Zeolite K-L (LTL) was synthesised via hydrothermal methods with a batch composition of 4K2O:10 SiO2:Al2O3:100H2O, following the method described by Bhat et al. Solution 1 was prepared by adding 2.267 g NaOH pellets (100% NaOH, Fischer) to 4.034 g of deionised water and stirred at room temperature until homogeneous. An amount of 1.572 g Al(OH)3 (100%, Fischer) was added and the weight noted, prior to heating the solution at 110°C until homogeneous. Any mass loss during heating was compensated for by re-adding the appropriate amount of deionised water. Solution 2 was prepared by adding 12.273 g of a colloidal solution of silica (Ludox, 40wt% SiO2, Aldrich) to 7.018 g deionised water and stirred until homogeneous. Solution 2 was slowly added to solution 1 and left to stir for 30 min at room temperature, to allow the formation of a viscous gel. This gel was then transferred to an autoclave and heated in an oven at 160°C for 3 days. The powder was recovered via Buchner filtration and washed with deionised water until the filtrate was neutral pH 7-8. Partial cation exchange of K + for Li + and Cs + was achieved by adding 2 g of K-L to 0.25 M and 0.5 M solutions of LiCl (Fischer 99.9%) and CsCl (Fischer 99.9%), respectively. The exchange process was performed 3 times at 95°C whilst stirring for 5 h. The final sample was filtered, washed with deionised water and oven dried in an oven at 80°C overnight.