with 91.7%retention of initial capacitance after 20,000 cycles at 10 A/g.Furthermore,a symmetrical supercapacitor assembled with N-Cl-G as the positive and negative electrodes(denoted as N-Cl-G//N-Cl-G)exhibits an energy density of 3.38 Wh/kg at a power density of 600 W/kg and superior cycling stability with almost no capacitance loss after 5000 cycles at 5 A/g.This study provides a scalable protocol for the facile fabrication of high-performance co-doped graphene as an electrode material candidate for supercapacitors.

Crystal structure transformation and lattice impurities migration of quartz during chlorine roasting

To investigate the effect of chlorine roasting on the migration and removal of trace elements in quartz lattice,firstly,an efficient pretreatment process,grinding–HCl washing–flotation–HF and HCl leaching,was used to remove the gangue minerals in quartz ore to obtain purified quartz for the preparation of high-purity quartz and the investigation of lattice impurities migration.The results showed that the high-purity quartz with total impurities less than 50μg/g could be obtained from purified quartz after being treated with chlorine at 1200°C.The variation of crystal structure and the lattice impurities migration of quartz during chlorine roasting were studied through in-situ XRD,TGA,SEM-EDS,ICP-MS,FT-IR and XPS analysis.It revealed that the decomposable impurities H_(2)O,-OH,and residual collectors in the crystal of purified quartz could be effectively removed through chlorine roasting above 900°C,which also had an obvious effect on the removal of low-valence trace elements Li,Na and K in the crystal of quartz but didn't affect the multivalent trace elements Al and Ti.This study revealed the removal and migration mechanism of the trace elements in quartz crystal during chlorine roasting.

Detection of Oxidants Such as Hydroxyl Radicals and Chlorine Electrogenerated on a BDD Electrode by Simple Methods

The aim of this work is to detect electrogenerated hydroxyl radicals and chlorine by simple and less expensive methods. Preparative electrolyses of perchloric acid (HClO4) and sodium chloride (NaCl) were performed on a boron-doped diamond (BDD) electrode. The hydroxyl radicals were quantified indirectly by assaying the samples from the HClO4 (0.1 M) electrolysis with a 10−4 M potassium permanganate solution. The investigations showed that the amount of hydroxyl radicals depends on the concentration of HClO4 and the current density. As for chlorine, a qualitative determination was carried out. A mixture of the electrolyte solution of HClO4 (0.1 M) + NaI (0.2 M) + 2 mL of hexane, taken in this order, leads to a purplish-pink coloration attesting to the presence of Cl2. The same test was carried out with NaBr and NaI giving pale and very pale pink colourations, respectively, showing that the intensity of the colouration depends on the strength of the oxidant present. In addition, oxidants were detected during the electrooxidation of metronidazole (MNZ). The results showed the participation of electrogenerated hydroxyl radicals. The generation of chlorine has also been proven. Furthermore, the degradation leads to a chemical oxygen demand (COD) removal rate of 83.48% and the process is diffusion-controlled.

Chlorine-Substituent Regulation in Dopant-Free Small-Molecule Hole-Transport Materials Improves the Effi ciency and Stability of Inverted Perovskite Solar Cells

Although doped hole-transport materials(HTMs)off er an effi ciency benefi t for perovskite solar cells(PSCs),they inevi-tably diminish the stability.Here,we describe the use of various chlorinated small molecules,specifi cally fl uorenone-triphenylamine(FO-TPA)-x-Cl[x=para,meta,and ortho(p,m,and o)],with diff erent chlorine-substituent positions,as dopant-free HTMs for PSCs.These chlorinated molecules feature a symmetrical donor-acceptor-donor structure and ideal intramolecular charge transfer properties,allowing for self-doping and the establishment of built-in potentials for improving charge extraction.Highly effi cient hole-transfer interfaces are constructed between perovskites and these HTMs by strategi-cally modifying the chlorine substitution.Thus,the chlorinated HTM-derived inverted PSCs exhibited superior effi ciencies and air stabilities.Importantly,the dopant-free HTM FO-TPA-o-Cl not only attains a power conversion effi ciency of 20.82% but also demonstrates exceptional stability,retaining 93.8%of its initial effi ciency even after a 30-day aging test conducted under ambient air conditions in PSCs without encapsulation.These fi ndings underscore the critical role of chlorine-substituent regulation in HTMs in ensuring the formation and maintenance of effi cient and stable PSCs.

Design of highly active and durable oxygen evolution catalyst with intrinsic chlorine inhibition property for seawater electrolysis

High-efficiency seawater electrolysis is impeded by the low activity and low durability of oxygen evolution catalysts due to the complex composition and competitive side reactions in seawater.Herein,a heterogeneousstructured catalyst is constructed by depositing NiFe-layered double hydroxides(NiFe-LDH)on the substrate of MXene(V_(2)CT_(x))modified Ni foam(NF),and abbreviated as NiFe-LDH/V_(2)CT_(x)/NF.As demonstrated,owing to the intrinsic negative charge characteristic of V_(2)CT_(x),chlorine ions are denied entry to the interface between NiFeLDH and V_(2)CT_(x)/NF substrate,thus endowing NiFe-LDH/V_(2)CT_(x)/NF catalyst with high corrosion resistance and durable stability for 110 h at 500 mA cm^(-2).Meanwhile,the two-dimensional structure and high electrical conductivity of V_(2)CT_(x) can respectively enlarge the electrochemical active surface area and guarantee fast charge transfer,thereby synergistically promoting the catalytic performance of NiFe-LDH/V_(2)CT_(x)/NF in both deionized water electrolyte(261 m V at 100 m A cm^(-2))and simulated seawater electrolyte(241 mV at 100 mA cm^(-2)).This work can guide the preparation of oxygen evolution catalysts and accelerate the industrialization of seawater electrolysis.

Effects of surface chlorine atoms on charge distribution and reaction barriers for photocatalytic CO_(2)reduction

Photocatalytic CO_(2)reduction to produce high value-added carbon-based fuel has been proposed as a promising approach to mitigate global warming issues.However,the conversion efficiency and product selectivity are still low due to the sluggish dynamics of transfer processes involved in proton-assisted multi-electron reactions.Lowering the formation energy barriers of intermediate products is an effective method to enhance the selectivity and productivity of final products.In this study,we aim to regulate the surface electronic structure of Bi_(2)WO_(6)by doping surface chlorine atoms to achieve effective photocatalytic CO_(2)reduction.Surface Cl atoms can enhance the absorption ability of light,affect its energy band structure and promote charge separation.Combined with DFT calculations,it is revealed that surface Cl atoms can not only change the surface charge distribution which affects the competitive adsorption of H_(2)O and CO_(2),but also lower the formation energy barrier of intermediate products to generate more intermediate*COOH,thus facilitating CO production.Overall,this study demonstrates a promising surface halogenation strategy to enhance the photocatalytic CO_(2)reduction activity of a layered structure Bi-based catalyst.

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.

Determination of Chlorine and Bromine in Plant Materials by Ion Chromatography

A method was developed for determination of chlorine and bromine in plant materials by ion chromatography using temperature programing-semi molten for sample preparation. Values of detection limits of the method found were 1.0×10^-5 for CI and 1.3×10^-6 for Br. The measuring range of the method found were 0.3-20.0 mg/L for CI and 4,0-120,0 μg/L for Br. The results obtained agreed quite well with those reference values.

Low-temperature chlorination roasting technology for the simultaneous recovery of valuable metals from spent LiCoO_(2)cathode material

With the continuous increase in the disposal volume of spent lithium-ion batteries(LIBs),properly recycling spent LIBs has become essential for the advancement of the circular economy.This study presents a systematic analysis of the chlorination roasting kinetics and proposes a new two-step chlorination roasting process that integrates thermodynamics for the recycling of LIB cathode materials.The activation energy for the chloride reaction was 88.41 kJ/mol according to thermogravimetric analysis–derivative thermogravimetry data obtained by using model-free,model-fitting,and Z(α)function(αis conversion rate).Results indicated that the reaction was dominated by the first-order(F1)model when the conversion rate was less than or equal to 0.5 and shifted to the second-order(F2)model when the conversion rate exceeded 0.5.Optimal conditions were determined by thoroughly investigating the effects of roasting temperature,roasting time,and the mass ratio of NH_(4)Cl to LiCoO_(2).Under the optimal conditions,namely 400℃,20 min,and NH_(4)Cl/LiCoO_(2)mass ratio of 3:1,the leaching efficiency of Li and Co reached 99.43% and 99.05%,respectively.Analysis of the roasted products revealed that valuable metals in LiCoO_(2)transformed into CoCl_(2) and LiCl.Furthermore,the reaction mechanism was elucidated,providing insights for the establishment of a novel low-temperature chlorination roasting technology based on a crystal structure perspective.This technology can guide the development of LIB recycling processes with low energy consumption,low secondary pollution,high recovery efficiency,and high added value.

Maintaining moderate levels of hypochlorous acid promotes neural stem cell proliferation and differentiation in the recovery phase of stroke

It has been shown clinically that continuous removal of ischemia/reperfusion-induced reactive oxygen species is not conducive to the recovery of late stroke.Indeed,previous studies have shown that excessive increases in hypochlorous acid after stroke can cause severe damage to brain tissue.Our previous studies have found that a small amount of hypochlorous acid still exists in the later stage of stroke,but its specific role and mechanism are currently unclear.To simulate stroke in vivo,a middle cerebral artery occlusion rat model was established,with an oxygen-glucose deprivation/reoxygenation model established in vitro to mimic stroke.We found that in the early stage(within 24 hours)of ischemic stroke,neutrophils produced a large amount of hypochlorous acid,while in the recovery phase(10 days after stroke),microglia were activated and produced a small amount of hypochlorous acid.Further,in acute stroke in rats,hypochlorous acid production was prevented using a hypochlorous acid scavenger,taurine,or myeloperoxidase inhibitor,4-aminobenzoic acid hydrazide.Our results showed that high levels of hypochlorous acid(200μM)induced neuronal apoptosis after oxygen/glucose deprivation/reoxygenation.However,in the recovery phase of the middle cerebral artery occlusion model,a moderate level of hypochlorous acid promoted the proliferation and differentiation of neural stem cells into neurons and astrocytes.This suggests that hypochlorous acid plays different roles at different phases of cerebral ischemia/reperfusion injury.Lower levels of hypochlorous acid(5 and 100μM)promoted nuclear translocation ofβ-catenin.By transfection of single-site mutation plasmids,we found that hypochlorous acid induced chlorination of theβ-catenin tyrosine 30 residue,which promoted nuclear translocation.Altogether,our study indicates that maintaining low levels of hypochlorous acid plays a key role in the recovery of neurological function.

Scalable Ir‑Doped NiFe_(2)O_(4)/TiO_(2) Heterojunction Anode for Decentralized Saline Wastewater Treatment and H_(2) Production

Wastewater electrolysis cells(WECs)for decentralized wastewater treatment/reuse coupled with H_(2) production can reduce the carbon footprint associated with transportation of water,waste,and energy carrier.This study reports Ir-doped NiFe_(2)O_(4)(NFI,~5 at%Ir)spinel layer with TiO_(2) overlayer(NFI/TiO_(2)),as a scalable heterojunction anode for direct electrolysis of wastewater with circumneutral pH in a single-compartment cell.In dilute(0.1 M)NaCl solutions,the NFI/TiO_(2) marks superior activity and selectivity for chlorine evolution reaction,outperforming the benchmark IrO_(2).Robust operation in near-neutral pH was confirmed.Electroanalyses including operando X-ray absorption spectroscopy unveiled crucial roles of TiO_(2) which serves both as the primary site for Cl−chemisorption and a protective layer for NFI as an ohmic contact.Galvanostatic electrolysis of NH4+-laden synthetic wastewater demonstrated that NFI/TiO_(2)not only achieves quasi-stoichiometric NH_(4)^(+)-to-N_(2)conversion,but also enhances H_(2)generation efficiency with minimal competing reactions such as reduction of dissolved oxygen and reactive chlorine.The scaled-up WEC with NFI/TiO_(2)was demonstrated for electrolysis of toilet wastewater.

基于ClO^(-)-HO_(2)-平衡机制的氯介导电催生^(1)O_(2)机理探究

鉴于单线态氧(^(1)O_(2))氧化能力强、对环境友好等特点,进一步揭示电化学过程中氯介导产^(1)O_(2)的反应机理不仅能够提高废水处理效果,还可以减少活性氯带来的副作用.因此,采用电化学测试、罗丹明B(RhB)模拟废水处理等手段评估Ir-Ta/Ti和Pt/Ti电极的性能,并探讨不同条件(Cl^(-)浓度、电极析氯活性、外加H_(2)O_(2)、通入O_(2))对电化学产^(1)O_(2)的影响.结果表明,以^(1)O_(2)为主导的电化学体系能够去除超过96%的RhB且可缩短降解路径.高效生成^(1)O_(2)的基础是维持体系中产生的次氯酸根(ClO-)与过氧氢根(HO_(2)-)之间的平衡,任何一方过量都会抑制^(1)O_(2)的产生.本次研究以期为促进不同环境情况下^(1)O_(2)的生成和电极的定向制备与改性提供理论依据.

聚酰胺膜耐氯改性及氯化修复研究进展

介绍了间苯二胺-均苯三甲酰氯和哌嗪-均苯三甲酰氯两种典型的PA膜,深入剖析其最新的氯化破坏机理.在此基础上,进一步探讨了针对这两种膜的耐氯改性方法,包括改变单体结构、本体掺杂技术、物理涂覆方法以及化学接枝手段等.对PA膜氯化修复领域的最新研究进展进行了简要论述,包括初期氯化后的还原法修复和氯化降解后的修补剂修复.分析表明,耐氯PA膜的研制仍面临巨大挑战,PA膜的耐氯改性研究应在不牺牲其分离性能的前提下,综合考虑膜的其他各项性能,灵活运用各种改性方法.

降温过程中NaCl盐渍土相变的电化学特征

氯盐渍土是中国西北寒旱区一种典型的盐渍土类型,其电化学特征是深入理解盐渍土腐蚀病害机理的关键。为探究盐渍土孔隙溶液相变与其电化学特征之间的联系,以NaCl盐渍粉质黏土为研究对象,测试了不同含盐量和温度条件下NaCl盐渍土的电化学阻抗谱。研究表明:NaCl盐渍土阻抗随着测试频率的增加而逐步降低,并在高频率时逐步达到稳定。NaCl盐渍土的阻抗模的对数值在冻结前随温度的降低线性增加,而在冻结后,冰晶和盐结晶的生成导致土体阻抗模值发生显著增加。NaCl盐渍土在冻结前表现为一段容抗弧,而在冻结后,由相变导致的土体水盐迁移使得土体在出现阻抗弧后又存在一段扩散阻抗。根据土体在冻结前后的导电路径,建立了土体在冻结前后的等效电路模型,并在此基础上分析了土体孔隙溶液相变与对应电路元件之间的联系。此研究对深入理解盐渍土电化学特征及孔隙溶液相变规律具有重要意义。

共混比对NR/CIIR共混物的拉伸取向及SIC行为的研究

采用机械共混和模压成型工艺制备了天然橡胶(NR)/氯化丁基橡胶(CIIR)复合材料,并对其硫化性能、机械性能、单轴拉伸取向性能、应变诱导结晶(SIC)、阻尼行为等进行了分析。透射电子显微镜(TEM)的结果显示,CIIR组分在共混物中呈现海岛结构分布,且边界清晰。随着CIIR占比增大,拉伸应力应变性能与纯NR相一致,但拉伸强度比纯NR下降明显;通过红外二向色性法分析发现,共混物的取向行为主要源于NR组分;同步辐射广角X射线衍射(WAXD)的测试结果表明,共混物中CIIR占比越高,SIC行为越弱;通过机械共混的方式,可以制备得到两者特性结合的NR/CIIR共混物,30 Hz条件下损耗因子从NR纯胶的0.1,增加至NR/CIIR 50/50(质量比)的0.18,上升幅度达80%,为隔震支座用橡胶材料的制备提供新思路。

再生骨料与废弃橡胶对自密实混凝土性能的影响

研究了水泥-粉煤灰混合浆液的水胶比(0.5~1.0)、浸泡时间(2.0~4.0 h)对再生骨料性能的影响,优选出了最佳的包浆处理方式,在此基础上制备了自密实混凝土(SCC),研究了未包浆再生骨料和包浆再生骨料的掺量(0、30%、50%、100%)、废弃橡胶颗粒掺量(0、5%、10%)对SCC工作性、力学性能和抗氯离子渗透性能的影响。结果表明:当混合浆液的水胶比为0.7、浸泡时间为3.5 h时,包浆再生骨料的综合性能最优;未包浆再生骨料、包浆再生骨料的掺入基本降低了SCC的工作性、28 d抗压强度、轴心抗压强度、劈裂抗拉强度、抗氯离子渗透性能,其中,包浆再生骨料对SCC性能的不利影响相对较小;废弃橡胶颗粒的掺入降低了SCC的工作性、28 d抗压强度、轴心抗压强度、劈裂抗拉强度,但提高了抗氯离子渗透性能;建立的强度指标换算公式精度较高。

Full-scale study of removal effect on Cyclops of zooplankton with chlorine dioxide

Cyclops of zooplankton propagated excessively in eutrophic water body and could not be effectively inactivated by the conventional disinfections process like chlorination due to its stronger resistance to oxidation. In this paper, a full-scale study of chlorine dioxide preoxidation cooperating with routine clarification process for Cyclops removal was conducted in a waterworks. The experimental results were compared with that of the existing prechlorination process in several aspects: including the Cyclops removal efficiencies of water samples taken from the outlets of sedimentation tank and sand filter and the security of drinking water and so on. The results showed that chlorine dioxide might be more effective to inactivate Cyclops than chlorine and Cyclops could be thoroughly removed from water by pre-dosing chlorine dioxide process. The GC-MS examination and Ames test further showed that the sort and amount of organic substance in the treated water by chlorine dioxide preoxidation were evidently less than that of prechlorination and the mutagenicity of drinking water treated by pre-dosing chlorine dioxide was substantially reduced compared with prechlorination.

Investigation of heavy metal partitioning influenced by flue gas moisture and chlorine content during waste incineration

The impact of moisture on the partitioning of the heavy metals including Pb,Zn,Cu and Cd in municipal solid waste （MSW） was studied in a laboratory tubular furnace.A thermodynamic investigation using CHEMKIN software was performed to compare the experimental results.Simulated waste,representative of typical MSW with and without chlorine compounds,was burned at the background temperature of 700 and 950°C,respectively.In the absence of chlorine,the moisture content has no evident effect on the volatility of Pb,Zn and Cu at either 700 or 950°C,however,as flue gas moisture increasing the Cd distribution in the bottom ash increased at 700°C and reduced at 950°C,respectively.In the presence of chlorine,the flue gas moisture reduced the volatility of Pb,Zn and Cu due to the transformation of the more volatile metal chlorides into less volatile metal oxides,and the reduction became significant as chlorine content increase.For Cd,the chlorine promotes its volatility through the formation of more volatile CdCl 2.As a result,the increased moisture content increases the Pb,Zn,Cu and Cd concentrations in the bottom ash,which limits the utilization of the bottom ash as a construction material.Therefore,in order to accumulate heavy metals into the fly ash,MSW should be dried before incineration.