Two New Green Scale Inhibitors in Water Treatment Chemicals
As the environmental protection industry has received strong support from the state, it has driven the rapid development of the water treatment industry. However, the choice of water treatment chemical still needs to choose a quality agent that is harmless to the environment. With the rise of green chemistry, a new class of water treatment chemicals has been developed. Here to recommend green environmentally friendly scale inhibitors.
In recent years, new green scale inhibitors appearing at home and abroad mainly include polyaspartic acid and polyepoxysuccinic acid. Because of their excellent biodegradability and high scale inhibition performance, they are recognized as true green scale inhibitors, and they have become a hot spot in development research.
1. Polyaspartic Acid Scale Inhibitor
Polyaspartic acid (PASP) is a kind of biopolymer developed by marine animal metabolism in recent years. Its molecule contains no phosphorus, no toxicity and no damage to the ecological environment. The utilized polyaspartic acid can be efficiently and stably degraded by microorganisms and fungi into end products that are harmless to the environment.
Therefore, polyaspartic acid (PASP) has good biodegradability. Its excellent scale inhibition and dispersion properties are especially suitable for inhibiting calcium carbonate and calcium phosphate scale in cooling water, boiler water and reverse osmosis membrane treatment.
Polyaspartic acid (PASP) is resistant to high temperatures and good thermal stability and can be used as a water treatment chemical high-temperature water systems. Therefore, it is currently recognized as a new generation of green scale inhibitors and water treatment chemicals. Studies have shown that optimizing the synthesis conditions, adding new functional groups to the PASP backbone through copolymerization and modification, making PASP polyfunctional, is a new trend in PASP scale inhibitor research.
PASP copolymers with a molecular weight between 2 000 and 4 000 have excellent scale inhibition properties. At a dosage of 2 mg/L, it has a 90% inhibition rate for calcium carbonate. The copolymer can also act as a dispersant for the nanomaterial calcium carbonate. Its optimum amount is two percent of the mass of calcium carbonate.
Using MA, ammonia and citric acid as raw materials, a polyaspartic acid copolymer excellent in scale inhibition performance is obtained. The synthesis method is simple, the raw material cost is low, and the industrial production can be carried out, which has a good development prospect.
A phosphonic acid-containing PASP was synthesized from phosphorus trichloride, formaldehyde and polysuccinimide, and its scale inhibition performance was studied.
The test results show that the performance of the calcium carbonate scale containing phosphorus acyl PASP is similar to that of PBTCA and HPA, but the performance of calcium block phosphate and stable zinc salt is superior. The performance of the low-phosphorus drug obtained by compounding with PBTCA, HPA and the like reaches the level of the common organic phosphine agent.
2. PESA scale inhibitor
Polyepoxysuccinic acid (PESA) is a phosphorus-free, nitrogen-free, biodegradable green water treatment agent. The molecule contains two functional groups, a carboxyl group, and an ether group.
Polyepoxysuccinic acid can be compounded with various inorganic scale inhibitors such as inorganic phosphates, organic phosphonates, polyacrylic acids, and polymaleic acids to form low-phosphorus or phosphorus-free scale inhibitors. The dual functions of corrosion inhibition and scale inhibition have a wide application range. PESA is suitable for cooling water treatment under high alkalinity, high hardness, and high-temperature conditions.
Experiments on the inhibition of calcium carbonate by sodium polyepoxysuccinate under different factors show that sodium polysuccinate has high scale inhibition performance and good thermal stability, and is long in high calcium ion concentration and high-temperature water system. Time retention still has a strong inhibitory effect on calcium carbonate.
Experts have carried out some research on the synthesis and scale inhibition performance of PESA. The synthetic raw material is the maleic anhydride, which is hydrolyzed by water and alkali to form maleate. The epoxidation is carried out under the catalysis of peroxide and vanadium catalyst. The reaction produces epoxy succinic acid which is then polymerized under a rare earth catalyst to give PESA.
Green chemistry is the development direction of scale inhibitors in the 21st century. Therefore, future work should focus on the three major objectives of performance, economy and environmental protection. On the basis of further improving existing products and improving quality, mechanism research and compounding research should be strengthened to reduce costs and reduce pollution.
In terms of new product synthesis, IRO has broken through existing ideas and actively utilized green chemical technology. First, the target molecule is green, using a clean process, synthesizing phosphorus-free, non-nitrogen, non-toxic, and easily biodegradable, truly environmentally friendly and effective scale inhibitor to completely replace the phosphorus-containing formula.
For the development of new varieties of water treatment agents, the overall idea of IRO is to synthesize more efficient and multifunctional agents through the combination of different monomers such as phosphono, amine, hydroxyl, amino, and sulfonic acid groups.