The effect of temperature from 25 to 300 degrees C on the precipitation of phosphorus (P) from struvite-saturated (MgNH4PO4 center dot 6H(2)O) solutions was explored. Scanning electron microscopy (SEM) revealed reduced particle size and a change in morphology from elongated to rhombohedral crystals with temperature. X-ray diffraction (XRD) and Fourier transform infrared spectroscopy (FT-IR) indicated that at 25 degrees C, the precipitate was struvite, while newberyite (MgHPO4 center dot 3H(2)O) formed at 100 degrees C, and magnesium pyrophosphate (Mg2P2O7) at 300 degrees C. Increased temperature reduced the association of ammonium and water of crystallization with the solid and increased P polymerization. The behavior of dissolved chromium (Cr) under these conditions was also assessed. Removal of Cr with the solid phase from Cr(III) solutions was observed at all temperatures, whereas removal from Cr(VI) solutions was significant only at 300 degrees C. X-ray absorption fine structure spectroscopy (XAFS) revealed that regardless of initial oxidation state in solution, Cr(III) was associated with the solid, interacting by the adsorption of short-range Cr polymers. Therefore, for struvite-saturated solutions, increasing the temperature changed both the mineralogy of the P phase recovered and enhanced the interaction of otherwise unreactive Cr(VI) with the substrate. These results have implications for the temperature-enhanced recovery of P from wastewater. (c) 2012 Elsevier Inc. All rights reserved.