TiO(OH)₂ Nanoparticle Composite Membranes for Enhancing the Hot Potash Process

The desorption process of CO2 absorbed by the hot-potash-alkali method was studied in this paper. In a traditional hot-potash-alkali process, the temperatures of KHCO3 aqueous solutions are high, moisture vaporization is serious, and energy consumption is high. We proposed that membrane desorption can be used instead of heating desorption and conducted relevant research. PDMS-PTFE-PVDF/PET was used as a composite membrane. The water evaporation considerably declined, and the decomposition conversion rate reduced to 25.5% as the equilibrium liquid-phase concentration decreased. Results show that the PDMS-PTFE-PVDF/PET composite membrane loaded with 1 wt % TiO(OH)2 nanoparticles can be used for membrane desorption, while the decomposition conversion rate of the KHCO3 aqueous solution decreased by only 4.2% after 10 cycles, and the effect was considerably improved. The comprehensive capture energy consumption was about 65% lower than that of the absorption-heating desorption process on account of the positive effect of TiO(OH)2 nanoparticles. Brief calculation, which is based on CO2 concentration tested by a gas analyzer and the linear fitting of the Arrhenius equation, demonstrates that the reaction activation energy can be reduced (Supporting Information).