Effective removal of thallium, recovery, and kinetic research by MnO2@HKUST-1 for wastewater

With the rapid development of ore refining, coal power plants, and mining, aqueous thallium pollution in natural waters has been reported over the past few decades. However, few thallium control technologies have been put into practice. In this study, a modified MOF adsorbent, MnO2@HKUST-1(MOH), was fabricated. Its chemical component shift, thermal stability, and microstructure changes during thallium adsorption were analyzed using TGA, XRD, XPS, and TEM-EDS techniques. The results showed a promising Tl+ removal rate of over 90 %, and an adsorption capacity of 178.8 mg/g was obtained at a pH of 5 and a temperature of 293 K. The dynamic behavior of Tl+ adsorption on MOH was simulated using power rate law expression (PRL), pseudo-first-order model (PFO), and pseudo-second-order model (PSO), which revealed a superior selection of Tl+ among other competing heavy metal ions (Cr3+, Fe3+, Ca2+, Zn2+, and Cu2+). The Tl+ removal mechanism was further studied, which was mainly forced by surface adsorption/desorption. Based on its efficient Tl+ removal rate, high adsorption capacity, promising regeneration property, and economical price, the MOH adsorbent has the potential to be a feasible option for smelting, ore refining, packaging, and testing wastewater treatment.