Synthesis and polymeric modification of hydroxyapatite from biogenic raw material for adsorptive removal of Co 2+ and Sr
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Synthesis and polymeric modification of hydroxyapatite from biogenic raw material for adsorptive removal of Co2+ and Sr2+ H. A. Elsanafeny1 · M. M. Abo Aly2 · M. A. Hasan1 · Y. F. Lasheen1 · M. A. Youssef1 Received: 31 May 2020 / Accepted: 22 September 2020 © Akadémiai Kiadó, Budapest, Hungary 2020
Abstract A gamma induced copolymerization process was applied to modify hydroxyapatite prepared from eggshell. The composite material was characterized by different physicochemical methods, and then it was used for removal of S r2+ and C o2+ ions 2+ 2+ from aqueous solutions as a function of pH, temperature, time, interfering ions, and initial S r and C o concentrations by applying batch adsorption technique. The maximum removal was obtained at pH 6, and 8 for Sr2+ and Co2+ ions respectively. Sorbents regeneration was successful with HCl eluent. Results showed good fitting to Freundlich isotherm than Langmuir. Kinetic data was well described by pseudo-second order equation. Keywords Eggshell · Hydroxyapatite · Copolymerization · Acrylic acid · Acrylonitrile · Adsorption of strontium and cobalt ions
Introduction The existence of radioactive contaminants in water has drawn attention of scientists over the past years especially since the nuclear accidents at Chernobyl and Fukushima, when different radionuclides were disposed into the surrounding environmental areas [1]. The released radionuclides may transports with water and adsorbed by the inorganic particulate matter and/or deposited in bottom sediments then it becomes a source of threat to the living beings. Radioactive strontium occurs in the environment as 89Sr and 90 Sr with half-lives of 51 days and 29 years respectively. 90Sr which is the soft β emitter of 0.5460 MeV energy is relatively mobile and can move down with percolating water to underlying layers of soil and into groundwater. Chemically, it resembles calcium; so it is easily incorporated into bone becoming part of the bone marrow tissue and damaging blood producing cells, and continues to irradiate localized tissues with the eventual development of bone sarcoma and leukemia [2]. Although cobalt is one of the most important * H. A. Elsanafeny [email protected] 1
Hot Labs and Waste Management Center, Egyptian Atomic Energy Authority, P. No. 13759, Cairo, Egypt
Chemistry Department, Faculty of Science, Ain Shams University, Cairo, Egypt
2
transition metals for the human body function it still a heavy metal that its presence in aqueous solution beyond certain limit could be a serious threat. In terms of radioactivity; 60Co (t1/2 = 5.3 years) present in low-level aqueous waste is the most important radionuclides in terms of the potential dose to humans during the operation of a disposal facility. Traces of such radionuclides if not properly treated could cause an adverse situation for living beings [3]. Several methods have been developed for pre-concentration or treatment of radioactive contaminants from aqueous solutions, but not all of them were acceptable methods due to cos
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