Capturing Lithium from Wastewater Using a Fixed Bed Packed with 3-D MnO2 Ion Cages

摘要

3-D MnO2 ion cages (CMO) were fabricated and shown to have a high capacity for lithium removal from wastewater. CMO had a maximum Li(I) adsorption capacity of 56.87 mg/g, which is 1.38 times greater than the highest reported value (41.36 mg/g). X-ray photoelectron spectroscopy indicated that the stability of the Mn-O-Mn-O skeleton played an essential role in Li adsorption. The lattice clearance had a high charge density, forming a strong electrostatic field. The Dubinin-Ashtakhov (DA) site energy distribution model based on Polanyi theory described the linear increase of Li adsorption capacity (Q(0)) with increasing temperature (Q(0) = k(3) x E-m + d(3) = k(3) X (a X T) + d(3)). Furthermore, the pore diffusion model (PDM) accurately predicted the lithium breakthrough (R-2 approximate to 0.99). The maximum number of bed volumes (BVs) treated was 1374, 1972, and 2493 for 200 mu g/L at 20, 30, and 40 degrees C, respectively. Higher temperatures increased the number of BVs that may be treated, which implies that CMO will be useful in treating industrial Li(I) wastewater in regions with different climates (e.g., Northern or Southern China).