Porous titanium scaffolds with high porosity and connected macropores are fabricated by adding zirconium acetate to control the ice crystal growth during freeze casting. The influences of zirconium acetate additives on the phase composition, pore structure, and mechanical properties of porous titanium are studied. As modified by zirconium acetate, the X-ray diffraction peaks of titanium moves to a smaller angle, and the zirconium is evenly distributed on the titanium matrix. With the increase in the concentration of zirconium from 0 to 60 g L −1 , the pore morphology of porous titanium changes from typical lamellar to the honeycomb, the pore size distribution becomes wider. The average pore size and porosity increases from 44 ± 11 to 126 ± 35 μm and from 46.4 ± 1.3 to 59.1 ± 1.3%, respectively. As the concentration of zirconium acetate is 40 g L −1 , the porosity and the pore size of the porous titanium scaffolds are comparable with those modified by 10 g L −1 zirconium acetate, but the compressive strength is 2.3 times higher. Zirconium acetate as an additive has an excellent performance in optimizing the pore structure and mechanical properties of water-based freeze-cast porous titanium.
Kai Luo,Wensheng Zhang,Jiayuan Ye,Jun Li,Zhongyuan Lu,Xuehong Ren
The physical and microscopic properties of γ-C 2 S and β-C 2 S under hydration, carbonation , and hydration–carbonation cycle reactions were investigated. The hydration–carbonation cycle reaction facilitated the carbon sequestration of C 2 S, and the generation of CaCO 3 filled the pores of the matrix and enhanced the matrix density in the carbon fixation reaction process. In the subsequent hydration and reaction process, the formation of hydration products increased the number of pores in the matrix and reduced the matrix density. Post-hydration, γ-C 2 S slurry became powder and had no mechanical strength . However, after carbonation reaction and two carbonation–hydration cycles, γ-C 2 S exhibited better mechanical properties than β-C 2 S.
Hao Li,Samah Awadh Ali Mahyoub,Wenjie Liao,Shuqian Xia,Hechuan Zhao,Mengya Guo,Peisheng Ma
The magnetic biochars were easily fabricated by thermal pyrolysis of Fe(NO 3 ) 3 and distillation residue derived from rice straw pyrolysis oil at 400, 600 and 800 °C. The effects of pyrolysis temperature on characteristics of magnetic biochars as well as adsorption capacity for aromatic contaminants (i.e., anisole, phenol and guaiacol) were investigated carefully. The degree of carbonization of magnetic biochars become higher as pyrolysis temperature increasing. The magnetic biochar reached the largest surface area and pore volume at the pyrolysis temperature of 600 °C due to pores blocking in biochar during pyrolysis at 800 °C. Based on batch adsorption experiments, the used adsorbent could be magnetically separated and the adsorption capacity of anisole on magnetic biochars was stronger than that of phenol and guaiacol. The properties of magnetic biochar, including surface area, pore volume, aromaticity, grapheme-like-structure and iron oxide (γ-Fe 2 O 3 ) particles, showed pronounced effects on the adsorption performance of aromatic contaminants.
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