Two professors at the Southern University of Science and Technology (SUSTech) have invented advanced technology to reduce C02 emissions. They developed a series of low-cost, green, and efficient porous nano-SiO2/Al2O3 supported solid amine CO2 adsorbents using solid waste as the main raw materials. Their studies were supported by the National Natural Science Foundation of China (NSFC), the National Key R&D Program of China, a tech company and have also been published in the well-known journals of Environmental Science & Technology and Chemical Engineering Journal in the environmental and energy fields.
Solid amine adsorbents are among the most promising CO2 adsorption technologies for biogas upgrading due to their high selectivity toward CO2, low energy consumption, and easy regeneration. However, in most cases, these adsorbents undergo severe chemical inactivation due to urea formation when regenerated under a realistic CO2 atmosphere. The porous nano-Al2O3 support was firstly synthesised from high-aluminium coal fly ash, and the active PEI was then impregnated on the nano-Al2O3 support to prepare the solid amine CO2 adsorbent, which possessed a superior CO2 adsorption capacity of 136 mg·g-1.
Significantly, this solid amine CO2 adsorbent showed stable adsorption capacity even regenerated under the pure CO2 atmosphere. Moreover, its CO2 adsorption capacity still maintained as high as 111 mg·g-1 adsorbent after 10 cycles, which was 5.5 times higher than that of traditional nano-SiO2 supported solid amine adsorbents.
This technical route can realise the high-value utilisation of coal fly ash and significantly improve the cyclic stability of solid amine adsorbent regenerated under the pure CO2 atmosphere. Therefore, it has broad application prospects in CO2 capture and separation processes such as industrial source CO2 capture and biogas upgrading.
On this basis, the research group continued to study in-depth the interaction mechanism of support-organic amine and the anti-urea chain formation mechanism of nano-Al2O3 supported solid amine CO2 adsorbents.
The results have shown that the unique cross-linking reaction between nano-Al2O3 support and organic amine molecules significantly inhibited the formation of urea chains in nano-Al2O3 supported solid amine CO2 adsorbents during the cyclic adsorption-regeneration process, thereby greatly improving the cyclic stability of CO2 adsorption capacity. The study further verified the long-term cyclic stability of nano-Al2O3 supported solid amine CO2 adsorbents, whose adsorption capacity decreased by only 29% after 100 cycles regenerated under the pure CO2 atmosphere.
This work not only clarifies the CO2 adsorption cycle stabilisation mechanism of nano-Al2O3 supported solid amine CO2 adsorbents, but also provides design ideas for the development of new high-stable solid amine CO2 adsorbents with anti-urea properties.
This technology is in line with China’s active participation in global climate governance and insists on promoting CO2 mitigation. General Secretary put forward the ambitious goal of striving to achieve carbon neutrality by 2060 at the 75th United Nations General Assembly.
The General Secretary stated that the COVID-19 pandemic reminds everyone that humankind should launch a green revolution and move faster to create a green way of development and life. Humans also need to preserve the environment and make Mother Earth a better place for all.
Humankind can no longer afford to ignore the repeated warnings of nature and go down the beaten path of extracting resources without investing in conservation. Humans cannot always pursue development at the expense of protection, and exploiting resources without restoration.
The Paris Agreement on climate change charts the course for the world to transition to green and low-carbon development. It outlines the minimum steps to be taken to protect the Earth. All countries must take decisive steps to honour this agreement. China will scale up its Intended Nationally Determined Contributions by adopting more vigorous policies and measures. China aims to have CO2 emissions peak before 2030 and achieve carbon neutrality before 2060.
