Improvement of lithium adsorption capacity by optimising the parameters affecting synthesised ion sieves

Recent study has shown that the spinel type of MnO₂ nanoparticles have a required capacity for lithium extraction from liquid resources. The low lithium adsorption capacity of synthesised ion sieves was found to be an important limiting parameter for their use in industrial applications. Therefore, increasing the uptake capacity of different ion sieves by studying the effect of six effective parameters, involving lithium salt compound, manganese salt compound, oxidising reagent, calcination temperature, heating time and Li/Mn mol ratio, on the synthesised ion sieves was investigated. Hence, in this reported work, a specific approach based on the L₉(3⁴) Taguchi orthogonal array was employed to evaluate these parameters and to optimise them in two separate stages. Also, the relative importance of each factor was determined using analysis of variance. Although, all mentioned parameters had a significant effect on lithium uptake capacity, the oxidising reagent and the lithium salt compound were the most effective factors. Also, an appropriate ion sieve with a lithium adsorption capacity of more than 9 mmol g^-1 was synthesised for the first time.