Removal of Uranium U(IV) from aqueous solution using acid treated spent tea leaves

Abstract

The adsorption technique has successfully removed toxic heavy metals from the aqueous solution over several decades. Among these metals, Uranium U(IV) is considered one of the more dangerous, toxic and radioactive elements, so there is a need to introduce cost-effective and environment-friendly biosorbents to remove U(IV) from environmental water. Though several biosorbents have been introduced, these spent tea leaves (STLs) are the most consumable product in south Asia, especially Pakistan and India. Almost every home in this region is consuming black tea and disposing it off in garbage. Herein, we introduce it as the useful and cost-effective bio absorbent for removing U(IV) from the aqueous solution. For the first time, a complete investigation and comparison of ASTLs (Acid treated spent tea leaves) for U(IV) removal from aqueous solution has been performed. The ASTL was characterized by SEM, XRD, and FT-IR. The experimental conditions were optimized and maximum adsorption of ASTL was found at pH ​= ​5.5 and 25 ​°C. The adsorption data followed Langmuir isotherm and the monolayer adsorption was 120.74 ​mg/g using only 2.0 ​g/L of ASTL. U(VI) adsorption onto ASTL was physicochemical in nature and followed both the pseudo-first and second-order kinetics. Being cheap, easily available, and with sufficient adsorption ability, ASTL can be used for the adsorption of U(VI) from wastewater ons sufficient adsorption ability. ASTL can be used to adsorption of U(VI) from wastewater on a commercial scale.