Catalyst Design of Pt-Modified Ni/Al2O3 Catalyst with Flat Temperature Profile in Methane Reforming with CO2 and O2

Pt(0.3)/Ni(10)/Al₂O₃, prepared by a sequential impregnation method, exhibited a more excellent performance in methane reforming with CO₂ and O₂ in terms of the catalytic activity and the temperature profile of the catalyst bed than Pt(0.3) + Ni(10)/Al₂O₃ prepared by a coimpregnation method, Ni(10)/Al₂O₃, Pt(0.3)/Al₂O₃, and Pt(10)/Al₂O₃. It is thought that this is because the surface Pt atoms on Ni catalyst can contribute to the enhancement of the catalyst reducibility.     

Grafted stock synthesis of ABS at the ultimate high ratio of polybutadiene to poly(styrene‐co‐acrylonitrile)

This study describes the emulsion grafting of styrene and acrylonitrile onto 60–70% polybutadiene (PB), in the presence or absence of tert‐dodecanetiol as a chain transfer reagent with a radical initiator, and the properties of the obtained grafted stock. There was no significant difference in terms of effect of the initiation mode on the grafting efficiency resulting from the high grafting reactivity of PB. However, the grafted stock with 70% PB prepared in the presence of tert‐dodecanetiol and the adequate selection of an initiation system gave a homogeneous dispersion of the PB particles into poly(styrene‐co‐acrylonitrile) (SAN) matrix. The initiation system involves tert‐butyl peroxylaurate, tert‐butyl peroxyacetate, and tert‐butyl peroxyisopropylcarbonate coupled with ferrous sulfate. The efficient coverage of the SAN grafted layer around 70% PB particles was observed by TEM to eventually give excellent impact resistance, high surface gloss, and good thermal resistance. The absence of tert‐dodecanetiol resulted in a toughness reduction of ABS. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 81: 3462–3470, 2001     

Dehydrogenative polycondensation of telechelically bis(dimethylsilyl)functionalized oligo(dimethylsiloxane)s or aromatics and 1,3,3,5,5,7,7,7-octamethyltetrasiloxane

Telechelically bis(hydrodimethylsilyl)-functionalized oligo(dimethylsiloxane)s or aromatics were found to give polymers constituting of alternating disilylene and oligodimethylsiloxane or 4,4′-diylaromatics as repeating units by dehydrogenative coupling reaction in the presence of palladium dibenzylideneacetone complex. The same catalyst gave polysilylenes with trisiloxane pendant from 1,1-dihydro-1,3,3,5,5,7,7,7-octamethyltetrasiloxane. Received: 18 October 1996/Accepted: 31 October 1996     

Polyethersulfone composite hollow-fiber membrane prepared by in-situ growth of silica with highly improved oily wastewater separation performance

In order to reduce surface aggregation and enhance the performance of PES membranes, a hydrophilic PES/TEOS HF membrane was developed for the treatment of wastewater containing oil. PES/TEOS was prepared via a sol-gel self assembly and dry–wet spinning method. Silicon dioxide sol was prepared from a mixture of tetraethoxysilane, ethanol, water, and acetic acid (acting as the catalyst). HF hybrid membranes were produced from dope solutions containing polyethersulfone, polyethylene glycol, silicon sol, and NMP. The membranes were characterized by field emission scanning electron microscopy (FESEM), atomic force microscopy (AFM), energy-dispersive X-ray spectroscopy (EDX), porosity, fourier transform infrared spectroscopy (FTIR), and contact angle measurements. The composite membranes were successfully used to treat wastewater containing oil and their separation performance were evaluated. The PES/TEOS-2 membrane displayed the best performance, with a permeate flux of 90.937 L/m² h and an oil retention of 99.98%. In addition, this membrane showed a higher pure water flux of 102.43 L/m² h as compared to PES-0 and PES/SiO₂–1 membranes (87.347 L/m² h and 91.949 L/m² h, respectively). The PES/TEOS-2 membrane also presented enhanced antifouling behavior with a FRR and a RFR of 93.33% and 11.22%, respectively. In addition, this membrane displayed excellent long-term recycling properties, making it a desirable candidate for oily wastewater separation applications.     

Preparation and Properties of Biodegradable Polymer Film Based on Polyvinyl Alcohol and Tropical Fruit Waste Flour

In this study, two different types of tropical fruit waste flour, rambutan waste flour (RWF) and banana waste flour (BWF), were blended with polyvinyl alcohol (PVOH) by solution casting method. The structure of the blend film was characterised by Fourier Transform Infrared Spectroscopy. The tensile strength and elongation at break of tropical fruit waste flour-filled polyvinyl alcohol were lower, but the tensile modulus was higher, than that of PVOH film. At a similar blend ratio, the tensile properties of the PVOH/RWF film were higher than the PVOH/BWF film, but the PVOH/BWF film showed higher water uptake than PVOH/RWF film.     

Planning of carbon capture and storage with pinch analysis techniques

Carbon capture and storage (CCS) is a means for reducing carbon dioxide (CO₂) emissions from fossil fuel combustion in power generation and industrial processes. It involves the capture of CO₂ for subsequent storage in various geological formations. The selection and matching of the power plants and storage sites are often an issue of optimisation due to various constraints, i.e., time of availability, injection rate, and storage capacity limits. In this work, a novel graphical targeting tool based on pinch analysis is proposed to address the planning problem of the storage of captured CO₂ from power generating plants into corresponding reservoirs. The main consideration for the problem is the time of availability of the latter, since reservoirs need to be developed prior to CO₂ storage. The time limitation is addressed by the graphical technique where time is taken as the governing element in solving the problem. Hypothetical examples are used to elucidate the proposed approach.     

Synthesis of polyvinylidene fluoride (PVDF) membranes for protein binding: Effect of casting thickness

Microporous polyvinylidene fluoride (PVDF) membranes were synthesized from PVDF/N‐methyl‐2‐pyrrolidinone (NMP) solutions using an immersion–precipitation method with a 2‐propanol/water mixture as a soft coagulant. The effects of membrane thickness on pore size distribution and surface/cross‐section morphology were studied using capillary flow porometry and scanning electron microscopy (SEM), respectively. All the synthesized membranes had a small range of pore size distribution, with the pore size decreasing with increasing casting thickness. The semicrystalline PVDF membranes demonstrated significant variations in morphology under SEM observation, with the existence of polymer agglomeration at a casting thickness of 500 μm and above. The protein binding capacity was observed to be highest at a casting thickness of 400 μm, where optimum pore morphology provided a large surface area for protein binding. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013     

Flow pattern measurement in a full scale silo containing iron ore

The flow pattern in a silo is important because it affects both the recovery of solids and the pressures on the silo wall during discharge. Wherever mass flow is not achieved, the boundary of the flow channel has significant implications for both the functional and structural design of the silo. Many techniques have been used for the study of flow patterns in model silos, but most cannot be used at full scale, and very few quality measurements at full scale have ever been made. This paper outlines a full scale experimental study in which the patterns of solids flow and the flow channel boundaries are reliably quantified.The full scale silo was specially designed, constructed and instrumented to exhibit funnel flow and to make observations of the solids flow pattern and the silo wall pressures. It had three outlets: one concentric, one fully eccentric and one in between. Three materials were used: iron ore pellets, slag fines and crushed basalt. This paper describes experiments involving iron ore pellets. The silo was seeded with radio frequency tags whose residence times were measured by detecting them on exit during discharge. The residence time data were studied to deduce the discharge flow pattern. This paper presents the results of three different flow pattern interpretation techniques: the best of them (mass-time relationships) is shown to give a very clear identification of the solids flow pattern and the flow channel boundary.     

表面活性剂在卜特兰水泥表面上的吸附行为(英文)

实验探索了脂肪醇聚氧乙烯醚硫酸盐 (AES)、氯化十六烷基吡啶 (CPC)、β -萘磺酸聚合物 (NS)以及烷基酚聚氧乙烯醚 (TX -10 )等四种不同类型的表面活性剂在普通硅酸盐水泥表面的吸附行为。研究表明 ,AES在水泥颗粒表面的吸附是一种快吸附 ,属于LS型 ;CPC在水泥颗粒表面的吸附过程则是一种慢吸附 ,受动力学因素所控制 ;NS的吸附量与其浓度成线性关系 :TX -10则基本上不被吸附。结果显示 ,被吸附的三种表面活性剂都是疏水基朝向水相 ,增加了水泥颗粒的疏水性。然而AES随着添加量的增大 ,由于吸附胶束的形成 ,使水泥颗粒表面经由亲水 -疏水 -亲水的变化过程。从表面电荷的变化来看 ,AES、NS的添加均使水泥表面Zeta电位有所增加 ,而CPC却使得水泥颗粒表面从带负电变到带正电。文中所提出的改进Stern双电层模型能很好地说明几种表面活性剂在水泥颗粒表面的吸附特性     

Proton exchange membranes prepared by simultaneous radiation grafting of styrene onto poly(tetrafluoroethylene‐co‐hexafluoropropylene) films. II. Properties of sulfonated membranes

Proton exchange membranes were prepared by radiation‐induced grafting of styrene onto commercial poly(tetrafluoroethylene‐co‐hexafluoropropylene) films using a simultaneous irradiation technique followed by a sulfonation reaction. The resulting membranes were characterized by measuring their physicochemical properties such as water uptake, ion exchange capacity, hydration number, and proton conductivity as a function of the degree of grafting. The thermal properties (melting and glass transition temperatures) and thermal stability of the membrane were also investigated using differential scanning calorimetry and thermal gravimetric analysis, respectively. Membranes having degrees of grafting of 16% and above showed proton conductivity of the magnitude of 10⁻² Ω⁻¹ cm⁻¹ at room temperature, as well as thermal stability at up to 290°C under an oxygen atmosphere. © 2000 John Wiley & Sons, Inc. J Appl Polym Sci 78: 2443–2453, 2000