Scale Inhibition Properties Research Articles

Synthesis and evaluation of an environmentally friendly phosphorus-free and nitrogen-free polymer as a scale and corrosion inhibitor

Polyepoxysuccinic acid (PESA) was modified by glycidyl (Gly) to obtain a phosphate-free and nitrogen-free polymer (Gly-PESA), and its scale and corrosion inhibition properties were studied.The effects of Gly-PESA concentration, calcium ion concentration and temperature to scale inhibition performance were studied by static scale inhibition method. The corrosion inhibition performance of Gly-PESA was studied by static weight-loss method. The morphology and structure of calcium scale and steel surface were characterized by spectroscopic and microscopic methods. The scale inhibition efficiency of Gly-PESA for CaCO3 and CaSO4 was 98.06% and 92.6%, respectively. Under the same experimental conditions, the scale inhibition effect of Gly-PESA was obviously better than that of PESA. Gly-PESA could effectively inhibit the growth of CaCO3 and CaSO4 crystals and cause their crystal lattice distortion or crystal dispersion. The corrosion inhibition efficiency of Gly-PESA for carbon steel was 78.17%. The adsorption of Gly-PESA on the surface of the steel test piece followed Langmuir adsorption isotherm, and formed a protective film, which increased the corrosion resistance of the steel test piece, thus effectively protecting the steel test piece. Therefore, Gly-PESA was a green scale and corrosion inhibitor, which solved the problem of environmental pollution.

Design of molecular scale inhibitors for high temperature industrial cooling water systems based on group synergistic effects

In high-temperature industrial circulating cooling water systems, the pursuit of environmentally friendly and efficient scale inhibitors is crucial. This study introduced a novel series of monomers with exceptional scale inhibition properties, designed and optimized using Density Functional Theory (DFT). An in-depth analysis of ρ and ∇2ρ at critical points in the electrostatic potential distribution was conducted through the Atoms in Molecules (AIM) approach. Fukui Function analysis was also employed during the thorough screening of optimal molecular pairs. The result of this study is the development of a new ternary scale inhibitor, MA-IA-VS, which not only demonstrates a strong affinity and high binding energy but also exceptional dispersibility and biodegradability, aligning with the principles of green chemistry. Experimental data indicates that MA-IA-VS effectively inhibits over 99 % of CaCO3 and CaSO4 scales at minimal dosages (30 mg·L-1 and 7 mg·L-1, respectively), yielding substantial environmental and economic benefits. Furthermore, the interaction mechanism between MA-IA-VS and scaling crystals were elucidated through molecular dynamics simulations and mechanistic studies, revealing that MA-IA-VS forms a protective layer on the surface of Fe (110). Additionally, the adsorption of MA-IA-VS prevents calcium scale from adhering to the metal surface and alters its concentration distribution in solution, thus realizing scale inhibition effect. This contributes to a deeper understanding of scale inhibitor mechanisms and establishes a robust theoretical and practical foundation for the design of novel, eco-efficient scale inhibitors.

Precipitation-free aluminum-air batteries with high capacity and durable service life

Aluminum-air batteries are potential candidates for future large-scale energy storage/conversion due to their high safety and energy density. However, aluminum-air batteries face the challenges of continuously accumulated discharge by-products and undesired parasitic hydrogen evolution reaction (HER), which induce inferior performance and service life. Here, HER-suppressing and precipitation-free molecular crowding electrolytes are developed using sodium polyacrylate (PANa) as the crowding agent by taking advantage of its molecular crowding effect and scale inhibition property. The introduced PANa reconfigures the hydrogen-bond networks of electrolyte to suppress the HER by molecular crowding effect. A more uniform electric field distribution can be found on the surface of aluminum anode in the electrolyte containing PANa by employing Comsol multiphysics simulation. In addition, the anion long chains of PANa are electrostatically adsorbed on the surface of Al(OH)3 by-products micro-crystal, resulting in the same negative charge on the surface of the micro-crystal to prevent further aggregation and precipitation. The fabricated flow-based aluminum-air battery exhibits an outstanding specific capacity of 2096 mAh g−1, demonstrating the remarkable positive effect of PANa-based molecular crowding electrolyte in aluminum-air batteries. This work provides new light on aqueous electrolyte design for high capacity and precipitation-free aluminum-air batteries.

Synthesis and evaluation of a new polymeric scale inhibitor with multiple scale inhibition properties

In this article, the monomers epoxy succinic acid (ESA) and maleic acid ethanolamine (PTA) were prepared, and then the terpolymer scale inhibitor P(ESA-AA-PTA) was synthesized by aqueous solution polymerization using ESA, PTA, and acrylic acid (AA) as monomers. The structures of the synthesized monomers and polymers were characterized by FTIR. The optimum synthesis conditions of the terpolymer were obtained by static scale inhibition experiment, and the effects of the amount of scale inhibitor, test temperature, test time, and solution pH on the inhibition performance of the four scales, CaCO3, CaSO4, BaSO4, and SrSO4, were discussed. The results showed that the best CaCO3 scale inhibition efficiency was 85% when the molar ratio of ESA:AA:PTA was 1:1:0.5, the initiator dosage was 10 wt%, the polymerization time was 3.5 hours and the polymerization temperature was 95 °C. In the optimum water environment, the scale inhibition efficiency of CaCO3 scale and CaSO4 scale reached 100%, BaSO4 scale could reach 75% and SrSO4 scale could reach 54%. P(ESA-AA-PTA) had better scale inhibition properties than the majority of commercially available oilfield scale inhibitors. SEM and XRD results showed that the addition of P(ESA-AA-PTA) scale inhibitor hindered the growth of crystals and made the microscopic morphology of scale samples changed.

Synthesis and Performance Study of Maleic Anhydride Binary Water Treatment Agent

A binary copolymer water treatment agent was synthesized by using maleic anhydride and sodium allyl sulfonate as raw materials and ammonium persulfate as initiator. The scale inhibition and dispersion properties of the copolymer were studied through static experiments. The results show that the binary water treatment agent has excellent scale inhibition and dispersion performance. Moreover, the polymer is an environment-friendly agent with good application prospects.

Study of maleic anhydride based water treatment agents

The research results of maleic anhydride water treatment agents in the past years were summarized and analyzed, which provided reference for further research and preparation of environmental protection water treatment agents. A binary copolymer product with excellent scale inhibition and dispersion properties was synthesised using maleic anhydride and sodium allyl sulfonate as monomers. The product was characterized and its properties were investigated. It was concluded that the product has excellent scale inhibition and dispersion performance and good biodegradability. The product is an environmentally friendly water treatment agent.

Study on scale inhibition properties of chitosan derivatives

The chitosan derivatives scale inhibitor CTS-AMPS was synthesized by using chitosan and 2-acrylamido-2-methylpropane sulfonic acid as raw materials and ammonium persulphate as initiator, and the structure of the product was determined by ATR-FTIR. The scale inhibition performance of CTS-AMPS for municipal water was tested. The results showed that when the concentration factor of municipal wastewater is 2.5 times and the dosage is 30 mg/L, the scale inhibition reached 76.6%. The results of SEM show that the scale inhibition performance of CTS-AMPS is mainly due to lattice distortion.

Polyaspartic acid-capped (4-[(2-aminoethyl) amino]-4-oxobutanoic acid as an efficient and green gypsum scale inhibitor and its scale inhibition mechanism

Two new yet structurally similar scale inhibitors (PASP-AAB and PASP-AAA), have been successfully synthesized through ring-opening reaction of polysuccinimide (PSI) with inexpensive (4-[(2-aminoethyl) amino]-4-oxobutanoic acid or glycylglycine. Static antiscaling experiments imply they could dramatically improve the antiscaling efficiency of gypsum, better than that of PASP. Moreover, the slightly different nitrogen atom position on the side chain of PASP-AAB and PASP-AAA enables the former efficiently inhibit the gypsum scale at low concentration (2.0 mg/L). In addition, our results indicate the antiscaling performance of PASP-AAB (at 4.0 mg/L) could maintain the excellent efficiency (>99 %) against gypsum for at least 7 days, better than that of some reported polymer-, and phosphorus-based industrial antiscalants. The very efficient gypsum scale inhibition property of PASP-AAB makes it as one of the very effective green antiscalants reported in the literature by now. Detailed mechanism studies reveal that the better calcium scale inhibition performance of PASP-AAB should be attributed to the easier formation of seven-membered chelation ring of side chain with Ca2+. The unprecedented nitrogen substitution effect disclosed in this work provides a new perspective for understanding the structure-activity relationship of the grafting-modified polymeric inhibitor, meaningful for developing other novel green scale inhibitors.

PH-responsive smart composite coating with active anticorrosion and efficient scale inhibition properties

In this work, porous polysulfone (PSF) microcapsules were prepared using the method of mixed solvent volatilization, these microcapsules were used as a carrier, 1-hydroxyethylidene-1, 1-diphosphonic acid (HEDP) was used as an active substance for scale and corrosion inhibition, and stearic acid (SA) was used as a coating to prepare a pH-responsive smart microcapsule slow-release filler. Then, the smart microcapsules were added to a polyurea resin to prepare a pH-responsive smart composite coating with anti-corrosion and scale inhibition properties. The results showed that SA/PSF/HEDP microcapsules have significant pH-triggering activity in an alkaline environment. The alkaline supersaturated CaCO3 solution test showed that the composite coating has excellent scale inhibition performance. This is attributed to the in the microcapsules being released to the coating surface, achieving the purpose of complexation and solubilization. Local electrochemical impedance spectroscopic (EIS) proved that the SP/SA/PSF/HEDP composite coating has good corrosion resistance. This is attributed to the release of corrosion inhibitors, which can form a dense protective film on the metal. The scale inhibition efficiency of the composite coating was as high as 78.57 %, and the impedance modulus value is increased by three orders of magnitude.

New insight into scale inhibition during tea brewing: Ca2+/Mg2+ complexing and alkalinity consumption

Scale not only affects the taste and color of water, but also increases the risks of osteoporosis and cardiovascular diseases associated with drinking it. As a popular beverage, tea is rich many substances that have considerable potential for scale inhibition, including protein, tea polyphenols and organic acids. In this study, the effect of tea brewing on scale formation was explored. It was found that the proteins, catechins and organic acids in tea leaves could be released when the green tea was brewed in water with sufficient hardness and alkalinity. The tea-released protein was able to provide carboxyl groups to chelate with calcium ions (Ca2+), preventing the Ca2+ from reacting with the carbonate ions (CO32−). The B rings of catechins were another important structure in the complexation of Ca2+ and magnesium ions (Mg2+). The carboxyl and hydroxyl groups on the organic acids was able to form five-membered chelating rings with Ca2+ and Mg2+, resulting in a significant decrease in Ca2+ from 100.0 to 60.0 mg/L. Additionally, the hydrogen ions (H+) provided by the organic acids consumed and decreased the alkalinity of the water from 250.0 to 131.4 mg/L, leading to a remarkable reduction in pH from 8.93 to 7.73. It further prevented the bicarbonate (HCO3−) from producing CO32− when the water was heated. The reaction of the tea constituents with the hardness and alkalinity inhibited the formation of scale, leading to a significant decrease in turbidity from 10.6 to 1.4 NTU. Overall, this study provides information to help build towards an understanding of the scale inhibition properties of tea and the prospects of tea for anti-scaling in industrial applications.

Inhibitory effect of novel green polymer (Aspartic-citric acid) on the process of nucleation during gypsum scale formation

The presence of metal salts in the process fluid in industries leads to scale deposition over the heating or cooling surfaces and causes an significant increase in the overall process and product cost of the product. This further reduces the efficacy of the equipment and the quality of the product is compromised. Hence, in order to avoid this various conventional additives containing nitrogen, phosphorous and sulphur are used as antiscaling agents due to their superior scale inhibition properties. However, excessive use of these antiscalants has created an imbalance in the ecosystem. Hence, there is a necessity to look for more reliable compounds that are as equally efficient as the conventional ones and are eco-friendly, biodegradable and cost effective. In the present study, homo and hetero polymers of aspartic acid and citric acid have been synthesized using condensation method and their antiscaling properties against gypsum deposition is been evaluated. Characterization of the synthesized polymers and deposited scale was performed by FTIR, GPC, SEM and XRD. The polymer showing the highest efficiency in the preliminary screening test was further evaluated to study its effect on the process of nucleation and crystal growth. The synthesized polymers were found to be efficient in inhibiting the scale deposition process at additive concentration as low as 3 ppm. The presence of additive (PAS-co-CA2) increased the induction time, surface free energy of formation, critical nuclei size and number of molecules per critical nuclei. Hence, rate of nucleation was reduced. Molecular weight and functional groups were the crucial factors in determining the scale inhibition properties of the polymer. The process of crystal formation and deposition was significantly retarded in presence of the additive with a change in the crystal morphology of the deposited crystals.

Superhydrophilic polyethersulfone (PES) membranes with high scale inhibition properties obtained through bionic mineralization and RTIPS

Reverse thermally induced separation (RTIPS) was used to obtain a separation membrane with a better internal structure for a higher water flux and a surface that could easily form a hydration layer. In comparison to the traditional modification method, this work focused on the aspect that the internal structure obtained by changing the membrane-making method provided easier adhesion conditions for the dopamine/TiO2 hybrid nanoparticles (DA/TiO2 HNPs) obtained by biomimetic mineralization. It provided a basis for exploring the variation in adhesion with the water bath temperature and the amount of titanium added through the study of turbidity point, SEM images, water contact angle, thermogravimetric test, EDX, AFM, XPS, FTIR and other test results. The SEM images proved that the membrane obtained through the RTIPS method had a porous surface and spongy internal structure, furthermore, additional polymers were adsorbed. Use of EDX demonstrated that biomimetic mineralization prevented the production of agglomerated titanium dioxide. XPS and FTIR spectra confirmed the introduction and immobilization of HNP aggregation. Moreover, a decrease in the surface roughness and water contact angle further suggested an improvement in the hydrophilicity of the modified membrane. The introduction of HNP at a higher water bath temperature helped increase the water flux up to ten times, moreover, the oil-water separation efficiency could still reach over 99.50%. Lastly, a cycle test of the modified membrane under the optimal conditions helped confirm that the membrane forming conditions at this time could provide a better environment for the formation of the hydrophilic layer, which was conducive to the recycling of the separation membrane. In summary, more fixed more hydrophilic particles could be obtained through the RTIPS method based on biomimetic mineralization to prevent the accumulation of titanium dioxide, thus helping improve permeability and anti-fouling of the membrane.

Synergistic effects of magnesium and EDTA on polymorphism and morphology of CaCO3 and its influence on scale

Calcium carbonate scale formation in the presence of magnesium ions has been studied between 60 and 100 °C. The samples were characterized using XRD, FTIR and FE-SEM techniques. The effect of EDTA on the polymorphism and morphology of calcium carbonate in presence of magnesium ions also have been reported. The study revealed that both magnesium and EDTA influence the crystallization behavior and morphology of the CaCO3 formed. The study also revealed that the effect need not be same under different temperatures and environments and the morphological transformation need not compulsorily represent the polymorphic transformation. The findings are explained by a two stage mechanism which revealed that the magnesium ions present in the system can favorably or adversely affect the scale inhibition property of the inhibitor depending on the concentration and temperature.

Development of Poly(aspartic-co-glutamic acid) Green Antiscalant for Calcium Carbonate Scale Inhibition

The performance of heat exchangers and water cooling systems is mainly affected by the major problem of calcium carbonate/sulphate based scale formation. Herein present paper, we are reporting synthesis, characterization and performance of novel aspartic-co-glutamic acid based polymer system as a green antiscalant. Aspartic-co-glutamic acid based polymer was developed using aspartic acid and glutamic acid as reactants and phosphoric acid as catalyst. Effect of different operating parameters viz. temperature, molar concentration of reactants, reaction time, etc. was studied thoroughly. The as-synthesized material was characterized by various physicochemical characterization techniques including fourier transform-Infrared (FTIR) spectroscopy, scanning electron microscopy (SEM) and X-ray diffraction (XRD) spectroscopy. The scale inhibition properties of the as-synthesised product were studied with respect to calcium carbonate at various pH and temperature range. Experimental results unveil that at 200 ppm concentration, the anti-scaling property of the as-synthesized material was found to be close to that of commercial antiscalant (KT-RO).

Anti-scaling of superhydrophobic poly(vinylidene fluoride) composite coating: Tackling effect of carbon nanotubes

Superhydrophobic poly(vinylidene fluoride)/fluorinated ethylene propylene/SiO2 (PFS) composite coatings incorporating various carbon nanofillers, such as carbon nanotubes (CNTs), carbon nanofibers (CNFs), graphene nanoplates (GnPs) and carbon black (CB) respectively, were successfully fabricated by spraying. The scale-inhibition properties of these coatings were tested in a CaCO3 supersaturated solution, and the deposited CaCO3 scale was characterized with SEM and XRD. The effects of carbon nanofillers on the surface roughness, surface energy, and scale inhibition behaviors of different coatings were studied. In contrast with GnPs, CNFs and CB, the CNTs were dispersed more uniformly in the PVDF matrix and formed a stronger bond with the polymer matrix. The addition of CNTs changed the morphology, increased the surface roughness, and further reduced the surface energy of the superhydrophobic PFS-CNTs composite coating owing to the tackling effect of CNTs. A stable air film was maintained on the surface of superhydrophobic PFS-CNTs composite coating, which was more favorable for superhydrophobic retention by wrapping air in the saturated CaCO3 solution. The CaCO3 scaling rate on the superhydrophobic PFS-CNTs composite coating was only 44 % of that on the hydrophobic PFS composite coating, which showing the highest antiscaling performance.

O,O’-二(甲基)二硫代磷酸二乙铵阻垢剂的合成与性能研究

O,O’-二(甲基)二硫代磷酸二乙铵阻垢剂的合成与性能研究

Evaluation of gypsum (CaSO4·2H2O) scale formation and its inhibition by different antiscalants by static and dynamic test

ABSTRACT Deposition of calcium salts or scaling on heat transfer surfaces is a major industrial problem around the globe. Scales get deposited in industrial process equipments severely affecting its life span, operating cost and adversely altering the process. Antiscalants are widely used for inhibition of metal salts formed in this water. In this study, chemical species like phosphates, various vinyl monomers and polymethacrylic acid are tested for their scale inhibition properties under static condition as per NACE standard and dynamic condition using SS and MS metal Strips. The performance of the compounds like Acrylic Acid, Malic acid, Succinic Acid and Polymethacrylic acid, studied during this working was found to be increasing with an increase in the number of a carboxylic (-COOH) group attached to its molecule. The presence of a negative charge over the carboxyl group plays an important role in the formation of ionic bond with the Ca2+ ions present in the liquid bulk. The carboxyl group attaches itself on the active sites of the crystal lattice and changes the crystal morphology significantly by blocking the active sites for its possible future growth.

Sulfonated Nonpolymeric Aminophosphonate Scale Inhibitors—Improving the Compatibility and Biodegradability

Phosphonate-based scale inhibitors are widely used in the upstream oil and gas industry, but many of them lack good compatibility with high calcium brines. Here, we report the synthesis of several nonpolymeric aminobismethylenephosphonates with an added sulfonate group to improve the compatibility. The chemicals are 2-(bis(phosphonomethyl)amino)alkane-1-sulfonic acid (alkane = methane, ethane, and propane labeled SI-1 to SI-3, respectively), N,N-bis(phosphonomethyl)cysteic acid (SI-4), and N,N-bis(phosphonomethyl) metanilic acid (SI-5). To screen their performance, we carried out dynamic scale loop inhibition performance tests for calcium carbonate and barium sulfate, thermal stability tests, and calcium compatibility tests up to 10 000 ppm calcium ions and compared them to some well-known oilfield scale inhibitors. Seawater biodegradation over 28 days (BOD28) was also investigated by the OECD 306 method. All new inhibitors demonstrated good calcite inhibition properties, but only SI-1 and SI-2 gave fairly good barite inhibition. SI-2 stood out as an excellent calcite inhibitor, suitable for use in very high calcium-containing brines. SI-2 could also provide protection against barite deposition under mild to medium scaling potentials and gave a reasonable rate of biodegradation (BOD28 = 46%). SI-1 and SI-4 gave BOD28 values of 79 and 84%, respectively, and can be classed as “readily biodegradable”. Of the two products, SI-1 seems the most promising for further studies given the better calcite and barite scale inhibition properties. Of the SIs tested, SI-5 showed the best thermal stability at 130 °C and could therefore be a useful downhole squeeze SI for fairly high-temperature wells. Its BOD28 value was 41%. Overall, the study highlights the difficulty of designing a scale inhibitor with all of the major features required for application over a wide range of field conditions.

UV/chlorine oxidation of the phosphonate antiscalant 1-Hydroxyethane-1, 1-diphosphonic acid (HEDP) used for reverse osmosis processes: Organic phosphorus removal and scale inhibition properties changes

Reverse osmosis (RO) technology plays an increasingly important role in municipal wastewater reclamation. However, the antiscalants used in RO systems showed adverse effects to the ecosystem: impending the removal of hardness from RO concentrates; inducing phosphorus pollution in receiving water; enhancing the trace metal migration in the environment. In this study, UV/chlorine advanced oxidation process was used to oxidize a typical phosphoric antiscalant (1-Hydroxyethane-1, 1-diphosphonic Acid, HEDP). UV/chlorine showed significant synergetic effects on HEDP degradation compared to UV irradiation or chlorination alone. Compared to UV/H2O2 oxidation, UV/chlorine process is more efficient for HEDP transformation with chlorine dosages ranging from 0.1 to 0.4 mmoL/L. Chorine dosage showed dual effects on HEDP oxidation by UV/chlorine: the increasing trend of transformation efficiency of HEDP got slower with increasing chlorine dosage. The transformation efficiency of HEDP by UV/chlorine oxidation decreased from 39% to 14% with pH increasing from 4.5 to 9.0, likely due to the higher quantum yields and lower radical quenching rates of HOCl than those of OCl−. The transformation efficiency of HEDP decreased 14% and 42% with 30 mM of chloride and bicarbonate, respectively. The presence of nitrate promoted the oxidation of HEDP by UV/chlorine: the transformation efficiency increased 5% and 83% with the presence of 5 mM and 30 mM nitrate, respectively. Based on the static scale inhibition tests, UV/chlorine oxidation is effective at removing the scale inhibition ability of HEDP. During UV/chlorine process, the maximum scale inhibition ratio decreased from 66% to 34% as the removal of phosphonate ligand from HEDP increased to 80%.

Scale inhibition properties of metallic cations on CaCO3 formation using fast controlled precipitation and a scaling quartz microbalance

Scale inhibition properties of metallic cations on CaCO3 formation using fast controlled precipitation and a scaling quartz microbalance