Comparative study for bioremediation of cobalt contaminated aqueous solutions by two types of marine macroalgae

Abstract

Biosorption is an efficient method for removing heavy metals from wastewater. Two dried marine macroalgae species; Ulva fasciata and Colpomenia sinuosa were used for bioremediation of cobalt polluted aqueous solutions. It was established that the optimum biosorption takes place at pH 6.0 and 7.0 for U. fasciata and C. sinuosa, respectively, with contact time 60 min for both species, initial Co(II) concentration 50 and 80 mg/L for U. fasciata and C. sinuosa, respectively, and biomass dosage 0.05 g/50 mL for both species. The biosorption mechanism of Co(II) onto the algal biomass was investigated utilizing the standard techniques. The isotherm models elucidated that Langmuir model fits the experimental data of Co(II) adsorption more than Freundlich model. The maximum biosorption capacity (qmax) obtained for C. sinuosa (62.5 mg/g) was greater than that for U. fasciata (40.0 mg/g). It was also found that the biosorption process using U. fasciata and C. sinuosa followed the second-order kinetic. The effect of calcium, magnesium, and sodium ions (Ca+2, Mg+2, and Na+) on the metal sorption potential by biosorbents was studied. The adsorption behaviour of U. fasciata and C. sinuosa in treating wastewater sample collected from Edku Lake was also investigated.