Chemically modified activated carbon decorated with MnO2 nanocomposites for improving lithium adsorption and recovery from aqueous media

Lithium (Li+) is considered as promising element in a variety of fields, including medicine, manufacturing, dyes, and the glass industry. Thus, the need for lithium has continued to escalate. Chemically modified activated carbon (CAC) supported with manganese dioxide (MnO2) nanoparticles was prepared using different manganese salt concentrations (0.1, 0.15, 0.12 and 0.2 M), a facile impregnation approach for enhancing the capacity of activated carbon for Li+ adsorption from aqueous media. The structural, morphological, physico-chemical and elemental properties were characterized by FE-SEM, EDAX, FE-TEM, FTIR, XRD, BET and ICP-OES. A batch experiment was performed to optimize the parameters (pH, adsorbent dose, and contact time) for Li+ adsorption. A kinetic study indicated that lithium sorption process followed a pseudo-second order reaction. Comparative analysis revealed that adsorption capacity of CAC increased with an increase in manganese loading, CAC-Mn0.1, CAC-Mn0.12, CAC-Mn0.15, and CAC-Mn0.2 with q(e) values of 50.1 mg/g, 65.04 mg/g, 69.93 mg/g and 88.5 mg/g respectively. A desorption study was performed to illustrate the benefits of sorbents by using HCl as an eluting agent. The competitive Li+ adsorption and reusability property during four adsorption/desorption cycle showed high selective Li+ adsorption with regeneration tendency, which enable the synthesized nanocomposites as potential candidature adsorbents for lithium recovery from aqueous solution. (C) 2019 Elsevier B.V. All rights reserved.