At present, the reported methods for removing heavy metal ions include membrane separation, chemical precipitation, solvent extraction, ion exchange, electrochemical, and advanced oxidation processes and adsorption. [3] Adsorption methods have been widely studied and applied because of their convenience and fast separation. As such, metal ions are affiliated to the adsorption material through physical adsorption, ion exchange, or surface complexation. [3,4] Subsequently, the adsorbent was separated and recycled. Common adsorption materials are in the form of aerogels, hydrogels, and composite membranes, [5] comprising cellulose, [6,7] activated carbon, [8] metal-organic framework, [9] clay, [10] graphene, [11] or biochar from aquatic plants. [12] For example, taking advantage of the high surfaceto-volume ratio of graphene, graphene oxide, and chitosan aerogels were used to remove copper ions by the complexation with amines and imines. [13] (3-glycidylpropyl) trimethoxysilane was used as a crosslinking agent for the hyperbranched polyethyleneimine and cellulose nanofibers. Copper ions were removed from wastewater by the complexation with amine and oxygen-containing groups (OH, CO, CO) on the cellulose aerogel. [14] Alginic acid is modified to amine-substituted carboxyl groups to improve the removal efficiency of lead ions in water. [15] Pan et al. prepared a hydrophobic polyvinyl formaldehyde sponge through the heterogeneous reaction of stearyl chloride with hydroxyl groups in a polyvinyl alcohol sponge. [16] Considering the oil/water mixture as a simulated oil slick system, these macroporous hydrophobic sponges showed high oil adsorption capacity, and the adsorbed oil could be collected by simple squeezing. The recovery factor was 94.8%.Key challenges still exist in realizing the aforementioned function and enhancing the efficiency of adsorption, especially when the adsorption of heavy metal ions in sewage is often hindered by oil contamination. Continuous effects are still required to develop an adsorbent that can remove heavy metal ions and separate oil from water. Herein, we propose a cost-effective heavy metal ion and oil adsorbent based on melamine sponge (MS) with in situ fluorescence properties. The cost-effective melamine sponge was silanized via a two-step hydrolysis reaction. The abundant amine groups and self-organized Schiffbase bonds endowed the sponge with fluorescence indicating Fabrication of multifunctional adsorbent of single-phase material is quite challenging and meaningful for water treatment. In this work, a polyaminosiloxane functionalized melamine sponge is used to remove both heavy metal ions and oil from water. Benefiting from its porous structure, superhydrophobic surface, and abundant amino groups on the surface, the sponge shows excellent performance in Cr(VI) removal and oil/water separation. Notably, the sponge exhibits fluorescent detection function for Cr(VI) owing to the packing of Schiff-base bonds, facilitating the adsorption process to be monitored in real time. The maxim...
