New insight into scale inhibition during tea brewing: Ca^(2+)/Mg^(2+) complexing and alkalinity consumption

Scale not only affects the taste and color ofwater,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 formationwas 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(Ca^(2+)),preventing the Ca^(2+)from reacting with the carbonate ions(CO_(3)^(2-)).The B rings of catechins were another important structure in the complexation of Ca^(2+)and magnesium ions(Mg2+).The carboxyl and hydroxyl groups on the organic acids was able to form fivemembered chelating rings with Ca^(2+)and Mg^(2+),resulting in a significant decrease in Ca^(2+)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(HCO_(3)^(-))from producing CO_(3)^(2−)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.

Synergistic scale inhibition of polyaspartic acid composite with magnetic field

Polyaspartic acid(PASP)composite,a scale inhibitor,was prepared from PASP,itaconic acid—acrylic acid—acrylic ester(IA-AA-AE)terpolymer and 2-phosphonobutane-1,2,4-tricarboxylic acid(PBTCA).The scale inhibition of PASP composite and the effect of its synergism with a magnetic field on scale inhibition were investigated.Calcium carbonate crystals in scale samples were characterized by means of SEM and XRD.The static and dynamic experiments show that the chelating function of PASP composite for Ca2+can be enhanced by synergism with a magnetic field.Under Ca2+650 mg/L,HCO3-1,300 mg/L and PASPcomposite 4 mg/L,the scale inhibition rate of PASP composite in magnetic water can increase by 10%in static state and by 20%in dynamic experiments.Scanning electron microscope(SEM)and X-ray diffraction(XRD)results show that calcite and aragonite can be completely transformed into vaterite by using PASP composite.

Surface lurking and interfacial ion release strategy for fabricating a superhydrophobic coating with scaling inhibition

The design and manufacture of anti-scaling surface is a prospective way to prevent scaling in oil field.In this work,a novel superhydrophobic Cu^(2+)-loaded and DTPMPA-modified anodized copper oxide(S-Cu^(2+)/D-ACO)coating was fabricated by modification of 1H,1H,2H,2H-perfluorodecyltriethoxysilane.The valid storing of scale inhibitors at the coating surface and the interfacial release of Cu^(2+)ions contribute to enhancing the anti-scaling of the S-Cu^(2+)/D-ACO coating.The water contact angle of the S-Cu^(2+)/D-ACO coating is 163.03°and exhibits superhydrophobicity,which makes it difficult for CaCO_(3)to deposit at the surface of the coating.DTPMPA will steadily lurk into the inner space,and Cu^(2+)will be loaded at the interface in the form of the DTPMPA:Cu^(2+)chelate.During the deposition of CaCO_(3),the dynamic release of DTPMPA can be realized by transferring DTPMPA:Cu^(2+)to DTPMPA:Ca^(2+).Interestingly,the released Cu^(2+)hinders the active growth of CaCO_(3).After 48 h of scaling,the mass of CaCO_(3)scale at the S-Cu^(2+)/D-ACO coating surface is only 44.1%that of the anodized copper oxide coating.The excellent anti-scaling performance of the S-Cu^(2+)/D-ACO coating is determined by the synergistic effect of the DTPMPA lurking and dynamic release,as well as the Cu^(2+)inhibition at the interface of superhydrophobic coating and against CaCO_(3)deposition.This research provides a new exploration for designing and fabricating anti-scaling superhydrophobic surface for oil field development.

An Eco-Friendly High-Effective Scale Inhibitor for High Salt Brine

Now the mining of high salt underground brine has been an important aspect of salt lake mining,which is the necessary support to the development of national economy.With the change of underground geological

Inhibition of CaCO_3 Scaling in Reverse Osmosis System by Zinc Ion

Scaling of reverse osmosis (RO) membrane surface is one of the main problems in desalination proc- esses. To mitigate scales, organic anti-scalants are often used. If the dosages of anti-scalants are reduced, by using other much cheaper scale inhibitors, RO running cost will decrease greatly. The present paper investigated the inhi- bition of CaCO3 precipitation by zinc ions in RO system. The results show that the zinc ion concentration of 2mg?L-1 was able to exert a marked suppression effect on both bulk precipitation of CaCO3 and on membrane scaling on waters of moderate hardness.

Microwave-assisted Synthesis of Modified Polyaspartic Acid in Solvent

Polyaspartic acid(PASP)is suitable for the inhibition of scale deposition from water.To enhance its in- hibition efficiency,PASP was modified by reacting aspartic acid(Asp)with glutamic acid(Glu)to provide Asp-Glu copolymer under microwave irradiation.The influence of reaction parameters on conversion,molecular weight and inhibition of CaCO3 precipitation was investigated Infra-red.(IR), 1H nuclear magnetic resonance( 1H NMR)and 13C nuclear magnetic resonance( 13C NMR)spectroscopies were used to characterize the copolymer.The results show that copolymerization of aspartic acid and glutamic acid is catalyzed by a small amount of phosphorous acid (H3PO4)in solvent,the product conversion is 98.05%under the following conditions:the molar ratio of glutamic acid to reactant[Glu/(Asp+Glu)]is 0.3 and that of catalyst(Cat)to reactant[Cat/(Glu+Asp)]is 0.05(0.65ml H3PO4),the volume of solvent dimethylformamide is 16ml,the microwave power used is 720W and the reaction for 3 min.The weight average molecular weight of copolymer synthesized under these conditions is 2709 and the inhi- bition rate for CaCO3 is 97.75%.

Effects of Copper-Zinc Alloy Doped with Rare Earth Elements on Crystal of Calcium Carbonate

A copper-zinc alloy doped with rare earth elements was prepared and the mechanism was demonstrated in a simulating boiler and circulating cooling water with rigidity 1 mmol·L-1. The polar curve and scale inhibiting ability of the alloy was tested by a corrosion measurement system and a scale inhibition evaluation system, respectively. Scale samples were characterized with SEM and XRD. It is found that the transfer of cations could be promoted by doping with proper rare earth elements, and the corrosion potentials descend by 25～126 mV. The results indicated that the copper-zinc alloy doped with rare earth elements has higher scale inhibiting ability of CaCO3. The growth of calcite was affected by zinc ions dissolved because of primary battery reaction, and the transition of calcium carbonate from aragonite to calcite was hampered resulting in the proportion of aragonite to calcite is changed from 1.7∶1 to 2.7∶1.

Effect of six kinds of scale inhibitors on calcium carbonate precipitation in high salinity wastewater at high temperatures

Precipitation of calcium carbonate （CaCOs） scale on heat transfer surfaces is a serious and expensive problem widely occurring in numerous industrial processes. In this study, we compared the scale inhibition effect of six kinds of commercial scale inhibitors and screened out the best one （scale inhibitor SQ-1211） to investigate its scale inhibition performance in highly saline conditions at high temperature through static scale inhibition tests. The influences of scale inhibitor dosage, temperature, heating time and pH on the inhibition efficiency of the optimal scale inhibitor were investigated. The morphologies and crystal structures of the precipitates were characterized by Scanning Electron Microscopy and X-ray Diffraction analysis. Results showed that the scale inhibition efficiency of the optimal scale inhibitor decreased with the increase of the reaction temperature. When the concentration of Ca^2＋ was 1600 mg/L, the scale inhibition rate could reach 90.7% at 80℃ at pH 8. The optimal scale inhibitor could effectively retard scaling at high temperature. In the presence of the optimal scale inhibitor, the main crystal structure of CaCOs changed from calcite to aragonite.

Molecular simulation of oligomer inhibitors for calcite scale

Molecular simulation was performed to study the interaction between CaCO3 crystal and several oligomer inhibitors, by using the equilibrium morphology method to calculate the growth morphology of CaCO3 without inhibitors. The calculated morphology agreed well with SEM photographs. Then, a double-layer model was built to investigate the interaction between calcite crystal and oligomer inhibitors containing maleic anhydride （MA） and acrylic acid （AA）. Interaction energy per gram of an oligomer inhibitor was introduced as a scale of inhibition efficiency of different monomers. The results indicated that, for calcite scale inhibition, acrylamide （AM） and vinyl phosphonic acid （VPA） were the most efficient monomers, while allylsulfonic acid （AS） was the poorest. Increasing proportion of AM in dimer inhibitor molecule would improve the inhibition efficiency of MA, though, for a trimer, such as MA-AA-AM, certain sequence of monomers in the inhibitor molecule was necessary besides higher proportion of AM.

Experimental study on the compatibility of scale inhibitors with Mono Ethylene Glycol

When both of the scaling and hydrate risks occur in deep water wells or subsea pipelines at the same time,the compatibility between scale and hydrate inhibitors should be paid more attention to for the risk prevention.In this paper,a new deep-water gas field found in the South China Sea is taken as a reference of project background to investigate the compati bility between scale inhibitors and hydrate inhibitors experimentally.Firstly a preliminary qualification evaluation of scale inhibitors was caried out,in which the static scale inhibition eficiency,the scale induction time,and the minimum effective concentrations of the selected scale inhibitors were tested.Then the effect of commonly used thermodynamic hydrate inhibitor MEG(Mono Ethylene Glycol)on the anti-scaling performance of scale inhibitors was evaluated.MEG-resisted scale inhibitors were further optimized.Finally,an extended discussion on the compati-bility of scale inhibition with hydrate inhibition was conducted.The experimental results showed that the scale inhi bitors HPMA and MA/AA were recommended with the best working concentration of 30 ppm.The high concentration inhibitors(30 wt%)can coexist with the same volume of pure MEG for more than 12-14 h at room condition and 60°C without any precipitation.The anti-scale fficiency of inhibitor with 30 ppm concentration is still up to 90%even at the presence of 20wt%MEG(after2-4 h at 95°C).Hence,in deep-water wellbore,compatible scale and hydrate inhi bitors can be injected together using one chemical pipeline.Besides,it is also found that the polymer scale inhibitors generally have good compatibility with MEG.It deserves further studies and can be regarded as one direction for scale inhibitor improvement in the future.