We present a simple synthetic route to hierarchically porous geopolymers using triglyceride oil for a reactive emulsion template. In the new synthetic method, highly alkaline geopolymer resin was first mixed with canola oil to form a homogeneous viscous emulsion which was then cured at 60°C to give a hard monolithic material. During the process, the oil in the alkaline emulsion undergoes a saponification reaction to be decomposed to water‐soluble soap and glycerol molecules which were then extracted with hot water to finally yield porous geopolymers. Nitrogen adsorption studies indicated the presence of mesopores, whereas the SEM studies revealed that the mesoporous geopolymer matrix are dotted with spherical macropores (10–50 μm) which are due to oil droplet template in the emulsion. Various synthetic parameters including the precursor compositions were examined to control the porosity. BET surface area and BJH pore volume of the materials were up to 124 m2/g and 0.7 cm3/g, respectively, and the total pore volumes up to 2.1 cm3/g from pycnometry.

A new class of highly active solid base catalysts for biodiesel production was developed by creating hierarchically porous aluminosilicate geopolymer with affordable precursors and modifying the material with varying amounts of calcium. For the catalysts containing $8 wt% Ca, almost 100% conversion has been achieved in one hour under refluxing conditions with methanol solvent, and the high catalytic activity was preserved for multiple regeneration cycles. Temperature-programed desorption studies of CO 2 indicate that the new base catalyst has three different types of base sites on its surface whose strengths are intermediate between MgO and CaO. The detailed powder X-ray diffraction (PXRD) and Xray photoelectron spectroscopic (XPS) studies show that the calcium ions were incorporated into the aluminosilicate network of the geopolymer structure, resulting in a very strong ionicity of the calcium and thus the strong basicity of the catalysts. Little presence of CaCO 3 in the catalysts was indicated from the thermogravimetric analysis (TGA), XPS and Fourier transform infrared spectroscopy (FT-IR) studies, which may contribute to the observed high catalytic activity and regenerability. The results indicate that new geopolymer-based catalysts can be developed for cost-effective biodiesel production.

Composite materials of hierarchically porous geopolymer and amorphous hydrous ferric oxide were produced and characterized as a new potentially cost-effective arsenic adsorbent. The arsenic removal capabilities of the iron (hydr)oxide (HFO) media were carried out using batch reactor experiments and laboratory scale continuous flow experiments. The Rapid Small-Scale Column Tests (RSSCT) were employed to mimic a scaled up packed bed reactor and the toxicity characteristic leaching procedure (TCLP) test of arsenic adsorbed solid material was carried out to investigate the mechanical robustness of the adsorbent. The best performing media which contained~20 wt% Fe could remove over 95 µg of arsenic per gram of dry media from arsenic only water matric. The role of the high porosity in arsenic adsorption characteristics was further quantified in conjunction with accessibility of the adsorption sites. The new hierarchically porous geopolymer-based composites were shown to be a good candidate for cost-effective removal of arsenic from contaminated water under realistic conditions owing to their favorable adsorption capacity and very low leachability.