氰化钾水溶液的辐解——Ⅱ.用纸色层法测定K~(14)CN溶液辐解产物的产额

用纸色层法分离了γ辐照空气饱和的K~(14)CN水溶液的辐解产物,得到了八个产物。以载体法成功地抑制了主要辐解产物在纸色层过程中的分解。根据H_2O_2浓度剂量曲线指示体系中氧浓度的别辐解产物的产额为:R_f=0(未知物)G(-CN~-)=0.17,甘氨酸G(-CN~-)=0.06;R_f=0.21(未知物)G(-CN~-)=0.08,氰酸盐G(-CN~-)=0.06,甲酞胺G(-CN~-)=0.07;R_f=0.67(未知物)G(-CN~-)=0.03.甲醛G(-CN~-)=0.08;R_f=0.84(未知物) G(-CN~-)=0.05。求得缺氧时各别辐解产物的产额为:R_f=0(未知物)G(-CN~-)=0.17,甘氨酸G(-CN~-)=0.51;R_f=0.21(未知物) G(-CN~-)=0.83,氰酸盐G(-CN~-)=0.55,甲酰胺G(-CN~-)=0.93;R_f=0.67(未知物)G(-CN~-)=0.03,甲醛G(-CN~-)=0.11;R_f=0.84(未知物)G(-CN~-)=0.14。以化学法测定了G(CO_3~(2-))=0.33,CO_3~(2-)的产额与体系中氧浓度的变化无关。     

电子束辐照处理模拟甲苯废气实验研究

以甲苯作为挥发性有机化合物的代表物质,在800keV电子束的辐照下,模拟甲苯废气的气量在0.5—1.2m3/h范围内,研究了甲苯初始质量浓度为1600—4630mg/m3时吸收剂量、甲苯初始浓度和湿度对于甲苯分解效率的影响。实验结果表明,电子束辐照可有效去除甲苯,甲苯初始质量浓度为1600mg/m3,辐照10kGy和40kGy,甲苯去除率分别为46.5%和72.2%;增加湿度也可提高甲苯去除率。用气相色谱-质谱仪(GC-MS)和离子色谱仪(IC)定性研究了辐解产物。甲苯辐解产物比较复杂,主要含有苯甲醛、甲酸等物质。也探讨了电子束辐照处理甲苯气体的主要机理,讨论了O2和.OH对于电子束辐照分解甲苯中的重要作用。     

γ射线辐照水溶液中氯霉素的降解研究

研究了γ射线辐照水溶液中氯霉素的降解规律,并对辐解产物进行了初步探讨.根据辐照前后高效液相色谱(High performance liquid chromatography,HPLC)图谱中氯霉素峰面积变化,分析得出氯霉素随吸收剂量和初始浓度的降解规律.利用液相色谱串联质谱(Liquid chromatography tandem mass spectrometry,LC/MS/MS),定性分析氯霉素的辐解产物.结果表明,氯霉素残留量随吸收剂量和初始浓度的变化关系满足指数方程;氯霉素辐射降解后形成了30个以上的辐解产物,它们在氯霉素检测波长278nm下的响应值均较低;确定了氯霉素在不同辐解条件下均出现的8种主要辐解产物,它们的准分子离子质量[M-H]分别为:353、337、335(A)、335(B)、319、289、127、166,并对主要辐解产物进行了初步的结构解析.     

超钚元素分离中使用的若干络合剂的γ辐解研究

本文研究了氨三乙酸(NTA)、二乙撑三胺五醋酸(DTPA)、和α-羟基异丁酸(α-HIBA)水溶液的γ辐解。测定了辐解气体量和破坏率与吸收剂量的关系。同时还测定了辐照溶液的pH值的变化。吸收剂量5×10~7rad时,pH=7.0的0.1M NTA/NH_4NO_3水溶液,pH=7.0的0.05MDTPA/NH_4NO_3水溶液,pH=3.7的0.4M α-HIBA/NH_4NO_3水溶液及0.4 M α-HIBA水溶液的辐解破坏率分别为～56%,～87%,～45%和37%。三种络合剂的辐解气体主要成分为氢和二氧化碳。NTA的辐解产物除气体外主要是亚氨基二乙酸(IDA)。     

辐照对盐酸克伦特罗降解效应的初步研究

采用电子束辐照处理盐酸克伦特罗,应用液相色谱串联质谱、红外光谱等技术研究盐酸克伦特罗辐照降解规律及辐解产物的结构,分析辐照对盐酸克伦特罗的降解效应。实验结果表明,原始浓度为18 mg·kg–1和45 mg·kg–1的盐酸克伦特罗水溶液浓度随吸收剂量增加而降低,且在吸收剂量为5 kGy和10 kGy时降解率达到90%以上;在低剂量下(≤5 kGy)盐酸克伦特罗分子的-OH和-Cl基团脱落,随着剂量的增加-OH,-NH2,-NH-和-C(CH3)3等基团也发生了不同程度的改变或脱落,表明电子束辐照可有效降解盐酸克伦特罗。     

H_2MEHP水溶液的γ辐解

前言萃取剂磷酸三丁酯(TBP)和二(2-乙基己基)磷酸酯(H_2MEHP)的降解产物(如HDBP、H_2MBP和H_2MEHP)的水溶液的辐解情况很少报道。仅在五十年代,有人报道过几种单烷基磷酸酯水溶液的辐解情况,发现除了产生H_3PO_4外,还生成不稳定的酰基磷酸酯;后来,有人报道HDBP、H_2MEHP等在同水相搅拌或溶于水的情况下辐     

PUREX流程中TBP辐解产物对Pu(Ⅳ)反萃的影响研究

PUREX流程中,萃取剂和稀释剂在强辐照场下会发生辐解,部分辐解产物使Pu(Ⅳ)的反萃变得困难。本文通过实验研究,获取了辐解产物与Pu(Ⅳ)保留的比例关系。结果表明,辐解产物磷酸二丁酯(HDBP)与羟胺(HAN)、稀硝酸难以反萃的Pu(Ⅳ)摩尔浓度之比约为2,磷酸一丁酯(H_2MBP)与HAN难以反萃的Pu(Ⅳ)的摩尔浓度之比为1～2。结合文献报导,获取了不同辐解产物在PUREX流程中的产生量,从而较系统地比较了各辐解产物对Pu(Ⅳ)反萃的影响程度,并对主要辐解产物在PUREX流程中不同Pu(Ⅳ)反萃工艺段的影响进行了讨论。结果表明:热堆乏燃料后处理流程中对Pu(Ⅳ)反萃造成影响的主要辐解产物为HDBP,快堆乏燃料后处理流程中对Pu(Ⅳ)反萃造成影响的主要辐解产物为HDBP和H_2MBP。     

甲醇水介质中717型三甲胺阴树脂的γ辐照稳定性研究

比较了OH~-型、Cl~-型和NO_3~-型聚苯乙烯三甲胺阴树脂(型号717)在水和甲醇两种介质中的γ辐照稳定性。结果表明:无论在水中还是在甲醇介质中受辐照,OH~-型树脂的辐照稳定性最差,NO_3~-型树脂最稳定。水的辐解产物OH基参与了主要辐解产物三甲胺的再辐解。     

1,10-菲咯啉-5,6-醌水溶液的γ辐解

采用60Coγ辐解，以异丙醇自由基为还原剂，研究了1，10－菲咯啉－5，6－醌（PQ）水溶液的单电子还原性质，获得了pH分别为9、≈7和≈4的水溶液幅照后的紫外、可见吸收光谱。pH9时吸收谱呈现出一个中心在490nm的宽吸收带，低于pH7，这个490nm附近的吸收要小得多，而且随溶液pH值的降低而下降。60Coγ辐解实验的观察与脉冲辐解结果一致。由此建议60Coγ辐解观察到的可见范围的吸收和脉冲辐解微秒范围所观察到的结果均由辐解终产物引起。质谱研究表明：pH3．3的水溶液经γ辐解生成一个质量数大于PQ的终产物。此终产物假定为由中性PQ半醌自由基歧化作用产生的PQH2．     

芘在离子液体与常规溶剂混合体系的脉冲辐解研究

以芘(Pyrene)作为探针分子,利用纳秒脉冲辐解技术研究了芘在乙腈、丙酮、环己烷、乙醇、及乙醇与季铵盐离子液体(三乙基庚基铵双三氟甲磺酰亚胺)混合体系中各种瞬态产物的吸收光谱,并观察了溶剂化电子的反应动力学。测定了芘在乙醇与离子液体混合溶剂中490nm处芘阴离子自由基(Py?-)生成的速率常数,随着溶液中离子液体体积的增大,芘阴离子自由基生成速率常数减缓。同时比较了乙醇及混合体系中离子液体不同体积比下Py?-生成表观速率常数的变化,进一步揭示了离子液体不同于普通溶剂的物理化学特性:离子液体中经电子束辐解后产生溶剂化电子,而溶剂化电子产生之前存在一个极短的干电子过程。     

Radiolysis of Hydrogen Cyanide in an Aqueous System, (III)

Dependence of radiolysis on pH in deaerated aqueous HCN (6 mM) has been investigated. The radiolytic yield of HCN decomposed, G(— HCN), decreases to a limiting value of 2.9 in the pH range while G(— HCN) at pH 5–8 is observed to be 5.8. The radiolytic yields of ammonia (G = 1.9), formaldehyde (G = l.l) and carbon dioxide (G = 0.6–0.8) are little affected by changes in pH. The formation of polymeric HCN is inhibited by decreasing pH. This can be explained as the result of the degradation from dimeric to monomeric form undergone by HCN, which is known to be an intermediate compound.

Based on experiments on the effect of adding Cl as OH radical scavenger, it is considered that formaldehyde and a part of ammonia are produced through methylenimine as intermediate.

The radiolysis of aqueous KCN is also studied for making a comparison of the radiolysis behavior between cyanide ions and undissociated HCN.     

A study of low-energy ion induced radiolysis of thiol-containing amino acid cysteine in the solid and aqueous solution states

The radiolysis of cysteine under plasma discharge and irradiation of low-energy ion beam was investigated. The damage of cysteine in aqueous solution under discharge was assessed via the acid ninhydrin reagent and the yield of cystine produced from the reaction was analyzed by FTIR. In addition, the generation of hydrogen sulfide was also identified. The destruction of solid cysteine under low-energy ion beam irradiation was estimated via monitoring IR bands of different functional groups (–SH, –NH₃, –COO^?) of cysteine, and the production of cystine from ion-irradiated solid cysteine after dissolution in water was also verified. These results may help us to understand the inactivation of sulphydryl enzymes under direct and indirect interaction with the low-energy ion irradiation.     

用于储氢材料的碳/掺杂碳气凝胶研究

通过溶胶凝胶工艺,以间苯二酚和甲醛为原料,采用常压干燥法制备有机气凝胶和金属掺杂有机气凝胶;在氮气保护下,经1050℃高温碳化获得碳/掺杂碳气凝胶;通过CO₂活化工艺优化样品微结构、提高其比表面积,获得了比表面积达2582m²/g的碳气凝胶样品。使用比表面积与孔隙度分析仪、扫描电镜（SEM）、透射电镜（TEM）、X射线衍射仪（XRD）对样品微观结构和气体吸附性能进行表征。通过溶胶 凝胶工艺实现了过渡金属的均匀掺杂,并研究了金属掺杂对碳气凝胶微结构特性的影响。结果表明,适当的金属掺杂可提高样品的比表面积和微孔体积。     

Radiolytic decomposition of 4-bromodiphenyl ether

Polybrominated diphenyl ethers (PBDEs) spread widely in the environment are mainly removed by photochemical and anaerobic microbial degradation. In this paper, the decomposition of 4-bromodiphenyl ether (BDE -3), the PBDEs homologues, is investigated by electron beam irradiation of its ethanol/water solution (reduction system) and acetonitrile/water solution (oxidation system). The radiolytic products were determined by GC coupled with electron capture detector, and the reaction rate constant of esol– in the reduction system was measured at 2.7×1010 L·mol–1·s–1 by pulsed radiolysis. The results show that the BDE-3 concentration affects strongly the decomposition ratio in the alkali solution, and the reduction system has a higher BDE-3 decomposition rate than the oxidation system. This indicates that the BDE-3 was reduced by effectively capturing esol– in radiolytic process.     

EB degradation of perfluorooctanoic acid and perfluorooctane sulfonate in aqueous solution

Electron beam (EB) degradation of perfluorooctanoic acid (PFOA) and perfluorooctane sulfonate (PFOS) in aqueous solutions was studied.It suggested that PFOA and PFOS degradation followed the pseudo-firstorder kinetics,and degradation rates increased with increasing initial pH.Radical scavengers' experiments indicated that hydrated electron and hydrogen radical were important in the electron beam degradation of PFOA and PFOS,especially hydrated electron.The decomposition efficiencies were 95.7％ for PFOA and 85.9％ for PFOS,by EB irradiation in an anoxic alkaline solution (pH =13).The potential degradation pathways of PFOA and PFOS by electron beam irradiation through defluorination and the removal of CH2 unit were proposed.     

Radiochemical synthesis of silver nanoparticles onto textile fabrics and their antibacterial activity

This paper presents a new technique for synthesizing silver nanoparticles immobilized on textile fabrics using a radiochemical process. In this process, the irradiation of a high-energy electron beam on an aqueous solution containing silver ions induces a reducing reaction that forms metallic silver nanoparticles. Small Ag particles of about 2–4 nm were observed together with relatively large particles of more than 10 nm. These nanoparticles are firmly immobilized on the surface of a support textile fabric without the need for any binder or surfactant. The amount of silver nanoparticles immobilized was found to depend on the water content of the support textile fabric, suggesting that the silver ions are reduced not only by radiochemical species generated by the radiolysis of water, but also by radiochemical species generated in the irradiated support fabric itself. The silver nanoparticles that were immobilized on the support textile fabric exhibited an excellent antibacterial activity across a wide antibacterial spectrum, even after a durability test involving washing the fabric 100 times.     

苯胺的脉冲辐解和激光光解研究

用脉冲辐解与激光光解时间分辨技术,从瞬态方面研究了苯胺Photo-Fenton降解的可行性。研究表明,水溶液中苯胺可为308nm的激光光电离,光电离的瞬态产物为阳离子自由基及脱质子后的中性自由基;并测得阳离子自由基脱质子转变为中性自由基的pKa值为7．5,以二苯甲酮为参比,测得苯胺光分解的量子产额极高（0．08）。应用脉冲辐解时间分辨技术研究了苯胺被羟基自由基降解的反应机理,结果表明,36％的羟基自由基直拉进攻－NH2形成苯胺,54％的羟基自由基与苯胺邻位加成,10％的羟基自由基与苯胺对位加成。     

Alpha radiolysis of nitric acid aqueous solution irradiated by 238Pu source

Alpha radiolysis of nitric acid aqueous solution by a ~(238)Pu source is investigated experimentally and theoretically.The time dependence of the nitrous acid yield on dose rate,nitric acid concentration,and nitrate ion concentration is studied.A novel kinetic model for the α-radiolysis of nitric acid aqueous solution is established,by considering the direct and indirect effects.The simulation results agree well with the experimental data,indicating the validity of our model to treat the reaction paths for generation and consumption of nitrous acid.It is shown that the redox reactions involving Pu cannot be neglected in theα-radiolysis of the solution.The results provide a better understanding of the α-ray radiolysis of aqueous nitric acid.     

A paradigm study for assessment of phenylalanine’s damage under arc-discharge irradiation

Energetic ions induce important biological effects and the research into radiolysis of amino acids can help to clarify radiolysis of proteins. For this purpose, arc-discharge induced radiolysis of the benzyl-containing aromatic amino acid phenylalanine in aqueous solution was studied and the damage was assessed quantitatively. The energetic ions were produced by arc-discharge in nitrogen and argon atmosphere. The arc-discharge induced chemical reactions of the biomolecule in aqueous solution were detected and analyzed by means of UV-Vis absorption, fluorescence, Fourier transformation infrared (FTIR) spectroscopy and high performance liquid chromatography (HPLC). Based on the multiple spectroscopic approach, the damage can be evaluated in a more reliable and convenient way. The fluorescence analysis in this case appears to be a more direct indicator for the assessment of damage, where it reveals that the damage increases with the irradiation time exponentially. On the contrary, the ‘plateau region’ or ‘saddle-shape’ apparently shown both in our rough absorption analysis and ninhydrin reaction test, similar to the previously reported feature of the dose effect for low-energy-ion induced damage, may be just a consequence with varied reactions and processes involved at different stages. This work thus demonstrated that application of appropriate combination of spectroscopic tools can effectively dissect the diversity of the radiolysis reaction system and assess the biomolecular damage properly.     

Modelling of time resolved and long contact time dissolution studies of spent nuclear fuel in 10 mM carbonate solution - A comparison between two different models and experimental data

Using two different models, radiation induced dissolution of spent UO₂ fuel has been simulated. One of the models is conventional homogeneous radiolysis simulations where two different geometrical constraints were used and the second model is the recently developed steady-state model. The results of the simulations are compared to each other and to experimental results from spent fuel leaching experiments performed in carbonate containing aqueous solution under Ar-atmosphere. The influence of radiolytically produced H₂ is incorporated (on the basis of a recently suggested mechanism) in both models and this reproduces the experimentally observed inhibition of spent fuel dissolution fairly well. The conventional radiolysis model reproduces the experimental concentrations of the radiolysis products H₂ and O₂ very well while it fails to reproduce the experimental H₂O₂ concentration. The reasons for this are discussed. The general trend in uranium concentration as a function of time is reproduced by both the conventional radiolysis model and the steady-state model. The conventional radiolysis model (in which the radiation dose is homogeneously distributed in the whole liquid volume) underestimates the uranium concentration while the steady-state model, which represents the worst case scenario, overestimates the concentrations to some extent. When applying the conventional radiolysis model, assuming that all the radiation energy is deposited within 40 μm from the fuel surface, the uranium concentrations during the initial part of the experiments are reproduced quantitatively. The differences between the models and the applicability of the models are discussed in some detail.