Barium removal from synthetic natural and produced water using MXene as two dimensional (2-D) nanosheet adsorbent

MXene as two dimensional (2-D) Titanium (III) Carbide (II) (Ti3C2Tx) nanosheets was synthesized and processed by etching bulk MAX phase Titanium (III) Aluminium Carbide (II) (Ti3AlC2) powders in HF solution. This material demonstrated an extraordinary efficiency for the removal of barium from synthetic produced/co-produced water. The synthesized nanosheet was characterized using field emission scanning electron microscopy (FE-SEM), the Brunauer, Emmett and Teller (BET) nitrogen surface area adsorption, X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD), particle size analysis and zeta potential. The effect of adsorption parameters such as adsorbent dosage, contact time, and initial barium concentration were investigated and the optimum parameters for maximum removal of barium have been investigated. The experimental adsorption equilibrium data were correlated by the Langmuir and Freundlich isotherms, while the sorption energy was calculated using Dubinin-Radushkevich (D-R) model. The kinetic data were analyzed using two kinetic models. Optimization of process variables including shaking speed, contact time, pH, and amount of MXene has been performed to determine the maximum adsorption capacity of barium from water. MXene has a combination of unique properties such as a large number of available active sites, hydrophilic surface, highly negative surface charge, chemical stability, reasonable surface area, and the possibility of cations intercalating through its layers. MXene showed a large sorption capacity, fast kinetics, enormous trace barium removal, and reversible adsorption properties which offer an efficient removal performance of barium with a capacity of 9.3 mg/g and removal efficiency reaching up to 100% under optimized conditions. (C) 2017 Elsevier B.V. All rights reserved.