Adsorption of antiviral and antibiotics by recyclable biochar derived from Dillenia indica: Impact of pyrolysis temperature and duration

This study aimed to remove emerging contaminants such as chloroquine (CQ), used extensively during the COVID-19 pandemic, and highly used antibiotics (ciprofloxacin, CP; tetracycline, TC; ampicillin, AMP; and amoxicillin, AMX) from wastewater. These drug pollutants cause irreparable harm to our environment. The study reports on the high-yield preparation of biochar (BC) from the waste of Dillenia indica (DI) fruit by pyrolysis. It also discusses the impact of temperature and residence time on the yield and properties of the BC. This DI biochar (DBC) represents an affordable and sustainable biosorbent for treating drug pollutants. The Freundlich isotherm model confirms that the adsorbate forms a multilayer on the DBC surface, and the pseudo-second-order kinetic model confirms the chemisorption. Notably, the adsorption of drug pollutants reaches equilibrium quickly (within 60 min). We found the maximum adsorption capacity for CP, CQ, TC, AMX, and AMP as 91.0, 99.0, 94.0, 7.0, and 5.0 mg g(- 1), respectively. DBC demonstrates outstanding removal efficiency and excellent recyclability up to 7 cycles. This investigation explores opportunities to convert waste into value-added products, i.e., waste management and subsequent application in pollutant removal.