Preparation and characterization of a novel porous silicate material from coal gangue

A novel porous silicate material (PSM) derived from coal gangue was successfully prepared and characterized by N-2 adsorption-desorption isotherms, thermogravimetric analysis, Fourier transform infrared spectroscopy, scanning electron microscopy, transmission electron microscopy, and X-ray diffraction measurements. The preparation procedure involved two steps: (1) SiO32- leaching from coal gangue by both activation and chemical approaches, and (2) preparation of the PSM by reaction of the leachate with Ca(OH)(2). It was found that the maximum SiO32- leaching yield was achieved at calcination temperature of 1000 degrees C, reaction temperature of 106 degrees C for 2 h, NaOH concentration of 25%, and the ratio of coal gangue to alkali of 0.5:1. The PSM was then easily prepared from the SiO32- leaching at 98 degrees C for 2 h with a Ca/Si ratio of 1.2:1 and the pH value of 12.70. The spectroscopic results showed that the PSM was mainly composed C, Ca, O, Si and Na, in the form of Ca2+, Na+, SiO32-, and CO32- ions. Some adsorbed water and/or surface water was observed. The adsorption behavior revealed that the CO2 adsorbed amount on PSM was 36.69 mg g(-1) at 293.15 k and ambient pressure with a pure CO2 flow rate of 120 mL min(-1) during 90 min. (C) 2015 Elsevier Inc. All rights reserved.