| Abstrakt: |
Nanoparticles of mixed n(Zr-Ce-Sm) oxide of crystalline size 11.7 nm are successfully synthesized by new green methods adopting Aloe vera gel as capping agent and evoking the principles of classical methods of homogenous precipitations. An active carbon is derived from stems of Artocarpus heterophyllus plant. The Artocarpus heterophyllus active carbon (AHAC), active carbon loaded with nanoparticles 'AHAC + n(Zr-Ce-Sm) oxide' and iron alginate beads doped with their admixture, 'AHAC + n(Zr-Ce-Sm) oxide-Fe.Ali', are investigated for their effectiveness for the simultaneous removal of lead and cadmium ions from water. Different extraction conditions are optimized for the maximum efficiency of the three sorbents by batch methods. The sorbents have shown good sorption nature for both the toxic ions at the pHs: 6.0 for active carbon, 6.5 for admixture and 7.0 for beads respectively at different equilibration times and dosages. The maximum adsorption capacities for Pb2+/Cd2+ ions are as follows: 15.0/20.0, 28.0/32.6, 34.0/44.3 mg/g for AHAC, admixture and beads respectively. The sorbents are characterized for various physicochemical parameters and structural aspects using XRD, FTIR, EDX and FESEM. The effects of co-ions on the simultaneous extraction are investigated. The mechanism of the adsorption process is analysed based on thermodynamic data and applicability of isotherms and kinetic models. Based on these, the mechanism of adsorption process involves the formation of a surface complex and/or ion-exchange between Pb2+/Cd2+ with the surface functional groups of adsorbents. The same is confirmed by IR investigations. The spent adsorbents can be regenerated and reused. The adsorbents developed are successfully used to treat the industrial waste water samples. The merit of this investigation is that the effective sorbents with high adsorption capacities are developed for the simultaneous remove of the highly toxic lead and cadmium ions from industrial wastewater. [ABSTRACT FROM AUTHOR] |
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