Porous materials prepared by heating derivatives from halloysite

Halloysite clay was subjected to serious treatment by trimethylsilylation and hydrochloric acid. The resulting derivatives were heated below 1473 Kin nitrogen or air to prepare thermally stable porous materials including larger pores than those in zeolite. The trimethylsilylated halloysite resulted in a thermally stable porous material, in an amorphous state, including extremely uniform pores of 1.7 nm. Another derivative also resulted in a thermally cable porous material but consisted of very heterogeneous pores. The thermal degradation behaviour of both derivatives is discussed in detail.