Inexpensive, effective, readily available materials—U. pinnatifida can be used for the removal of heavy metals from solution. Column experiment should be the next research for the biosorption of metal ions by this biomass. From the results of the present study obtained, the following conclusions can be drawn:
1.
U. pinnatifida can be obtained without excessive cost. Thus, it is cheapness and sufficiency as biomass for sorption of metal ions than other types of biosorbent materials found in literature.
2.
The obtained results strongly demonstrated that pH, biomass doze, initial metal concentration and contact time affect the metal ions uptake capacity of biosorbents.
3.
U. pinnatifida treated by CaCl2 solution can be used for removal of nickel and copper ions from aqueous solutions effectively. The maximum uptake capacity for nickel and copper was 24.71 and 38.82 mg/g at pH 4.7 and 4 initial concentration 50 mg/L for 120 min.
4.
The suitability of sorption isotherm models for the sorption of nickel and copper are Langmuir and Temkin, respectively. And the best isotherm models described the isotherm data with high R2 and low values of ɛ2.
5.
Metal ion uptake capacity tests have shown that the biosorption process can be better described by pseudo-second-order kinetic model.