Hierarchical 3D Architectured DMSA-Functionalized SA/GO-Cellulose Monoliths Via Direct Ink Writing: Enhanced Cu²⁺ Removal and Synergistic Adsorption Mechanisms

To effectively deal with the hazards posed by copper ions in wastewater. In this study, 2,3-dimercaptosuccinic acid (DMSA)-modified graphene oxide (GO) printing inks were firstly prepared in a cellulose-based solution, followed by the use of sodium alginate (SA) to improve the rheological properties of the printing inks. Finally, three-dimensional hybrid network structures (DMSA-GO/CE) with excellent adsorption properties were prepared by direct ink writing (DIW) printing. Due to the supporting effect of cellulose, a well-developed pore network was formed inside the DMSA-GO/CE, which provided a faster transport channel and a larger storage space for the adsorption of copper ions. In addition, the introduction of -SH resulted in more abundant adsorption active sites for DMSA-GO/CE. The adsorption experiments showed that the maximum adsorption capacity of DMSA-GO/CE reached 250 mg/g at pH = 5.0 and 303.15 K, and the adsorption equilibrium was reached in 90 min. After five cycles, the removal rate of copper ions by DMSA-GO/CE only decreased by 13.5%, and the performance and structure remained stable. This superb adsorption capacity was not only attributed to the unique pore structure but also to the chelating effect of the -SH group introduced by DMSA. We performed dynamic adsorption column experiments, and the results derived from the Thomas model showed that the maximum adsorption saturation time was 3240 min. Therefore, the DMSA-GO/CE prepared by 3D printing can effectively alleviate the hazards caused by heavy metals, has the advantages of environmental friendliness and sustainable use, and has a broad application prospect in the field of green and efficient removal and recycling of heavy metals in wastewater.