Preparation of non-swelling hydrogels and investigation on the adsorption performance of iron ions

We prepared a novel cellulose-based non-swelling hydrogel material PAAS-CMC-BPEI by a one-step method. A large number of strong hydrogen bonds were formed between carboxymethyl cellulose (CMC) and sodium polyacrylate (PAAS) and ethylene imine polymer (BPEI). The hydrogel did not show any swelling even after being immersed in water for 6 months, and the hydrogel can maintain its original function and size for a more extended period. SEM tests visually demonstrate the structural characteristics of the hydrogel, whose tight three-dimensional network structure imparts a macroscopically non-swelling property to the hydrogel. This non-swelling property maintains the initial state and function of the hydrogel and possesses the properties of the material itself well. The FTIR test proves that the main factor in the formation of this tight structure is the formation of a large number of internal hydrogen bonds. In addition, the PAAS-CMC-BPEI hydrogel exhibited high adsorption efficiency for ferrous ions in water. The adsorption conforms to a quasi-secondary kinetic equation and is mainly chemisorption. The use of this non-swelling hydrogel for the adsorption of ferrous ions holds promise for efficient, simple and fast operation in the field of wastewater treatment in the future.