Preparation of binderless honeycomb silicalite-1 monolith by using bundled palm fibers as template

Honeycomb silicalite-1 monolith (HSM) was prepared by first binding 27 palm fibers with two Teflon o-rings to form bundled palm fibers, followed by hydrothermal synthesis in a silicalite-1 synthesis solution and removal of the template by calcination. The effect of pH value of the synthesis solution on dissolution of palm fibers was studied. The results indicated that only the centers of palm fibers were dissolved when the pH value of synthesis solution was less than 11, thus keeping original shape of palm fibers. The influence of synthesis cycles was also examined and it was found that two cycles of syntheses were necessary to maintain concrete structure of the resulting HSM. The prepared HSM, with a diameter of 2.3 mm and a length of 15 mm, contained 27 cells, each with a diameter and wall thickness of 350-400 and 25-35 lm, respectively. The specific surface area of the HSM was about 396 m² g^-1. After ultrasonic treatment in water with an ultrasonic frequency of 40 kHz for 60 min, the HSM had a weight loss of only about 5.5%, indicating the strong mechanic strength.