Preparation and characterization of porous metakaolin-based inorganic polymer spheres as an adsorbent. (25th December 2015)

• Record Type: Journal Article
• Authors: Tang, Qing; Ge, Yuan-yuan; Wang, Kai-tuo; He, Yan; Cui, Xue-min
• Is Part Of: Materials & design. Volume 88(2015:Dec.)
• Page Start: 1244
• Page End: 1249
• Publication Date: 2015-12-25
• Subjects: Geopolymer -- Sphere -- Suspension solidification -- Porous structure -- Adsorption; Materials -- Periodicals; Engineering design -- Periodicals; Matériaux -- Périodiques; Conception technique -- Périodiques; Electronic journals; 620.11
• DOI: 10.1016/j.matdes.2015.09.126
• Languages: English
• ISSNs: 0264-1275

Abstract

Abstract: This paper describes a simple and effective process for fabricating porous metakaolin-based inorganic polymer spheres. The process for making porous geopolymer spheres (PGS) by a suspension and solidification method was experimentally established, and the following conditions yielded the optimal compositions: n (SiO2 )/ n (Na2 O) = 1.6 in a sodium silicate solution, n (Na2 O)/ n (Al2 O3 ) = 1, n (H2 O)/ n (Na2 O) = 16, sodium dodecyl sulfate (K12 ) foaming agent = 1.5 mass%. This procedure was based on the rapid solidification mechanism of a geopolymer paste in a high-temperature suspension. Pore structure analysis of the geopolymer spheres revealed that the pore size distribution centered mainly at 15 nm, which indicated the presence of a large BET surface area (53.95 m 2 /g) of a mostly mesoporous nature. The bulk density of the spheres was 0.79 g/cm 3, and their total porosity was 60.30%; these results indicated the availability of numerous active sites for binding with Cu 2 +, Pb 2 +, Ca 2 + and other ions. The results showed that porous geopolymer spheres are a low-cost, convenient, and environment-friendly adsorbent for removing metal ions. Graphical abstract: Highlights: Porous geopolymer spheres were fabricated by suspension solidification. Geopolymer paste formed into spheres in PEG at temperatures above 70 °C. This work resulted in a novel adsorbent material to remove metal ions from water.