Facile preparation of a novel iminodisuccinate modified chitin and its excellent properties as a silver bioadsorbent and antibacterial agent

A novel iminodisuccinate modified chitin (ICH) was prepared using crab shells via a one-step facile procedure. The ICH with grafting degree of 1.46 and deacetylation degree of 47.68 % possessed maximum adsorption capacity of 2572.41 mg/g for silver ions (Ag(I)).The ICH also exhibited good selectivity and reusability. The adsorption followed better with the Freundlich isotherm model, while fitted well with both the Pseudo-first-order and Pseudo-second-order kinetics models. The characteristical results showed that the excellent Ag(I) adsorption capability of ICH should be attributed to both looser porous microstructure as well as additional functional groups-grafting molecular. Moreover, the Ag-loaded ICH (ICH-Ag) showed remarkable antibacterial properties against six typical pathogenic bacteria strains (Escherichia coli, Pseudomonas aeruginosa, Enterobacter aerogenes, Salmonella typhimurium, Staphylococcus aureus, and Listeria monocytogenes), with the corresponding 90 % minimal inhibitory concentrations ranged 0.426-0.685 mg/mL. Further study on the silver release, microcell morphology, and metagenomic analysis suggested that many Ag nanoparticles were formed after the Ag(I) adsorption, and the antibacterial mechanisms of the ICH-Ag involved both cell membranes destruction and intracellular metabolism disturbing. This research presented a coupling solution of crab shell wastes treatment with chitin-based bioadsorbents preparation, metal removal and recovery, as well as antibacterial agent production.