Preparation, characterization and application of geopolymer-based tubular inorganic membrane

Inorganic membrane (IM) has been widely concerned in the fields of water filtration and gas treatment. Compared to ceramic and organic membrane, geopolymer inorganic membrane (Geo-IM) has a good application prospect in many fields due to their low cost and excellent properties. In this paper, a green, environmentalfriendly, fine performance and controllable pore structure tubular inorganic membrane prepared by using cheap slag reinforced metakaolin based geopolymer can be used for water filtration and flue-gas treatment. The experimental results show that the compressive strength and flexural strength of the sodium based Geo-IM are increasing from 7 MPa and 1.37 MPa to 14 MPa and 2.12 MPa respectively. In other word, the compressive strength and flexural strength of potassium based Geo-IM were increased by 100% and 54.74% respectively compared with that of sodium based Geo-IM, it is helpful for the inorganic membrane to withstand certain pressure. The thermogravimetric (TG) analysis showed that the potassium based Geo-IM has good thermal stability. By measuring the compressive strength of the IM at 0?1000 ?C, it can be seen that the potassium-based inorganic membrane (K-WG-IM) can withstand the temperature of 800 ?C. The specific surface area of K-WGIM is about 77 m2?g- 1, the porosity is about 70%, and the water flux is 100?8000 kg?m- 2?h-1 (25 ?C, 1 MPa). The filtration performance of the Geo-IM was characterized by the self-made water filtration and flue-gas treatment device in the laboratory. It is found that the Geo-IM could capture particulate matter (PM) with particle size greater than 1.67 ?m in carbon black aqueous solution, and the removal rate of PM2.5 in flue-gas was as high as 97%, and the removal rate was still above 90% when the flue-gas temperature reached 600 ?C. In a word, the tubular Geo-IM with low-cost, high-efficient and green properties has considerable potential in the practical applications.

Automated summary

This study prepared a green, environmentally friendly, fine performance, and controllable pore structure tubular inorganic membrane using cheap slag reinforced metakaolin based geopolymer, which can be used for water filtration and flue-gas treatment. The experimental results showed that the compressive strength and flexural strength of the sodium-based Geo-IM increased, while the potassium-based Geo-IM exhibited better thermal stability and could withstand higher temperatures. The filtration performance of the Geo-IM was characterized by a self-made water filtration and flue-gas treatment device in the laboratory, demonstrating good removal rates for particulate matter and PM2.5 in different solutions.