What is the difference between the chemical composition of molecular sieve and silica gel? What is the difference between their adsorption properties?

Silicate and acid mixture can form silicate gel, silicate gel by static, washing, drying and activation of silica gel, it is an excellent polar adsorbent, water and other polar substances have a strong adsorption, the adsorption occurs on the surface of the physical adsorption, and can be regenerated. And molecular sieve is a class of synthetic insoluble silica-aluminate, is a class of high-efficiency adsorbent, characterized by a large specific surface area, pore size uniformity, with good mechanical strength and thermal stability. They are covered with cavities of the same size between molecules, with small holes, and certain liquid or gas molecules are adsorbed when they enter the cavities.