Recovery of orthophosphate ions from aqueous solutions using La/GO composites
| Autor: | Shan-Shan Chu, 朱珊姍 |
|---|---|
| Rok vydání: | 2019 |
| Druh dokumentu: | 學位論文 ; thesis |
| Popis: | 107 Graphene oxide (GO)/Lanthanum oxide (La2O3) composites (abbreviated as La/GO) were employed as adsorbents to study the removal of orthophosphate (PO43－) from industrial effluents. The effects of different adsorbents and composite ratio for PO43－adsorption was first investigated. The adsorption performance under various water quality factors and the adsorption/desorption operations were then studied. La/GO showed the best performance on PO43－ adsorption as compared to other adsorbents. The adsorption amounts of PO43－ were 49.94 and 148.44 mg/g with initial concentrations of 50 and 200 mg/L, respectively. The adsorption amounts of PO43－ increased as the solution ionic strength increased but decreased as the solution pH value decrease probably due to the increase of H+ which enhances the surface positively charged surface of La/GO. In the alkaline conditions, the adsorption amounts of PO43－ decreased probable because of the competitive adsorption between PO43－ and OH－. In the temperature experiments, PO43－ is easily adsorbed in the high temperature indication that adsorption process is endothermic. From the results of Langmuir model, adsorption of PO43－ to La/GO surface is s monolayer adsorption. Thermodynamics indicate that adsorption process is spontaneous. Desorption results indicated adsorbed PO43－ on La/GO could be readily desorbed by NaOH solution and could be employed in the cyclic recovery with adsorption/desorption of PO43－ from wastewater. In summary, the La/GO composites possess good performance for adsorption/desorption of PO43－and possibly become promising adsorbents for PO43－ recovery in wastewater treatment of high-tech industrial effluents. |
| Databáze: | Networked Digital Library of Theses & Dissertations |
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