Diclofenac adsorption using a low-cost adsorbent derived from Guazuma ulmifolia Lam. fruit via chemical and thermal treatment

Diclofenac (DCF) presents one of the highest acute toxicities among all non-steroidal anti-inflammatory drugs and it has been detected in surface waters and wastewater treatment plants. Since conventional processes typically used in wastewater treatment plants do not completely remove emerging contaminants such as DCF, in this study, it was analyzed the adsorption capacity of a low-cost adsorbent derived from Guazuma ulmifolia Lam. fruit for the adsorption of DCF from water. The maximum adsorption capacity of the adsorbent for DCF was 27.80 +/- 0,92 mg g(-1) and adsorption equilibrium was reached after 1440 min. The pseudo-first order kinetic and Langmuir and Freundlich model's behavior were observed in this complex adsorption process. The mechanism proposed in this study suggested that DCF adsorption occurred via pi-pi interactions and hydrogen bonding. Given the importance of researching new alternatives for drug removal from water, this research demonstrated that the adsorbent used presented a good capacity for DCF removal and it is a promising, inexpensive, eco-friendly, and readily available adsorbent, particularly in Latin America.