Cadmium Removal from Giant Squid (Dosidicus gigas) Hydrolysate in Fixed-Bed Columns Packed with Iminodiacetic Resin: Tools for Scaling up the Process

Giant squid hydrolysate (GSH) elaborated from different batches from a fishing company was evaluated for cadmium removal. Fixed-bed column packed with iminodiacetic resin as adsorbent was used. GSH solution at different cadmium concentrations were fed in the fixed-bed column and breakthrough curves were evaluated. A high degree of metal removal from the solution was achieved and the saturation point (C-e/C-0 <= 0.8) was achieved more quickly at higher concentrations of cadmium. The maximum capacity of adsorption (q(0)) was obtained using the Thomas model, where 1137.4, 860.4, 557.4, and 203.1 mg g(-1) were achieved using GSH with concentrations of 48.37, 20.97, 12.13, and 3.26 mg L-1, respectively. Five cycles of desorption of the resin with HCl (1 M) backflow and regeneration with NaOH (0.5 M) were also evaluated, where no significant differences (p-value > 0.05) were observed between each cycle, with an average of 935.9 mg g(-1) of q(max). The in-series columns evaluated reached a total efficiency of 90% on average after the third column in GSH with a cadmium concentration of 20.97 mg L-1. This kind of configuration should be considered the best alternative for cadmium removal from GSH. Additionally, the chemical composition of GSH, which was considered a quality parameter, was not affected by cadmium adsorption.

Automated summary

The study evaluated the effectiveness of giant squid hydrolysate (GSH) in removing cadmium. The fixed-bed column experiment showed that metal removal was faster at higher cadmium concentrations, and the saturation point was reached quickly. The maximum adsorption capacity, calculated using the Thomas model, was positively correlated with GSH concentration. The cyclic desorption and regeneration experiments showed that the adsorption performance remained stable. The results suggest that the configuration with consecutive columns is an effective alternative for removing cadmium from GSH, without affecting its chemical composition.