Evaluation of Phosphorus Removal from Aqueous Solution by using Metal-Loaded Orange Waste

B.K. Biswas, K. Inoue, K. Ohto, H. Harada, and H. Kawakita (Japan)


Phosphorus, orange waste, wastewater treatment, biodegradable material, adsorptive removal.


Efficient and cost effective non-conventional adsorption gels were prepared from orange waste by saponification, which is followed by immobilization with metal ions (La(III), Ce(III) and Zr(IV)). Such immobilization facilitated to improve adsorption capacities as well as diminish aqueous solubility. The adsorptive behavior of the gels for phosphate was investigated and it was found that the gel loaded with zirconium exhibited excellent adsorption capacity (57 mg-P/g), which was higher than that of commercial adsorbents. A ligand exchange mechanism was postulated as the predominant process of the adsorption. Kinetic studies at various temperatures confirmed an endothermic adsorption process, which followed the pseudo-second-order rate law. Continuous flow experiments for phosphorus demonstrated that the gels can be useful for preconcentration and complete removal of phosphorus. Consistent nine consecutive adsorption-elution cycles revealed the stability and efficiency of the Zr(IV)-loaded orange waste gel for recycling purpose.

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