Lithium is a valuable metal which can be recovered from various sources such as seawater, wastewater, and brine. In this study, lithium is recovered from shale gas produced water, a by-product from shale gas production, which contains a lithium concentration of 95 mg/L. The shale gas produced water also contains a very high concentration of organic compounds, especially n-alkanes. There has not been much study about the effect of organic compounds on lithium adsorption. Therefore, the influence of alkanes on lithium adsorption by ion-sieve adsorbent, H<sub>2</sub>TiO<sub>3</sub> in shale gas produced water was investigated in this study. Kinetic and isotherm study were carried out for the produced water with and/or without organic compounds. The lithium adsorption in both produced water samples were found to be pseudo-second-order reactions and fitted in Langmuir isotherm showing lower theoretical maximum adsorption capacity in the produced water with alkane than in the solution without organics. Also, adsorption and desorption capacity of each cation were determined for the produced water with different types of alkanes. To observe the characteristics of the adsorbent when alkanes were added, the particle size and zeta potential of the adsorbent were analyzed in different conditions. Size and zeta potential of the adsorbent changed when alkanes were added to the solution, which could affect the lithium adsorption and desorption capacity. With increasing hexane concentration, the zeta potentials were decreased and the average size of the adsorbent was increased. The increased size of the adsorbent could have resulted in the lower desorption capacity of lithium involving chemisorption.

Influence of alkanes on adsorption characteristics of lithium and adsorbent

2019 Fall National Meeting

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