The Studaying Of The Novel Scale Inhibitor For Reverse Osmosis Systems And Evaluation Of Scale-Inhibition

The technical background of this thesis is based on the research of a novel scale inhibitor and evaluation of scale inhibition. The aim of this thesis is to develop a high efficient scale inhibitor which can substitute the normal imported scale inhibitors in reverse osmosis systems (RO) in order to reduce water treatment cost. Copolymers of acrylic acid/acrylamide were synthesized using peroxide as initiator and water as solvent. The best technique condition was confirmed by orthogonal experiments, and the effects of the amount of initiator, synthetic temperature and the weight ratio of acrylic acid and acrylamide on scale-inhibition were investigated. The copolymer synthesized at the best technique condition was named as YSW-21, and the qualifications of YSW-21were mensurated, molecular weight was determined by GPC, and the viscosity and the molecular weight of YSW-21vs. the effectiveness of scale inhibition were studied. And the structure of YSW-21was characterized with IR and NMR. The effectiveness of YSW-21for CaSO4and CaCO3depositions was obtained with beaker tests. Crystals of CaSO4were analyzed by XRD to study the scale-inhibition mechanism. The results are follows:1. The performance of copolymer inhibitor was greatly influenced by the amount of initiator, synthetic temperature and the weight ratio of acrylic acid to acrylamide, and the effectiveness of the copolymer synthesized at the conditions of the amount of initiator C4, synthetic temperature B2and the ratio of acrylic acid’s weight to acrylamide’s A3is the highest. YSW-21’s scale-inhibition was directly affected by viscosity or Molecular weight of copolymer. When the viscosity of YSW-21is in the rage of6.8-7.3mL/g or molecular weight is in the rage of4000～6000, the effectiveness of YSW-21on controlling scales is much better.2. YSW-21as scale-inhibitor for RO system possesses quite good effect on controlling CaSO4and CaCO3depositions, and at the conditions of high Ca2+ions and8mg/L of dose, the effectiveness of scale inhibition for CaSO4reaches91.2%, and the effectiveness of scale inhibition for CaCO3also gets upwards of85%. Ca2+, SO42-and pH value could hardly influence the efficiency of YSW-21on controlling CaSO4deposition. And the efficacy can maintain for102hours under25℃, even at the temperature of60℃, it can keep80hours. Compared with the normal imported scale inhibitor Flocon-135at the same conditions, YSW-21performances are much more excellently on tolerance for Ca2+, Fe2+, Sr2+and Ba2+, and more easily cooperates with flocculation and disinfectant.3. The scale was detected by XRD, and the results showed YSW-21had an excellent crystal modification effect on calcium sulphate crystal. It would make calcium sulphate crystal more loose and difficult to deposit.On the whole, YSW-21is a kind of no phosphor scale inhibitor with high performance/price ratio which has wonderful and steady scale-inhibition, and can replace the normal imported scale inhibitors for RO systems at all, so that the cost of water treatment can be reduced. Therefore, YSW-21would possess favorable market in the future.