Abstract
The feasibility of using nano-cryptomelane for elimination of cobalt and cesium metal ions from their single and binary solutions was studied. In this respect, the material was prepared and characterized to confirm its chemical composition and structure. Results illustrate that the synthesized nano-cryptomelane has a tunnel structure with particle size ranged between 4 and 6 nm. The material feasibility was detected by conducting a series of batch experiments for determination of the kinetic and equilibrium performance of the removal process. All characteristic Raman bands for Mn–O lattice vibrations within the (2 × 2) tunnel structure of MnO6 octahedral are observed which confirm formation of nano-cryptomelane. The specific surface area (SSA) for nano-cryptomelane was calculated and equal to 299.03 m2/g while the surface fractal information (Ds) was2.53. The process sensitivity to changes of H+ concentration is attributed to changes in structural elements-species distribution at the solid/aqueous interface. The pH optimum value was desired at pH 5 for exchange of Cs+ and/or Co2+ with K+ ions. The equilibrium studies show that Langmuir isotherm model was more fitted to the experimental data than that of Freundlich model.
Highlights
The amassing of hazardous metal ions through the food chain accompanied with a harmful effects for the human health to reduce these effects and for environmental protection, sequestration of these contaminates from wastewater is very important process
The previous work illustrated that nano-cryptomelane can be synthesized using several methods such as sol–gel route, hydrothermal treatment procedure of birnessite and oxidation of Mn2+ by KMnO4, H2O2 or K2S2O8 in acidic refluxing conditions.The main target of this work is utilization of synthesized nano-cryptomelane for retention of cesium and cobalt metal ions from single and binary solutions
The low-frequency Raman bands at 183 and 286 cm−1are ascribed to an external vibration that derives from the translational motion of the MnO6 octahedral; the Raman bands at 330 and 386 cm−1 are specific to the Mn–O bending vibrations; The Raman bands located at 512 and 574 cm−1 may attributed to displacement of the oxygen atoms relative to the manganese atoms along the octahedral chains
Summary
The amassing of hazardous metal ions through the food chain accompanied with a harmful effects for the human health to reduce these effects and for environmental protection, sequestration of these contaminates from wastewater is very important process. Keywords Nano-cryptomelane · Binary solution · Cobalt · Cesium · Sorption Nano sized metal oxides (NMOs) have a high specific tendency for sorption of metal ions from liquid solutions; the most widely studied ones are aluminum oxides, titanium oxides, cerium oxides and manganese oxides.
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