Microstructure of gamma-ray developed polymeric nanocomposite respecting cesium and cobalt removal from aqueous...

The nanoparticles of fly ash (FA) were obtained by high energy ball milling of their parent Class C kind for subsequent synthesis of poly(acrylamide-acrylic acid)/fly ash (poly(AM-AA)/FA) nanocomposite. The gamma-radiation induced polymerization was applied to achieve this concern. Different techniques were utilized to characterize such nanocomposite. The sorption abilities of the synthesized nanocomposite toward ⁶⁰Co²⁺ and ¹³⁴Cs ⁺ radionuclides were evaluated using batch and fixed-bed column approaches. Batches were designed at constants of solution pH (6.5-7.0 ± 0.02), nanocomposite particle size and dosage (106-250 μm and 0.1 L/g, respectively). The microstructure of such nanocomposite (<100 nm) was mainly amorphous with porous rough surfaces containing homogenous distribution of the incorporated nano-FA. About 56.46 and 47.9 mg/g of Co²⁺ and Cs⁺ were sorbed at equilibrium with an ion exchange reaction mechanism. Langmuir, Freundlich and Dubinin-Radushkevich D-R isotherm model parameters were calculated indicating the favorability of all sorption processes. The spontaneous and endothermic natures of sorption were observed by the calculated ΔG^° and ΔH^° thermodynamic parameters, respectively. Thomas, Yoon-Nelson and Adams Bohart models were fitted to the fixed-bed column data at varied conditions. The predicted sorption capacities of Thomas were very close to those obtained experimentally. Modeling of the fixed-bed column data dominates that the external mass transfer kinetics was predominant in the initial parts of the fixed-beds. Values required for retaining 50% of the initial sorbate concentration were extended from 89.05 to 68.55 to 177.2 and 149.3 min for ⁶⁰Co²⁺ and ¹³⁴Cs ⁺ radionuclides, respectively, by increasing bed depth from 1.5 to 3.0 cm. Modification of FA to its nano-scale form with the subsequent synthesis of a nanocomposite material having sorption capabilities made a duplicate beneficial environmental concern.