Double-hydrophilic polyether antiscalant used as a crystal growth modifier of calcium scales in cooling-water systems

摘要

In this study, we synthesized a novel double-hydrophilic poly(ethylene glycol) (PEG)-based crystal growth modifier polyethylene glycol double-ester of maleic anhydride/ acrylic acid named PEGDMA/AA, whose structure was still linear but also had some differences from a traditional chelating linear polymer, in which the PEG segment was incorporated. The scale inhibition behavior of PEGDMA/AA was evaluated by means of a static scale inhibition method. As the polymerization degree of PEG_nDMA was 8 (n = 8), the maximum inhibitory toward calcium carbonate (CaCO_3) and calcium sulfate (CaSO_4) were 89.0 and 98.8% at dosage levels of 12 and 3 mg/L, respectively. Comparisons with other inhibitors were also carried out. Characterization of the CaCO_3 and CaSO_4 scales with scanning electron microscopy and transmission electron microscopy proved that great changes in the size and morphology of the calcium scales took place under the influence of PEG_8DMA/AA. X-ray diffraction and diffraction patterns further confirmed the impact of PEG_8DMA/AA as a crystal growth modifier. The three supposed mechanisms, (1) chelating solubilization, (2) multilayer type of adsorption, and (3) electrostatic repulsion function, are also described in detail.