A novel ε-polylysine-modified microcrystalline cellulose based antibacterial hydrogel for removal of heavy metal

A new type of double-network hydrogel, cross-linked with microcrystalline cellulose grafted with ε-polylysine (MCC-PL) and N,N-methylene bisacrylamide/acrylic acid, was synthesised to efficiently inhibit bacterial proliferation and remove heavy metals. The physicochemical properties of the MCC-PL hydrogel (MCC-PLH) were characterised using scanning electronic microscopy, Fourier transform infrared spectroscopy, X-ray diffraction, thermogravimetric analysis, and differential thermogravimetric analysis. The adsorption results showed that the optimal adsorption conditions were temperature of 313 K at pH of 5 and 6 of Pb²⁺ and Cu²⁺, respectively. The adsorption mechanism of MCC-PLH5 was successfully determined using Freundlich isotherm, pseudo-second kinetics, and intra-particle diffusion model, in conjunction with X-ray photoelectron spectroscopy. Adsorption thermodynamic studies indicated that the process was spontaneous and endothermic. Antibacterial experiments showed that PL-grafted MCC hydrogel exhibited more efficient and durable antibacterial activity than MCC, indicating its potential for water decontamination.