The decarbonization of industry, particularly in "hard-to-decarbonize" sectors like combustion plants, poses a significant challenge due to the limited availability of low-carbon options. Carbon capture, utilization, and storage (CCUS) offers a promising solution to this challenge. Chemical precipitation is one method of converting CO2 into precipitated mineral carbonates, which can be stored and converted into valuable materials. This study explores fluidized-bed homogeneous crystallization (FBHC) technology for recovering carbonate from simulated CO2-enriched flue gas, resulting in stable calcium carbonate granules. Factors such as pH, carbonate concentration, reactor type, and reactants significantly impact carbonate removal and crystallization efficiency. Optimal conditions were found at 0.086M input carbonate concentration, pH 9.0, and using a two-stage reactor, achieving 99.9% removal and 93.2% crystallization efficiency. Potassium-based absorbents yield higher crystalline intensity and larger granules compared to sodium. X-ray diffractometry confirms the composition of calcium carbonates, demonstrating FBHC's effectiveness for CO2 capture and storage. Utilizing calcium carbonate granules for carbon dioxide sequestration can potentially reduce emissions, pending resolution of investment and feasibility challenges.

The widespread application of antibiotics, such as tetracycline (TC), has led to severe environmental problems. Herein, the rod-like Mn0.3Cd0.7S (MCS) coupled with flower-like FeNi8-LDH self-assembled from nanosheets S-scheme heterojunction is successfully constructed by a simple physical ultrasonic-assisted combined with a grinding method. The optimized MCS/30FeNi8-LDH heterojunction exhibits excellent photocatalytic degradation of TC under visible light with a removal rate of 72.5% within 30min along with excellent cycling stability, which enhanced 14.5 and 1.68 times compared to those of pristine FeNi8-LDH and MCS. The correlation between S-scheme heterojunction and photocatalysis performance clarify the rapidly transfer pathway of photogenerated carriers between MCS and FeNi8-LDH. The trapping experiment confirms •O2- and h+ are the primary active species, with h+ playing a dominant role in the degradation process. The enhanced photocatalytic degradation performance can be attributed to the formation of S-scheme heterojunction with well-matched band alignment, which remains the powerful reduction capability of generated electrons of FeNi8-LDH and more robust oxidation capability of photogenerated holes of MCS. This work not only provides a potential solution for photocatalysis degrading TC, but also expands the S-scheme heterojunction construced strategy to the realm of energy storage and conversion.

Sulfite is deemed as a promising precursor to produce highly reactive species for contaminants remediation. Herein, the urchin-like Ni-Fe-Mo sulfide (NiFeMoSx) was anchored in-situ on nickel foam as the cathode to activated CaSO3 for efficient degradation of tetracycline (TC) under natural condition. The degradation efficiency reached 92.7% within 60min, which was about 1.81 times higher than that of the electro-Fenton process based on NiFeMoSx. The beneficial performance came from the synergistic activation of CaSO3 by simultaneous rapid redox cycles of Fe(II)/Fe(Ⅲ) and Ni(II)/Ni(Ⅲ) on the NiFeMoSx cathode. Specifically, the primary intermediates Fe(Ⅱ)-HSO3- and Ni(Ⅱ)-SO32- triggered a series of radical chain reactions, accompanied the reduction of Ni(Ⅲ)/Fe(Ⅲ) by electrochemistry and electron donor of Mo(Ⅳ) and S2- on the surface of the catalyst. The regeneration of the Fe(Ⅱ)/Ni(Ⅱ) was quickly realized and subsequently triggered the chain reactions, which would accelerate the formation rate of reactive species, such asSO4∙−, ·OH, O2∙− and 1O2, of which 1O2 and O2•- played important roles on degradation TC. This work provides a promising application for the efficient removal of persistent organic pollutants by metal sulfide activated sulfite.