Recovering electrical energy from forward osmosis process through amorphous silicon oxide crosslinked vanadium pentoxide-reduced graphene oxide membrane

• Published in: Chemical engineering journal (Lausanne, Switzerland : 1996) Vol. 469; p. 143964
• Main Authors: Deka, Priyamjeet, Roy, Sonali, Jyoti Konch, Tukhar, Rani Bora, Barsha, Gogoi, Raktim, Bikash Neog, Arindom, Sundararajan, Krishnaraajan, Subbiah, Senthilmurugan, Raidongia, Kalyan
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 01.08.2023
• Subjects: Electrochemical energy-generation; FO-coupled energy process; Forward osmosis; Nanofluidic; Reduced graphene oxide; Vanadium pentoxide; FO-coupled energy process; Reduced graphene oxide; Vanadium pentoxide; Forward osmosis; Nanofluidic; Electrochemical energy-generation
• ISSN: 1385-8947; 1873-3212
• DOI: 10.1016/j.cej.2023.143964

[Display omitted] •The possibility of synchronised energy harvesting in the FO process is demonstrated.•Robust FO membranes are prepared by crosslinking 2D flakes of VO and rGO with aSiO.•The FO performance of the VO-aSiO-rGO was better than commercial CTA membrane.•Nearly 26% of the power used for liquid pumping recovered through electrochemistry.•The energy recovering possibility in realistic scenarios was tested using tea solutions as the FS. Forward osmosis (FO) is a promising technology for energy-efficient water treatment but suffers from the drawback of reverse solute flux which often results in energy loss. Recent research has been directed toward reducing energy consumption and improving efficiency in the FO process. However, there remains a significant gap in utilization the inevitable reverse solute flux. Our study introduces an innovative approach to minimize energy consumption by transforming this reverse solute flux into sustainable electricity. Here, we fabricated membranes using two-dimensional flakes of vanadium pentoxide (VO) and reduced graphene oxide (r-GO) and cross-linked with amorphous silicon oxide (aSiO). The optimized VO-aSiO-rGO membrane showcases a remarkable ability to recover nearly 26% of the power applied for liquid pumping, exhibiting a significant advancement in the FO process. The membrane also outperforms commercial CTA-based FO membranes by achieving superior water fluxes (∼45 L/m2.h) and low specific reverse salt fluxes (SRSF) (∼0.13 g/L), indicating its superior separation efficiency for concentration applications. Moreover, the VO-aSiO-rGO membrane demonstrated stable performance with a water flux of 28.5 L/m2.h over 40 h of continuous operation. Additionally, it successfully generated output voltage and current values up to 293 mV and 32.2 µA, respectively, with a 106 fold salinity gradient, leading to a power density of ∼ 4.72 W.m−2. The study also explored energy-recovering possibilities and crystal production in realistic scenarios using different concentrations of tea as the feed solutions. The results of this work not only address the critical gap in the efficient use of energy in the FO process but also provide a significant breakthrough towards sustainable and efficient water treatment technologies with integrated energy recovery systems.