Low-cost farmed shrimp shells could remove arsenic from solutions kinetically.

The purpose of this study was to explore the ability of shrimp shell to remove arsenic (As) from aqueous solutions by experimental and modeling analyses. The shells of two species of farmed shrimp, black tiger shrimp (Penaeus monodon) and white shrimp (Litopenaeus vannamei), were chosen to be the sorbents. The results indicate that sorption capacities of black tiger shrimp and white shrimp shells were estimated to be 8.1 x 10(-3) to 5.0 x 10(-1) and 7.8 x 10(-3) to 2.4 x 10(-1)mgg(-1), respectively. Results show that the sorption capacities of the shell of black tiger shrimp did not significantly differ from those of white shrimp by through analysis of variance ANOVA (F=1.50, n=18, P>0.05). This study found that Langmuir and Fruendlich isotherm models described the adsorption processes well (r(2)>0.90). The Langmuir-based maximum adsorption capacity was estimated to be 0.125-0.126 mg g(-1), whereas the Fruendlich-based adsorption capacities ranged from 0.105 to 0.124 mg g(-1). Model analysis based on pseudo-second-order kinetics reveals that sorption capacity of shrimp shell increases with the initial As concentration and retention time in water. Based on isotherm and kinetic analyses, the sorption capacity of shell of black tiger shrimp is slight higher but insignificant than that of shell of white shrimp for As removal from solution. A combination of experiments and modeling suggests that shrimp shell, as a waste material, could be utilized potentially for the removal of As from an aqueous medium. Although the As-removal capacity of shrimp shell was lower than those of natural and chemical sorbents, using shrimp shells as sorbents is less expensive and could increase the additional benefit of shrimp products.