Green Routes for Synthesis of Zeolites

A brief overview of recently reported green routes for synthesizing zeolites, including reduction or elimination of organic templates, use of green solvents such as ionic liquids (ILs) or complete elimination of solvent, and efficient heating of the starting gels. To overcome the disadvantages of using organic templates, nontoxic templates and template recycling steps have been employed in zeolite syntheses. The best way to reduce the aqueous wastes is a solvent-free (solventless) synthetic green route. Microwave-assisted synthesis of zeolites in the absence of solvents and organic templates would be a simple, fast, low-cost, environmentally benign, and safe route, which completely fulfills the requirements of green chemistry. The solvent-free synthesis of zeolites raises many questions in terms of its potential for large-scale applications, including the role of the initial grinding, the mechanism of solvent-free synthesis, the interaction between the organic SDAs and the silica, and the properties of the products.