Preparation of adsorption materials by combustion method: a new approach to the preparation of magnesia doped with trace zirconium

Abstract

As a very promising material for CO₂ capture owing to its appealing properties, such as abundant basic sites and a higher theoretical adsorption capacity, there are a variety of MgO-based adsorbent (MA) preparation methods reported in numerous studies. Zirconia is usually studied as a carrier; however, little research is focused on the preparation of MA by trace ZrO₂-doping. Since the preparation of MA is complex and time-consuming, it is imperative to find a facile and efficient method to simplify the preparation process and produce MA with high performance for CO₂ capture. In this experiment, salicylic acid was used as a combustion aid to prepare MA with different doping contents of ZrO₂. Among the as-obtained samples, under the calcination temperature of 550 °C and the calcination time of 160 min, the MA doped with 2% ZrO₂ prepared by the combustion of MgO and ZrO₂ complexes without washing and a filtration process showed excellent performance. As confirmed by CO₂-TPD, the adsorption of CO₂ over the adsorbent was mainly chemical adsorption, and the adsorbent that had a larger specific surface area provided numerous surface basic sites. Besides, the micro crystals of MgO were widely separated due to the employment of ZrO₂ as a dispersant, avoiding the accumulation of MgO through CO₂ adsorption–desorption cycles. This study provides a meaningful idea for the preparation of modified MA for CO₂ capture.