Cadmium removal for marine food application: comparative study of different adsorbents

Cadmium adsorption was studied using resin, zeolite and fish bone to identify alternatives for the removal of cadmium from giant squid hydrolyzed. Optimized pH and adsorbent dose for the standard cadmium solution were determined in preliminary assays under batch conditions. The adsorption kinetic was determined by pseudo-first-order, pseudo-second order and Elovich models. On the other hand, adsorption isotherms were fitted to the Langmuir and Freundlich models. A good correlation was observed by the three adsorbents between the experimental data and the pseudo-second-order kinetic model, with correlation coefficient values (R-2) greater than 0.99, while Freundlich was the best fitted for all the adsorbents. From comparative study between the standard cadmium solution and giant squid hydrolyzed, standard solution had a better cadmium removal than giant squid hydrolyzed. These results were attributed to the complexity of giant squid hydrolyzed, the interference of other metals and the presence of amino acids, which led to competition for active sites. In terms of reusability of the adsorbents, resin could be repeatedly used in cadmium adsorption without detectable losses with respect to initial adsorption capacities. The use of resin and fish bone as adsorbents for cadmium in giant squid hydrolyzed processing is a good alternative for remove cadmium in aqueous food marine ingredient by batch method.

Automated summary

The study identified resin and fish bone as effective alternatives for removing cadmium from giant squid hydrolyzed, with standard cadmium solution showing better removal efficiency compared to the giant squid hydrolyzed. The study also found resin to be reusable in cadmium adsorption without detectable losses in initial adsorption capacities.