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- MakaleYalnız künye2026Scopus SJRQ2Selective extraction of rare earth elements from end-of-life NdFeB magnets via low-temperature NH4Cl-based chlorination roasting and water leaching
Kumas, Cavit; Prasetia, Hendra; Sumardi, Slamet; Astuti, Widi; Mufakhir, Fika Rofiek; Daulay, Amru; Wicaksono, Mahruri Arif
Neodymium-iron-boron (NdFeB) magnets are critical components in the transition to a low-carbon energy economy due to their superior magnetic properties. They have significantly higher rare earth element (REE) content (25-35%) compared to natural resources (0.15-2%), making end-of-life NdFeB magnets a valuable secondary REE source. In this study, the selective recovery of REEs from end-of-life NdFeB magnets was investigated using water leaching following chlorination roasting with NH4Cl. A series of experiments was conducted to evaluate the effect of NH4Cl on the NdFeB magnet ratio, roasting temperatures, and roasting duration. Under optimal conditions (300 degrees C, 3 h, NH4Cl at twice the stoichiometric requirement), the roasted products were subjected to water leaching (500 rpm, 90 degrees C, liquid - solid ratio of 20 mL/g, 1 h). resulting in over 95% REE dissolution. Rare earth oxalates were precipitated from the pregnant leach solution with 90% efficiency using 1.5 times the stoichiometric requirement of oxalic acid. Subsequent calcination at 850 degrees C for 2 h yielded rare earth oxides with 99.8% REE purity. Moreover, the dissolution of iron was effectively suppressed through a simple two-stage Fe(OH)3 precipitation step, providing a more economical and selective recovery route. Les aimants de n & eacute;odyme-fer-bore (NdFeB) sont des composants critiques de la transition vers une & eacute;conomie & eacute;nerg & eacute;tique & agrave; faible carbone gr & acirc;ce & agrave; leurs propri & eacute;t & eacute;s magn & eacute;tiques sup & eacute;rieures. Ils ont une teneur en & eacute;l & eacute;ments de terres rares (ETR) sup & eacute;rieures (25-35%) aux ressources naturelles (0.15-2%), ce qui rend les aimants de NdFeB en fin de vie une source secondaire pr & eacute;cieuse d'ETR. Dans cette & eacute;tude, on a examin & eacute; la r & eacute;cup & eacute;ration s & eacute;lective des ETR des aimants de NdFeB en fin de vie par lixiviation aqueuse apr & egrave;s grillage chlorurant avec du NH4Cl. On a effectu & eacute; une s & eacute;rie d'exp & eacute;riences pour & eacute;valuer l'effet du rapport NH4Cl/aimant de NdFeB, des temp & eacute;ratures et de la dur & eacute;e de grillage. Dans des conditions optimales (300 degrees C, 3 h et une concentration de NH4Cl deux fois sup & eacute;rieure & agrave; la st oe chiom & eacute;trie requise), on a soumis les produits grill & eacute;s & agrave; une lixiviation aqueuse (500 tr/min, 90 degrees C, rapport liquide/solide de 20 mL/g, 1 h) conduisant & agrave; une dissolution de plus de 95% des ETR. On a pr & eacute;cipit & eacute; les oxalates de terres rares & agrave; partir de la solution de lixiviation enrichie avec une efficacit & eacute; de 90% en utilisant 1.5 fois la quantit & eacute; st oe chiom & eacute;trique requise d'acide oxalique. Une calcination ult & eacute;rieure & agrave; 850 degrees C pendant 2 h a produit des oxydes de terres rares d'une puret & eacute; de 99.8%. De plus, la dissolution du fer & eacute;tait efficacement supprim & eacute;e par une simple & eacute;tape de pr & eacute;cipitation de Fe(OH)3 en deux phases, offrant une voie de r & eacute;cup & eacute;ration plus & eacute;conomique et plus s & eacute;lective.
- MakaleAçık Erişim2014Scopus SJRQ2Assessment of kinetics, thermodynamics, and equilibrium parameters of Cu(II) adsorption onto Rosa canina seeds
Serencam, Huseyin; Ozdes, Duygu; Duran, Celal; Senturk, Hasan Basri
Rosa canina seeds (RCS) is considered as a low-cost and promising adsorbent in removal of metal ions; hence, in the present study, we aimed to test the adsorptive removal of Cu(II) ions from aqueous solutions by utilizing RCS in a batch process. After characterization of RCS by using several techniques, the effects of various experimental parameters such as initial pH of aqueous solution, contact time, initial Cu(II) concentration, RCS concentration, temperature, and electrolyte concentration were studied upon the adsorption process. The desorption conditions of Cu(II) ions from the loaded RCS were also evaluated. Maximum Cu(II) adsorption was found to occur at pH 6.0 and the equilibrium was established after 60 min of contact time. The adsorption isotherms were described by means of Langmuir, Freundlich, Temkin, and Dubinin Radushkevich models. The adsorption kinetics were analyzed using pseudo-first-order, pseudo-second-order, Elovich and intraparticle diffusion models and the adsorption data were well described by the pseudo-second-order model. Thermodynamic parameters such as the Gibbs free energy (ΔG), enthalpy (ΔH), and entropy (ΔS) changes were also evaluated and it has been found that the adsorption process was feasible, spontaneous, and endothermic in the temperature range of 278-313 K.
AtıfScopus19WoS20OpenAlex19
İncele - MakaleAçık Erişim2014Scopus SJRQ2Kinetics, thermodynamics, and equilibrium evaluation of adsorptive removal of methylene blue onto natural illitic clay mineral
Ozdes, Duygu; Duran, Celal; Senturk, Hasan Basri; Avan, Hilal; Bicer, Burcin
The natural illitic clay mineral (NICM) has been used as a low cost and highly effective adsorbent in the removal of a toxic cationic dye, methylene blue (MB), from aqueous solution by a batch adsorption technique. The effects of experimental parameters such as initial pH of the aqueous solution, contact time, initial MB concentration, adsorbent concentration, ionic strength, and temperature were studied in detail upon the adsorption process. The process was found to be independent of initial solution pH and the adequate equilibrium time for the adsorption of MB onto NICM was only 60 m. The experimental data were analyzed by the Langmuir, Freundlich, Temkin and Dubinin-Radushkevich isotherm models and showed a good fit with both the Langmuir and Freundlich isotherm models. The monolayer adsorption capacity of NICM was found to be 24.87 mg g-1 by using Langmuir isotherm model. The kinetics of the adsorption were tested using pseudo-first-order, pseudo-second-order, and intraparticle diffusion models. The results showed that the adsorption of MB onto NICM proceeds according to the pseudo-second-order model. Thermodynamic parameters indicated that the present adsorption process was feasible, spontaneous, and endothermic in nature.
AtıfScopus45WoS39OpenAlex51İncele - MakaleYalnız künye2013Scopus SJRQ2Biosorption properties of Morus alba L. for Cd (II) ions removal from aqueous solutions
Serencam, Huseyin; Ozdes, Duygu; Duran, Celal; Tufekci, Mehmet
The abundantly available industrial waste product Morus alba L. pomace (MAP) is one of the cost-effective biosorbent for removal of metal ions from aqueous solutions. Hence, in the present study, we aimed to test the ability of MAP to remove Cd(II) ions through batch biosorption process. Firstly, MAP was characterized using several techniques, and then the influence of various experimental parameters such as initial pH of the aqueous solution, initial Cd(II) concentration, contact time, MAP concentration, and temperature were evaluated upon the biosorption process. It was found that the maximum uptake of Cd(II) ions occurred at initial pH 6.0 and optimum contact time was observed as 60 min. Cd(II) ions adsorption on MAP analyzed by the Langmuir and Freundlich isotherm models and the maximum monolayer biosorption capacity of MAP was found to be 21.69 mg g-1 by using the Langmuir isotherm model. The pseudo-first-order, pseudo-second-order, Elovich, and intraparticle diffusion models were employed to describe the biosorption kinetics. In order to investigate the thermodynamic properties of the biosorption process, the changes in the Gibbs free energy (â̂†G), enthalpy (â̂†H), and entropy (â̂†S) were also evaluated and it has been concluded that the process was feasible, spontaneous, and endothermic in the temperature range of 5-40 C.
AtıfScopus38WoS36OpenAlex46
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