Preparation and modification of zeolite a from kaolin for catalytic methanation of carbon dioxide

Abstract

Different types of zeolite including zeolite a are prepared from natural kaolin originated in Vietnam. Raw kaolin was collected from Phu Tho, Vietnam, underwent metakaolization at 650°C within 2 hours and alkalination with NaOH to synthesize various zeolitic samples. Various characterization techniques were performed, including X-ray diffraction, fourier-transform infrared spectroscopy, and scanning electron microscopy. Different concentrations of NaOH were utilized to study the difference of the prepared zeolite. Nickel-doped zeolite a samples with different nickel loading were also prepared via ion exchange method and were employed as catalyst for the hydrogenation of carbon dioxide (CO₂) to obtain methane (CH₄). The best catalytic activity of 55.2% CO₂, conversion and 92.7% CH₄, selectivity was achieved with 10%Ni/ZM1 at 350°C, 1 atm, H₂:CO₂: ratio of 4:1, and gas hourly space velocity of 9,000 mL.g⁻¹.h⁻¹. This study demonstrates a promising pathway of modifying Vietnamese natural kaolin as a low-cost but an effective alternative material for the preparation of zeolite A and its application in the carbon dioxide methanation reaction.