Effect of pH on lithium extraction from geothermal brine using nanofiltration membrane

Lithium is the element that is currently the most sought-after. Lithium is the primary material for making batteries, ceramic materials, and motor vehicle fuel. Following Minister of Energy and Mineral Resources Regulation No. 20 of 2021 and Minister of Trade Regulation No. 100 of 2020 concerning lithium, an essential element in manufacturing batteries, lithium liquefaction in Indonesia is being intensified. In Indonesia, many active volcanoes are a source of power for electricity generation, namely geothermal, which has a waste product in the form of geothermal brine, which contains lithium. This is very profitable for Indonesia in the process of producing lithium. One of them is lithium extraction using the nanofiltration method. And in this study, a nanofiltration process was operated using a nanofiltration membrane with a Dead-End module which is very simple to use for the process. The process in this study first made a geothermal brine draw solution from NaCl, KCl, MgCl₂, CaCl₂, and LiCl₂. Prepare 100 ml of draw solution using a dead-end nanofiltration membrane module for the nanofiltration process by using a pH variation at a pressure of 7 Bar. This study observes the filtration process by finding the permeate flux during the lithium extraction process using the nanofiltration method. The result of this research is that the more alkaline a permeate solution, the higher the change and the faster the time needed for the nanofiltration process.