Microporous and Mesoporous Materials | 2021
Solid-phase synthesis of bi-functionalized porous organic polymer for simultaneous removal of Hg(II) and Pb(II)
Abstract
Abstract The post-modification has been promoted as an efficient approach to achieve task-specific functionalization, but conventionally consumes huge amounts of solvent, which brings great challenges in environmental risks and energy efficiency. In this work, a bi-functionalized adsorbent is fabricated by a simple yet efficient solid-phase post-modification approach. Through one-pot ball milling at room temperature, 3-mercaptopropyltri-methoxysilane (3-MPTS) and 3-aminopropyltrimethoxysilane (3-APTS) are simultaneously grafted on the polyhydroxy naphthalenediol-based porous organic polymers (NTPOP). The operating conditions are optimized through an orthogonal experiment (L9(34)), which shows superior efficiency that at room temperature by consumption only 1\u202fmL ethanol, it takes 2\u202fh to successfully graft 1\u202fmmol silylation reagent on 1g NTPOP at 300\u202frpm. The obtained bi-functionalized adsorbent NTPOP-SH-NH2 shows excellent adsorption performance with high Langmuir adsorption capacity of Hg(II) of 357\u202fmg\u202fg−1 and Pb(II) of 212\u202fmg\u202fg−1, and the second-order rate constant of 0.3003\u202fmg−1 min-l and 0.1687\u202fg\u202fmg−1 min-l, respectively. More importantly, in a natural water containing organic compounds and various inorganic salts, NTPOP-SH-NH2 shows strong tolerance with the adsorption performance of Hg(II) and Pb(II) maintains almost unchanged. Furthermore, NTPOP-SH-NH2 exhibits extensive applicability for multi heavy metals ions, such as Hg(II), Pb(II), Cd(II), Cr(III), and Ni(II), that an extremely high removal efficiency of higher than 99% was achieved for each metal ion when they co-exist in the natural aqueous solution. Therefore, this environmentally friendly solid-phase post-modification method provides a promising strategy for the synthesis of bi-functionalized adsorbents with high removal efficiency of heavy metal ions.