Selective uranyl ion-imprinting with clickable amidoxime-functionalized pullulan.

Manufacturing a highly effective sorbent for removing UO22+ ions from aqueous effluents is vital for safeguarding the environment and recovering valuable resources. This research presents an innovative strategy employing adsorbents derived from pullulan, specifically tailored with furfuryl-amidoxime (FAO), to improve their affinity for UO22+ ions. The formation of a UO22+ ion-imprinted sorbent (U-II-P) was achieved by crosslinking the UO22+/FAO-modified pullulan (FAO-P) complex with bis(maleimido)ethane (BME) via click Diels-Alder (DA) cyclization, enhancing its attraction and specificity for UO22+ ions. Detailed characterization of the synthesis was performed using NMR and FTIR spectroscopy, and the sorbent's external textures were analyzed using scanning electron microscopy (SEM). The U-II-P sorbent showcased outstanding preference for UO22+ over other metallic ions, with the most efficient adsorption occurring at pH 5. It exhibited a significant adsorption capacity of 262 mg/g, closely aligning with the predictions of the Langmuir adsorption model and obeying pseudo-second-order kinetic behavior. This investigation underlines the effectiveness of FAO-P as a specialized solution for UO22+ ion extraction from wastewater, positioning it as a viable option for the remediation of heavy metals.

Ion-imprinted aminoguanidine-chitosan for selective recognition of lanthanum (III) from wastewater.

Developing a sorbent for the removal of La3+ ions from wastewater offers significant environmental and economic advantages. This study employed an ion-imprinting process to integrate La3+ ions into a newly developed derivative of aminoguanidine-chitosan (AGCS), synthesized via an innovative method. The process initiated with the modification of chitosan by attaching cyanoacetyl groups through amide bonds, yielding cyanoacetyl chitosan (CAC). This derivative underwent further modification with aminoguanidine to produce the chelating AGCS biopolymer. The binding of La3+ ions to AGCS occurred through imprinting and cross-linking with epichlorohydrin (ECH), followed by the extraction of La3+, resulting in the La3+ ion-imprinted sorbent (La-AGCS). Structural confirmation of these chitosan derivatives was established through elemental analysis, FTIR, and NMR. SEM analysis revealed that La-AGCS exhibited a more porous structure compared to the smoother non-imprinted polymer (NIP). La-AGCS demonstrated superior La3+ capture capability, with a maximum capacity of 286 ± 1 mg/g. The adsorption process, fitting the Langmuir and pseudo-second-order models, indicated a primary chemisorption mechanism. Moreover, La-AGCS displayed excellent selectivity for La3+, exhibiting selectivity coefficients ranging from 4 to 13 against other metals. This study underscores a strategic approach in designing advanced materials tailored for La3+ removal, capitalizing on specific chelator properties and ion-imprinting technology.