RESEARCH ARTICLE Comparison of Jordanian and standard diatomaceous earth as an adsorbent for removal of Sm(III) and Nd(III) from aqueous solution Imad Hamadneh 1 & Abdulmonem Alatawi 2 & Ruba Zalloum 1 & Rula Albuqain 3 & Shorouq Alsotari 3 & Fawwaz I. Khalili 1 & Ammar H. Al-Dujaili 4 Received: 4 February 2019 /Accepted: 25 April 2019 /Published online: 21 May 2019 # Springer-Verlag GmbH Germany, part of Springer Nature 2019 Abstract In this study, Jordanian diatomaceous earth (JDA) and commercial diatomaceous earth (standard diatomaceous earth, SDA) were used for adsorption of samarium (Sm)(III) and neodymium (Nd)(III) ions from aqueous solutions using batch technique as a function of initial concentration of metal ions, adsorbent dosage, ionic strength, initial pH solution, contact time, and temperature. Both adsorbents were characterized by Fourier transform infrared (FTIR), X-ray fluorescence (XRF), X-ray diffraction (XRD), scanning electron microscopy (SEM), Brunauer–Emmett–Teller surface area, and cation exchange capacity (CEC). Maximum metal ion uptake was observed after 100 min of agitation, and the uptake has decreased with increasing temperature and reached a maximum at pH ≈ 5. Different types of adsorption isotherms and kinetic models were used to describe the Nd(III) and Sm(III) ion adsorption. The experimental data fitted within the following isotherms in the order Langmuir > Dubinin–Radushkevich (DR) > Freundlich and the pseudo-second-order kinetic model based on their coefficient of determination (R 2 ), chi-square (χ 2 ), and error function (F error% ) values. Maximum adsorption uptakes, according to the Langmuir model, were obtained as 188.679 mg/g and 185.185 mg/g for Sm(III) and 169.492 mg/g and 149.254 mg/g for Nd(III) by JDA and SDA, respectively. The results of thermodynamic parameters showed that the adsorption of Sm(III) and Nd(III) ions onto JDA and SDA is a feasible, spontaneous, exothermic, and entropy driven. The best recovery for Sm(III) and Nd(III) was obtained when the 0.05 M EDTA + 0.05 M H 3 PO 4 mixture was used as an eluent. Keywords Adsorption . Kinetic . Isotherms . Thermodynamic . Samarium(III) . Neodymium(III) Introduction Samarium(III) (Sm 3+ ) and neodymium(III) (Nd 3+ ) are well known rare-earth elements (REEs). Due to their superior spectroscopic and magnetic properties, they have been widely used in different chemical and industrial applications such as organometallic compounds, luminescent compounds, artistic glasses, optic filters, catalysis, metallurgical machinery such as laser, petroleum chemical industry, glass ceramics, elec- tronic information storages, textile, light industry, pharmacy, and environmental chemistry (Hinton et al. 2012; Minowa 2008; Younis et al. 2014); electronic components, electrolysis, leather working, photography, etc. (Oliveira et al. 2007; Lacin et al. 2005); and superconductors, steel modifiers, and hydro- gen storage (Hu et al. 2006; Gu et al. 2001). Published reports mention that production of REEs has bad impact towards human and environment which lead this sector to come under intense public scrutiny in recent years because of a convergence of environmental narratives around natural resource extraction (Ayari et al. 2007). Different techniques such as chemical precipitation, ion exchange, membrane fil- tration (Saito et al. 2004 ), coagulation and flotation Responsible editor: Tito Roberto Cadaval Jr * Ammar H. Al-Dujaili ah.aldujaili@gmail.com 1 Department of Chemistry, Faculty of Science, University of Jordan, Amman 11942, Jordan 2 Department of Natural Sciences, College of Sciences and Humanities, Fahad Bin Sultan University, Tabuk, Saudi Arabia 3 Cell Therapy Center (CTC), University of Jordan, Amman 11942, Jordan 4 Hamdi Mango Center for Scientific Research, University of Jordan, Amman 11942, Jordan Environmental Science and Pollution Research (2019) 26:20969–20980 https://doi.org/10.1007/s11356-019-05294-9