Investigation of Effect of Influent Concentration and Flow Rate on Nickel Biosorption using Protonated Cystoseira indica Brown Alga in a Packed Bed Column and Modeling the Experimental Data

Background and Objectives: Biosorption is a new and inexpensive technique in heavy metals removal and recovery from aqueous solutions. In order to evaluate the potential of this method for the removal of nickel ions, biosorption of nickel ions from aqueous solution was studied using Cystoseira indica biomass in a packed bed column. Materials and Methods: The uptake capacity of nickel ions was investigated using protonated biomass at different influent concentrations and flow rates. In addition, the experimental breakthrough curve obtained under definite experimental conditions was modeled using Thomas, Yoon & Nelson, Dose-Response, and Belter models. Results: It was found that increasing influent concentration from 58 to 100 mg/l led to the increase of driving force for mass transfer and uptake capacity raised from 55.84 to 95.69 mg/g. The investigation of flow rate effect showed when the process is intraparticle mass transfer controlled, a slower flow rate favors the sorption. In the case of external mass transfer control, a higher flow rate decreases the film resistance and leads to an increase in mass transfer. Modeling the experimental data revealed that the abovementioned models were suitable to predict the breakthrough curves, especially Dose-Response. Measurement of pH of the effluent solution indicated that ion exchange is one of the main mechanisms of nickel biosorption using this biosorbent. Conclusion: The results of this study are complementary of the batch equilibrium sorption experiments. Therefore, from process viewpoint, this biomass can be proposed in the sorption columns as a sorbent for nickel ions