Phosphorus recovery as struvite from eutropic waters by XDA-7 resin

Abstract

Phosphorus releases into aquatic environment and its subsequent contribution to eutrophication have resulted in a widespread global pollution issue. However, phosphorus is a non-renewable source. The potential supplies of phosphorus are decreasing worldwide. Therefore, removal and recovery of phosphorus from the eutropic waters is important, emergent and necessary. In this research, experiments for recovering phosphate from eutropic waters by anion exchange combined with struvite precipitation were conducted. The results indicated that the prepared XDA-7 resin was an effective adsorbent for phosphate. The adsorption isotherm of XDA-7 resin was found to be a modified Freundlich type. The maximum phosphate adsorption (20.9 mg/g) occurred in the pH range of 6.0-8.0. Phosphate adsorbed on the XDA-7 resin was effectively desorbed with 8% NaCl solution, and the resin was able to be regenerated with 3% NaClO and 4% NaOH solutions. Phosphate desorbed from the resin was recovered as magnesium ammonium phosphate (struvite). The obtained struvite was analyzed by acid dissolution method, scanning electron microscope (SEM) and Fourier transform infrared spectroscopy (FTIR). The struvite precipitate was found to be 75.8% in purity, a high-value fertilizer.

Removal of Phosphate by Ion Exchange Resin: Kinetic and Thermodynamic Study

“…On the other hand, at high concentrations, the formation of ion aggregation prevents the penetration of the phosphate ions into the particles of the resin and the exchange process becomes slow 15 , this phenomenon can be translated by the appearance of a saturation plateau (Fig. -2), which indicates any further addition of phosphate ions will be meaningless.The maximum adsorbed amount was 120.63 mg/g, this quantity is higher compared to the quantity eliminated by other resins like macroporous resin XDA-7 (20.9 mg/g) 16 and a strong base resin Dowex 21KXLT (39 mg/g) 17 . Table-1 summarized adsorption maximum capacity of some other adsorbents used for phosphate removal from aqueous solution.…”

Fixed Bed Adsorption Study on Phosphate Removal Using Nanosized FeOOH‐Modified Anion Resin

“…by the formation of inner-sphere surface complexes between phosphate and FeOOH [23,24]. The adsorption performance of nanosized FeOOHmodified anion resin was much better than some other kinds of anion resin (with adsorption capacity of 12.09 [25], 20.9 [26], and 26.5 mg/g [27], resp. ).…”

pH Effect on Phosphorus Removal in Synthetic Wastewater by Using Electric Arc Furnace Lab-Scale Filter

“…The pH value below 6 is a dominant chemical precipitation while above 8 is adsorption. Adsorption of phosphate ion is effective to adsorb phosphate ion at a pH of 5-8 as mentioned by [4] while [8] stated that adsorption occur at pH 6.0 -8.0. Adsorption efficiency has a great impact on substrates by chemical composition and the adsorbent usually contain alumina, iron, magnesium and calcium oxide, which is can contribute to phosphorus removal by using precipitation and adsorption processes.…”