Performance on calcium scales inhibition in the presence of a novel double-hydrophilic block terpolymer

Abstract

An effective method for controlling scale formation in circulating cooling water system is the use of scale inhibitors. A novel multi-functional scale inhibitor AA-APES-H 3 PO 3 terpolymer, was prepared by acrylic acid (AA), ammonium allylpolyethoxy sulfate (APES), and phosphorous acid (H 3 PO 3) and the structural properties were identified by Fourier transform infrared and 1 H-NMR. The inhibitory power of the terpolymer was determined by using a static scale inhibition method. The polymer's effectiveness on calcium scales was assessed by using X-ray diffractometer, scanning electron microscopy (SEM) and transmission electron microscopy (TEM). It is shown that AA-APES-H 3 PO 3 terpolymer exhibited an excellent ability to control the formation of CaCO 3 scale at a mole ratio of 2/1 (AA/APES) with an inhibition efficiency of 92.6% at a level of 8 mg L-1 , and at the same time, it maintained a superior efficiency even at increasing solution temperature, pH value, and Ca 2+ concentration. Compared with commercial inhibitors, the order of preventing the precipitation of calcium carbonate was AA-APES-H 3 PO 3 > EDTMP > HEDP > PESA > PAA. Also the terpolymer displayed a superior ability to prevent calcium phosphate with approximately 100% inhibition efficiency at the dosage of 6 mg L-1 .

Synthesis and performance evaluation of carboxyl‐rich low phosphorus copolymer scale inhibitor

“…Figure 12a exhibited the XRD spectra of calcium carbonate crystals without and with the addition of IA‐MA‐SHP. Calcite, aragonite, and vaterite are three mineral phases of CaCO 3 33,34 . As shown in Figure 12a, the main diffraction peaks of CaCO 3 in the absence of copolymer are distributed on the (104) plane, corresponding to the characteristic peaks of calcite crystals.…”

“…In Figure 12b, with the addition of the copolymer, in addition to the (104) (113) and (202) crystal faces corresponding to calcite peaks, the (110), and (300) crystal faces corresponding to the characteristic peaks of Vaterite and the (122) crystal face corresponding to the characteristic peak of aragonite appear. These results indicate that the copolymer can inhibit or interfere with the growth of calcite and induce the growth of Vaterite and aragonite, making it difficult to adhere to the material surface and easy to disperse in aqueous solutions 34 …”

“…The low phosphorus copolymer IA‐MA‐SHP contains both carboxyl and phosphonate groups in one molecule, and the carboxyl and phosphonate groups can chelate the positively charged Ca 2+ , 34,38 which allows the copolymer to strongly adsorb to the crystalline matrix of calcium scale and interfere with further crystal growth, 38 which includes adsorption, nucleation and crystal growth processes. It was observed in static experiments that supersaturated solutions without scale inhibitors would rapidly become turbid, while supersaturated solutions with scale inhibitors would remain clarified.…”

Preparation of carboxy sulfonic acid‐containing copolymer scale inhibitors and their scale inhibition effect on CaCO3

“…From Figure 8a, it can be seen that the CaCO 3 crystals untreated with scale inhibitor showed calcite structure with regular rhombic-hexahedral shape, smooth surfaces, and directional stacking growth. 4,31 The structure of the CaCO 3 scale was significantly impaired by the addition of a 10 mg L À1 scale inhibitor (Figure 8b), where CaCO 3 crystals lost their sharp edges and the morphology changed from rhombic to fragments with relatively loose stacking. At a concentration of 20 mg L À1 (Figure 8c), oblate spherical particles with sharp edges completely disappeared and the crystals were completely twisted and distorted can be seen in the SEM images.…”

“…14,28 Phosphorus-containing scale inhibitors have not been prioritized because they hydrolyze under certain conditions, producing insoluble calcium phosphate precipitates and discharging phosphorus, leading to water pollution. [29][30][31] Given the above points, we tried to introduce amide and sulfonic acid functional groups into the copolymer to obtain a scale inhibitor with temperature and salt resistance.…”