Arsenic adsorption in aqueous solution and immobilization in soils and using hand warmers

Adsorption is a commonly used method for arsenic remediation. The adsorption and immobilization effectiveness of arsenic by soil particles and used hand warmers was studied. The adsorption effectiveness at equilibrium of soil particles in 10 ppm As(III) solution was: clay (77.70%) > silt (69.24%) > sand (41.35%). In 1000 ppm As(III) solution, 17.02 mg As(III) was adsorbed onto each gram of hand warmers at equilibrium, which was significantly higher than other adsorbents. For As(III) adsorption from aqueous solution, soil samples and hand warmers were well fitted to the pseudo secondorder model and the Freundlich model. After 8 weeks of soil incubation, the sequential extraction procedure data indicated the labile fractions of arsenic (F1 and F2) decreased with the addition of hand warmers. Meanwhile, the percentage of the most stable fraction, F5, increased. These results are valuable for the future application of used hand warmers as an adsorbent/amendment for arsenic decontamination.