Evaluations of pH and High Ionic Strength Solution Effect in CadmiumRemoval by Zinc Oxide Nanoparticles

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作者：

MH Salmani，S Zarei.，MH Ehrampoush，S Danaie.

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摘要：

For human and environmental health protection, it is necessary toremove excess cadmium in industrial wastewaters before discharging themto environment. Some laboratory experimental batch study was done toevaluate the effects of the initial cadmium concentration, adsorbentdose, pH, ionic strength, and contact time on the cadmium removalefficiency by zinc oxide nanoparticles. All tests were performed in 100ml solution at constant temperature of 25°C and mixing rate of 150rpm. The residual cadmium concentration in the solution was determinedusing flame atomic absorption spectroscopy. Statistical analyses wereperformed on data using SPSS16 software by applying Mann-Whitney andKruskal-Wallis tests and the result designing graphs were providedusing Excel software. Finally, experimental data were analyzed usingadsorption isotherm and kinetic equations. The results show thatcadmium removal efficiency increases with an increase in the adsorbentdose and contact time and decreases with the increase in initialconcentration of cadmium. Furthermore, it is observed that by raisingthe ionic strength of solution 30 fold, the adsorption rate isincreased from 90.7% to 62.3%. Due to regression coefficient(≥0.99), the adsorption process follows Langmuir isotherms modeland pseudo-second order equation. Attending to the outcomes, zinc oxidenanoparticles have proper efficiency in the removal of cadmium fromaqueous solutions. So, they can be used in treatment of the wastewaterscontaining cadmium ions. However, its efficiency is deeply dependant onthe ion strength and the interactions of other metals in wastewater.

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关键词：

cadmium ionic strength adsorption zinc oxide nanoparticles

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年份：

2014