Synthesis of pH-responsive sodium alginate-g-tetrapolymers via N[sbnd]C and O[sbnd]C coupled in situ monomers: A reusable optimum hydrogel for removal of plant stressors

Abstract

For envisaging the optimum exclusions of plant stressors, a new strategy has been reported for structure-property-performance optimization of scalable and reusable multifunctional multipolymer hydrogels. For this, twelve sodium alginate-g-[2-acrylamido-2-methylpropane sulfonic acid-co-2-(N-(3-(2-hydroxyethoxy)-2-methyl-3-oxopropyl)propionamido)-2-methylpropane-1-sulfonic acid-co-2-(3-(2-(isobutyryloxy)ethoxy)propanamido)-2-methylpropane-1-sulfonic acid-co-(hydroxyethyl)methacrylate], i.e., SALG-g-[AMPS-co-NHMOPMPS-co-IBEPMPS-co-HEMA/1] (i.e., 2) have been designed and synthesized via in situ attached two monomers, i.e., NHMOPMPS and IBEPMPS, in solution polymerization of only two monomers, i.e., AMPS and HEMA. The structures of 1 and 2; properties of adsorbed 2, i.e., Mn(II)-2, As(III)-2, and Zr(IV)-2; in situ attached NHMOPMPS and IBEPMPS monomers; grafting of SALG; thermal stabilities; surface properties; high-performance adsorption; and reusability have been explored via 1H/13C NMR, FTIR, XPS, TGA, XRD, SEM, and DLS analyses and measuring network parameters, pHPZC, %graft-ratio, %gel-content, and thermodynamic-parameters. The optimum hydrogel 2 among twelve as-synthesized hydrogels has selectively been chosen for the high-performance exclusions of plant stressors, i.e., Mn(II), As(III), and Zr(IV), because of the maximum of 690 g g−1 swelling, 1.19 × 107 g molecular weight between crosslinks, and 3.81 × 10−11 crosslink density. The maximum adsorption capacities of Mn(II), As(III), and Zr(IV) are 180.56, 199.94, and 188.96 mg g−1, respectively, within 5–100 ppm and at 308 K for 0.02 g 2.