Synthesis and application of an environmentally friendly antiscalant in industrial cooling systems

Allylpolyethoxy carboxylate macromonomers possessing polyethylene oxygen long chains were synthesized by advanced technology of the polyether cap.A novel double-hydrophilic block copolymer was prepared through free radical polymeric reactions in aqueous solution and its performance on CaCO3 inhibition and dispersancy activity towards Fe2 O3 was evaluated in recirculating cooling water systems.The study shows that acrylic acid-allylpolyethoxy carboxylate has a significant ability to inhibit the precipitation of calcium carbonate and an excellent dispersing capability to stabilize iron Ⅲ in industrial cooling systems. X-ray diffraction shows that there is a number of vaterite crystals in the presence of the phosphorous free and non-nitrogen copolymer. The change in crystal forms is also confirmed by the Fourier-transform infrared spectra the scanning electron microscopy and the transmission electron microscopy. The inhibition mechanism is proposed and it shows that the interactions between calcium and polyethylene glycol PEG are the fundamental impetus for restraining the formation of the scale in cooling water systems.

Preparation and application of a phosphorous free and non- nitrogen scale inhibitor in industrial cooling water systems

A novel environmentally friendly type of calcium carbonate, zinc （Ⅱ） and iron （Ⅲ） scale inhibitor Acrylic acidallylpolyethoxy carboxylate copolymer （AA- APEL） was synthesized. The anti-scale property of the AA-APEL toward CaCO3, zinc （Ⅱ） and iron （Ⅲ） in the artificial cooling water was studied through static scale inhibition tests. The observation shows that both calcium carbonate, zinc （Ⅱ） and iron （Ⅲ） inhibition increase with increasing the dosage of AA-APEL. The effect on formation of CaCO3 was investigated with combination of scanning electronic microscopy （SEM）, transmission electron microscopy （TEM）, X-ray powder diffraction （XRD） analysis and fourier transform infrared spectrometer, respectively. The results showed that the AA-APEL copolymer not only influenced calcium carbonate crystal morphology and crystal size but also the crystallinity. The crystallization of CaCO3 in the absence of inhibitor was rhombohedral calcite crystal, whereas a mixture of calcite with vaterite crystals was found in the presence of the AA- APEL copolymer. Inhibition mechanism is proposed that the interactions between calcium or iron ions and polyethylene glycol （PEG） are the fundamental impetus to restrain the formation of the scale in cooling water systems.