Potassium citrate-derived porous carbon with high CO2 capture and Congo red adsorption performance

The objective is to achieve the goal of carbon neutrality, controlling CO₂ emissions is a primary problem to be solved in the current environmental protection field. Eliminating the environmental pollution of dyes in industrial wastewater is also an urgent problem to be solved in the field of environmental protection. The adsorption technique is an effective way to deal with these two issues. Developing high-efficiency adsorbents is an essential work in the adsorption field. In this work, a simple carbonization method has been developed to prepare porous carbon. The morphology and structure of the prepared porous carbon were investigated by scanning electron microscopy, X-ray photoelectron spectroscopy, X-ray diffraction, and surface area measurement. By studying the influence of preparation conditions on the structure and properties of the prepared carbon materials, it was found that the carbon materials prepared at 900 ℃ (PCMCA-900) exhibited a high specific surface area of 1476 m² g⁻¹ and a high total pore volume of 0.951 cm³ g⁻¹. The PCMCA-900 showed the highest CO₂ uptake of 7.67 mmol g⁻¹ at 0 ºC and the adsorption capacity of PCMCA-900 decreased by less than 5% after 10 times recycling. Moreover, when PCMCA-900 was used as an adsorbent to remove Congo red in water, an adsorption capacity of 652.3 mg g⁻¹ was achieved. Therefore, potassium citrate-derived porous carbon is a desirable candidate for excellent CO₂ adsorption and Congo red in industrial wastewater.