Removal of nitrate from constructed wetland in winter in high-latitude areas with modified hydrophyte biochars

In high-latitude areas, nitrate treatment from constructed wetlands is often not so good in winter. The study aims to develop an efficient and economic technology to remove nitrate from constructed wetland under the conditions of winter temperature. We conducted laboratory experiments to investigate the removal of nitrate from aqueous solution and wastewater by modified hydrophyte biochars from constructed wetlands. The second-order model fit the nitrate desorption kinetics of modified hydrophyte biochars with a high coefficient of determination (R²>0.99). Freundlich isotherms performed well to fit the nitrate sorption data (R²>0.98) of modified hydrophyte biochars. Batch adsorption experiments also showed that both initial solution pH and coexisting anions could affect the adsorption of nitrate onto modified hydrophyte biochars. Our results suggested that modified hydrophyte biochars might be a promising alternative wastewater treatment technology for nitrate removal from constructed wetland in winter in high-latitude areas.     

耐火水泥改性研究

采用水化－煅烧－细磨方法对高铝水泥和纯铝酸钙水泥进行活化处理。测量了改性水泥的粒度、比表面积、凝结时间。试验结果表明，改性处理使以上耐火水泥的颗粒尺寸大大降低，比表面积增加；改性水泥中无大颗粒存在，其凝结时间满足施工要求．用改性水泥结合的浇注料的强度明显高于用原水泥结合的浇注料的强度。     

载体改性对重整预加氢催化剂性能的影响

采用无定形硅铝和纳米二氧化钛对氧化铝载体进行改性,并制备了催化剂。通过N2物理吸附、XRD、H2-TPR和NH3-TPD等手段研究了载体改性对催化剂的织构、物相、酸性的影响,并考察了其对重整预加氢反应性能的影响。结果表明,引入无定形硅铝提高了催化剂的比表面积,催化剂的弱酸和中强酸位增加,但对催化剂的还原性能影响不大;而添加TiO2则降低了催化剂的比表面积和孔容,促进了氧化钼的还原,催化剂的中强酸位增加。载体改性后催化剂的性能得到了很大的改善,无定形硅铝改性的效果更加明显,制备的催化剂在入口温度低30℃的工艺条件下,脱硫、脱氮性能仍优于引入前的催化剂。     

改性碳纳米管及其复合材料在废水处理中的应用现状及展望

碳纳米管（carbon nanotube, CNT）具有高比表面积、高吸附能力、优良的导电性和化学稳定性等,但其在水中存在分散性差和催化能力低等问题。为了提高其在废水处理中性能,需要对CNT进行改性,制备复合材料。本文总结了CNT表面改性和复合材料制备方法,论述了改性CNT及其复合材料在电化学氧化、电化学还原、电化学过滤、光催化和膜分离等处理技术中的应用研究进展,并就未来研究方向进行了展望。指出了CNT在未来废水处理方面应用的研究重点包括：①设计经济、方便、温和的改性路线,继续寻求获得新型高效改性CNT及其复合材料,并兼顾稳定性;②开发基于改性CNT及其复合材料特性的废水处理新装置和反应工艺;③关注因改性CNT及其复合材料流失引起的生物、生态效应。     

由竹脚手架制备的活性炭经化学修饰后的表征(英文)

In this study,bamboo scaffolding was used to produce activated carbon by carbonization at 600 ℃ and 900 ℃ with the purge of nitrogen.The 600 ℃ char was then further modified chemically by acids and alkalis by reflux for 6 hours.The produced chars were then characterized by nitrogen adsorption isotherm,He pyncometry,pH,elemental analysis and Boehm titration.For most of the chemically modified carbons,the micropore surface areas and volumes have increased compared with the 600 ℃ char,while the mesopore surface areas and volumes slightly decreased,which may have been due to the dissolving of some of the permeated inorganic matter and oxidizing deposited carbon that blocks the pore openings.For the acidic modified carbons,larger amounts of acidic groups were present in the carbons after being activated by phosphoric acid,phosphoric acid further treated with 2 mol·L-1 nitric acid,and calcium hydroxide.Although carbon treated with 2 mol·L-1 and 5 mol·L-1 nitric acid also produced high acidity,the surface areas and pore volumes were relatively low,due to the destruction of pores by nitric acid oxidation.The reduction of porosity may impair the adsorption capacity.     

半焦的高温活化改性

采用物理和化学的方法对半焦进行改性处理,考察了改性条件对半焦孔容、孔径及比表面积的影响,获得最佳改性条件:煅烧温度850℃,煅烧时间120 min,水蒸气体积分数14%。实验结果表明,改性后的半焦具有发达的孔径结构和较高的比表面积,可以作为脱硫剂的载体。     

有机硅改性醋丙乳液的合成

采用共聚、乳化和引发体系对醋丙乳液进行改性。在改性方面,采用有机硅对醋丙乳液进行共聚改性,提高了醋NSL液与基材之间的附着力和耐水性。乳化剂的改性主要集中在开发复配型表面活性剂和具有反应活性的乳化体系上。采用烷基酚聚氧乙烯（10）醚（OP-10）和十二烷基硫酸钠（SPS）进行复配其有很好的乳化效果。采用热引发体系,其最佳引发温度在75～85℃之间。通过这几方面的改性获得综合性能优异的有机硅改性的醋丙乳液。     

Formation of modified areas of porous glass saturated with glycerin under the action of laser radiation

The formation of modified areas with changed optical properties in the volume of thin plates of porous glass (composition of 94.73SiO₂ · 4.97B₂O₃ · 0.30Na₂O), saturated with glycerin—a substance with a high polarization capacity, under the action of laser radiation was investigated. A continuous wave ytterbium fiber laser with radiation wavelength λ = 1.07 μm weakly absorbed by porous glass was used as the radiation source. When the radiation power was within the range of 9.6–16.5 W and the irradiation time was 270–300 s, optical-grade modified areas were obtained. During the experiment, the dependences of temperature in the spots of the impact and of the power of the radiation transmitted through a thin plate of porous glass, on irradiation time were registered.     

Reaction of “unreactive” silicone: synthesis of long-chain alkyl fluorosilicone via a simple siloxane equilibration process

Polymer Bulletin - Long-chain alkyl silicone is a type of modified silicones that finds potential applications in various areas. Long-chain alkyl fluorosilicone (LCAFS) can be considered as a...     

Electro-oxidation of glycerol on platinum dispersed in polyaniline matrices

Films of polyaniline (PAni) were electrosynthesized on gold and glassy carbon substrates. The morphology of the films was verified using scanning electron microscopy (SEM) and, as expected, the PAni film formed on glassy carbon presented fibrillar morphology, while that formed on gold presented fibrils on top of a more compact structure. Different amounts of platinum were electrodeposited into the polymer matrices at constant potential and the electrocatalytic activities of the electrodes were evaluated for glycerol electro-oxidation in acidic medium. Furthermore, the active areas of such modified electrodes were determined from the charges involved in the electro-oxidation of an adsorbed carbon monoxide monolayer. Considering the real active areas, the modified electrode with the gold substrate presents higher electrocatalytic activity for glycerol oxidation than that with the glassy carbon substrate. This difference is mainly related to their morphological characteristics and platinum particle sizes.     

聚氨酯防水涂膜材料的改性及应用

用自制的ＥＭ树脂对聚氨酯防水涂膜进行了改性，提高了粘接性能及耐腐蚀性能。并介绍了改性材料的性能和用途。     

氟化石墨的合成及应用研究

氟化石墨作为石墨的改性材料,在越来越多的方面得到了广泛的应用,也引起了许多科技工作者的兴趣。本文从氟化石墨的结构和性质入手,着重叙述了氟化石墨的各种合成方法和应用。     

微生物诱导碳酸钙沉淀技术改良黄土湿陷性研究

为有效降低黄土地区遇水产生的湿陷性,以兰州黄土为研究对象,利用微生物诱导碳酸钙沉淀(MICP)技术对黄土湿陷性进行研究。首先对MICP处理前后黄土的无侧限抗压强度及湿陷系数进行评价,然后利用CT扫描技术分析MICP改良后的黄土微观特征,进一步探究MICP改良机理。试验结果表明:经MICP处理后的黄土试样无侧限抗压强度显著提高,最高可达150 kPa,黄土湿陷性有效降低;随着胶结液浓度不断增加,碳酸钙生成量持续增加,但在胶结液浓度大于1.25 mol/L时,碳酸钙生成量呈下降趋势;改良后黄土试样的孔隙率、孔隙等效直径等指标均降低。     

Surface areas of fillers in polymers by small-angle X-ray scattering

The surface areas of Aerosil silicas in air and dispersed in a silicone rubber have been determined by analysing small-angle X-ray data according to the methods of Porod and Debye. Broad agreement with the manufacturers' BET (Brunauer-Emmett-Teller) area values is obtained. The silica surface area and basic state aggregation are not measurably modified by milling into the rubber.     

Design,synthesis, and evaluation of amino-terminated oxidization modified peanut shell as adsorbent of microcolumn for Sudan-I detection and efficient recovery

Sudan I, as a common pigment, is harmful to people’s health. In this work, the alkaline peanut shell as the base, epichlorohydrin and DMF as the solvent, with HBP-NH₂ as the ligand to compose terminal amino-branched peanut shell. Optimization of the modified peanut shell was carried out at different temperatures, different molar ratios of reagents, and different time intervals in HBP-NH₂ using response surface methodology (RSM) for the first attempt. The structure of modified peanut shell was characterized by FT-IR and elemental analysis. The adsorption properties of the modified peanut shell for Sudan I were investigated by batch and column experiments. Batch adsorption results suggested that modified peanut shell had a high adsorption capability for Sudan I and its maximum saturated adsorption capacity was 248.14 mg/g at 308 K, estimated from the Langmuir model. The modified peanut shell and its metal complexes were studied by TGA and SEM. Furthermore, the modified peanut shell can be eluted easily using 2 mol/L NaOH. HBP-NH₂-P not only has a potential application for the selective removal of Sudan I from waste solutions but also has an application in the analysis and detection areas.     

Metal particle modification of composite matrices for customized density applications

A key aspect of composite technology lies in the ability to design a part to a specific strength and thickness. Recently, new applications were identified where it was desirable to vary the density in specific areas of a part. In this work, a model prepreg system was modified with fine metal and thermoplastic particles for specific weight tailoring. These particles were placed on the prepreg surface, forming a partially interlayer modified composite when laid up and cured. Experiments were performed on the specific gravity and fracture toughness of laminates made from the prepregs. The results showed that it is possible to tailor the density of a composite system without changing the manufacturing process or fracture toughness requirements.     

壳聚糖的化学改性(Ⅱ)

概述了近十年来壳聚糖化学改性方面取得的其它一些研究进展,主要包括酶改性、脱氧胆酸改性和树枝状高分子杂化改性等,并且对改性壳聚糖的生物降解性能进行了讨论。改性壳聚糖可广泛应用于食品、农业、医药及环保等领域。     

TiO2对重整预加氢催化剂性能的影响

采用纳米TiO₂对氧化铝进行改性,并以改性氧化铝为载体制备系列催化剂,通过N₂物理吸附、XRD、H₂-TPR和NH₃-TPD等方法研究TiO₂对催化剂的孔结构、物相和酸性的影响,并考察TiO₂对重整预加氢反应性能的影响。结果表明,添加TiO₂降低催化剂的比表面积和孔容,促进氧化钼的还原,增强催化剂的中强酸,催化剂性能得到较大改善,在入口温度低10 ℃的条件下,催化剂仍具有较好的脱硫和脱氮性能。     

Preparation and Characterization of SnO2-Based Composite Metal Oxides: Active and Thermally Stable Catalysts for CH4 Oxidation

A series of SnO₂-based catalysts modified by Fe, Cr and Mn were prepared by the combination of redox reaction and co-precipitation methods, and applied to catalytic CH₄ oxidation. The modified catalysts show generally higher activity than the unmodified SnO₂. XRD analysis indicates that Fe, Cr and Mn cations could be incorporated into the lattice of rutile SnO₂ (cassiterite) to form solid solution structure. As a result, more reducible and active oxygen species was formed in the samples, as substantiated by the H₂-TPR results. Moreover, the specific surface areas of the modified catalysts are much higher than that of pure SnO₂ and their crystallite sizes are smaller, indicating they are more resistant to thermal sintering. Indeed, the high specific surface areas and the formation of more active oxygen species in the modified samples are believed to be the predominant reasons leading to their enhanced CH₄ oxidation activity. Eventually, it is noted that SnCrO displays not only remarkable CH₄ oxidation activity, but also potent resistance to SO₂ and water deactivation, which makes it a promising catalyst with the potential to be applied in some real CH₄ oxidation processes.     

改性竹炭对4-硝基苯酚的吸附行为研究

采用硝酸对竹炭进行改性,考察了改性竹炭对水溶液中4-硝基苯酚的吸附热力学和动力学特性。结果表明,与原竹炭相比,硝酸改性竹炭的比表面积、孔容及对4-硝基苯酚的吸附量显著提高。在实验条件下,动力学过程用二级吸附动力学模拟具有很好的线性相关性,通过二级吸附模型计算出的平衡吸附量与实验值相符。改性竹炭对4-硝基苯酚的吸附行为可用Langmuir和Freundlich等温式进行描述,相关性都较好,但更符合Langmuir公式。求得热力学参数ΔH=28.36 kJ/mol,ΔS=168.88 J/(K.mol),ΔG分别为-19.41(10℃)、-22.86(30℃)、-26.16(50℃)kJ/mol,表明改性竹炭对4-硝基苯酚的吸附是吸热、自发的过程,以物理吸附为主。