BET theory

About: BET theory is a research topic. Over the lifetime, 9046 publications have been published within this topic receiving 286142 citations.

Effect of hydrolysis conditions on morphology and crystallization of nanosized TiO2 powder

Abstract: Nanosized titania powders were prepared by controlling the hydrolysis of TiCl4 in aqueous solution. The powders were characterised by TEM, HREM, XRD, ED, and BET techniques. In the presence of a small amount sulphate ions, when TiCl4 solution hydrolysed at 70°C, the obtained powder was pure anatase and its primary particle size was 3.5 nm, which is finer than that of alkoxide-derived powders, moreover, its anatase-rutile transformation was retarded. However, at the same temperature, in the absence of SO42− the synthetic powder was a mixture of the anatase and rutile, the primary particle size in the rutile phase was 4.3 nm. When TiCl4 solution hydrolysed at 20°C, the prepared TiO2 powder was amorphous and its BET surface area was as high as 501 m2/g. The results of UV–Vis absorption spectra indicate that the presence of sulphate ions accelerated the growth of TiO2 clusters to anatase.

Influence of Carbonization Temperature on Physicochemical Properties of Biochar derived from Slow Pyrolysis of Durian Wood (Durio zibethinus) Sawdust

Abstract: The objective of this study was to explore the influence of pyrolysis temperature on the physicochemical properties of biochar synthesized from durian wood (Durio zibethinus) sawdust. Surface morphological features, including the porosity and BET surface area of biochars, provide appropriate dimensions for growing clusters of microorganisms with excellent water retention capacity in soil. Oxygen-containing surface functional groups play a vital role in improving soil fertility by increasing its cation and anion exchange capacities with reduced leaching of nutrients from the soil surface. Biochar was produced via slow pyrolysis of woody biomass (WS) using a fixed bed reactor under an oxygen-free atmosphere at different pyrolysis temperatures (350, 450, and 550 °C). The biochars obtained were characterized using ultimate and proximate analyses, Brunauer-Emmett-Teller (BET) surface area, field-emission scanning electron microscopy (FE-SEM), Fourier transform infrared spectroscopy (FTIR), and X-ray diffraction (XRD). The yield of biochar decreased from 66.46 to 24.56%, whereas the BET surface area increased sharply from 2.567 to 220.989 m2/g, when the pyrolysis temperature was increased from 350 to 550 °C. The results highlighted the effect of pyrolysis temperature on the structure of the biochar, which could be advantageous for agricultural industries.

Synthesis of Triazine-Based Porous Organic Polymers Derived N-Enriched Porous Carbons for CO2 Capture

Abstract: Porous carbon with both high CO2 uptake and CO2/N2 selectivity is desired for reducing the cost of carbon capture. Here, we report the preparation of N-enriched porous carbons (NPCs) derived from the low-cost triazine-based porous organic polymers using KOH as the activating agent under N2. The results indicate that the nitrogen content and textural properties of the NPCs can be effectively adjusted by the polymer precursors and the carbonization temperature. Impressively, the NPCs have an enriched N content (5.56–11.33 wt %) and abundant porosity (BET surface area: 394–1873 m2/g, pore volume: 0.27–1.56 cm3/g), endowing them with high CO2 uptake (120–207 mg/g at 273 K and 1.0 bar) and acceptable CO2/N2 selectivity (Henry’s law: 14.3–16.8). In particular, the ultra micropore volume (d ≤ 0.8 nm) is proven a key factor for the CO2 uptake, while both the ultra micropore volume and N content contribute the CO2/N2 selectivity. Our described work will provide a strategy to initiate developments of rationally des...

Low-density organic and carbon aerogels from the sol–gel polymerization of phenol with formaldehyde

Abstract: Low-density organic and carbon aerogels are prepared from the sol–gel polymerization of cheap phenol with formaldehyde using NaOH as the base catalyst, followed by ethanol supercritical drying. The effects of the preparation conditions, including the mole ratio of phenol to NaOH (P/C), the mole ratio of phenol to formaldehyde (P/F), phenol–formaldehyde (PF) concentration and gelation temperature, on the gelation time, the bulk density as well as the physical and chemical structures of the resultant organic and carbon aerogels were studied. The experimental results of TEM and nitrogen adsorption showed that the phenol derived organic and carbon aerogels have a three-dimensional network that consists of interconnected bead-like particles with diameters of approximately 10–15 nm, which define numerous mesopores less than 50 nm. The highest measured BET surface area and mesopore volume of the carbon aerogels obtained reached 714 m 2 g −1 and 1.84 cm 3 g −1 , respectively.