In recent years there has been a significant increase in the demand for lithium all over the world. Lithium is widely used primarily in the production of batteries for electric vehicles and portable electronic devices, and in many other industries such as production of aluminum, ceramics, glass, polymers, greases, and pharmaceuticals. In order to maintain the balance between supply and demand for lithium on the global market, it is essential to search for alternative sources of this element. Therefore, efforts are being made to obtain lithium from unconventional sources, an example of which is the recovery of lithium from oilfield brines. This article provides an up-to-date review of the literature in this particular field based on data from different sources (scientific literature databases, patent databases, company websites and industrial online newspapers). The current achievements and future perspectives for the lithium recovery from brines generated during oil and gas extraction were critically reviewed. An emphasis was placed on chemistry of lithium-contained oilfield brines, technologies (both pretreatment and direct lithium extraction) suitable for lithium recovery and industrial results obtained from pilot trials.

Oil (and natural gas) field brines can be considered promising sources of lithium for the sustainable supply of a growing market. To date, many materials have been developed for direct lithium recovery from brines, but most often these materials have been tested under various conditions, what makes it impossible to compare them. The aim of this research is to provide knowledge that would enable the comparison and selection of effective sorbents for different types of brines. For this purpose, an eight-step experimental protocol was employed. The recovery tests started with a pure lithium solution (300 mg/kg), and then other salts were gradually added, resulting in a brine containing Li⁺ (220 mg/kg), Na⁺ (7.21 wt%), Ca²⁺ (3.0 wt%) and Mg²⁺ (1000 mg/kg). For selected cases, the effect of pH was also investigated. Fifty materials (including ion exchange resins, organophosphate extractants, mineral adsorbents) were examined, for which the distribution coefficient and lithium recovery were determined. Moreover, for the most promising materials, lithium over magnesium selectivity and lithium ion capacity were determined. Only γ-Al₂O₃, TiO₂ and MnO_x-based powders keep their effectiveness in ultra-high salinity ranges and in the presence of high concentrations of Ca²⁺ and Mg²⁺ in alkaline solution.

Oilfield brine is the largest byproduct stream generated during the extraction of crude oil and natural gas and may be considered a resource for the production of potable water and valuable raw materials. The high salinity of such waters limits the application of typical membrane-based techniques. In most oilfields, waste cold energy from the process of the low-temperature separation of natural gas is available and may be used as a source of cold for the freezing desalination (FD) of brine. As a result of the FD process, two streams are obtained: partially desalinated water and concentrated brine. The partially desalinated water may be suitable for non-potable applications or as a feed for membrane desalination. The concentrated brine from the FD could be used as a feed for the recovery of selected chemicals. This paper focuses on verifying the above-described concept of the freezing desalination of oilfield brine on a laboratory scale. The brine from a Polish oilfield located in the Carpathian Foredeep was used as a feed. Four freezing–thawing stages were applied to obtain low-salinity water, which subsequently was treated by reverse osmosis. The obtained permeate meets the criteria recommended for irrigation and livestock watering. The concentrated brine enriched with iodine (48 mg/L) and lithium (14 mg/L) was subjected to recovery tests. Ion exchange resin Diaion NSA100 allowed us to recover 58% of iodine. Lithium recovery using Mn- and Ti-based sorbents varies from 52 to 93%.

Direct lithium extraction from unconventional resources requires the development of effective adsorbents. Crown ether-containing materials have been reported as promising structures in terms of lithium selectivity, but data on adsorption in real, highly saline brines are scarce. Crown ether-grafted graphene oxides were synthesized using 2-hydroxymethyl-12-crown-4, hydroxy-dibenzo-14-crown-4 and epichlorohydrin as a source of anchoring groups. The obtained carbonaceous materials were used to prepare chitosan–polyvinyl alcohol composites. The prepared materials (and intermediate products) were characterized using FTIR, XRD, Raman spectroscopy and SEM-EDS methods. Adsorption tests were performed in a pure diluted LiCl solution ([Li] = 200 mg/kg) as well as in a real, highly saline oilfield brine ([Li] ≈ 220 mg/kg), and the distribution coefficients (K_d) were determined. The obtained results show that K_d in pure LiCl solution was in the range of 0.9–75.6, while in brine it was in the range of 0.2–2.3. The study indicates that the high affinity for lithium in pure LiCl solution is mostly associated with the non-selective interaction of lithium ions with the graphene oxide matrix (COOH groups). It was also shown that the application of dibenzo-14-crown-4 moiety to graphene oxide modification groups increases the affinity of the composite material for lithium ions compared to an analogous material containing 12-crown-4-ether groups.

Direct lithium extraction (DLE) represents an emerging technology with considerable potential for lithium recovery from low-grade brines. Nonetheless, DLE still faces several unresolved challenges, particularly concerning the purity of the resulting lithium eluates. The DLE eluate obtained in this study contained approximately 3600 mg/L Li, 2350 mg/L Ca and 1200 mg/L Na. Sorbent-based purification is regarded as one of the most efficient methods for eluate treatment. Among sorbents, titanium phosphates, zirconium phosphates, and zirconium aminotris (methylenephosphonates) are known for their high sorption capacities toward various metal ions. Therefore, this study aimed to develop a zirconium–titanium phosphate–phosphonate sorbent capable of removing impurities from DLE eluates. As a result, a novel powdered ZrTiPO₄-ATMP sorbent was synthesized under mild conditions. Subsequently, a granular composite sorbent, ZrTiPO₄-ATMP@PVDF, was prepared using PVDF as a binder. The obtained materials were characterized using XRD, FTIR, SEM-EDS, CHN analysis, and BET analysis. The sorption performance of the composite material was evaluated during the purification of eluates obtained from real oilfield brine. Under optimal conditions, calcium and magnesium removal efficiencies exceeded 95%, while sodium removal reached 60%. At the same time, lithium losses remained below 20%. These losses can be further minimized by returning the regeneration solution to the sorption step.