Mineral-derived Li4SiO4-based adsorbent for post-combustion CO2 capture: An experimental and kinetic investigation

Li4SiO4-based adsorbent is considered as a promising choice for the CO2 removal from power plants'; flue gases. However, the relatively high raw materials cost still limits its industrial applications. In this work, aiming to reduce the cost of Si-source, three novel natural occurring minerals including the pumicestone, the montmorillonite and the attapulgite were employed as Si-sources for the production of Li4SiO4-based ad-sorbents. The phase composition, surface morphology as well as the cyclic CO2 ad-desorption performance of obtained adsorbents were experimentally and kinetically investigated. It is found that the Si content of minerals directly determines the adsorption capacity of adsorbents, resulting in a relatively high and stable capacity of nearly 0.1 g/g within 22 cycles for the pumicestone derived adsorbent compared with other ad-sorbents obtained from minerals. Moreover, the excess Ca inside the minerals is found forming CaO, which is harmful to the desorption performance of adsorbent owing to the occurrence of Li-Ca&-CO2 interactions. As a consequence, Si-source with high Ca content was proven inadaptable for the synthesis of Li4SiO4-based adsorbent, which provides guidance for the future selection of mineral Si-sources in this field. (C) 2020 The Combustion Institute. Published by Elsevier Inc. All rights reserved.

Automated summary

This study investigates the feasibility of using different natural minerals as Si sources to prepare Li4SiO4-based adsorbents, with pumicestone identified as a potential alternative material. The Si content in the minerals directly influences the adsorption capacity of the adsorbents.