Chemical control of struvite scale by a green inhibitor polyaspartic acid

Abstract

A green scale inhibitor, polyaspartic acid, is reported for the first time to effectively inhibit struvite formation and promote struvite dissolution.

Controlled Synthesis of Struvite Nanowires in Synthetic Wastewater

“…In short, it is obvious that struvite crystals get slenderer with pH i increase in the presence of 3.5 wt % NaCl. This variation trend of struvite agrees well with our previous study dealing with the effect of polyaspartic acid on struvite growth and the results reported by Ma et al in the absence of NaCl. This is because high precipitation rate and changes in aqueous speciation decrease the activities of Mg 2+ (aq), NH 4 + (aq), and PO 4 3– (aq), leading to the limitation of struvite growth at higher pH i .…”

“…As shown in Figure c and d, the Raman vibrational bands of the nanowire are in good agreement with the reported pure struvite, further confirming that the nanowires are struvite. After a series of tedious FESEM analyses, however, a slice of plate-like structure was found (Figure S1 of the Supporting Information), resembling the appearance of cattiite reported in our previous study . EDX analysis (inset in Figure S1) reveals that the plate-like crystal contains Mg, P, and O elements, corresponding to the elemental composition of cattiite.…”

“…It has been reported that several physicochemical parameters such as pH, mixing energy, and foreign ions can influence the particle size of struvite. , Matynia et al observed that an increase of pH from 8 to 11 can lead to about 5.5-fold decrease of the mean crystal size of struvite . Our previous study also found that the struvite crystals become slimmer with the increase of pH . Mixing energy is another parameter that can exert an influence on struvite crystal size and shape, and more elongated struvite crystals were harvested in lower mixing speeds .…”

“…All the experiments were conducted at a constant temperature of 25 ± 1 °C. Synthetic wastewater was prepared according to our previous study . That is, 0.0407 g of MgCl 2 ·6H 2 O was dosed to 40 mL of deionized water in a 50 mL beaker under vigorous stirring to form solution A.…”

“…35 Our previous study also found that the struvite crystals become slimmer with the increase of pH. 36 Mixing energy is another parameter that can exert an influence on struvite crystal size and shape, and more elongated struvite crystals were harvested in lower mixing speeds. 37 Moreover, the presence of foreign ions is also known to affect struvite crystallization.…”