Effective removal of radioactive 90Sr by CuO NPs/Ag-clinoptilolite zeolite composite adsorbent from water sample: isotherm, kinetic and thermodynamic reactions study

Abstract

In this research, the natural zeolite named clinoptilolite (NCp) was considered as an applicable base structure for subsequent preparation and modification by pre-selected chemical agents to use for removal/adsorption goals in progress. To make Na-clinoptilolite form, the mentioned zeolite undergoes variations by treating with NaCl salt. Ion exchange procedure was utilized to imprint silver ions (Ag ? ) from silver (I) nitrate solution as silver precursor on the modified clinoptilolite zeolite structure to attain Ag-clinoptilolite zeolite. Tenorite (CuO) NPs have been then dispersed and deposited on the external surface of the pre-prepared Ag-clinoptilolite zeolite through impregnation method to prepare the CuO NPs/Ag-clinoptilolite zeolite as a novel composite adsorbent. A series of analyses techniques including SEM-EDAX, XRD and FT-IR were applied for characterization and identification of crystal structure, morphology and elemental composition of the synthesized samples. The removal and adsorption process of radioactive strontium-90 ( 90 Sr) by CuO NPs/Agclinoptilolite zeolite composite adsorbent was exploited under various experimental conditions including pH, amount of adsorbent and the contact time at room temperature and the final optimized procedure used for removal of probable presence of 90 Sr in water sample of Bushehr city. Adsorption isotherm models including Langmuir, Freundlich, Temkin, D-R, H-J and Hasley have been applied and equilibrium adsorption data was better fitted to the Freundlich, Temkin, H-J and Halsey isotherms. The reaction kinetic information was studied by utilizing pseudo first and second orders, Elovich and Intra particle diffusion kinetic models. The adsorption kinetics is finely described by the pseudo second-order model. The energy of activation E a calculated using the Arrhenius equation was found to be 44.75 kJ/mol. Further, the evaluation of the thermodynamic parameters such as DG 0 , DH 0 and DS 0 , denoted that adsorption process of 90 Sr was spontaneous and illustrates a chemical adsorption properties and exothermic nature of the adsorption. The obtained results revealed that 90 Sr ions were removed by CuO NPs/Agclinoptilolite zeolite composite under optimized conditions after 6 h with a yield more than 97 %.

Zeolite Used for Optimized Removal of Radioactive Cobalt with Response Surface Methodology

“…The more the adsorbent dosage will result the better the decontamination factor. Determination of the optimum quantity of adsorbent is a key parameter and affects the whole adsorption process [2,3]. The main adsorption mechanism is that cations in the zeolite structure can exchange with cations in the radioactive solutions freely through the cavities [14].…”

“…Many radioactive elements have a long time of half-life. They are not going to be neutralized easily [3]. Reduction of radioactive waste is necessary owing to human health problems accompanied by the aggregation of radioactive elements [4].…”

Suvremena sredstva za dekontaminaciju bojnih otrova

“…21,34,47,[60][61][62][63][64][65][66] Istraživanja Fig. 6 -Action mechanism of Ag zeolites Y and 2-CEES [67][68] Slika 5 -Mehanizam hidrolitičkog raspada CWA imitanta DMMP na zeolitu 48 Fig. 4 -Brönsted and Lewis acids position in the structure of zeolites 54,56 Osim prirodnih i sintetskih zeolita, u novije vrijeme istražuju se kompozitni zeolitski materijali koji se sastoje od prirodnih zeolita poput klinoptilolita i nanokristalnih metalnih oksida.…”

“…Učinkovitost u uklanjanju radioaktivnog stroncija pokazao je kompozitni materijal CuO NPs/Ag-klinoptilolit koji se sastoji od nanočestica bakrova(II) oksida i srebrnog klinoptilolita gdje su srebrni ioni inkorporirani u strukturu zeolita ionskom izmjenom. [68][69] Osim poroznih materijala, slojevite krutine kao što su gline mogu se razmatrati kao dobri kandidati za uklanjanje kemijskih ratnih agensa. Njihove prednosti, kao što su velika robusnost, dobra kemijska otpornost i mali troškovi proizvodnje, svrstavaju glinu u skupinu obećavajućih katalizatora za oksidaciju CWA.…”

Zeolite-Polymer Composite Materials as Water Scavenger

“…Used as a filler, zeolites confer a certain permeability and selectivity to the composite material [ 41 ] due to their shape discrimination resulting from their narrow pore distribution [ 41 , 42 , 43 ]. As for the powder form, zeolite composite can be used for the removal of polluting cations present in wastewater [ 44 , 45 ]. Patents reporting drying solutions based on zeolitic composite materials are mentioned in the literature [ 46 , 47 ], all of which are trying to exploit the zeolite performance once it is blended into polymers.…”