Poly (Amidehydrazide) Hydrogel Particles for Removal of Cu2+ and Cd2+ Ions from Water

Abstract

Poly(amidoamine)s (PAMAM) are very effective in the removal of heavy metal ions from water due to their abundant amine and amide functional groups, which have a high binding ability to heavy metal ions. We synthesized a new class of hyperbranched poly(amidehydrazide) (PAMH) hydrogel particles from dihydrazides and N,N′-methylenebisacrylamide (MBA) monomer by using the A2 + B4 polycondensation reaction in an inverse suspension polymerization process. In Cd2+ and Cu2+ ion sorption tests, the synthesized dihydrazide-based PAMH hydrogel particles exhibited sorption capacities of 85 mg/g for copper and 47 mg/g for cadmium. Interestingly, the PAMH showed only a 10% decrease in sorption ability in an acidic condition (pH = 4) compared to the diamine-based hyperbranched PAMAM, which showed a ~90% decrease in sorption ability at pH of 4. In addition, PAMH hydrogel particles remove trace amounts of copper (0.67 ppm) and cadmium (0.5 ppm) in water, below the detection limit.

Synthesis and CO2 Capture of Porous Hydrogel Particles Consisting of Hyperbranched Poly(amidoamine)s

“…To exploit the strengths of wet-scrubbing and a dry type adsorbent, we designed a hydrogel absorbent that works in an aqueous phase. A hydrogel is introduced because hydrogels are widely used as adsorbents for various substances such as heavy metal ions, dyes, and carbon dioxide due to their high adsorption performance and ease of use in an aqueous solution [ 39 , 40 , 41 , 42 , 43 , 44 , 45 , 46 ]. Because amines are verified carbon dioxide absorbers in wet-scrubbing processes by forming carbamate and ammonium bicarbonate with CO 2 , we adopted poly(amidoamine) (PAMAM) as our key functional material.…”