Antimonite Removal Using Marine Algal Species

Three seaweed species ( Turbinaria conoides, Sargassum sp., and Ulva sp.) were examined to assess their ability to sequester antimonite [Sb(III)] ions from aqueous solution. Among these species, both T. conoides and Sargassum sp. showed higher Sb(III) biosorption potential than Ulva sp. The pH-edge experimental results revealed the involvement of negatively charged groups in the biosorption of Sb(III). Biosorption isotherms obtained at pH 6 indicated that T. conoides provided higher uptake of Sb(III) (18.1 mg/g) than Sargassum sp. (14.9 mg/g) according to the Langmuir model. Kinetic studies indicated that the rates of Sb(III) removal by both brown seaweeds were high, with 95% of the process completed within 45 min. A pseudo-first-order model was found to describe the kinetic data satisfactorily with a high correlation coefficient and low percentage errors. Desorption experiments with 0.1 M HCl showed that it is possible to regenerate T. conoides for its continued use as a biosorbent for up to three sorption–desorption cycles without significant loss in sorption capacity.