Electro-Driven Materials and Processes for Lithium Recovery-A Review.

The mass production of lithium-ion batteries and lithium-rich e-products that are required for electric vehicles, energy storage devices, and cloud-connected electronics is driving an unprecedented demand for lithium resources. Current lithium production technologies, in which extraction and purification are typically achieved by hydrometallurgical routes, possess strong environmental impact but are also energy-intensive and require extensive operational capabilities. The emergence of selective membrane materials and associated electro-processes offers an avenue to reduce these energy and cost penalties and create more sustainable lithium production approaches. In this review, lithium recovery technologies are discussed considering the origin of the lithium, which can be primary sources such as minerals and brines or e-waste sources generated from recycling of batteries and other e-products. The relevance of electro-membrane processes for selective lithium recovery is discussed as well as the potential and shortfalls of current electro-membrane methods.

Enhanced removal of organic using LaFeO3-integrated modified natural zeolites via heterogeneous visible light photo-Fenton degradation.

LaFeO3 (LFO)-doped acid-modified natural zeolites were prepared by an impregnation-calcination method for the first time. Their effectiveness as photo-Fenton catalysts was evaluated using decolorization of Rhodamine B (RhB) as an organic model. The sample 1HNZ-30LFO was synthesized by using the support of 1HNZ, which was produced via the acid (1 N HCl) treatment of natural zeolite (NZ) at 80 °C for 3 h. It was consisting of approximately 30 wt% LFO and exhibited a higher removal rate of RhB, especially photocatalytic performance, than the pure LFO and parent 1HNZ. This was attributed to the synergistic effect of good adsorption ability of modified zeolite host and a large number of active sites provided by LFO guest for photo-Fenton reaction. Various operational parameters including catalyst dosage, H2O2 concentration, solution pH and dye concentration were examined in the photo-Fenton catalytic degradation of RhB. 98.3% of RhB was degraded under the conditions of 0.8 g L-1 1HNZ-30LFO, 10 mg L-1 RhB, 10 mM H2O2 and initial pH of 6. The catalytic activity of 1HNZ-30LFO was largely retained after 4 cycles of use and recycle; suggesting it could be a promising heterogeneous photocatalyst for dye degradation in wastewater via the photo-Fenton process.

Adsorption and photo-Fenton catalytic degradation of organic dyes over crystalline LaFeO3-doped porous silica.

LaFeO3 (LFO)-doped mesoporous silica (HPS) (HPS-xLFO with theoretical LFO/silica molar ratio x = 0.075, 0.15, 0.3) was successfully prepared via impregnation of metal ions into the porous silica HPS-0LFO support and subsequent calcination. The characterization studies suggest that increasing the doping of LFO, which exhibited a particle size of ∼10-15 nm, in the silica support led to a reduction in surface area and bandgap of the resulting catalyst. The use of HPS-0.15LFO yielded a superior removal rate (98.9%) of Rhodamine B (RhB), thanks to the effective dark adsorption and visible light-induced photo-Fenton degradation, both of which were greater than those of pure LFO crystals. This enhancement could be explained by the unique properties of the mesoporous silica support. In particular, the wide-opening mesopores created a large surface area to dope LFO as active sites and minimize diffusion of RhB into pores during the photo-Fenton reaction. The photo-Fenton catalytic degradation of RhB could reach 98.6% within 90 min exposure to visible light irradiation under optimized conditions: RhB concentration = 10 mg L-1, catalyst dosage = 1 g L-1, pH = 6 and H2O2 = 15 mM. Moreover, the recycle and reuse test proved the good stability and repetitive use of HPS-0.15LFO for high performance RhB removal.