Sunflower seed husks as a cost-effective adsorbent for chloroquine removal from water

The increased production and consumption of pharmaceuticals represent a potential environmental threat. Thus, advanced treatments are necessary to remove pharmaceutical products from water. A promising removal alternative is low-cost adsorbents, due to their availability, low processing, and favorable results. This study used sunflower seed husks (SSH) and chemically treated sunflower seed husks (TSSH) as bioadsorbents to remove chloroquine from water. Results showed that the pseudo-second-order is the kinetic model with the best fit for both adsorbents. As for isothermic models, the best fit for SSH was Langmuir, and for TSSH, Freundlich. Maximum adsorption capacities of qe=168.09±22.98 mg/g and qe=185.91±27.23 mg/g were found through the isothermic models for SSH and TSSH, respectively. In addition, SSH reached 80% of its initial adsorption capacity after three adsorption-desorption cycles, indicating physisorption and good applicability due to its reusability. Thus, SSH is an efficient adsorbent for chloroquine removal with excellent regeneration capacity, low production cost, and low waste production. This study serves as a model for the use of SSH in the removal of contaminants of emerging concern.