Amine-impregnated silica zeolite from microalgae ash at different calcination temperatures for CO2 capture

Microalgae is an excellent type of biomass for bio-energy production due to its high calorific value and fast growth. However, a large amount of ash would be generated during microalgae utilization. In this work, MCM41 was prepared from microalgae ash. The materials were calcined at different temperatures (450 degrees C, 500 degrees C, 550 degrees C, and 600 degrees C), and the effect of calcination temperature was investigated. Polyethyleneimine (PEI) was loaded in MCM41 by the impregnation method at different loading amounts (30%, 40%, 50%, and 60%). The CO2 capturing capacity was measured. The results showed that the MCM41 calcined at 450 degrees C was the optimal material, which performed the most developed pore structure. Amine loading enhanced the CO2 capturing capacity of MCM41. The CO2 capturing capacity increased as PEI loading amount increased. The highest CO2 adsorption amount was 2.275 mmol/g with 60% amine loading at 25 degrees C and 1 bar. Adsorption temperature had a mild impact on CO2 capture, and its CO2 adsorption amount decreased slightly with an increase in the adsorption temperature. It was considered that the CO2 uptake of amine-impregnated MCM41 kept stable at different temperatures below 100 degrees C. Also, it showed good cyclic stability. After 10 cycles, the CO2 capturing capacity of 1.6 mmol/g was exhibited.

Automated summary

Microalgae ash was converted into MCM41, and the impact of calcination temperature and PEI loading amount on CO2 capture capacity was investigated. The optimal material was found to be MCM41 calcined at 450 degrees C, with increasing CO2 adsorption capacity as PEI loading amount increased.