Controlled Synthesis of Struvite Nanowires in Synthetic Wastewater

Abstract

Controlled struvite crystallization is regarded as a promising route to phosphorus recovery from wastewaters, and has been the topic of extensive research in the last two decades. Most studies made great efforts to elevate the quantity of struvite recovered from various wastewaters, but little attention has been focused on the struvite quality which affects the agronomic response. The improvement of struvite quality can raise its value in fertilizer markets and improve the economical sustainability of struvite crystallization technology. In this study, we report a facile method for the synthesis of struvite nanowires by regulating NaCl concentration and initial pH (pH i ) in synthetic wastewater. The identification and characterization of the synthesized products were done using X-ray powder diffraction, field emission scanning electron microscopy, energy dispersive X-ray spectroscopy, Raman spectroscopy, nuclear magnetic resonance spectroscopy, X-ray photoelectron spectroscopy, and Zeta potential Analyzer. Our results reveal that both NaCl concentration and pH i play important roles on the phase composition and morphology of products in the crystallization system. In particular, a mass of struvite nanowires with high yield can be obtained at NaCl concentration ranging from 3.5 to 4.5 wt % at pH i 11.0, and the mechanism for the formation of struvite nanowires was systematically investigated. As struvite has been regarded as a fertilizer, struvite nanowires can potentially act as a new kind of nanofertilizer with higher efficiency.

Engaging a Battle on Two Fronts: Dual Role of Polyphosphates as Potent Inhibitors of Struvite Nucleation and Crystal Growth

“…The formation of inorganic scale, such as struvite (MgNH4PO4ˑ6H2O), is often an unwanted outcome that negatively impacts the efficiency of commercial processes, such as water treatment [1][2][3][4][5][6][7][8][9][10][11] , and is implicated in pathological diseases, such as infection stones 12,13 . Management of patients with infection stones is challenging due to the high recurrence rates, and without appropriate treatment can result in death from sepsis.…”

Fabrication of Pd/Mg2P2O7 via a Struvite‐Template Way from Wastewater and Application as Chemoselective Catalyst in Hydrogenation of Nitroarenes

“…As shown by XRD patterns in Figure 1, the as‐synthesized struvite was demonstrated to have a distinctive orthorhombic structure by indexing intensity and position of XRD reflection peaks to the database for mineral identification. The result implied the main crystalline phase was well indexed to struvite [Mg(NH 4 )PO 4 ⋅ 6H 2 O] (PDF# 15–0762) with minor cattiite [Mg 3 (PO 4 ) 2 ⋅ 22H 2 O] [29] . The same orthorhombic system Mg 2 P 2 O 7 was confirmed after pyrolysis of struvite, that is, after release of some gaseous substances.…”

“…As shown by XRD patterns in Figure 1, the as-synthesized struvite was demonstrated to have a distinctive orthorhombic structure by indexing intensity and position of XRD reflection peaks to the database for mineral identification. The result implied the main crystalline phase was well indexed to struvite [ [29] The same orthorhombic system Mg 2 P 2 O 7 was confirmed after pyrolysis of struvite, that is, after release of some gaseous substances. In this research the Pd nanoparticles were synthesized according to the previous method, [30] and the face-centered cubic structure of Pd (PDF#46-1043) was ob- served based on plans of (111), (200), and (220) as shown in the XRD pattern (Figure S1 in the Supporting Information).…”

“…Currently the high concentration of phosphate and ammonium was found in many lakes of east China, and the eutrophication pollution was serious. [3] To reconcile eutrophication, a good choice is to precipitate the soluble N, P nutrients and transform them into inorganic minerals, that is, to mineralize such pollutants. [4] Struvite is one of the common N-and P-containing minerals with a formula of MgNH 4 PO 4 • 6 H 2 O, sometimes been referred to the misnomer "triple phosphate".…”

“…Although nitrogen and phosphorus are essential nutrients for bioactivities, [1,2] over enrichment with such nutrients can be an environmental concern for rivers, lakes, wetlands, streams, and reservoirs worldwide. Currently the high concentration of phosphate and ammonium was found in many lakes of east China, and the eutrophication pollution was serious [3] . To reconcile eutrophication, a good choice is to precipitate the soluble N, P nutrients and transform them into inorganic minerals, that is, to mineralize such pollutants [4] .…”