Fabrication of nano-sized Ca(OH)2 with excellent adsorption ability for N2O4

Uniform nano-sized calcium hydroxide (Ca(OH)2) monocrystal powder was synthesized from calcium oxide in a surfactant solution via a digestion method by decreasing the surface tension of the reaction system to control the growth of crystalline Ca(OH)2. The Ca(OH)2 monocrystal powder samples were characterized by means of scanning electron microscopy (SEM), transmission electron microscopy (TEM), high resolution transmission electron microscopy (HRTEM), X-ray diffraction (XRD), Brunauer–Emmett–Teller (BET), and Fourier transform-infrared spectroscopy (FT-IR). The NOx adsorption ability of the samples was evaluated, and the influence of various types and concentrations of surfactants on powder agglomeration and then the specific surface area in the precipitation process were studied. The specific surface area of the samples was found as high as 58 m2/g and 92 m2/g and the particle size, 300–400 nm and 200–300 nm in the presence of 10 wt% PEG600 and 0.086 mL/L SDS at a reaction time of 5 h, respectively. The product has an exceptionally strong adsorption ability for NOx, which makes it a highly promising adsorbent for emission control and air purification.

Figure optionsDownload as PowerPoint slideHighlights
► Nano-size Ca(OH)2 was synthesized from CaO in the presence of PEG and SDS.
► Nano-size Ca(OH)2 samples are fabricated using digestion method.
► Nano-size Ca(OH)2 with the specific surface area as high as 58 m2/g and 92 m2/g.
► Samples P-10-5 and S-0.086-5 have uniform pore sizes of 5–14 nm and 5–9 nm.
► Samples P-10-5 and S-0.086-5 have 59.43% and 94.67% high NOx removal rate.