Well-defined functional mesoporous silica/polymer hybrids prepared by an ICAR ATRP technique integrated with bio-inspired polydopamine chemistry for lithium isotope separation

Abstract

Mesoporous silica/polymer hybrids with well-preserved mesoporosity were prepared by integrating the initiators for continuous activator regeneration (ICAR) atom transfer radical polymerization (ATRP) technique with the bio-inspired polydopamine (PDA) chemistry. By manipulating the auto-oxidative polymerization of dopamine, uniform PDA layers were deposited on the surfaces and pore walls of ordered mesoporous silicas (OMSs), thereby promoting the immobilization of ATRP initiators. Poly(glycidyl methacrylate) (PGMA) brushes were then grown from the OMSs by using the ICAR ATRP technique. The evolution of the mesoporous silica/polymer hybrids during synthesis, in terms of morphology, structure, surface and porous properties, was detailed. And, parameters influencing the controlled growth of polymer chains in the ICAR ATRP system were studied. Taking advantage of the abundant epoxy groups in the PGMA platform, post-functionalization of the mesoporous silica/polymer hybrids by the covalent attachment of macrocyclic ligands for the adsorptive separation of lithium isotopes was realized. Adsorption behavior of the functionalized hybrids toward lithium ions was fully investigated, highlighting the good selectivity, and effects of temperature, solvent and counter ions. The ability for lithium isotope separation was evaluated. A higher separation factor could be obtained in systems with softer counter anions and lower polarity solvents. More importantly, due to the versatility of the ICAR ATRP technique, combined with the non-surface specific PDA chemistry, the methodology established in this work would provide new opportunities for the preparation of advanced organic-inorganic porous hybrids for broadened applications.

Novel Functionalized Cellulose Microspheres for Efficient Separation of Lithium Ion and Its Isotopes: Synthesis and Adsorption Performance

“…Subsequently, they prepared a novel AB15C5 grafted mesoporous silica via atomic transfer radical polymerization. By controlling the chain length of grafting polymer, the adsorbents showed a maximum adsorption capacity up to 6.97 mg·g −1 and a separation factor of 1.038 ± 0.002 of 6 Li/ 7 Li [12], indicating that with the increase of adsorption capacity of Li + , the separation factor of lithium isotopes decreased. Besides the inorganic support, various synthetic polymers have been used as a matrix.…”

Optimisation of Surface-Initiated Photoiniferter-Mediated Polymerisation under Confinement, and the Formation of Block Copolymers in Mesoporous Films

“…Ordered mesoporous silicas (OMSs) are an ideal support structure due to their high specific surface area, dimensional stability, and their uniform, ordered channel structure with tuneable pore size and geometry [3,4]. Furthermore, the rich surface hydroxyl groups available on the silica surface are a convenient handle for various synthetic transformations [3].…”

“…Ordered mesoporous silicas (OMSs) are an ideal support structure due to their high specific surface area, dimensional stability, and their uniform, ordered channel structure with tuneable pore size and geometry [3,4]. Furthermore, the rich surface hydroxyl groups available on the silica surface are a convenient handle for various synthetic transformations [3]. These properties have afforded OMSs significant research interest over the last several decades, attracting attention for application in a broad range of fields from catalysis to controlled drug delivery [2,4,5,6,7,8].…”

“…Surface-initiated atom transfer radical polymerisation (SI-ATRP) remains the most widely investigated technique due to its wide range of polymerisable monomers with controllable molecular weight and narrow dispersities, chemical tolerance, and mild polymerisation conditions [3,18]. While several techniques such as initiators for continuous activator regeneration (ICAR) [3] and activators (re)generated by electron transfer (A(R)GET) [10] have been implemented to reduce the concentration of the copper catalyst that contaminates the final material, ATRP systems are more onerous, requiring numerous components to mediate a controlled polymerisation. This could severely limit the pore size that can be functionalised in terms of the control achievable and the polymer content.…”

Synthesis of Acryl Group-Modified Adsorption Resins and Their Adsorption Properties for Matrine and Oxymatrine in Aqueous Solutions

“… 15 Various chromatographic stationary phase or separation materials have been prepared via the ATRP technology and applied in the processes of nucleoside/protein detection, 16 solid-phase extraction, 17 and isotope enrichment. 18 By controlling the amount of monomers or the reaction time, the different degrees of grafting adsorbents can be obtained. This strategy would provide an opportunity to analyze the relationship between the content of functional groups and adsorption affinity of the target alkaloid.…”