Sulfur Migration Enhanced Proton-Coupled Electron Transfer for Efficient CO2 Desorption with Core-Shelled C@Mn3O4.

Transforming hazardous species into active sites by ingenious material design was a promising and positive strategy to improve catalytic reactions in industrial applications. To synergistically address the issue of sluggish CO2 desorption kinetics and SO2-poisoning solvent of amine scrubbing, we propose a novel method for preparing a high-performance core-shell C@Mn3O4 catalyst for heterogeneous sulfur migration and in situ reconstruction to active -SO3H groups, and thus inducing an enhanced proton-coupled electron transfer (PCET) effect for CO2 desorption. As anticipated, the rate of CO2 desorption increases significantly, by 255%, when SO2 is introduced. On a bench scale, dynamic CO2 capture experiments reveal that the catalytic regeneration heat duty of SO2-poisoned solvent experiences a 32% reduction compared to the blank case, while the durability of the catalyst is confirmed. Thus, the enhanced PCET of C@Mn3O4, facilitated by sulfur migration and simultaneous transformation, effectively improves the SO2 resistance and regeneration efficiency of amine solvents, providing a novel route for pursuing cost-effective CO2 capture with an amine solvent.

Performance and mechanisms of alkaline solid waste in CO2 mineralization and utilization.

CO2 mineral sequestration using alkaline solid waste (ASW) is a promising strategy for synergistically reducing CO2 emissions and reusing industrial waste. However, improvement the carbonation degree still remains challenges due to the sluggish leaching rate of Ca/Mg ion at low pH. To the issues, this study proposed an amine-mediated CO2 absorption and mineralization process with six common ASWs, as well an ecological utilization route of CO2-ASW productions. Experimental results indicated that calcium carbide slag (CS) had greater CO2 mineralization capacity (86.2 g-CO2/kg-CS) than other ASWs, while stirring rate and particle size played a more important role during CO2 capture. Amine-mediated CO2 capture was verified to be more excellent with steel slag (SS) as mineral medium. When the MEA concentration was increased to 2 mol/L, the extraction efficiency of Ca2+ was increased by 35 %, leaded to the CO2 removal efficiency significantly promoted from 49 % to 92 %. The characterization of structural morphology referred spherical aragonite or needle-bar calcite was dominant for the porous mineralization products (30.6 m2/g). High germination index of pea seed (112.1 % at a dose of 10 g/L) inferred the negligible toxicological effects of tiny MEA residue over SS mineralization products, after centrifugally washing treatment. Pea seeds cultivated with mineralized products after centrifugal washing can achieve a growth rate of about 4 mm/d. Overall, this work provides a feasible route to apply the porous CO2-ASWs production into water conservation in arid and sandy land.

Energy-Efficient Biphasic Solvents for Industrial Carbon Capture: Role of Physical Solvents on CO2 Absorption and Phase Splitting.

Physical solvent is a promising alternative for the phase splitting of solvent to drastically reduce the regeneration energy during CO2 capture. Here, an aqueous biphasic solvent, optimally composed of 30 wt % polyamine (N, N-dimethylpropylamine, DMPA) and 50 wt % physical solvent (polyethyleneglycol dimethyl ether, NHD), is prepared, which presents high cyclic loading, low regeneration energy, and good stability. L16(45) orthogonal tests are performed to comprehensively evaluate the mass-transfer kinetics and the effect of crucial conditions, verifying the weak effect of NHD solvent on mass transfer. The solvent effect of NHD could decrease the energy barrier of carbamate generation from zwitterions (DMPA+COO-) to enhance chemical absorption. The low polarity of the NHD solvent provides source motivation and accelerates phase splitting. Time-space resolution distribution of CO2 capacity is established based on a scale-up separator with 5 L solvent, which supports multiscale force analysis for the various stages during phase splitting. The drag force of the homogeneous cluster was first introduced into separation dynamics, referred to as an important reason for the various splitting behaviors of a scale-up separator.