No abstract

Dipotassium hydrogen phosphate (K 2 HPO 4 ) has been investigated as an excellent salting-out agent to recover (acetone + butanol + ethanol) (ABE) from a prefractionator. The increasing additions of K 2 HPO 4 •3H 2 O to the ABE system under unsaturated conditons show strong salting-out effects on the ABE. This favorable saltingout effect is based on the hydration of the charged ions. The HPO 4 2− ions may destroy the "hydration shell", but the crescent concentrations of K 2 HPO 4 make positive salting-out effects on the ABE. More acetone, 1-butanol, and ethanol are recovered after higher-level concentrations of K 2 HPO 4 solution are added to the ABE system. Meanwhile, the equilibrium time shortens. A higher temperature can also make the equilibrium time shorter. The smallest amount of K 2 HPO 4 in the organic phase causes no trouble for the (salting-out + distillation) process in an industrial application.

The development of high-performance carbon anode for sodium-ion batteries is limited by the sluggish kinetics and structural instability. Expanded interlayer spacing, nitrogen doping, and mesoporous structure engineering have emerged as promising strategies to overcome these challenges. Simultaneously achieving graphene nanodomains construction, high-efficient nitrogen doping, and rational mesoporous structure engineering is challenging. Herein, a strategy of pyrolyzing SiO 2 @ lignin amine urea-formaldehyde resin is proposed for deliberate manipulation of graphene nanodomains, edge-nitrogen doping, and specific mesoporous distribution in amorphous lignin-derived carbon based on polycondensation-template. The obtained carbon material exhibits a nitrogendoping level of 6.03 at% with a high edge-nitrogen ratio of up to 84.4%, highconnectivity mesoporous structure, and graphene nanodomains with expanded interlayer spacing. The optimized carbon material delivers a reversible capacity of 234 mAh g −1 at 100 mA g −1 , superior rate capability of 129 mAh g −1 at 2 A g −1 , and excellent cycling stability. In addition, the surface-dominated sodium-ion storage mechanism is identified by in situ electrochemical impedance spectroscopy. Furthermore, the optimized carbon can function as an outstanding anode for full cells. This work proposes a new avenue for designing high-performance carbon for low-cost and high-rate sodium-ion batteries.

Thirty compounds including salts, saccharides, and alkalies have been investigated as possible salting-out agents to recover (acetone + butanol + ethanol) (ABE) from a prefractionator. The most promising salt is potassium carbonate. The mechanisms of salting-out by potassium carbonate are summarized as hydration and hydrogen-bond breaking. The thermodynamic study of salting-out by potassium carbonate has been investigated and shows that the salting-out process is endothermic and a process of entropy increment. The extractant of saturated potassium carbonate solution should be double that of the sketchy ABE solution. When the salting-out process is performed at 333.15 K instead of 298.15 K, equilibrium time is shortened from 9 to 3 min. Energy demand in an industrial application shows that salting-out produces 25.13 %, even 35.42 % less energy consumption than that of the conventional distillation process.

The salting-out phase equilibria for acetone, 1-butanol, and ethanol (ABE) from dilute aqueous solutions using potassium carbonate (K 2 CO 3 ) and dipotassium hydrogen phosphate trihydrate (K 2 HPO 4 Á3H 2 O) as outstanding salting-out agents were investigated. Increasing the salt concentration strengthened the salting-out effects and improved the distribution coefficients of all three solvents (ABE) significantly. Temperature had a slight effect on the phase equilibria. The K 2 HPO 4 solution (69 wt %) showed a stronger salting-out effect than the K 2 CO 3 solution (56 wt %) on recovering ABE from dilute aqueous solutions. Dilute aqueous solutions containing more solvents increased the recoveries of acetone and 1-butanol, while the results showed a negligible effect on the solubility of ABE. The solubility of ABE was also correlated well with the molar number of salt per gram of water in the aqueous phase. A new equation demonstrated this satisfactorily.