High crosslinked sodium carboxyl methylstarch-g-poly (acrylic acid-co-acrylamide) resin for heavy metal adsorption: its characteristics and mechanisms

Abstract

A lower expansive heavy metal adsorbent, high crosslinked sodium carboxyl methylstarch-g-poly (acrylic acid-co-acrylamide) resin (HCAA), has been prepared by enhancing the crosslinking degree of the traditional water-absorbing polymer under the graft copolymerization reaction. Further heavy metal adsorption experiments, morphology analysis, and structure characteristic observations indicate that HCAA resin has an excellent heavy metal adsorption properties for Cr 3+ , Cu 2+ , Ni 2+ , and Zn 2+ of 80.08, 158.07, 155.71, and 137.15 mg/g, respectively. The nanoholes in network structures of HCAA resin expanding in solution provide an effective diffusion and exchange channels for heavy metal ions and Na + . The adsorption process of HCAA containing -COONa is attributed to ion exchange process, and its essence is to form the coordination bond with heavy metals. The adsorption capacity differences of -COO − have been explained by using the coordination chemistry theory. In addition, the adsorption selectivity of an expansive adsorbent containing -COONa are heavy metals > H2O >> Na + . Our research puts forward an insight that increasing the crosslinker content on the basis of the traditional super absorbent resin can obtain a lower expansive adsorbent to heavy metal pollutants.

Starch‐Based Superabsorbent Hydrogel with High Electrolyte Retention Capability and Synergistic Interface Engineering for Long‐Lifespan Flexible Zinc−Air Batteries

“…[30] The neutralization of AA monomers by adding alkali (e.g., KOH) is adopted to decrease the acidity of the solution system contributing to an easier grafting process with starch monomers. [35] All the pre-dissolved monomers (e.g., starch and AA) tend to generate free radicals to transform the monomers into a series of high molecular polymers with long chains under the role of the initiator. [35] Then, plenty of crosslinking sites are formed in the presence of the crosslinker translating the long-chain molecules into a polymeric network structure, [35] as shown in Figure 1a.…”

“…The optical photos are shown in Figure S1, SSHPE‐1 is an elastic gel with no fixed shape due to the low cross‐link density which refers to the density of junctions formed within a hydrogel. The crosslinking density is known to contribute to the gel stiffness [35] . SSHPE‐2 and SSHPE‐3 are transparent quasi‐solid‐state gels.…”

Modeling and Simulation of Polymerization Processes

“…[192] Synthesis and characterization of poly (acrylonitrile-g-lignin) by semi-batch solution polymerization and evaluation of their potential application as carbon materials [193] High crosslinked sodium carboxyl methylstarch-g-poly (acrylic acid-co-acrylamide) resin for heavy metal adsorption: its characteristics and mechanisms. [194] Preparation and characterization of PLLA/chitosan-graft-poly (ε-caprolactone) (CS-g-PCL) composite fibrous mats:…”

Preparation of Poly(acrylic acid-acrylamide/starch) Composite and Its Adsorption Properties for Mercury (II)

“…Figure 12 further confirms this view. When the solution temperature exceeds 45 • C, the increase of temperature cause the decrease of adsorption capacity [40].…”