**3.5 Solventless method**

Solventless synthesis methods are more advantageous because they allow the fabrication of MOFs without the use of toxic solvents and create a new identity through studies of a few solventless synthesis of MOFs [59]. Mechanosynthesis is a fast, scalable, and nontoxic method for producing MOFs. It involves ball bearings in a stainless-steel vessel with reagents and a stoichiometric amount of solvent [60]. Solventless synthesis reduces solvent toxicity by expelling it from the reaction. The nanocrystalline nature of the material is provided by the finishing, which can be biosynthesized quickly at room temperature. After the vessel has been completely closed and the reagent kits have been pulverized by proper mixing, the metal–organic framework is addressed (**Figure 13**).
