Tongji University

About: Tongji University is a education organization based out in Shanghai, China. It is known for research contribution in the topics: Population & Adsorption. The organization has 76116 authors who have published 81176 publications receiving 1248911 citations. The organization is also known as: Tongji & Tóngjì Dàxué.

Synthesis and Heavy‐Metal‐Ion Sorption of Pure Sulfophenylenediamine Copolymer Nanoparticles with Intrinsic Conductivity and Stability

Abstract: Novel copolymer nanoparticles were easily synthesized with a polymerization yield of 59.3 % by an oxidative precipitation polymerization of aniline (AN) and m-sulfophenylenediamine (SP) in HCl without any external stabilizer. The polymerization yield, size, morphology, electroconductivity, solubility, solvatochromism, lead and mercury ion adsorbability of the HCl-doped copolymer salt particles were studied by changing the AN/SP ratio. The AN/SP (80:20) copolymer particles are found to have the minimal number-average diameter(84.4 nm), minimal size polydispersity index (1.149), high stability, good long-term stability, powerful redispersibility in water, high purity, and clean surface because of a complete elimination of the contamination from external stabilizer. The copolymer salts possess a remarkably enhanced solubility, interesting solvatochromism, and widely adjustable electroconductivity moving across nine orders of magnitudes from 10(-9) to 10(0) S cm(-1). The AN/SP (70:30) copolymer particles have the highest Hg2+ adsorbance and adsorptivity of 497.7 mg g(-1) and 98.8 %, respectively, which are much higher values than those of other materials. The sorption mechanism of lead and mercury ions on the particles is proposed. The copolymer bases with 5-10 mol % SP unit show excellent film formability, flexibility, and smooth appearance. The copolymer should be very useful in the fabrication of cost-effective conductive nanocomposite with low percolation threshold and in removal of toxic metallic ions from waste water.

Electronic structures and enhanced photocatalytic properties of blue phosphorene/BSe van der Waals heterostructures

Abstract: Constructing van der Waals heterostructures can enhance two-dimensional (2D) materials with desired properties and greatly extend the applications of the original materials. On the basis of density functional theory calculations, we verify that a blue phosphorene (BlueP)/BSe inter-layer heterostructure possesses an indirect gap and intrinsic type-II band alignment. In particular, this heterostructure is found to be a potential photocatalyst for water splitting under different pH conditions and exhibits enhanced optical properties in the visible and ultraviolet light zones. Besides, we confirm that the band gap, band edge position, and optical absorption of the BlueP/BSe heterostructure can be tailored by biaxial strain. And the tensile strain increases the optical absorption significantly over the entire energy range of visible light, which can increase the efficiency of solar energy conversion. Furthermore, we determine that adjusting the number of sublayers is another effective method to modulate the band gaps and band alignments of heterostructures. Our studies provide a promising route to design new BlueP-based vdW heterostructures and explore their potential applications in electronic and optoelectronic devices.

Nanoengineering Super Heat-Resistant, Strong Alumina Aerogels

Abstract: Because of ultralow thermal conductivity, excellent catalytic activity, and better heat resistance than silica aerogel, alumina-based aerogel has drawn great interest as thermal insulators and catalysts. However, it is too fragile and sinters above 1000 °C (it shrinks drastically, >50%, and leaves the surface area as low as 10–70 m2/g at 1300 °C), which badly limits its high-temperature applications. Herein, super heat-resistant, strong alumina aerogels are prepared via a novel acetone-aniline in situ water formation (ISWF) method combined with novel modification techniques: supercritical fluid modification (SCFM) and hexamethyldisilazane gas phase modification. The heat resistance of alumina aerogel is enhanced up to 1300 °C via this method. The shrinkage of the optimized alumina aerogel is reduced to as low as 1 and 5% and the corresponding surface area reaches up to 152–261 and 125–136 m2/g after being heated to 1200 and 1300 °C for 2 h, respectively. The strength is significantly increased by more tha...

Verification and modeling of three-stage permanent deformation behavior of asphalt mixes

Abstract: In laboratory testing of asphalt mixtures, the relationship between the number of load repetitions and permanent deformation has been found to include three distinct stages, namely the primary, secondary and tertiary stages. Similar permanent deformation behavior has also been observed in the field accelerated pavement testing data. It is argued that the three-stage permanent deformation behavior is a basic material property and to comprehensively model asphalt layer behavior, it is necessary to develop a model that accurately characterizes this behavior. In this paper, each of the well-known models critically reviewed appears that they are limited to characterizing only the primary stage. Therefore, a new three-stage model is proposed to describe all three stages. Moreover, an algorithm is established to determine the model parameters from typical laboratory data. The algorithm can also be used to identify the transition point between stages, such as flow number. The proposed model and algorithm are demonstrated through laboratory test results. The analysis results match the field performance.