Performance of an environmentally friendly anti-scalant in CaSO4 scale inhibition

Abstract

2015) Performance of an environmentally friendly anti-scalant in CaSO 4 scale inhibition, Desalination and Water Treatment, 53:1, 8-14, A B S T R A C TThe precipitation of calcium sulfate (CaSO 4 ) scale on heat transfer surfaces widely occurs in numerous industrial processes. For the control of calcium sulfate scale, a novel environmentally friendly type of scale inhibitor Acrylic acid-oxalic acid-allypolyethoxy carboxylate (AA-APEM9) was synthesized and characterized, and the anti-scale property of the AA-APEM9 copolymer towards calcium sulfate in the artificial cooling water was studied through static scale inhibition tests. It was shown that AA-APEM9 exhibited excellent ability to control calcium sulfate scale, with approximately 97.1% calcium sulfate inhibition at a level of 4 mg/L AA-APEM9. Scanning electron microscopy and X-ray powder diffraction studies have been performed to identify the change in crystal surfaces by the addition of the copolymer. Inhibition mechanism is proposed that PAA can recognize and react with positively charged calcium ions on the surface of inorganic minerals and water-compatible PEG segments increase its solubility in water.

A Comparative Performance Evaluation of Some Novel “Green” and Traditional Antiscalants in Calcium Sulfate Scaling

“…For 3 mg⋅dm −3 reagent dosage, a further differentiation between PAAS (3000-5000 Da), HEDP, and PBTC becomes possible: PAAS (3000-5000 Da) > PBTC > HEDP. In Table 3, our ranking is presented along with literature data [7,9,[12][13][14][15][16][17][18][20][21][22]. Surprisingly, the results of all known comparative studies of the inhibitor efficiency are obtained under different experimental conditions and none of them follow NACE protocol.…”

“…Increasing environmental concerns and discharge limitations have forced the scale-inhibitor chemistry to move toward "green antiscalants" that are readily biodegradable and have minimal environmental impact. Intensive efforts are applied recently to develop the "green" alternatives to organophosphonates and nonbiodegradable polyacrylates [2,4,[7][8][9]. Among these novel inhibitors, such chemicals as polymaleates (PMA), polyaspartates (PASP), and polyepoxysuccinates (PESA), as well as their various derivatives including copolymers with PA, are the most promising.…”

“…It is important to note that the new antiscalants should have acceptable levels of performance at cost-effective dose rates. This requirement raises a problem of reliable tests, which permit a correct "old red" and "novel green" inhibitors 2 Advances in Materials Science and Engineering efficiency comparison [8][9][10][11][12][13][14][15][16][17][18][19][20][21][22]. Unfortunately, most of the data published on calcium sulfate deposition are considering a single antiscalant or a single group of similar reagents studied under hardly comparable conditions [8-11, 19, 21, 22], for example, different supersaturation index, brine composition, temperature, and measurement technique.…”

Effect of Cu2+ on the nucleation kinetics and crystallization of rod-shaped CaSO4·2H2O in aqueous solution

“…Numerous investigations on the inorganic and organic additives affect the crystallization have been well documented. [21][22][23][24][25][26] Organic acids and carboxyl-rich polymers such as fulvic acid (FA), 27 sodium dodecyl sulfonate (SDS), 28,29 and polyacrylic acid (PAA) 30 have been shown to be particularly effective in inhibiting induction period for crystallization. The mechanism of action of organic additives is mainly to complex the active groups of organic substances or to adsorb Ca 2+ in aqueous solution, reduce the supersaturation of the system to prolong the induction time of DH crystals, and form a shell-like structure on the surface of the crystal.…”

Simple and Rapid High-Yield Synthesis of Sub-100 nm Nano-SiO2·0.5H2O Particles Based on Wollastonite

“…The effort of using wollastonite as the cheap silicon source made the cost down. The by-product CaSO 4 could also help reduce the production cost because it is widely used as the green environmentally friendly material [26]. The novel preparation method provides a pathway to control the agglomeration and improve the dispersity of nano-SiO 2 •0.5H 2 O particles.…”