Removal of roxarsone from synthetic livestock wastewater by sodium alginate loading with micro-scale zerovalent iron

Roxarsone (ROX) as a feed additive in livestock industry could be transported and migrated with manure in soil and aquatic environments, which pose a serious environmental problem due to the long-term accumulation and exposure of arsenic (As). In this study, sodium alginate (SA) loaded micro-scale zerovalent iron (ZVI) was chosen as one macromolecular polymer adsorbent in order to remove residual ROX from synthetic livestock wastewater. The results showed that the maximum adsorption capacity of SA-ZVI for ROX were about 156.4mg ROX g(-1). The possible adsorptive mechanism is mainly due to the reaction of hydrogen bonding and electrostatic interactions. Furthermore, the results documented that about 93% of total As sequestrated by SA-ZVI could be recovered and the content of As in the recovered product was 105.64 +/- 1.58 mg As g(-1).