An environmentally friendly batch bioadsorption study of the radionuclides 67Ga from aqueous solutions by fibrous tea waste

The radionuclides 67Ga is used in nuclear medicine. This paper presents a bioadsorption study of 67Ga from aqueous solution by solid tea factory waste. The experimental parameters were chosen as temperature, pH, stirring speed, nominal particle size and bioadsorbent dose in the ranges of 10.0–40.0 °C, 2.0–8.0, 300–720 rpm, 0.15–1.4 mm and 1.0–15.0 g/L, respectively. The most effective parameter was determined to be pH, and then temperature, particle size, and bioadsorbent dose in decreasing order. Fourier transform infrared spectroscopy was performed for the characterisation of the bioadsorption of 67Ga on tea waste. The equilibrium results showed that the data exhibited good agreement with the isotherm models of Freundlich, Halsey, and Handerson and Smith. In thermodynamic analysis, ΔG and ΔH values were determined and their values demonstrated that the bioadsorption process was endothermic and spontaneous. Bioadsorption kinetics analysis proved that the rate corresponded to a pseudo second order model, and that the bioadsorption mechanism is governed by intra-particular diffusion.