Water Treatment Agent Research Articles

A Review of Research Progress in the Preparation and Application of Ferrate(VI)

Ferrate(VI) is a green and efficient water treatment agent for drinking and wastewater. It is widely used in water treatment because it has multi-functional uses such as oxidation, algae removal, disinfection, and adsorption flocculation. It does not cause secondary pollution to the environment. This paper compares ferrate(VI) with other water treatment agents and discusses three methods of preparing ferrate(VI). The removal, adsorption, and control of organic matter, algae, disinfection by-products, and heavy metal ions in water when ferrate(VI) was used as an oxidant, disinfectant, and coagulant were summarized. Ferrate(VI) has some advantages in removing toxic, harmful, and difficult-to-degrade substances from water. Due to the disadvantages of ferrate(VI) such as oxidation selectivity and instability, it is necessary to develop the hyphenated techniques of ferrate(VI). In this review, three hyphenated techniques of ferrate(VI) are summarized: ferrate(VI)–photocatalytic synergistic coupling, ferrate(VI)–PAA synergistic coupling, and ferrate(VI)–PMS synergistic coupling.

Preparation and Characteristics of the Fired Bricks Produced from Polyaluminum Chloride Slag and Glass Powder

Polyaluminum chloride slag produced in the production of water treatment agents pollutes the environment and wastes land resources in the process of landfill and waste. In order to solve the resource waste of researching polyaluminum chloride slag, it was used to prepare sintered bricks. In this study, sintered bricks were prepared from polyaluminum chloride slag and glass powder. Taking compressive strength, water absorption, linear shrinkage and bulk density as measurement indexes, the effects of the glass powder content (0–10 wt%), molding moisture (10–20%), molding pressure (15–27.5 MPa), heating method (heat preservation at 400 °C and 1000 °C for 2 h, heat preservation at 500 °C and 1000 °C for 2 h, and heat preservation at 1000 °C for 2 h), heating rate (2–10 °C/min) and sintering temperature (900–1100 °C) on the performance of sintered brick and the conditions for meeting Chinese standards were studied. Then, the sintered bricks prepared at different temperatures were characterized by X-ray diffraction and scanning electron microscopy. The results show that the compressive strength (bulk density) increases and the water absorption decreases with the increase of the glass powder content, molding pressure, molding moisture and sintering temperature. Moreover, the linear shrinkage increases with the increase of the molding pressure, molding moisture and sintering temperature, but decreases with the increase of the glass powder content. When the glass powder content of the sintered brick is 10 wt%, with molding moisture of 20 wt%, molding pressure of 25 MPa, heating mode to directly raise the temperature to the target temperature, heating speed of 10 °C/min and sintering temperature of 1100 °C, the properties, pH value and leaching toxicity of sintered bricks meet the requirements of Chinese standard brick MU15. XRD and SEM analyses showed that with the increase of the sintering temperature, new albite and amphibole phases were formed in the structure, and quartz and other silicate minerals melted to form a liquid phase, making the structure more compact and the performance better. The research results provide a reference for the comprehensive utilization of polyaluminum chloride slag.

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.

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.

NEW COMPOSITE MATERIALS AND PROCESSES FOR CHEMICAL, PHYSICO-CHEMICAL AND BIOCHEMICAL TECHNOLOGIES OF WATER PURIFICATION

In traditional methods of water purification, the use of chemical reagents leads to the appearance of toxic by-products and wastes that require complex energy-consumption processing technologies. In accordance with the principles of sustainable development and “green” technologies, a significant revision of existing water treatment methods is required. The review highlights the main trends of innovative development of water purification and disinfection technologies. Modifications of water treatment agents (flocculants, sorbents, membranes) by integration of nanoparticles, environmentally compatible materials and “smart” composites into traditional structures are described. The use of composite nanoparticles is promising, particularly the use of particles with the “magnetic core – shell” structure, in which functional elements are attached to the surface, that provide the selective capture of contaminants, including pathogenic microorganisms. The existence of the magnetic core makes it possible to manipulate particles by the applied magnetic field, which is important for their complete extraction from the water upon completion of their functions. The use of new composite flocculants containing inorganic and organic components capable of ensuring highly effective capture of contaminants from the water, significantly reduces the volumes of flocculants and generated sludges and therefore allows to reduce the cost of the sludges processing and the harm of their disposal in the environment. New carbon nanostructures and natural polymers have an important role to play. In the new generation membranes, the disperse nanoparticles may provide antibacterial and photocatalytic properties, resulting in the high efficiency of disinfection and purification. A novel trend is the development of hybrid structures of coagulants and membranes with the properties which are regulated by the external stimulus, which are temperature, pH, light, electric, magnetic and electromagnetic fields. The use of such «smart» structures will increase the purification efficiency, reduce energy consumption and water purification waste volumes, due to the decrease in membranes fouling. The use of biopolymers and composites based on plant raw materials for the water purification is attractive due to their natural decontamination under the influence of the components of the environment, such as air, soil micro-organisms and sunlight, but also due to the absence of the secondary pollution. Among innovative chemical water treatment technologies Advanced Oxidation Processes play an important role, in particular, by involving electromagnetic fields and ultrasonic activation. By these methods, harmful organic impurities and pathogens are destroyed without the intensive use of chemicals or the production of toxic by-products. The integration of biochemical wastewater treatment with a microalgae growing system can become a promising waste-free, cost-effective "green" technology.

One pot synthesis of Cu–Ni–S@Ni foam for the simultaneous removal and detection of norfloxacin

The residual antibiotics in the environment will pose a threat to the environment and human health. Thus, it is imperative to develop a smart water treatment material to remove and detect antibiotics from aqueous environment simultaneously. In this study, magnetic Cu–Ni–S@Ni foam was synthesized by liquid phase vulcanization method to in-situ load Cu–Ni–S nanostructures on the surface of Ni foam. The novelty of this material is the combination of adsorption-flocculation technology and semi-quantitative detection technology. Batch experiments showed that Cu–Ni–S@Ni foam has a high removal rate of norfloxacin (NOR) (96.92%), wide pH adaptability (pH = 4.0–10.0) and strong ion interference resistance (0.1–100 mmol/L). According to the Langmuir isotherm, the removal capacity can reach 417.4 mg/g at 25 °C, which is much higher than that of other water treatment agents reported in most studies. Characterization analysis indicated that the main removal mechanisms are surface complexation, cation bridging, electrostatic attraction, precipitation and flocculation. Transmission FTIR detection experiments showed that NOR on Cu–Ni–S@Ni foam has easily recognizable FTIR fingerprints; the intensity of characteristic peaks roughly reflects the concentration information of NOR to some extent. This semi-quantitative detection method, requiring simple operation without the fabrication of KBr tablet, has a wide linear range (5–100 mg/L) and a low limit of detection (4.6 mg/L). Therefore, Cu–Ni–S@Ni foam can be used for simultaneous removal and semi-quantitative detection of NOR in wastewater. It has potential application value in wastewater treatment and water quality monitoring.

New nanoadsorbent based on magnetic iron oxide containing 1,4,7,10-tetraazacyclododecane in outer chain (Fe3O4@SiO2-cyclen) for adsorption and removal of selected heavy metal ions Cd2+, Pb2+, Cu2+

Magnetic Fe3O4@SiO2-cyclen nanoparticles were prepared and used as adsorbent for Cd2+, Pb2+ and Cu2+ from aqueous solution removal process controlled with differential pulse anodic stripping voltammetry (DPASV) and hanging mercury drop electrode (HDME). Nanomaterial was synthesised in three-step process co-precipitation of Fe3O4 core, coating with silane and N-(3-(triethoxysilyl)propyl)-1,4,7,10-tetraazacyclododecane-1-carboxamide silane functionalisation. The effectiveness of each step of the synthesis was confirmed using scanning electron microscopy (SEM), high-resolution X-ray photoelectron spectroscopy (XPS), powder X-ray diffraction (pXRD) and fourier-transform infrared spectroscopy (FT-IR) techniques. The Fe3O4@SiO2-cyclen nanoparticles were employed for Cd2+, Pb2+ and Cu2+ ions elimination from individual and mixed solutions by carrying out titration with a suspension of nanocomposites. The binding level for all ions both in the individual solutions and in the mixture was very similar at high levels. For Cd2+ and Cu2+ ions sorption efficiency level was from 83% to 89%, while for Pb2+ ions it was slightly lower at the level over 73%. In all cases, the equilibrium adsorption capacity parameter was over 1 mg/g and reached definitely higher values for individual ions solutions. The research results revealed that Fe3O4@SiO2- cyclen nanoparticles can be a promising adsorbent for magnetic heavy metal ions water treatment agents.

Study on the synthesis and properties of an environmentally friendly water treatment agent

An environment-friendly and effective polymer IA/SMAS was synthesized via a green method, the IA/SMAS as an effective scale inhibitor. In addition, explained its possible scale inhibition mechanism. The long-term application of phosphorus-containing or nitrogen-containing water treatment agents can easily lead to the eutrophication of water bodies. Here, a random copolymer IA/SMAS was synthesized by itaconic acid (IA) and sodium methacrylate sulfonate (SMAS) monomer by the aqueous polymerization method. The optimal synthesis conditions were as follows: a raw material mass ratio (IA:SMAS) of 2:1, a temperature of 95 °C and a reaction time of 6 h. In addition, ammonium persulfate and isopropanol were both added at 5 % of the total raw material mass. The copolymer IA/SMAS was characterized by infrared spectroscopy (IR), elemental analysis, nuclear magnetic resonance (NMR), field emission scanning electron microscopy (FESEM), and EDS. Its molecular weight and distribution were analyzed by gel chromatography (GPC). Static methods were used to evaluate copolymers and their performance in synergy with electrostatic fields. The scale inhibition mechanism of the copolymer and its synergistic effect with electrostatic field were also studied by a scanning electron microscope (SEM) and X-ray diffraction (XRD). The results show that the copolymer had excellent scale inhibition performance for calcium carbonate and good dispersion effect on iron oxide. The addition of the electrostatic field improved the scale inhibition performance of IA/SMAS copolymer by 16 %. Thus, the copolymer is a phosphorus-free and nitrogen-free water treatment agent that achieves excellent performance and can significantly disrupt the surface morphology and crystalline structures of crystals.

Cerium Oxide on a Fluorinated Carbon-Based Electrode as a Promising Catalyst for Hypochlorite Production.

Sodium hypochlorite (NaOCl) is widely used as a disinfectant agent for water treatment and surface cleaning. A straightforward way to produce NaOCl is by the electrolysis of an aqueous sodium chloride (NaCl) solution. This process presents several side reactions decreasing its efficiency with hypochlorite reduction on the cathode surface being one of the main detrimental reactions. In this work, we have studied carbon-based electrodes modified with cerium oxide (CeO2), fluorine, and platinum nanoparticles as cathodes for hypochlorite production. Fluorination was carried out electrochemically; the polyol method was used to synthesize platinum nanoparticles; and the hydrothermal process was applied to form a CeO2 layer. Scanning electron microscopy, FTIR, and inductively coupled plasma (ICP) indicated the presence of cerium oxide as a film, fluorine groups on the substrate, and a load of 3.2 mg/cm2 of platinum nanoparticles and 2.7 mg/cm2 of CeO2. From electrochemical impedance spectroscopy, it was possible to demonstrate that incorporating platinum and fluorine decreases the charge transfer resistance by 16% and 28%, respectively. Linear sweep voltammetry showed a significant decrease in hypochlorite reduction when the substrate was doped with fluorine from −16.6 mA/cm2 at −0.6 V to −9.64 mA/cm2 that further reduced to −8.78 mA/cm2 with cerium oxide covered fluorinated electrodes. The performance of the cathode materials during hypochlorite production improved by 80% compared with pristine activated carbon cloth (ACC) electrodes. The improvement toward hindering NaOCl reduction is probably caused by the incorporation of a partial negative charge upon doping with fluorine.

Experimental and theoretical studies of fluorescent-tagged scale inhibitors for calcium scale inhibition

A novel fluorescent-tagged scale inhibitor (HPTS-AA-CS-X) containing fluorescent monomer, acrylic acid, and chitosan were designed and prepared. The structures and thermal stability of HPTS-AA-CS-X were characterized by FTIR, TGA and 1H NMR. HPTS-AA-CS-2% had excellent fluorescence performance (R2 was 0.9916). Different experimental factors (temperature, pH value, using time, and Ca2+concentration) were studied. HPTS-AA-CS-2% is an efficient scale inhibitor in calcium carbonate (10 mg/L, 93.8%) and calcium sulfate (5 mg/L, 94.2%). The scale inhibition mechanism was studied by SEM, XRD, XPS, and DFT. For calcium carbonate, HPTS-AA-CS-2% prevent growth of crystal surface, the crystallinity decreased, and crystal shape changed from calcite to aragonite with poor stability. HPTS-AA-CS-2% does not change crystal type of calcium sulfate, but it will reduce crystal strength of calcium sulfate. This work shows the potential and possibility of HPTS-AA-CS-2% for calcium scale inhibition and provides experimental and theoretical basis for developing a new fluorescent-tagged water treatment agent.

A Nickel-Containing Polyoxomolybdate as an Efficient Antibacterial Agent for Water Treatment

In view of the water pollution issues caused by pathogenic microorganisms and harmful organic contaminants, nontoxic, environmentally friendly, and efficient antimicrobial agents are urgently required. Herein, a nickel-based Keggin polyoxomolybdate [Ni(L)(HL)]2H[PMo12O40] 4H2O (1, HL = 2-acetylpyrazine thiosemicarbazone) was prepared via a facile hydrothermal method and successfully characterized. Compound 1 exhibited high stability in a wide range of pH values from 4 to 10. 1 demonstrated significant antibacterial activity, with minimum inhibitory concentration (MIC) values in the range of 0.0019–0.2400 µg/mL against four types of bacteria, including Staphylococcus aureus (S. aureus), Bacillus subtilis (B. subtilis), Escherichia coli (E. coli), and Agrobacterium tumefaciens (A. tumefaciens). Further time-kill studies indicated that 1 killed almost all (99.9%) of E. coli and S. aureus. Meanwhile, the possible antibacterial mechanism was explored, and the results indicate that the antibacterial properties of 1 originate from the synergistic effect between [Ni(L)(HL)]+ and [PMo12O40]3−. In addition, 1 presented effective adsorption of basic fuchsin (BF) dyes. The kinetic data fitted a pseudo-second-order kinetic model well, and the maximum adsorption efficiency for the BF dyes (29.81 mg/g) was determined by the data fit of the Freundlich isotherm model. The results show that BF adsorption was dominated by both chemical adsorption and multilayer adsorption. This work provides evidence that 1 has potential to effectively remove dyes and pathogenic bacteria from wastewater.

Homogeneous Blend PVDF Porous Membrane Without Pore-Forming Agent for Water Treatment

Homogeneous Blend PVDF Porous Membrane Without Pore-Forming Agent for Water Treatment

An ultra-high sensitivity fluorescence sensor based on fluorescence technology

An ultra-high sensitivity fluorescence sensor with 1 ng/L-level detection limit was developed for water treatment applications, in which fluorescent tracing method is applied by using PTSA (1, 3, 6, 8-pyrenetetrasulfonic acid, sodium salt) to indicate the concentration of water treatment agents. This sensor consists of an optical part for fluorescence excitation and detection, as well as a signal processing and control circuit. The optical part employs a compound parabolic concentrator structure and achieves 6-fold increase in the collected fluorescence intensity. The circuit handles the determination procedures such as LED emission modulation, detector signal processing and concentration determination of water treatment agents. For PTSA with ultrapure water in ultra-low concentration range of 0 – 0.1 μg/L, a detection limit of 7 ng/L is demonstrated. The sensor has benefits of low cost, high accuracy and ease of deployment, which is promising for real-time detection of water treatment agents concentration in industrial cooling water circulation system.

An effective titanium salt dosing strategy for phosphorus removal from wastewater: Synergistic enhancement of chemical and biological treatment

Titanium salt coagulant, as a new type of water treatment agent, has been widely studied, but most researches do not consider its effect on the biological treatment. In this study, different doses of TiCl4 were added to the biological phosphorus removal (BPR) system to investigate the impact of TiCl4 on BPR. The results showed that the addition of TiCl4 not only significantly reduced the phosphorus concentration in effluent (below 0.5 mg/L), but also kept it stable. Moreover, the sedimentation performance of activated sludge was improved, which was superior to the control group. According to the results of flow cytometry (FCM), a small amount of TiCl4 significantly improved the bioactivities, but excessive dosage caused inhibition. When the dosage of TiCl4 below 20 mg/L, polyphosphate accumulating metabolism (PAM) was strengthened. In addition, the richness of microbial community and the relative abundance of Candidatus Accumulibacter clades also increased. However, when the dosage reached 60 mg/L, the relative abundance of Candidatus Competibacter increased and the BPR system was deteriorated. This study suggests that the addition of appropriate concentration of TiCl4 can realize the synergistic enhancement of biological and chemical phosphorus removal in sewage treatment.

Removing Malachite Green and Leucomalachite Green From Freshwater and Seawater With Four Water Treatment Agents

Malachite green (MG) residue in aquatic environments can adversely affect food chains. To solve this problem, many adsorbents have been developed to remove MG from aqueous solutions. These adsorbents exhibit benefits in different aspects such as low cost, nontoxicity, and environment friendliness. Zeolite, oyster shell powder (OSP), humic acid (HA), and Chloride dioxide (ClO2) are widely used agents for water purification, indicating their potential to remove MG from both freshwater and seawater. Liquid chromatography tandem mass spectrometry was performed as a valid analytical method for measuring MG and its metabolite leucomalachite green (LMG). The analysis examined linearity, specificity, accuracy, precision, and limit of quantification. We found that three agents—zeolite, OSP, and HA—have high affinity for MG and LMG in both freshwater and seawater because of their physicochemical properties; ClO2 exhibited even greater efficiency for MG and LMG degradation due to its oxidation capacity. The MG removal efficiency of zeolite, OSP and HA in freshwater was 100%, 87.52%, and 100%, respectively. In the MG-containing seawater, the removal efficiency of zeolite, OSP and HA was 95.24%, 6.57%, and 89.36%, respectively. The LMG removal efficiency of zeolite, OSP and HA in freshwater was 100%, 53.56%, and 100%, while in seawater, the LMG removal efficiency of zeolite, OSP and HA was 100%, 62.70%, and 84.65%, respectively. ClO2 treatments in both freshwater and seawater expressed 100% removal efficiency. The adsorption capacity of three water agents in MG-containing freshwater decreased in the order: zeolite = HA > OSP; in MG-containing seawater: zeolite > HA > OSP. Whereas the adsorption capacity of three water agents in LMG-containing freshwater decreased in the order: zeolite = HA > OSP; in LMG-containing seawater: zeolite > HA > OSP. In this study, four water treatment agents are reported to remove MG and LMG from freshwater and seawater, indicating their potential for reducing the amount of hazardous MG and LMG residue in aquatic environments.

Ripe indexes, hot water treatments, and biocontrol agents as synergistic combination to control apple bull’s eye rot

ABSTRACT DA-meter hand-held instrument, hot water treatment (HWT) and biocontrol agents (BCAs) represent an alternative solution to synthetic fungicides. In the present study, the three strategies were combined to reduce Neofabraea vagabunda virulence on apple fruit cv ‘Cripps Pink’. In vitro assays were conducted by testing different heat treatment timing (10, 5, and 3 min at 45°C) influence on pathogen mycelial growth together with BCAs (Aureobasidium pullulans L1 and L8, and Trichoderma harzianum Th1). The combined activities of HWT 45°C × 5 min and both BCAs volatile and no-volatile compounds displayed the complete control of the pathogen. In vivo, DA-meter was used to measure the index of absorbance difference (IAD) of chlorophyll-α content on apple and to separate fruit into two different ripening classes, immediately wound inoculated with N. vagabunda conidial suspension, and treated with HW and BCAs. In vivo results showed how the combined action of HW and BCAs completely inhibited the pathogen. Also, the less ripe apple class showed a decrease of fungal incidence by 16.2% with respect to the riper class. At harvest and after four months of storage at 0°C, quality parameters of both apple classes heat treated and untreated, such as firmness (FF), soluble solid contents (SSC), and pH were measured without showing any substantial differences. Obtained results open new perspectives on organic apple productions.

Magnetic Hyperbranched Molecular Materials for Treatment of Oily Sewage Containing Polymer in Oilfield Compound Flooding.

With the continuous improvement in oilfield development and the application of tertiary oil recovery technology, the water content of oilfield-produced fluids has gradually increased, and a large number of oilfield sewage with complex components has also been produced after oil–water separation, and effective treatment is urgently needed. ASP flooding sewage contains alkali, various surfactants, polymers, microemulsion oil droplets, and solid impurities, which are difficult to be effectively treated by traditional water treatment agents and methods. In this study, aminopropyl triethoxysilane (APTES) was used to modify the nano-Fe3O4 coated with tetraethyl silicate (TEOS). The product was used as the ferromagnetic nano-core for the iterative reaction of Michael addition and ester amidation to synthesize a magnetic hyperbranched polyamide amine, and its performance in the treatment of ASP flooding wastewater was evaluated experimentally. For the preparation of APTES-modified Fe3O4@SiO2 (FOSN) product, TEOS was coated over Fe3O4 in an ethanol aqueous solution environment and then APTES was added dropwise. The first-generation branched product (1-FSMN) was obtained by the reaction of FOSN and methyl acrylate graft product (FOSN-M) with ethylenediamine, and the highest yield was 93.7%. The highest yield of the second-generation branched product (2-FSMN) was 91.6%. In this study, a composite flooding wastewater sample from a block in the Bohai oilfield was taken. The suspended solids content was 143 mg/L, the oil content was 921.09 mg/L, the turbidity was 135 NTU, and the zeta potential was −47 mV. The third-generation hyperbranched polymer (3-FSMN) and its quaternary ammonium salt (3-FSMN-Q) performed best in the appropriate dosage range, with the highest oil removal rate of 97%, suspended solid removal rate of 90.3%, turbidity reduction rate of 86.6% and zeta potential reduction rate of 88%. For 3-FSMN and its quaternary ammonium salt, the gravity/magnetic PAC compound treatment experiment was carried out. In the settlement time of only 5 min, 3-FSMN/PAC and 3-FSMN-Q/PAC can achieve the maximum oil removal rate of 87.1% and suspended solids removal rate of 87.3% for polymer containing wastewater from ASP flooding, and 86.3 and 86.0% for 120 mg/L. Its treatment capacity was much better than that of common treatment agent combination (CPAM/PAC).

Isolation of napin from Brassica nigra seeds and coagulation activity to turbid pond water

Abstract Approach to fresh water is limited due to the growing world population and supply of clean drinking water is a global challenge. Pond water is widely used for drinking in developing countries and it has higher turbidity during rainy seasons. This purpose requires a large number of chemical coagulants that lead to a high cost of treatment. Therefore there is a need to find an economical and natural coagulant to treat turbid water. Coagulation activity is an ability of a liquid, changing to a solid or semi-solid state after sometime period of time. This study focuses on the isolation of coagulant proteins from Brassica nigra seeds responsible for water clarification. The coagulant protein (napin) was purified, quantified and identified. Napin protein was precipitated with 70% saturation of ammonium sulfate solution combined with dialysis and size-exclusion chromatography. SDS-PAGE showed that isolated napin has a molecular weight of 16 kDa. Protein quantification was done by using a NanoDrop spectrophotometer. The coagulation activity of the napin protein was measured against synthetic clay solution and turbid pond water. The coagulation assay results showed that napin protein from Brassica nigra has 85% and Moringa seeds extract has 87% coagulation activity against the synthetic clay solution after 120 min. However, the coagulation activity of napin protein against the turbid pond water was higher 85% compared to Moringa seed extract of 80%. The active coagulant napin protein would be helpful in establishing cheaper methods in scaling up the coagulant protein from the Brassica nigra seeds acting as a potential agent for water treatment.

Preparation of Film-Forming Amine Emulsion as Boiler Water Treatment Agent

In this study, the preparation method of the film-forming amine emulsion is explored by changing the sequence of different reagents, OLDA concentration, experimental temperature and OLDA/cyclohexylamine ratio. The stability of the film-forming amine emulsions prepared under different conditions is studied by observing if the emulsion delamination occurred after standing for several days. Results indicate that the sequence of different reagents, OLDA concentration, experimental temperature and OLDA/cyclohexylamine ratio affect the formation and stability of the film-forming amine emulsion obviously. The maximum content of OLDA in the film-forming amine emulsion could reach to 1.5 wt%, OLDA/cyclohexylamine ratio could be changed from 1:1 to 1:2.5, and room temperature could be as the experimental temperature. The stable film-forming amine emulsion could be prepared under the optimal conditions.

Bisphosphonates as Potential Inhibitors of Calcification in Bioprosthetic Heart Valves (Review).

As early as 50 years ago, bisphosphonates turned from a water treatment agent into one of the most widely used groups of drugs for the treatment of various diseases of calcium metabolism (bone tissue resorption, oncological complications of neurodegenerative diseases and others). Years of research on bisphosphonates have contributed to the understanding of their molecular and cellular pathways of their action. All bisphosphonates have a similar structure and common properties, however, there are obvious chemical, biochemical, and pharmacological differences between them. Each bisphosphonate has its own unique profile. This review summarizes data on the mechanisms of action of bisphosphonates, demonstrates the experience and prospects for their use for the modification of cardiovascular bioprostheses, since the issue of preventing bisphosphonate calcification has not been settled yet.