冷冻胶粉粒度对橡胶胶料力学性能的影响

研究了冷冻胶粉粒度对橡胶胶料力学性能的影响,发现添加冷冻胶粉会使胶料的力学性能下降,胶粉粒度越大,胶料性能下降的程度越严重。同时还发现,薄通处理可以改善胶粉的表面活性,减轻胶粉粒度对胶料性能的影响,改善胶料的力学性能。     

Application of surface molecular imprinting adsorbent in expanded bed for the adsorption of Ni(2+) and adsorption model

A new surface molecular imprinting adsorbent (SMIA) was used in an expanded bed. The expansion ratio and adsorption performance were studied at different volumetric rates, inlet concentrations, and pH values. A model based on the Adams-Bohart adsorption model of breakthrough curves was established. The predicted curves had good agreement with the experimental curves. The breakthrough time (T(1/2)) decreased with increasing inlet concentration when the outlet concentration was half the initial concentration (C/C(0)=0.5). The inlet concentration had little effect on the adsorption rate constant (k(1)) value when the initial concentration (C(0)) was above 150 mg/L. However, T(1/2) values increased with increasing initial pH of the inlet solution, and the k(1) value decreased due to the competition between H(+) and Ni(2+).     

Adsorption property of direct fast black onto acid-thermal modified sepiolite and optimization of adsorption conditions using Box-Behnken response surface methodology

The adsorption of direct fast black onto acid-thermal modified sepiolite was investigated. Batch adsorption experiments were performed to evaluate the influences of experimental parameters such as initial dye concentration, initial solution pH and adsorbent dosage on the adsorption process. The three-factor and three-level Box-Behnken response surface methodology (RSM) was utilized for modeling and optimization of the adsorption conditions for direct fast black onto the acid-thermal modified sepiolite. The raw sepiolite was converted to acid-thermal modified sepiolite, and changes in the fourier transform infrared spectrum (FTIR) adsorption bands of the sample were noted at 3435 cm^-1 and 1427 cm^-1. The zeolitic water disappeared and the purity of sepiolite was improved by acid-thermal modification. The decolorization rate of direct fast black adsorbed increased from 68.2% to 98.9% on acid-thermal modified sepiolite as the initial solution pH decreased from 10 to 2. When the adsorbent dosage reached to 2.5 g·L^-1, 2.0 g·L^-1, 1.5 g·L^-1 and 1.0 g·L^-1, the decolorization rate was 90.3%, 86.7%, 61.0% and 29.8%, respectively. When initial dye concentration increased from 25 to 200 mg·L^-1, the decolorization rate decreased from 91.9% to 60.0%. The RSM results showed that the interaction between adsorbent dosage and pH to be a significant factor. The optimum conditions were as follows: the adsorbent dosage 1.99 g·L^-1, pH 4.22, and reaction time 5.2 h. Under these conditions, the decolorization rate was 95.1%. The three dimensional fluorescence spectra of direct fast black before and after treatment showed that the direct fast black was almost all adsorbed by the acid-thermal modified sepiolite.     

The calculation of equivalence factor for ecological footprints in China: a methodological note

The Ecological Footprint (EF), a physical indicator to measure the extent of humanity’s use of natural resources, has gained much attention since it was first used by Wackernagel and Rees in 1996. In order to appraise land area types with different levels of productivity, they introduced the concept of an equivalence factor. This relates to the average primary biomass productivities of different types of land (i.e. arable land, pasture, forest, water/fishery, built-up land and fossil energy land) to the regional average primary biomass productivity of all land types in a given year. Hence, the equivalence factor is an important parameter in the EF model and it directly affects the reliability of all results. Thus, this article calculates equivalence factors on the national and provincial levels in China based on Net Primary Production (NPP) from MODIS 1 km data in 2008. Firstly, based on the Light Utility Efficiency and CASA model, the NPP of different biologically productive lands of China and of different provinces was calculated. Secondly, China’s equivalence factor for 6 land area types was calculated based on NPP: arable land and built-up land has an equivalence factor of 1.71, forest and fossil energy land has a factor of 1.41, pasture has a factor of 0.44 and water/fishery 0.35; Finally, the equivalence factor of 6 land area types in different provinces was also calculated. The NPP of each ecosystem type varies along with the equivalence factor in different provinces. However, the ranking of the equivalence factors in different provinces remain the same, with that of arable land being the largest, and the water/fishery being the smallest.     

富氧空位MoO2强化Fe2+/过一硫酸盐体系降解四环素

采用NaBH₄超声还原法合成了富含氧空位的MoO₂,并通过多种表征方法证明了氧空位的存在.10-MoO₂作为助催化剂显著增强了Fe²⁺/过一硫酸盐体系催化性能,构建的10-MoO₂/Fe²⁺/PMS体系可快速降解四环素（TC）,10 min内对TC的降解率接近100%.系统研究了各种影响因素对TC降解效果的影响,探讨了助催化剂的稳定性及该体系的实用性.电化学、铁离子循环及自由基捕获实验的结果表明,由于氧空位（O_vacancy）的存在,降低了MoO₂的电阻,增强了电子转移能力,加速了Fe³⁺/Fe²⁺循环,提高了活性氧物种的产率,从而增强了Fe²⁺/PMS类芬顿体系的催化活性.本研究为类芬顿法处理抗生素废水提供了一种新的视角.     

Human bronchial epithelial cell injuries induced by fine particulate matter from sandstorm and non-sandstorm periods: Association with particle constituents

Epidemiological studies have demonstrated the exacerbation of respiratory diseases following sandstorm-derived particulate matter(PM) exposure.The presence of anthropogenic and biological agents on the sandstorm PM and the escalation of PM 2.5 μm(PM2.5)pollution in China have led to serious concerns regarding the health effects of PM2.5during Asian sandstorms.We investigated how changes in PM2.5composition,as the weather transitioned towards a sandstorm,affected human airway epithelial cells.Six PM2.5samples covering two sandstorm events and their respective background and transition periods were collected in Baotou,an industrial city near the Gobi Desert in China.PM samples from all three periods had mild cytotoxicity in human bronchial epithelial cell line BEAS-2B,which was positively correlated with the contents of polycyclic aromatic hydrocarbons and several metals.All PM samples potently increased the release of interleukin-6(IL-6) and interleukin-8(IL-8).Endotoxin in all samples contributed significantly to the IL-6 response,with only a minor effect on IL-8.Cr was positively correlated with both IL-6 and IL-8 release,while Si was only associated with the increase of IL-6.Our study suggests that local agricultural and industrial surroundings in addition to the sandstorm play important roles in the respiratory effects of sandstorm-derived PM.     

Cause of PM2.5 pollution during the 2016-2017 heating season in Beijing, Tianjin, and Langfang, China

To investigate the cause of fine particulate matter(particles with an aerodynamic diameter less than 2.5 um,PM2.5) pollution in the heating season in the North China Plain(specifically Beijing,Tianjin,and Langfang),water-soluble ions and carbonaceous components in PM_2.5were simultaneously measured by online instruments with 1-hr resolution,from November 15,2016 to March 15,2017.The results showed extreme severity of PM_2.5 pollution on a regional scale.Secondary inorganic io...     

不同镉污染农田土壤上秸秆和炭化秸秆分解动态及其对土壤镉的吸附特征

通过温室土壤培养实验,研究不同镉污染农田土壤上不同的作物秸秆和炭化作物秸秆还田后的分解动态和还田秸秆材料对污染土壤中镉的吸附特征,探讨秸秆和炭化秸秆还田做为重金属镉污染农田土壤修复剂的可行性。实验结果表明,还田的油菜秸秆和玉米秸秆在2种镉污染水稻土壤上6个月分解了43％-65％,秸秆炭化后还田则很稳定,2种镉污染土壤上还田6个月时累计分解量小于5％。2种镉污染土壤上还田的秸秆和炭化秸秆随还田时间延长镉含量逐渐增加。模拟镉污染土壤上,相同时期油菜秸秆中镉含量显著高于玉米秸秆,油菜秸秆炭中镉含量显著高于玉米秸秆炭。在镉污染土壤上,还田的玉米秸秆、油菜秸秆、玉米秸秆炭和油菜秸秆炭对土壤镉的净吸附量相近,均小于1．1μg／g。在模拟镉污染土壤上还田的油菜秸秆和油莱秸秆炭对土壤镉净吸附量最高分别达到2．74μg／g和7．03μg／g,分别是玉米秸秆和玉米秸秆炭的2倍,且显著高于其在镉污染土壤上的净吸附量,具有高的吸附能力。     

农村室内薪柴燃烧的颗粒物和炭黑排放因子

室内薪柴燃烧是大气污染的重要来源,其排放的污染物对气候变化和人体健康都有很大影响。对该来源排放量的可靠估算是进行排放效应分析和合理控制的重要前提,而估算的可靠性主要取决于燃料消耗量和排放因子的准确性。目前,我国针对农村柴灶薪柴燃烧颗粒物排放因子的测定数据很少,变异很大,不足以支持可靠的排放清单估算。测定了9种薪柴(枫桦、兰考泡桐、黑杨、大叶风杨、楝树、枣树、柿树、桑树和桃树)在中国北方典型农村炉灶中燃烧产生的颗粒物(PM)、有机碳(OC)和元素碳(EC)的排放因子。受燃料种类、性质和燃烧条件的影响,测得的排放因子差别较大。9种薪柴各自的PM、EC和OC的排放因子变化范围分别为(0.74±0.13)～(6.23±1.47)g.kg-1,(0.10±0.06)～(0.97±0.28)g.kg-1和(0.14±0.03)～(3.81±0.92)g.kg-1(以干质量计)。全部薪柴的PM、EC和OC的排放因子均值和标准差分别为(2.58±2.15)、(0.29±0.31)和(0.98±1.24)g.kg-1。室内薪柴燃烧PM、EC和OC排放因子之间呈显著的相关性关系。各种薪柴燃烧排放的颗粒物粒径分布相似,均以细颗粒物为主,PM2.1占PM10总质量的90%以上。此外,除EC排放因子外,薪柴燃烧的PM和OC排放因子与校正燃烧效率显著负相关(P<0.05)。细颗粒物组分PM2.1与校正燃烧效率显著负相关(P<0.05),与燃料含水量显著正相关(P<0.05)。