Approximately four million years of human history has passed. We have
been using materials to make a variety of tools. The first materials
used were naturally occurring materials such as animal bones, stones,
wood etc.; and some of these familiar materials are porous. Porous
materials are so familiar that they are sometimes forgotten or ignored.
The taste experience of ice cream is created not only by adjusting
ingre- dients, but also by including air as an ingredient, i.e. pores
that give the smooth texture of ice cream. This book is designed to
describe and explain about pores, the synthesis of materials with pores
(porous materials), and applications of porous materi- als. This book is
intended for engineers and scientists of different disciplines and
specialities, and is expected to be useful in the design and synthesis
of porous materials for existing as well as potential new applications.
Let us rediscover pores. K. Ishizaki, S. Komameni and M. Nanko January
1998 1 Introduction 1.1 WHAT ARE POROUS MATERIALS? Porous materials are
dermed as solids containing pores. Figure 1.1 shows different porous
materials. Generally speaking, porous materials have a porosity of
0.2-0.95. The porosity means the fraction of pore volume to the total
volume. Porous materials have been used in various applications from
daily necessities, such as purifying drinking water by activated carbon
or porous ceramics, to uses in modern industries, for example removing
dusts from high purity process gases for semiconductor production.
