## 4 Conclusions  
Three novel silica-based polyamine composite resins were synthesized through in situ solution polymerization and post-modification strategies. Among them, the resin with the longest polyamine chain, TEPA, demonstrated the best overall performance. SiPMA-DETA and SiPMA-TETA were mesoporous adsorbents, while SiPMA-TETA was a macroporous adsorbent. Adsorption equilibrium was achieved in less than 10 min, and desorption was completed in under 3 min. SiPMA-DETA, with the shortest polyamine chain, exhibited the highest uranium adsorption efficiency of 83% in 100 mM Na\({}_{2}\)SO\({}_{4}\), and SiPMA-TETA exhibited the highest adsorption capacity (>198.95 mg/g). The adsorption process for SiPMA-TETA followed the pseudo-second-order kinetic model and the Langmuir isotherm model, indicating a chemisorption process. Additionally, SiPMA-TETA removed over 90% of uranium from both TW and RW. After five cycles of adsorption and desorption, the removal efficiency remained high, demonstrating excellent stability. FTIR and XPS analyses revealed that the N-containing functional groups in the SiPMA-TETA adsorbent bound to the UO\({}_{2}\)(CO\({}_{3}\))\({}_{3}\)\({}^{2-}\) anion in the solution and acted as an effective adsorption site for the UO\({}_{2}\)(CO\({}_{3}\))\({}_{3}\)\({}^{2-}\) anion in the solution. Overall, SiPMA-TETA demonstrated strong potential for the rapid treatment of uranium-containing water in environmental water systems.  
**Supplementary Materials:** The following supporting information can be downloaded at [[https://www.mdpi.com/article/10.3390/toxics12100704/s1](https://www.mdpi.com/article/10.3390/toxics12100704/s1)]([https://www.mdpi.com/article/10.3390/toxics12100704/s1](https://www.mdpi.com/article/10.3390/toxics12100704/s1)): Section S1. Synthesis of SiPMANs; Section S2. Batch experiments; Section S3. Introduction of the mathematical models used; Section S4. Experiments on the reusability of SiPMA-TETA; Section S5. Sample preparation for the adsorption mechanism investigation; Section S6. Experimental results; Figure S1. MA-and-DVB-crosslinked copolymerization (a) and substitution reaction between SiPMA and TEPA (b); Table S1. Elemental contents of SiPMAN resins; Table S2. Parameters obtained by fitting adsorption isotherm data for different solutions; Figure S2. Well water of Mt. Yumu, Hengyang City (a); water collected from Xiangjiang River, Jiefang Road, Hengyang City (b); and tap water from Science and Innovation Building 406, University of South China (c); Figure S3. Adsorption isotherms for uranium removal by SiPMA-TETA in ultrapure water (UPW) and groundwater (temperature 298 K, t: 2 h, pH = 6, \(m/v\): 0.01 g/30 mL); Figure S4. Desorption kinetics.  
**Author Contributions:** Conceptualization, T.F.; methodology, W.L. and S.N.; software, P.Z.; validation, P.Z.; formal analysis, L.C.; investigation, P.Z.; resources, H.W. and L.C.; data curation, P.Z.; writing--original draft, P.Z.; writing--review and editing, L.C.; supervision, L.C., W.L. and S.N.; project administration, L.C. and Y.W.; funding acquisition, Y.W. All authors have read and agreed to the published version of the manuscript.  
**Funding:** This work was funded by the National Key R&D Program of China [grant number 2023 YFC2908105], the National Natural Science Foundation of China [grant number 12405384], the Scientific Research Project of Hunan Education Department [grant number 21B0400], the Natural Science Foundation project of Hunan Province [grant number 2023J]J40527] and the Science and Technology Innovation Program of Hunan Province [grant number 2023 RC1067].  
**Institutional Review Board Statement:** Not applicable.  
**Informed Consent Statement:** Not applicable.  
**Data Availability Statement:** Data are contained within the article and Supplementary Materials.  
**Conflicts of Interest:** The authors declare no competing financial interests.