三氯异氰脲酸氯化改性天然橡胶硫化胶的研究

制备三氯异氰脲酸(TCCA)水性氯化溶液,用其对天然橡胶(NR)硫化胶进行表面氯化改性,研究氯化时间对表面改性效果的影响。结果表明:随着氯化时间的延长,NR硫化胶中的石蜡向表面的迁移量越小,NR硫化胶表面的Cl和N原子占比和NR硫化胶的剥离强度均先增大后减小,NR硫化胶表面的微裂纹增多及裂纹边缘更不平整;当氯化时间为6 min时,NR硫化胶表面的Cl和N原子占比和NR硫化胶的剥离强度达到最大值。

柠檬酸体系化学镀镍稳定剂的研究

针对柠檬酸化学镀镍体系,以镀液的氯化钯稳定时间及镀速为评价指标,选择2-巯基苯并咪唑(MB)和二乙基二硫代氨基甲酸钠(DDTC)作稳定剂,先考察它们单独使用时的效果,然后考察两者复配使用时的效果。结果表明:MB和DDTC均是柠檬酸体系化学镀镍的优良稳定剂,既可以单独使用,也可以复配使用。复配使用时的效果好于单独使用时的效果。两者的最佳复配量为:MB 2mg/L+DDTC 3mg/L。此时,镀液的氯化钯稳定时间长达2.50h,镀速较快(11.8μm/h)。

Effects of Slow-Mixing on the Coagulation Performance of Polyaluminum Chloride （PACI）

Conventional jar tests and on-line size monitoring were used to investigate the effects of slow-mixing intensity and duration on residual turbidity and floc size during charge neutralization coagulation and sweep floc- culation with polyaluminum chloride. The compensatory effect of slow-mixing on coagulation performance fol- low!ng inadequate_or excessive rapid-mi_xing was also examined. It is found that slowTmixing intensity has a more marked positive ettect on charge neutralization coas;ulatlon tlaan on sweep tlocculatlon. llle optimal root-mean- square velocity gradient, G, for slow-mixing is 15 s-＇ for both coagulation mechanisms, and charge neutralization coagulation requires a longer slow-mixing duration. The optimal slow-mixing duration, based on residual turbidity,is longer than the time to tbrm the largest mean Ilocs. The optimal product of G and mixing duration, GT, lbr slow-mixing during charge neutralization coagulation （13500） are higher than that during sweep flocculation （4500） and both are less than the range of values recommended by the American Water Works Association （24000-84000）.The optimal GT value under various slow-mixing conditions increases with G. Appropriate extension＇of slow-mixing duration during charge neutralization coagulation can improve coagulation performance after an inadequate or excessive rapid-mixing duration, but during sweep flocculation, appropriate shortening of slow-mixing duration after an excessive rapid-mixing or appropriate extension of slow-mixing duration after an inadequate rapid-mixing is favorable.

Homogeneous Acetylation of Cellulose at Relatively High Concentrations in an Ionic Liquid

At relatively high cellulose mass concentrations(8%,10%,and 12%),homogeneous acetylation of cellulose was carried out in an ionic liquid,1-allyl-3-methylimidazolium chloride(AmimCl).Without using any catalyst,cellulose acetates(CAs)with the degree of substitution(DS)in a range from 0.4 to 3.0 were synthesized in one-step.The effects of reaction time,temperature and molar ratio of acetic anhydride/anhydroglucose unit(AGU) in cellulose on DS value of CAs were investigated.The synthesized CAs were characterized by means of FT-IR, NMR,and solubility,mechanical and thermal tests.After the acetylation,the used ionic liquid AmimCl was easily recycled and reused.This study shows the potential of the homogeneous acetylation of cellulose at relatively high concentrations in ionic liquids in future industrial applications.

Durability of sea-sand containing concrete:Effects of chloride ion penetration

This paper describes an orthogonal experiment on the effect of water/cement ratio,water consumption per cubic meter,curing time,and type of sand on the response＂resistance to chloride ion penetration＂.A sea-sand containing concrete was used for the trials.An analysis of chloride ion diffusion coefficients at different factor levels was performed.A predictive model of chloride ion diffusion in concrete is developed through regression analysis.The experimental results show that when the water/cement ratio varies from 0.45 to 0.60,and the water consumption per cubic meter varies from 185 to 215 kg,and the curing time varies from 30 to 180 d then the size of the effects fall in the order（most significant first）： curing time,type of sand,water consumption per cubic meter,and water/cement ratio.Chloride ion penetration is reduced,and better durability of the concrete is observed,with longer curing times,less water consumption per cubic meter,and a smaller water/cement ratio.

Study on the Effect of the Fe^2＋/NaClO Oxidation of CN

The effects of various parameters on the removal rate of CN were discussed in the paper. The results showed that under the conditions of 30℃ pH = 3.0, Fe2＋ dosage was 80 mg/L, the NaCIO concentration of 0.10 mol/L, reaction time in 60 min, Fe2＋ has a satisfactory catalytic activation, and the removal rate of CN was about 37.89%.

Chloride Stress Corrosion Cracking of 316 Austenitic Stainless Steel

SCC （stress corrosion cracking） is environmentally well-known as a failure caused by exposure to a corroding while under a sustained tensile stress. SCC is most often rapid, unpredictable. Failure can occur in a short time as a few hours or take years and decades to happen. Most alloys are liable to SCC in one or more environments requiring careful consideration of alloy type in component design. In aqueous chloride environments austenitic stainless steels and many nickel based alloys are common to perform poorly. SCC of austenitic stainless steels of types 316 was investigated as a function of applied stress at room temperature in sodium chloride solutions using a constant load method. The experiment uses a spring loaded fixture type and is based on ASTM G49 for experiment method, and E292 for geometry of notched specimen. The stress depends on fracture appearance and parameters of time to cracking, and cracking growth. The results explained in terms of comparison between the two concentrations of sodium chloride solutions.

Relative Effectiveness of Ultraviolet Light Irradiation and Chlorination against Indigenous Bacteriophage and Bacteria in Primary Treated Wastewater

The effectiveness of chlorine and ultraviolet light at inactivating indigenous microbes in primary treated wastewater was examined in this study. The inactivation rates for somatic colipahge and F-specific bacteriophage were less than 2.5 log and 1 log, respectively, at either free chlorine doses of 6, 15 mg/L and 30 mg/L after 30 minutes contact time. However, E. coli and total coliforms were susceptible to chlorination and inactivated more than 4 log within first 15 minutes of contact time at any chlorine dosage tested. In contrast, the inactivation of bacteriophage was increased when increasing UV fluence. At the same disinfection effectiveness against E. coli, UV disinfection was more effective than chlorination against F-specific bacteriophages.

多因素对聚氯乙烯和废弃液晶显示屏协同热解氯化提铟的影响

聚氯乙烯(polyvinyl chloride,PVC)和废弃液晶显示屏(liquid crystal displays,LCDs)协同热解,可利用PVC产生的氯化氢提取LCDs中的铟,实现废弃PVC塑料和LCDs废物综合利用。通过PVC和LCDs协同热解实验,在PVC热解温度和载气流速一定条件下,采用采用Design-Expert 8.0.5b软件对氯铟比、氯化温度、氯化时间等因素进行实验方案设计和结果分析。结果表明,在其他操作条件一定的前提下,氯铟比、氯化温度、氯化时间对铟回收率的影响均为显著;通过分析实验结果并建立数学模型,最终得到实际可操作的最佳实验条件,其结果为氯化温度为500℃、氯化时间为30 min和氯铟比为11∶1,铟回收率为97.50%。本研究对于废弃PVC塑料和LCDs的资源化综合利用具有重要的参考价值。

Effect of Sodium Chloride and Proline on Embryo Formation and Germination through in vitro Micropropagation of Date Palm （Phoenix dactylifera L.） cv. Barhee [11]

The effect of NaCI and proline on somatic embryos formation and germination of date palm （Phoenix dactylifera L.） cv. Barhee was studied. Quarters of shoot tips were cultured on MS solid growth media supplied with different concentrations of salt （NaCI） （0.5%, 1%, 1.5%, 2%, 2.5% and 3%, respectively） and proline （25, 50 and 75 mg L1） either individually or in combination. Results showed that the addition of NaC1 （starting at 1%） caused a significant increase in the cylindrical embryos formation time, while their lengths and fresh weights were decreased at salt concentrations （0.5% and 2%）. No significant effect was noticed on the formation time by using proline except at concentration of 25 mg L^-1 which caused an increase in their lengths and fresh weights. The interaction between all salt concentrations and proline （25 mg LL） caused a significant increase in the formation time as well as in their lengths and fresh weights. The addition of NaC1 to the media caused a significant effect on the germination time and a reduction on the percentages of somatic embryo germination starting at 2% and the following ones. A reduction in the lengths of radicals and the plumules of the formed embryos was noticed at 1.5% NaCI. Proline addition reduced the initial time and increased the germination percentages as well as the lengths of radicals and plumules. The interaction between salt and proline treatments caused a significant reduction in the initiation time and an increase in the germination percentages and lengths of radicals and plumules.

Determination of Trihalomethanes in Water Samples Using Headspace Solid-Phase Microextraction Gas Chromatography

The chlorination process is one of the water treatment method used for the disinfection of water. The disinfection by products are trihalomethanes such as chloroform, dichloromethane, dibromochloromethane and bromoform. A headspace solid-phase microextraction method has been developed for determination oftrihalomethanes in water samples. The experimental parameters such as the stirring rate, extraction time, extraction temperature and desorption time were investigated. The linearity, detection limits and percentage recovery were evaluated. The optimum conditions were stirring rate 800 rpm/min, extraction time 6 min, extraction temperature 20 ~C, desorption time 2.5 min and desorption temperature 220 ~C. The detection limits were 0.01 ~g/L and the recoveries were in the range of 86-110 %, The proposed method was successfully applied to determination of THM4 in tap water samples. The THM4 contents were varied depending on the sample sites and the season. The total THM4 contents in cool, summer and rainy season were in the range of 27.58-41.89, 32.06-60.73 and 46.26-69.87 p.g/L, respectively. Confirmation of the detected compounds in water samples were performed by gas chromatograph-mass spectrometer. The mass spectra of the target compounds in water samples is in good agreement with trihalomethanes standard spectra.

In-situ measurement of atmospheric CFC-11 at the Shangdianzi Global Atmosphere Watch(GAW) Regional Station

An in-situ GC-ECD system was used to measure halocarbons at Shangdianzi （SDZ） GAW regional station. In this paper, we reported observational results of atmospheric CFC- 11 （CCI3F） mixing ratios from April 2007 to March 2008. The CFC- 11 time series showed large variability. Approximately 62% observed values were filtered as non-background data. The median, 10% and 90% percentiles of CFC-11 background mixing ratios were 245.4 ppt （10-12 mol/mol）, 244.6 ppt and 246.1 ppt, respectively; whereas those of non-background CFC- 11 mixing ratios were 254.7, 246.6 and 272.1 ppt, respectively. Significant differences in background and non-background CFC-11 mixing ratios were observed between summer and autumn, mainly because of the CFC-11 stored in loam being prone to atmospheric release in hot seasons. Comparison of tile SDZ data with the five AGAGE stations suggested agreement with mid-high latitude Northern Hemisphere stations MHD, THD and RPB. The SDZ data were higher than that of Southern Hemisphere stations CGO and SMO. Higher CFC-11 mixing ratios measured in different seasons were always associated with winds from the W-WSW-SW sector, indicating that the airflow coming from this wind sector has a positive contribution to CFC- 11 concentrations. The CFC-11 mixing ratios were higher in autumn and summer than in spring and winter, in which its mixing ratios were very close to the atmospheric background level. This was happened especially when airflow originated from the NNE-NE-ENE-E sector, indicating the air masses coming from these wind directions was relatively clean.