Chitin/egg shell membrane@Fe3O4 nanocomposite hydrogel for efficient removal of Pb2+ from aqueous solution

• Published in: RSC advances Vol. 12; no. 7; pp. 4417 - 4427
• Main Authors: Jia, Baoquan, Liu, Dingna, Niu, Chengyu, Yu, Qili, Ren, Jie, Liu, Qingye, Wang, Haiqiang
• Format: Journal Article
• Language: English
• Published: Cambridge Royal Society of Chemistry 28.01.2022; The Royal Society of Chemistry
• Subjects: Adsorption; Agricultural production; Agricultural wastes; Aqueous solutions; Chemical bonds; Chemical reactions; Chemistry; Chitin; Diffusion rate; Eggs; Epichlorohydrin; Heavy metals; Hydrogels; Iron oxides; Kinetic equations; Membranes; Nanocomposites; Nanoparticles
• ISSN: 2046-2069; 2046-2069
• DOI: 10.1039/d1ra08744d

The development of adsorbents by using the byproducts or waste from large-scale industrial and agricultural production is of great significance, and is considered to be an economic and efficient strategy to remove the heavy metals from polluted water. In this work, a novel chitin/EM@Fe3O4 nanocomposite hydrogel was obtained from a NaOH/urea aqueous system, where the proteins of egg shell membrane and Fe3O4 nanoparticles were chemically bonded to chitin polymer chains with the help of epichlorohydrin. Due to the existence of a large number of –NH2, –OH, –CONH–, –COOH and hemiacetal groups, the adsorption efficiency for Pb2+ into the absorbent was dramatically enhanced. The experimental results revealed that the adsorption behavior strongly depends on various factors, such as initial pH, initial Pb2+ concentration, incubation temperature and contact time. The kinetic experiments indicated that the adsorption process for Pb2+ in water solution agreed with the pseudo-second-order kinetic equation. The film diffusion or chemical reaction is the rate limiting process in the initial adsorption stage, and the adsorption of Pb2+ into the nanocomposite hydrogel can well fit the Langmuir isotherm. Thermodynamic analysis demonstrated that such adsorption behaviors were dominated by an endothermic (ΔH° > 0) and spontaneous (ΔG° < 0) process.