Ce-UiO-66-F4-based composites decorated with green carbon dots for universal adsorption of organic pollutants containing hydrogen bond donors and its application exploration

Abstract

Efficient and stable water purification is essential for the protection of water resources. Current adsorbents based on metal–organic frameworks face limitations of restricted active sites and single adsorption objects. In this study, we developed a cost-effective and environmentally friendly Tea-L-CDs@Ce-UiO-66-F4 composites by growing Tea and L-tryptophan carbon dots (Tea-L-CDs) over Ce-UiO-66-F4 MOF, and the interaction force was enhanced by hydrogen bonding (-F/O/N…H-O-, -F/O/N…H-N-, etc.) to achieve universal adsorption. In detail, the maximum adsorption capacity (qm) of the adsorbent for trypan blue (TB), congo red (CR), and CR (adjust pH) was 773.4, 1428.6, and 4761.9 mg/g. The universal experiment showed that the composites exhibited excellent qm for alizarin red S (ARS, 662.7 mg/g) and rhodamine B (RdB, 374.0 mg/g). Meanwhile, Tea-L-CDs@Ce-UiO-66-F4 composites maintained good anti-interference ability (salt solution, temperature, etc.). Remarkably, the adsorption capacity of the adsorbent for dyes exceeded 97 % of qm within 1 min of contact time. The adsorption performance of synthetic material for TB, CR, ARS, and RdB is better than most of the adsorbents, especially the qm for TB is higher than any adsorbent previously reported. Besides, this adsorbent had excellent storage stability in the air for 30 days. Based on this nanomaterial, we successfully developed an automated dye filtration and contamination assessment system for blocking dye-attached adsorbent and online detection of dye residues after water purification. Thus, the synthesized Tea-L-CDs@Ce-UiO-66-F4 composites, with universal adsorption, high efficiency, and good storage stability, hold great potential for wastewater purification.