CO 2 capture, utilization, and storage (CCUS) is a promising technology wherein CO 2 is captured and stored in solid form for further utilization instead of being released into the atmosphere in high concentrations. Under this framework, a new process called accelerated carbonation has been widely researched and developed. In this process, alkaline materials are reacted with high-purity CO 2 in the presence of moisture to accelerate the reaction to a timescale of a few minutes or hours. The feedstock for accelerated carbonation includes natural silicate-minerals (e.g., wollastonite, serpentine, and olivine) and industrial residues (e.g., steelmaking slag, municipal solid waste incinerator (MSWI) ash, and air pollution control (APC) residues). This research article focuses on carbonation technologies that use industrial alkaline wastes, such as steelmaking slags and metalworking wastewater. The carbonation of alkaline solid waste has been shown to be an effective way to capture CO 2 and to eliminate the contents of Ca(OH) 2 in solid residues, thus improving the durability of concrete blended with the carbonated residues. However, the operating conditions must be further studied for both the economic viability of the technology and the optimal conditions for CO 2 reaction.
Manganese oxide electrodes composed of interconnected nanowires are electrochemically synthesized in manganous acetate solution at room temperature without any template and catalyst. Annealing temperature affects the electrode morphology, crystallization, and electrochemical performance. Scanning electron microscope (SEM) results show that nanowires are uniformly distributed and sizes are about 12-18 nm in diameter; the diameter decreases to about 8-12 nm after annealing at 300 degrees C. X-ray diffraction (XRD) and transmission electron microscope (TEM) images indicate that nanowires have poor crystalline characteristics. The higher the annealing temperature, the higher the crystalline degree is in manganese oxide. The synthesized anode material shows a much larger capacity than the traditional graphite materials for lithium storage. After annealing at 300 degrees C, the electrode's reversible capacity reaches 800 mAhg(-1), and the specific capacity retention remains nearly constant after 100 cycles.
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