Vol.:(0123456789) 1 3 Journal of Radioanalytical and Nuclear Chemistry https://doi.org/10.1007/s10967-019-06668-6 Salvadora Persica branches biomass adsorbent for removal of uranium(VI) and thorium(IV) from aqueous solution: kinetics and thermodynamics study Mazen K. Nazal 1  · Mohammad Al‑Bayyari 2  · Fawwaz I. Khalili 3 Received: 21 April 2019 © Akadémiai Kiadó, Budapest, Hungary 2019 Abstract Adsorption isotherms of U(VI) and Th(IV) in water were obtained and removal kinetics was studied. The main functional groups on the surface of Salvadora Persica branches adsorbent were identifed using a Fourier-transform infrared and the surface morphology of adsorbent was characterized by a Scanning Electron Microscope. Efects of the U(VI) and Th(IV) initial concentrations, contact time, the mass of adsorbent loading, pH of the solution were investigated at 25 ± 0.3 °C. The efciencies with which this adsorbent removes U(VI) and Th(IV) from their solutions in water are reported. The adsorption isotherm ftted the Freundlich model. The adsorption of U(VI) and Th(IV) follows the pseudo-second order kinetic with squared correlation coefcients (R 2 ) close to 1.0. The thermodynamic parameters (i.e. the free energy ( ΔG o ads ), the enthalpy ( ΔH o ads ) and the entropy of adsorption ( ΔS o ads ) for the adsorption of U(VI) and Th(IV) on the Salvadora Persica branches adsorbent were reported. Keywords Environment · Radioactive elements · Adsorption isotherms · Removal efciency · Thermodynamic of adsorption Introduction The radioactive actinides such as uranium and thorium can be found in rocks, soil and groundwater. In addition, the main essential elements in the nuclear energy program are uranium and thorium. Uranium and thorium ions which exist in the environment are hazardous to the environment and human health due to their toxicity and radioactivity. The contaminated water with the uranium and thorium radioac- tive elements can cause many dangerous diseases and many biological studies have reported that these elements are considered as a carcinogen for the pancreas, kidney, lung, liver, immune-system and neuro-system [1, 2]. Moreover, separation, removal and purifcation of uranium and tho- rium ions from their ores and nuclear waste have become major topics and have attracted the attention of researchers in recent years. Therefore, and due to the safety regulations and economic benefts, the separation and removal of these radioactive ions are necessary and important to minimize their discharge into the environment. There are various tech- niques used for the removal and separation of the U(VI) and Th(IV) radioactive ions, such as solvent extraction, pre- cipitation and ion exchange [3–6] and adsorption [7, 8]. The adsorption technique for removal and separation of U(VI) and Th(IV) radioactive ions from their host media using adsorbents is promising because of the following reasons; it is simple, highly efcient, cost-efective and environment friendly. In the last few years, many researchers have worked on developing various adsorbents for removal of U(VI) and Th(IV) ions such as activated carbon, cement, silica, zeolite, coir pith, clay minerals, bayberry tannin onto bovine serum albumin Nano-spheres [9] and natural organic matter [10, 11] were tested for that purpose. However, highly available and low-cost adsorbents with high removal capacities are still needed. * Mazen K. Nazal mazennazal@kfupm.edu.sa 1 Center for Environment and Water, Research Institute, King Fahd University of Petroleum and Minerals, Dhahran 31261, Saudi Arabia 2 College of Science and Health Professions King Saud Bin Abdulaziz University for Health Sciences, National Guard Health Afairs, Jeddah, Saudi Arabia 3 Department of Chemistry, Faculty of Science, The University of Jordan, Amman 11942, Jordan