Search

Si 2 N 2 O composites were achieved via direct ink writing technique and pressureless sintering. The design and optimization of inks and the effect of mass ratio of Si 3 N 4 and SiO 2 on the phase composition, microstructure, mechanical properties and dielectric properties of composites were systematically investigated. The inks exhibit superior stability and printability. Increasing SiO 2 content facilitated densification and enhancement of mechanical property. The generation of β-Si 3 N 4 and Si 2 N 2 O and the nucleation of cristobalite were restrained by high content SiO 2. The ceramic composites with the flexural strengths from 74.1MPa to 104.9MPa and low dielectric constant (≤4.68) were fabricated. This strategy provides a systematic reference for synthesis of high-performance porous Si 2 N 2 O composites based on the DIW. [ABSTRACT FROM AUTHOR]

Geopolymers have high application potential due to their outstanding ion exchange ability. A novel direct ink writing (DIW) geopolymer adsorption sieve (GAS) preparation strategy was proposed. The preparation and optimization of DIW inks and the adsorption properties and mechanism of GAS for methylene blue (MB) were systematically investigated by characterization and density functional theory (DFT) calculation. The GASs exhibited desired adsorption rates for MB in both dynamic (83.6% at 200 min) and static (97.1% in 7 days) states. The adsorption kinetic was fitted well by the pseudo-first-order model at the early stage and eventually was transformed to fit well by the pseudo-second-order model and indicated the boundary liquid layer diffusion and intraparticle diffusion were all rate-limiting factors. The exploration of adsorption mechanism confirmed that the adsorption of GAS for MB was affected by the coordination of electrostatic action, hydrogen bonds and electrons transfer. The proposed strategy provides a promising reference for design and preparation of eco-friendly 3D printing adsorbent systems. [Display omitted] • A novel strategy for geopolymer adsorption sieve based on direct ink writing was proposed. • The geopolymer adsorption sieves with high molding accuracy and good pore distribution were successfully prepared. • The geopolymer adsorption sieves exhibit considerable dynamic and static adsorption properties. • The adsorption mechanism was proposed based on experiments and DFT calculation. [ABSTRACT FROM AUTHOR]