Preparation of Ag/AgBr@cellulose-based gel beads for the removal of Rhodamine B from water

To address the issues of low efficiency and difficulty in recovery of powdered photocatalysts in practical applications, cellulose-based gel beads loaded with Ag/AgBr (Ag/AgBr@Gel) were prepared by utilizing the fiber dissolution effect of lithium bromide trihydrate molten salt. The dissolution and gelation processes of cellulose were investigated, and the physical and chemical structures of Ag/AgBr@Gel were characterized by means of SEM, FT-IR, XRD, and XPS. The absorption spectrum of the material was examined, and its adsorption and photocatalytic degradation effects on rhodamine B (RhB) in water were explored. The results show that Ag/AgBr@Gel has a band gap of 2.40 eV and excellent light absorption performance, exhibiting good adsorption and photodegradation effects on RhB in water with an overall removal rate of over 99%. The adsorption rate and photodegradation rate are affected by pH and positively correlated with the number of gel beads. The photodegradation process conforms to the Langmuir-Hinshelwood kinetic model (R² > 0.99), with ·O₂⁻ and ·OH radicals being the main active species. The material can withstand a maximum deformation of 87% and a pressure of 120 MPa, maintain stability in water for more than 300 days, and retain over 90% of its photocatalytic activity after 5 cycles of use. It can be completely degraded in soil within 12 days, thus being a green water treatment functional material with promising applications in the field of wastewater treatment.