Synergistic Function between Phosphorus-Containing Flame Retardant and Multi-Walled Carbon Nanotubes towards Fire Safe Polystyrene Composites with Enhanced Electromagnetic Interference Shielding

As a universal polymer material, polystyrene (PS) is widely applied in electrical devices and construction. Thus, it is necessary to improve the flame retardancy and electromagnetic shielding properties of PS material. In this work, PS/silicon-wrapped ammonium polyphosphate/Inorganic acid-treated multi-walled carbon nanotubes composites (PS/SiAPP/aMWCNT, abbreviated as PAC) were prepared via methods of filtration-induced assembly and hot-pressing. Morphology and structure characterization demonstrated that SiAPP and aMWCNT had good dispersion in PS and excellent compatibility with the PS matrix. Thermogravimetric analysis revealed that the addition of aMWCNT to PS improved its thermal stability and carbon-forming characteristics. The peak heat release rate, the peak carbon monoxide production rate, and the peak smoke production rate of the PAC10 composite decreased by 53.7%, 41.9%, and 45.5%, respectively, while its electromagnetic shielding effectiveness reached 12 dB. These enhancements were attributed to the reason that SiAPP and aMWCNT synergistically catalyzed the char generation and SiAPP produced free radical scavengers and numbers of incombustible gases, which could decrease the oxygen concentration and retard the combustion reaction. Therefore, the assembled PS/SiAPP/aMWCNT system provides a new pathway to improve the flame retardant and electromagnetic shielding properties of PS.     

Hybrid Carbon Supports Composed of Small Reduced Graphene Oxide and Carbon Nanotubes for Durable Oxygen Reduction Catalysts in Proton Exchange Membrane Fuel Cells

We demonstrated highly active and durable hybrid catalysts (HCs) composed of small reduced graphene oxide (srGO) and carbon nanotubes (CNTs) for use as oxygen reduction reaction (ORR) catalysts in proton exchange membrane fuel cells. Pt/srGO and Pt/CNTs were prepared by loading Pt nanoparticles onto srGO and CNTs using a polyol process, and HCs with different Pt/CNT and Pt/srGO ratios were prepared by mechanically mixing the two components. The prepared HCs consisted of Pt/CNTs well dispersed on Pt/srGO, with catalyst HC55, which was prepared using Pt/srGO and Pt/CNTs in a 5:5 ratio, exhibiting excellent oxygen reduction performance and high stability over 1000 cycles of the accelerated durability test (ADT). In particular, after 1000 cycles of the ADT, the normalized electrochemically active surface area of Pt/HC55 decreased by 11.9%, while those of Pt/srGO and Pt/C decreased by 21.2% and 57.6%, respectively. CNTs have strong corrosion resistance because there are fewer defect sites on the surface, and the addition of CNTs in rGO further improved the durability and the electrical conductivity of the catalyst. A detailed analysis of the structural and electrochemical properties of the synthesized catalysts suggested that the synergetic effects of the high specific surface area of srGO and the excellent electrical conductivity of CNTs were responsible for the enhanced efficiency and durability of the catalysts.     

Highly Selective Electrochemical CO2 Reduction to C2 Products on a g-C3N4-Supported Copper-Based Catalyst

Herein, a novel approach used to enhance the conversion of electrochemical CO₂ reduction (CO₂R), as well as the capacity to produce C₂ products, is reported. A copper oxide catalyst supported by graphite phase carbon nitride (CuO/g-C₃N₄) was prepared using a one-step hydrothermal method and exhibited a better performance than pure copper oxide nanosheets (CuO NSs) and spherical copper oxide particles (CuO SPs). The Faradaic efficiency reached 64.7% for all the C₂ products, specifically 37.0% for C₂H₄, with a good durability at −1.0 V vs. RHE. The results suggest that the interaction between CuO and the two-dimensional g-C₃N₄ planes promoted CO₂ adsorption, its activation and C-C coupling. This work offers a practical method that can be used to enhance the activity of electrochemical CO₂R and the selectivity of C₂ products through synergistic effects.     

新型碳材料质子交换膜燃料电池Pt催化剂载体的研究进展

质子交换膜燃料电池(PEMFC)具有能量转换效率高、功率密度大、室温启动快、噪音低和零污染等特点,有望减少二氧化碳排放量,缓解能源危机,在轨道交通、航空航天等领域具有广阔的应用前景。催化剂是PEMFC的关键材料, Pt催化氧还原反应活性和稳定性好,是广泛使用且很难被取代的电催化剂。然而Pt储量低、价格昂贵,导致PEMFC成本较高,使用Pt载体可减少PEMFC的Pt负载量,提高Pt利用率。碳材料具有成本低廉、比表面积大、孔结构丰富、电导率和表面性质可调等特性,是广泛应用的Pt载体。商用的炭黑载体对Pt的利用效率低,抗电化学腐蚀性较差。为了进一步提高PEMFC的性能和持续性,需要研发能够均匀负载Pt、高效利用Pt、抗电化学腐蚀性强且导电性好的碳载体,进而实现PEMFC的大规模应用。炭气凝胶、碳纳米管和石墨烯等新型碳载体具有独特的结构和性质,可以提高PEMFC性能和寿命,引起了研究者的广泛关注。本文对近年来PEMFC新型碳材料Pt载体的研究进展进行了较为详细的综述,并对其发展趋势作出了适当评论。     

基于改进完全局部二值模式火焰特征提取的 转炉炼钢终点碳含量预测

转炉炼钢火焰图像特征的准确提取是预测终点碳含量的关键,针对于火焰图像相似性高进而难以区分碳含量相近的火焰图像,导致无法准确精准预测碳含量的问题,提出一种改进完全局部二值模式(improved complete local binary pattern,ICLBP)的彩色纹理特征提取方法,用于提取不同碳含量下更具区分性的炉口火焰图像特征并进行终点碳含量的预测.首先,在不同颜色通道下采用局部相位量化(local phase quantization,LPQ)提取图像相位信息,与CLBP提取的图像幅值信息组合成融合特征ICLBP_MP,以增强CLBP算法结构的鲁棒性;然后,通过改进的颜色信息加权策略对其进行加权,以增强火焰图像的颜色对比度信息;最后,使用K近邻回归模型对碳含量进行预测.实验结果表明,碳含量预测在0.02％误差范围内的准确率为83.9％.     

双膜法处理污水厂出水用于工业回用

青岛市黄岛区属于严重缺水地区,水资源短缺已成为制约地区经济发展的瓶颈,拟以污水厂合格出水为原水,实现中水精制满足工业用水需求。精制中水回用站占地为1. 86 hm²,项目采用BOO形式,总投资为2. 1亿元,以污水厂达到一级A标准的出水为原水,为黄岛区北部工业园区用水大户供水。设计产水量为20 000 m³/d,设计进水量为34 776 m³/d,设计外排水量为14 616 m³/d。回用站分为产水、浓水及污泥三个系统,产水系统以高效石灰软化沉淀池、超滤、两级反渗透为核心,设计总回用率为57. 49%,脱盐率> 98%,TDS≤100 mg/L;浓水系统以活性炭沉淀池为核心,出水达到一级A标准;污泥系统采用板框压滤机,污泥含水率<80%后外运。系统实际运行效果良好,达到设计要求。     

生物粉末活性炭/超滤组合工艺处理微污染原水

针对微污染原水中存在的有机物和氨氮等污染物,采用生物粉末活性炭/超滤(BPAC/UF)组合工艺进行处理。结果表明,当进水氨氮浓度较低时,硝化细菌活性较差,无法充分发挥生物降解作用,氨氮去除率较低,同时有机物去除率也较低;当进水氨氮浓度在0. 6 mg/L左右时,可以形成稳定的生物活性炭,组合工艺对氨氮的去除率较高,且对有机物的去除率较为稳定。进水中主要以分子质量<5 ku的有机物为主,组合工艺对这部分有机物的去除率也最高。组合工艺对疏水性物质的去除,主要依靠生物粉末活性炭的吸附降解和膜面滤饼层的截留作用。NaClO强化反冲洗可以很好地降低跨膜压差的增长速度,当NaClO浓度为400 mg/L、反冲洗时间为10min时可达到最佳清洗效果。     

不同水源下臭氧/生物活性炭运行参数的优化

近年来,臭氧/生物活性炭工艺在国内得到广泛应用,在控制饮用水中消毒副产物的生成方面起到了重要作用。研究与生产实践表明,臭氧/生物活性炭运行参数的优化对其净水效能的发挥至关重要。针对江苏J水厂采用的H和X两个水质差异较大的水源,建立了中试装置,开展了以控制消毒副产物为目标的臭氧/生物活性炭运行参数优化研究。结果表明:随着臭氧投加量的增加,系统对H与X水源中三卤甲烷生成势(THMFP)的去除率先上升后逐渐平稳,对卤乙酸生成势(HAAFP)的去除率呈现先增加后降低的趋势;随着炭床停留时间的延长,生物活性炭工艺对THMFP、HAAFP的去除率均呈先上升后平稳的趋势。综合考虑THMFP和HAAFP的去除效能,优化后的臭氧/生物活性炭工艺运行参数如下:针对H水源,臭氧投加量为0. 5 mg/L,炭床停留时间为12 min;针对X水源,臭氧投加量为2. 0 mg/L,炭床停留时间为12 min。     

基于高精度温度传感器的多股碳纤维导线潜伏性缺陷检测方法

为提升多股碳纤维导线的质量,研究基于高精度温度传感器的多股碳纤维导线潜伏性缺陷检测方法。利用布里渊光时域反射技术设计高精度温度传感器,并将单根光纤植入多股碳纤维导线中,通过注入窄谱光源来实现温度采集。采用外差检测法对窄谱光源进行处理,获取多股碳纤维导线的温度采集结果。采用平均处理方法滤除温度数据内部的噪声。基于滤波后的温度数据,建立多股碳纤维导线的温度场逆问题模型,并利用牛顿迭代法对模型进行求解,从而得到多股碳纤维导线的热导率。实验证明,该方法能够有效地采集多股碳纤维导线的温度,并成功滤除99%的内部噪声。检测无缺陷多股碳纤维导线的热导率是235 W/m·k,基于此,该方法也能够根据与无缺陷导线的热导率的差异有效地检测导线的潜伏性缺陷。值得注意的是,当导线的负荷电流增加时,该方法的潜伏性缺陷检测效果更佳。     

NaOH、甘油的水溶液浸出三氧化二锑的机理研究

NaOH、甘油或木糖醇的水溶液浸出锑氧粉得到双金属醇盐 ,溶液在一定的碱性条件下能保持稳定 ;本文对NaOH、甘油的水溶液浸出三氧化二锑生成甘油亚锑酸钠的机理及其稳定性作了一系列的研究