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A high-performance mesoporous biochar (MBCX) was fabricated from chicken bone via a facile and low-energy consumption pyrolysis process without any additional activators and templates. The physicochemical properties of biochar were carried out by elemental compositions, N2 adsorption-desorption isotherms, FTIR, and TG. The results illustrated that lower carbonization temperature leaded to a lower specific surface area and more polar functional groups. And the meso-structure of biochar was obtained at 350 °C. Combined with the result of batch experiment, Cr(VI) adsorption capacity was decreased with the increasing in pyrolysis temperature, which suggested that the removal performance was depended on the functional groups of mesoporous biochar rather than the surface area. Kinetic analysis showed that the Cr(VI) adsorption process on MBCX was suitable for Elovich kinetic. The experimental data was well explained by Langmuir isotherm models. And the maximum adsorption capacity was 58.195 mg/g, which was higher than that of most report pristine biochars. This work not only paved a way for subsequent mesoporous biochar preparation but also demonstrated the application potentials of MBCX as an environment benign Cr(VI) adsorbent.

Appropriate disposal of hyperaccumulator biomass is a problem inhibiting the widespread use of phytoremediation technology. In the present study, kinetic analysis of the pyrolysis process of Sedum plumbizincicola, the behaviour of heavy metals and bio-oil composition were studied. The kinetic analysis of the pyrolysis process shows that activation energy (E) changed from 150 to 186 kJ mol−1 and the frequency factor (A) changed from 1.34 × 1011 to 8.99 × 1015 s−1. At temperatures of 450–750 °C more than 66.3 % of zinc (Zn) remained in the char. More than 87.6 % of the cadmium (Cd) was found in the bio-oil. Pyrolysis at 650 °C led to the highest yield of alkanes with low-oxygen compounds found in the bio-oil. Pyrolysis at 650 °C can likely offer a valuable processing method for S. plumbizincicola and recovery of Zn from the char and recovery of Cd from the bio-oil will be attempted in future research.

TiC was synthesized by reactive pyrolysis of a mixture of poly(dimethylsilaacetylide), [-MeSi(H)C≡C-] n , Ti, and TiSi 2 particles under Ar atmosphere between 1100 °C and 1400 °C. The pyrolysis products were studied by means of X-ray diffraction (XRD), scanning electron microsphere (SEM), and Energy-Disperse Spectrometer (EDS). The results showed that TiC crystals appeared at 1200 °C accompanied by Ti 5 Si 3 . At 1400 °C, single crystalline phase TiC was obtained. By changing the ratio of raw materials, TiC crystals with different morphologies, including octahedron, truncated-octahedron, and polyhedral were prepared.

A polymeric precursor, polysiloxazane (PSON), for SiCON ceramics has been synthesized by the partial hydrolysis of MeViSiCl2, MeHSiCl2 ,a nd MeSiCl 3 followed by ammonolysis reaction of the hydrolyzed inter- mediates with NH3. The structure and thermal properties of the polymeric precursor were investigated by means of Fourier transfer infrared spectra (FTIR), 1 H-NMR, 29 Si-NMR, gel permeation chromatography, and thermogra- vimetric analysis. The structure of the SiCON ceramics derived from the pyrolysis of PSON was characterized by FTIR and X-ray diffraction. The as-synthesized PSON pro- duced mainly a-Si3N4 crystalline phase during pyrolysis at 1500 � Cu nder N 2 atmosphere, whereas when pyrolyzed at 1500 � C under Ar atmosphere, crystalline phases of a/b-SiC and/or a-Si3N4 were detected. V C 2012 Wiley Periodicals, Inc. J fAppl Polym Sci 126: 853-859, 2012

A new polymeric precursor, perhydropolysiloxazane (PSNO), for silicon oxynitride (SiON) ceramic was synthesized by a simple one-pot procedure involving partial hydrolysis of H2SiCl2 and the following ammonolysis reaction of the hydrolyzed intermediates with NH3. The structure of new polymer was characterized with perhydropolysiloxane (PHSO) and perhydropolysilazane (PHSN) as reference substances. The conversion of PSNO to ceramic was investigated by TGA, FT-IR, and solid 29Si-NMR analyses. A Si-rich Si2N2O ceramic was produced upon pyrolysis of PSNO at 1400°C under N2 atmosphere. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011

Three new borazine derivatives, 2,4,6-tri(allylamino)borazine (CH 2 =CHCH 2 NHBNH) 3 (1), 2,4,6-tri(3-ethynylanilino)borazine (CH≡CC 6 H 4 NHBNH) 3 (2), and 2,4,6-tri(4-propargyl oxyanilino)borazine (CH≡CCH 2 OC 6 H 4 NHBNH) 3 (3) were synthesized by reaction of 2,4,6-trichloro-borazine Cl 3 B 3 N 3 H 3 (TCB) with corresponding primary amines, respectively. Their thermal behavior was studied by differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA). These molecules were easily crosslinked via thermal polymerization of reactive ethynyl or vinyl groups. The pyrolytic residues of borazines were investigated by X-ray photoelectron spectroscopy (XPS), powder X-ray diffraction (XRD), and scanning electron microscopy (SEM). The analytic results indicated that B-C-N ceramics were formed upon pyrolysis of the borazines under an inert atmosphere.

Free-growth morphology of crystalline grains was firstly observed within the cavities of titanium silicon carbide (Ti 3 SiC 2 ) ceramic prepared by in-situ reaction of polycarbosilane (PCS) and metal titanium. The pores produced by pyrolysis of PCS in Ti 3 SiC 2 ceramic can offer space for free growth of Ti 3 SiC 2 and the liquid of CaF 2 additive promoted the formation of Ti 3 SiC 2 within such cavity. The perfect two-dimensional morphology reflects the growth of Ti 3 SiC 2 single crystals. The growth mechanism of concentric layers on the {0 0 1} face was proposed. Berg's effect on the step movement was put forward and analyzed. From the view of the process of the movement of growth units, the reasons of stability and why it could be destroyed were discussed.

Bulk quantity and long-scale amorphous SiO2 nanowires have been prepared simply by direct pyrolysis of an iron-modified perhydropolysilazane (Fe-PHPS) at 1300 °C in the flowing Ar atmosphere. Scanning electronic microscope (SEM) study shows that most SiO2 nanowires have smooth surface and they consist of straight and smoothly curved parts, with diameters in the range of 50 to 200 nm and lengths up to 200 μm. Beside this normal form of SiO2 nanowires via the typical vapor-liquid-solid (VLS) mechanism, four other different helical forms of nanowires, named spring-shaped nanowires, twinborn nanospring, fishbone-shaped nanowires and braided-like helical SiO2 nanowires, are also observed. The formation of these nanowires is proposed to be the modulated contact angle anisotropy (CAA) mechanism based on the VLS mechanism.

A new kind of polytitanosilazane (PTSZ) precursor for Si/C/N/Ti-based ceramic was synthesized from the condensation reaction of silazane lithium salts and titanium tetrachloride (TiCl4). Titanium in the precursors was bonded to silazane compounds in the Si—N—Ti bond. The obtained PTSZs were characterized by Fourier transform infrared (FTIR), nuclear magnetic resonance (NMR), and elemental analyses. The PTSZs were pyrolyzed at 900 to 1300°C under nitrogen, argon, and ammonia atmosphere, respectively, to give amorphous inorganic products. The results indicated that ceramic yields of PTSZs were much higher than that of their corresponding silazane oligomers and ceramic yields increased with the increase in Ti content in PTSZs. Precursors containing reactive vinyl groups gave higher pyrolytic yields. The pyrolytic yield under ammonia is lower than that under nitrogen and argon. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 92: 2733–2739, 2004

Si–C–Ti powder was synthesized by reactive pyrolysis of poly(methylsilaacetylene)(PSCC) precursor mixed with metal Ti powder. Pyrolysis of PSCC/Ti mixture with certain atomic ratio was carried out in argon atmosphere between 1300 °C and 1500 °C. The metal-precursor reactions, and phase evolution were studied using X-ray diffraction and scanning electron microscopy equipped with EDX. Ti3SiC2 phase was obtained from reaction of PSCC and Ti for the first time. Ti3SiC2 formation started at 1300 °C and its amount increased significantly at 1400 °C. In addition, liquid formed by additive CaF2 could promote the formation of Ti3SiC2 phase.

Large-area, crack-free inverse opal photonic crystals were successfully fabricated by conventional colloidal self-assembly method with poly(St-MMA-AA) as the opal template and a thermosetting polysilazane as the infiltrating polymer. The phenomenon of self-healing of cracks in the opal template was observed and attributed to the unique rheology property of the used polysilazane. Under an optimized pyrolysis condition, a hybrid inverse opal photonic crystal with its refractive index at 2.21, filling fraction of the solid material at 0.66, and area around 8 mm × 10 mm was prepared.