MXene-Coated Membranes for Autonomous Solar-Driven Desalination

Abstract

Clean water supply in off-grid locations remains a stumbling stone for socio-economic development in remote areas where solar energy is abundant. In this regard, several technologies have already introduced various solutions to the off-grid freshwater predicament; however, most of them are either costly or complex to operate. Nonetheless, photothermal membrane distillation (PMD) has emerged as a promising candidate with great potential to be autonomously driven by solar energy. Instead of using energy-intensive bulk feed heating in conventional MD systems, PMD membranes can directly harvest the incident solar light at the membrane interface as an alternative driving energy resource for the desalination process. Because of its excellent photothermal properties and stability in ionic environments, herein, Ti 3 C 2 T x MXene was coated onto commercial polytetrafluoroethylene (PTFE) membranes to allow for a self-heated PMD process. An average water vapor flux of 0.77 kg/m 2 h with an excellent temporal response under intermitting lighting and a photothermal efficiency of 65.3% were achieved by the PMD membrane under one-sun irradiation for a feed salinity of 0.36 g/L. Naturally, the efficiency of the process decreased with higher feed concentrations due to the reduction of the evaporation rate and the scattering of incident sunlight toward the membrane photothermal surface, especially at rates above 10 g/L. Notably, with such performance, 1 m 2 of the MXene-coated PMD membrane can fulfill the recommended daily potable water intake for a household, that is, ca. 6 L/day.

Extremely high-efficiency solar steam generation, robust and scalable photothermal evaporator based on ZIF-67@MXene/rGO decorated rock wool

“…47 For the RW/ZMG sample, the weak Raman shi peak at 148 cm −1 (E g 1 mode) correlates to the PVA matrix interrupting the in-plane vibrations of Ti 2 and C atoms. 48 Moreover, the peaks at 198 and 274 cm −1 related to the A 1g out of plane MXene are due to the incomplete removal of Al, 49,50 which is consistent with the XRD result in Fig. 2i, and is commonly observed for MXene treated with HCl and LiF.…”

Tuning the Work Function of Ti3C2Tx MXene by Molecular Doping without Changing its Surface Functional Groups

“…They adopt the formula of M n +1 X n T x ( n = 1–4), where M is an early transition metal (e.g., Ti, Mo, V, etc. ), X is C and/or N, T represents the surface-terminating species (O, OH, F, and Cl), and x denotes the population of T . , To date, MXenes have been exploited in numerous applications, including energy storage, − sensing, − electromagnetic interference shielding, , plasmonics, − optoelectronics, , solar-derived applications, − energy harvesting, and many more. − Such recognizable multifunctionality is mainly associated with the versatile surface chemistry of MXenes, more specifically, their surface terminations ( T x ).…”

Inventions, innovations, and new technologies: Solar Desalination

“…Illustration of contactless steam generation [31] Localized and interfacial heating concept was also used for membrane distillation (MD). Mustakeem et al [33] investigated MXene-coated MD membrane for autonomous (off grid) solar-driven desalination. They reported a system efficiency of 65.3% which was stable for different cycles.…”