Sulfonated poly (ether ether ketone) composite cation exchange membrane for NaOH production by electro-electrodialysis using agro-based paper mill green liquor. Issue 6 (December 2021)

• Record Type: Journal Article
• Authors: Goel, Priya; Mandal, Priyabrata; E., Bhuvanesh; Shahi, Vinod K.; Chattopadhyay, Sujay
• Is Part Of: Journal of environmental chemical engineering. Volume 9:Issue 6(2021)
• Publication Date: 2021-12
• Subjects: Cation exchange membrane -- Sulfonated graphene oxide -- Electro-electrodialysis -- Green liquor -- NaOH production; Chemical engineering -- Environmental aspects -- Periodicals; Environmental engineering -- Periodicals; Chemical engineering -- Environmental aspects; Environmental engineering; Periodicals; 660.0286
• DOI: 10.1016/j.jece.2021.106409
• Languages: English
• ISSNs: 2213-2929

Abstract

Abstract: Causticizing process of pulp and paper mills, is highly energy intensive and environmentally unsafe. We report environmental friendly electro-electrodialysis (EED) process using in-house prepared cation exchange membranes (CEMs) for NaOH production from green liquor solution (GLS) of agro-based paper mills. Different composite CEMs with varied composition of sulfonated graphene oxide (SGO) incorporated sulfonated poly (ether ether ketone) (SPK) were synthesized. Best optimized CEM (SPK-3 with 3.0 wt% SGO loading) exhibited 1.75 mmol·g −1 cation exchange capacity, 32.01% water uptake, 11.41% swelling ratio, conductivity 0.037 S·cm −1, and 0.97 counter-ion transport number with high alkaline and thermo-mechanical stabilities. Industrial GLS was used for NaOH production by EED at 60 mA·cm −2 current density. Optimized SPK-3 membrane produced 1.17 mol·L −1 of NaOH with 61.4% current efficiency ( η ), and 2.58 kW·h·kg −1 energy consumption (EC) during 4 h of EED process. Under similar operating conditions, pristine (SPK), and commercial CEM (FKB-PK-130), showed inferior performance. Longevity of SPK-3 CEM was assessed with industrial GLS for fifty cycles of EED experiments 4 h duration each. Reported results are promising for sustainable NaOH production from industrial GLS of pulp and paper mills, and provide a resourceful alternate for industrial waste. Graphical Abstract: ga1 Highlights: One-step NaOH production from green liquor with "zero liquid effluent". Efficient composite cation exchange membrane for electro-electrodialysis. Excellent membrane stability for treatment of industrial green liquor. Pre-optimized current density and flow rate for maximum NaOH production. Sustainable route compared to energy intensive conventional multistep process.