在这项工作中,用乙酰乙酸乙酯对壳聚糖进行化学修饰是通过碱催化反应进行的,其中表氯醇促进了插入以及亲核取代反应,以将1,3-二氧代部分接枝到基础生物聚合物的线性链上,以建立特异性和选择性去除U(VI)。将改性壳聚糖(EAA-CS)嵌入富含磷酸盐的海藻酸盐基质(PASA)中。稍后,制备了不同WO3与PASA质量比的WO3掺杂复合材料,XPS,SEM-EDS,XRD,和元素映射分析。WO3为化学稳定的无机-有机复合材料做出了重要贡献,并改善了多孔结构。在制备的复合材料中,MCPS-3微球,质量比为30.0%w/w,在最佳pH4.5时表现出对U(VI)的优异吸附能力。成功的U(VI)吸附通过在392.25和381.36eV处存在两个U4f峰进行验证,这归因于U4f5/2和U4f7/2子峰,强度比分别为3:4。间歇模式吸附动力学遵循伪二阶速率方程(R2≈0.99,qe,th≈116.88mg/g,k2=0.86×10-4g/mg。min-1)和平衡吸附数据与Langmuir(在310K和pH=4.5时R2=0.99,qm=343.85mg/g,KL=2.00×10-2L/mg)和Temkin模型(R2≈0.99)。热力学参数ΔHo(30.51kJ/mol),ΔSo(0.19kJ/mol。K)和在298、305和310K时的ΔGo(-25.64,-26.89和-27.91kJ/mol),分别,表明吸收过程是可行的,吸热和自发。基于这些发现,可以合理地得出结论,MCPS-3可能是一种更好的基于水凝胶的生物材料,可用于可观的铀回收。
In this work, chemical modification of the chitosan with ethyl acetoacetate was performed through a base-catalyzed reaction in which epichlorohydrin facilitated the insertion as well as nucleophilic substitution reaction to graft the 1,3-dioxo moiety across the linear chains of the base biopolymer to establish specificity and selectivity for U(VI) removal. The modified chitosan (EAA-CS) was intercalated into phosphate rich alginate matrix (PASA). Later on, the WO3-doped composites with different WO3 to PASA mass ratio were prepared and characterized using FTIR, XPS, SEM-EDS, XRD, and elemental mapping analysis. WO3 significantly contributed to chemically stable inorganic-organic composites with improved porous texture. Among the prepared composites, MCPS-3 microspherical beads, having mass ratio of 30.0 % w/w, exhibited excellent sorption capacity for U(VI) at an optimal pH 4.5. The successful U(VI) sorption was validated by the existence of two U4f peaks at 392.25 and 381.36 eV due to U4f5/2 and U4f7/2 sub-peaks with an intensity ratio of 3:4, respectively. Batch mode sorption kinetics followed pseudo-second-order rate equation (R2 ≈ 0.99, qe,th ≈ 116.88 mg/g, k2 = 0.86 × 10-4 g/mg.min-1) and equilibrium sorption data aligns with Langmuir (R2 = 0.99, qm = 343.85 mg/g at 310 K and pH = 4.5, KL = 2.00 × 10-2 L/mg) and Temkin models (R2 ≈ 0.99). Thermodynamic parameters ΔHo (30.51 kJ/mol), ΔSo (0.19 kJ/mol.K) and ΔGo (-25.64, -26.89, and - 27.91 kJ/mol) at 298, 305, and 310 K, respectively, suggested that the uptake process is feasible, endothermic and spontaneous. Based on these findings, it is reasonable to conclude that MCPS-3 could be a better hydrogel-based biomaterial for appreciable uranium recovery.