The reuse potential of spent ZIF-8@GO-COOH nano adsorption materials: Study on their impact on the hydration mechanism and mechanical properties of cement-based composites

Spent adsorbents often contain harmful substances, which may have an impact on the ecological environment if these substances enter the environment. This study mainly introduces a safe treatment method for solid waste formed after heavy metal ions are adsorbed by an efficient adsorbent, ZIF-8@GO-COOH. This work mainly discusses the impact of solidifying the spent adsorbent in the cement system on the cement mechanical properties and hydration process. The experimental results showed that when the dosage of the spent adsorbent was 0.01%, 0.02%, 0.03%, and 0.04%, respectively, the compressive strength of 28 d was increased by 4.24%, 6.16%, 7.19%, and 8.87%, respectively, compared with the cement without spent adsorbent. Introducing spent ZIF-8@GO-COOH in the cement production process does not have a negative impact on the cement mechanical properties, and can refine the cement pore structure and dense microstructure, thereby improving the compressive strength. The Toxicity Characteristic Leaching Procedure (TCLP) results showed that solidifying the spent adsorbent with cement can effectively reduce the leaching of heavy metal ions in the spent adsorbent. This study solidifies the spent ZIF-8@GO-COOH nanoadsorbent material into the cement system as a sustainable alternative to landfilling. This treatment method has certain economic benefits and safety, and has some reference significance for promoting the development and improvement of spent adsorbents and improving their safe treatment and reuse.