Study of Mo (VI) removal from aqueous solution: application of different mathematical models to continuous biosorption data

Molybdenum (vi) biosorption process was investigated by marine algae cystoseria indica pretreated with 0.1 mcacl2 solution in a packed bed column. the biosorbent was characterized by ftir, bet and sem analyses. theresults showed that mo (vi) ions should be chelated with the hydroxyl, carboxyl and amine groups of the biomass.the effects of inlet metal concentration and flow rate on biosorption process were investigated and theexperimental breakthrough curves were obtained. results showed that the maximum biosorption capacity ofca-pretreated c. indica for mo (vi) was found to be 18.32 mg/g at optimum flow rate of (1.4 ml/min). thecontrolled-rate step shifted from external to internal mass transfer limitations, as the flow rate increased. also, it wasobserved that the breakthrough and exhaustion time decreased from 17.14 hr to 9.05 hr and from 0.006 h to0.002 hr respectively, with the increase of flow rate from 0.7 to 2.1 ml/min. the increase in the initial concentrationof mo (vi) solution from 30 to 95 ml min-1 increases the adsorption capacity from 18.32 to 30.19 mg/g anddecreases the percentage of mo (vi) removal from 61 to 38%. also, the treated volume was the greatest (1.42 l) atthe lowest inlet concentration. column data obtained under different conditions were described using the thomas,yoon and nelson, yan and belter models. the breakthrough curve predictions by belter model were found to bevery satisfactory.