Sequestration of trivalent arsenic from aqueous solution by using banana peels (Musa paradisiaca L.) modified in calcium alginate beads

Abstract

Banana peels (Musa paradisiaca L.) was modified into calcium alginate beads via entrapment, were used as biosorbent for the removal of arsenic (III) in aqueous solution. The extent of arsenic (III) removal capacity was tested by the material by varying the solution parameters such as effect of pH, biosorbent dose concentration, initial arsenic (III) concentration, contact time, temperature and agitation rate. Desorption efficiency of banana peels modified into calcium alginate beads was highest for sulphuric acid followed by hydrochloric acid and nitric acid. The biosorption process followed pseudo-second-order kinetics and biosorption data were best fitted to linearly transformed Langmuir isotherm with correlation coefficient of R 2 = 0.9951. Maximum biosorption capacity calculated from Langmuir isotherm was found to be 52.083 mg g -1 . The thermodynamic study confirmed that reaction of biosorption of arsenic (III) was spontaneous, endothermic and increasing randomness of the solid solution interfaces. The results indicating that calcium alginate beads have better biosorption properties than other naturallyoccurring materials like algae, flower wastes and minerals like zeolite and bentonite. This study demonstrated that alginate beads are good candidates for a fast and efficient removal of arsenic (III) from aqueous solution.