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In an attempt to widen the family of Phosphorus Metal Halides (MxPyXz) and enable new applications, post-synthetic modifications to the MxPyXz, Cu2P3I2 have been reported. While such a technique suggests access to an entirely new family of MxPyXz-based materials, we report, in this work, that the ion-exchange process seemingly influences important properties such as the crystallographic pattern and vibrational modes.

The strength of chemically pre-stressed glass depends on the depth of surface flaws and the value of the pre-stress. So far, some research has been conducted on this topic; however, there were always uncertainties regarding the flaw depth and the pre-stress profile. Consequently, this research characterises the pre-stress profile using experimental methods. The latter include measuring the depth of layer (DoL) and the surface compressive pre-stress (CS) with FSM-7000 h and verifying the achieved DoL with the Na+ and K+ distribution through the thickness obtained from the SEM/EDS analysis. Results demonstrate that the amount of K decreases parabolically (second-order) to a certain value and then remains constant. Based on this observation and some boundary conditions, the equation of the pre-stress profile was obtained for thin chemically pre-stressed aluminosilicate glass (Falcon®) with 8 h and 24 h processing durations in molten salt at 460 °C. A non-strengthened glass (NSG) was also used as a reference for comparison. Then, three artificial laser-induced flaws with accurately controlled depths is tested by means of a clamp bender. The results of the strength tests demonstrated very low deviations in the failure stress. It was shown that even when the depth of the flaw is higher than the DoL, which means that the flaw tip enters the zone with the pre-tensile stress, there is still considerable resistance from the surrounding intact area. Furthermore, it was confirmed that the pre-stress strain energy for 24 h processing is larger than for 8 h, leading to more fragmentation after failure under a similar loading condition. Finally, it was found that the fracture toughness is not constant through the pre-stressed glass thickness, and it is dependent on the pre-stress profile with the peak value at the glass surface

Sucrose crystallization process is greatly inhibited by high Na+, K+ and Ca2+ content in the crystallizing medium—sugar juice. In this study, unmodified pressed sugar beet pulp was used as a weak polyfunctional cation exchanger for the removal of Na+, K+ and Ca2+ from an alkalized sugar juice in a closed-loop column system. Cation removal effect was evaluated through the influence of temperature (30–70 °C), pH (8.5–12.5) and volume (150–300 ml) of alkalized juice. Sugar beet pulp exhibited the highest Ca2+ removal (56.58%) at 70 °C and pH value of 12.5, indicating strong impact of cation solubility, precipitation and valence. Milder conditions of alkalized sugar juice such as temperature (50 °C) and pH value (10.5) contributed to the maximum removal of Na+ (15.07%) and K+ (10.58%). Component analysis of the heteroporous sugar beet pulp with total porosity of 53% and specific surface area of 0.9 m2/g indicated hydroxyl and carboxyl groups as the main centers for an ion-exchange process in the material used, which was confirmed by FTIR analysis. This is the first time that unmodified pressed sugar beet pulp (PSBP) has been used as biosorbent for Na+, K+ and Ca2+ removal in a closed-loop column system., This research is financed by The Ministry of Education, Science and Technological Development (Serbia), project No. 451-03-68/2022-14/200222. The authors would like to acknowledge the support from Ministry of Education, Science and Technological Development (Serbia) for the textural analysis, project No. 451-03-68/2022-14/200134.

The radionuclides of cesium (Cs) and strontium (Sr) are dangerous products of nuclear fission that can be accidentally released into wastewater. In the present work, the capacity of thermally treated natural zeolite (NZ) from Macicasu (Romania) to remove Cs+ and Sr2+ ions from aqueous solutions in batch mode was investigated by contacting different zeolite quantities (0.5, 1, and 2 g) of 0.5–1.25 mm (NZ1) and 0.1–0.5 mm (NZ2) particle size fractions with 50 mL working solutions of Cs+ and Sr2+ (10, 50, and 100 mg L−1 initial concentrations) for 180 min. The concentration of Cs in the aqueous solutions was determined by inductively coupled plasma mass spectrometry (ICP-MS), whereas the Sr concentration was determined by inductively coupled plasma optical emission spectrometry (ICP-OES). The removal efficiency of Cs+ varied between 62.8 and 99.3%, whereas Sr2+ ranged between 51.3 and 94.5%, depending on the initial concentrations, the contact time, the amount, and particle size of the adsorbent material. The sorption of Cs+ and Sr2+ was analyzed using the nonlinear form of Langmuir and Freundlich isotherm models and pseudo-first-order (PFO) and pseudo-second-order (PSO) kinetic models. The results indicated that the sorption kinetics of Cs+ and Sr2+ on thermally treated natural zeolite was described by the PSO kinetic model. Chemisorption dominates the retention of both Cs+ and Sr2+ by strong coordinate bonds with an aluminosilicate zeolite skeleton.

Carbon materials constitute a broad family of solids that encompass a high variety of physical and chemical properties, including morphology. These materials have shown to be very useful as catalysts supports and, in this context, also for the heterogenization of metal complexes owing catalytic properties. This work is mainly, the summary of the results obtained in several research projects focused on developing heterogenized molecular catalysts by exploiting the properties of a plethora of carbon materials to address several immobilization procedures. Spanish government (PB98-0983, PPQ2002-1025, MAT2009-07150, Prometeo 2009/047, MAT2012-32832, CTQ2015-66080-R, PROMETEOII/2014/010, RTI2018-095291-B-I00, PROMETEO/2018/076).

Ion-exchange reactions are commonly used to develop novel metastable electrode materials for alkali-ion batteries that cannot be synthesized using direct chemical reactions. In this study, the electrochemical K to Na ion-exchange reaction mechanisms in a layered KxCoO2 cathode as a model system were investigated using operando and ex situ structure characterization techniques. Some level of K ions was observed to remain in the layered structure during the electrochemical ion-exchange reactions. Interestingly, the K ions are well separated from the Na-rich phases in the discharged state, and they form an intermediate phase in which K and Na ions are mixed at the top of charge. We discovered that such residual K ions prevent the collapse of the layered structure in the high-voltage regime, thereby improving the cycling stability in a Na-battery system.

Cation exchange resins are widely used for water softening and demineralization all over the world. Deposition, metabolism, and growth of bacteria and fungi on the resin beads cause capacity and performance losses, especially during repeated use in cyclic and long-term operations. Over the last decades, modification of different materials by silver nanoparticles (AgNPs) has demonstrated to present significant opportunities in mitigating biofouling problems. The paper deals with a novel facile technique of introducing silver colloids (AgC) into cation exchange resin, providing the formation of silver micro- and nano-inclusions on the cation resin beads. The scanning electron microscope (SEM) measurements have confirmed a spherical shape and uniform distribution of AgC (50 – 1000 nm) on the surface of the resin. To evaluate the antibacterial and fungicidal properties of AgC on the cation resin beads, we have used Aureobasidium sp., Penicillium sp., and Staphylococcus aureus cultures. AgC coating has proved to efficiently prevent bacteria/biofilm growth on the cation resin beads and thereby significantly increase the service life of the cation exchange resin, especially in hot climatic conditions. Possible antibiofouling mechanisms of the modified nanocomposite cationite have been discussed. Since 2020, the modified silver-containing cationite has been successfully utilized for water softening systems of boiler equipment in Uzbekistan, demonstrating the suitability of the suggested facile coating technique for reducing fouling of cation-exchange resin.

Modified or low-salinity waterflooding of carbonate oil reservoirs is of considerable economic interest because of potentially inexpensive incremental oil production. The injected modified brine changes the surface chemistry of the carbonate rock and crude oil interfaces and detaches some of adhered crude oil. Composition design of brine modified to enhance oil recovery is determined by labor-intensive trial-and-error laboratory corefloods. Unfortunately, limestone, which predominantly consists of aqueous-reactive calcium carbonate, alters injected brine composition by mineral dissolution/precipitation. Accordingly, the rock reactivity hinders rational design of brines tailored to improve oil recovery. Previously, we presented a theoretical analysis of 1D, single-phase brine injection into calcium carbonate-rock that accounts for mineral dissolution, ion exchange, and dispersion (Yutkin et al. in SPE J 23(01):084–101, 2018. 10.2118/182829-PA). Here, we present the results of single-phase waterflood-brine experiments that verify the theoretical framework. We show that concentration histories eluted from Indiana limestone cores possess features characteristic of fast calcium carbonate dissolution, 2:1 ion exchange, and high dispersion. The injected brine reaches chemical equilibrium inside the porous rock even at injection rates higher than 3.5 $$\times$$ × 10$$^{-3}$$ - 3 m s$$^{-1}$$ - 1 (1000 ft/day). Ion exchange results in salinity waves observed experimentally, while high dispersion is responsible for long concentration history tails. Using the verified theoretical framework, we briefly explore how these processes modify aqueous-phase composition during the injection of designer brines into a calcium-carbonate reservoir. Because of high salinity of the initial and injected brines, ion exchange affects injected concentrations only in high surface area carbonates/limestones, such as chalks. Calcium-carbonate dissolution only affects aqueous solution pH. The rock surface composition is affected by all processes.

Lignosulfonate features sulfonate groups, which makes it soluble in water and hence, suitable for a wide range of applications. However, its characterization is challenging because of its limited solubility in organic solvents. Thus, this study investigated the chemical and thermal characteristics of ion-exchanged sodium lignosulfonate (Na-LS) and compared it with those of industrial kraft lignin derived from softwood and hardwood. The results demonstrated that the ion exchange successfully converted Na-LS to lignosulfonic acid (H-LS), as proven by the Fourier-transform infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS), and elemental analysis. H-LS has a greater apparent molecular weight than those of Na-LS and softwood and hardwood kraft lignin (SKL and HKL). According to 31P nuclear magnetic resonance (NMR) analysis, H-LS has less phenolic OH than SKL and HKL, indicating that it has more polymeric chains. Furthermore, H-LS has substantially more native side chains, such as β-O-4 units, than SKL and HKL. Thermal analysis revealed that H-LS has a greater glass temperature (Tg) than SKL and HKL, although Na-LS has a lower Tg than SKL and HKL. In addition, H-LS degraded faster than Na-LS did because the acid condition accelerated degradation reaction.

Electrochemical treatments in (waste)water management show high potential in the global water resource crisis, but are often limited by the ion-exchange membrane (IEM) performance. Low chemical resistance and fouling are major issues in the development of next-generation IEMs. Sulfonated silica-based nanofiber cation-exchange membranes (CEMs) offer a promising solution to these issues due to their superior chemical resistance and self-cleaning properties. Via the direct electrospinning of a sol–gel solution starting from tetraethyl orthosilicate (TEOS) and 3-mercaptopropyl triethoxysilane (MPTES), nanofiber membranes with an ion-exchange capacity (IEC) of 1.3 mmol g−1 can be produced without the need of an additional matrix. The produced nanofiber CEM performs excellent in lab-scale electrochemical tests, with a resistance of 3.2 ± 0.4 *10-3 Ω m2 and a Coulombic efficiency of ± 70 % for the transport of Na+ using a current density of either 128 or 256 A/m−2. Furthermore, the nanofiber CEM shows outstanding resistance against strong acidic solutions and chlorine. After fouling of the membrane with CaCO3, the nanofiber CEM shows self-cleaning properties, eliminating the need for an additional cleaning step during usage. These results illustrate the excellent performance of the silica-based nanofiber CEM for industrial water treatment applications.

Inorganic sorbents are more selective in comparison with commercial ion exchange resins towards of metal ions. However, inorganic sorbents characterized not high kinetic properties. One of the way to increase the kinetic rate of inorganic sorbents is to reduce the particle size of these materials, other way is synthesizing inorganic sorbents as porous products from powder materials. A sample of such inorganic sorbents is titanium phosphate of various compositions. Studying the properties of microfilters based on composition titanium phosphate - porous titanium has been developed. The sorbents based on acidic titanium phosphate Ti(HPO4)2-H2O were used for filtering solution with Fe(II) content. It is found that the number of impregnations with inorganic sorbent modificator is important and influence filtration process. The obtained results demonstrated that after the first impregnation of porous material with a smaller pore size, it is possible to obtain such sorbent as a mass content of powder material. By varying the ionic form of titanium phosphate, the porosity of titanium, the amount of impregnation, it could be possible effect on the sorption Fe(II). The sorption properties of titanium-titanium phosphate microfilters were studied by potentiometric titration in the NaCl-NaOH system, as well as the sorption of Fe2+ ions. The degree of purification for Fe(II) from solution with a concentration of 10 mg/l is 64 %. Application an electric potential to the microfilter of porous titanium - phosphate titanium increases the degree of purification of Fe(II) to 88 %. По відношенню до іонів металів неорганічні сорбенти є селективнішими порівняно з промисловими іонообмінними смолами, але ці сорбенти характеризуються невисокими кінетичними властивостями. Одним із способів підвищення кінетичної швидкості неорганічних сорбентів є зменшення розміру частинок цих матеріалів, іншим способом є синтез неорганічних сорбентів у вигляді пористих продуктів на основі порошкових матеріалів. Зразком таких неорганічних сорбентів є фосфат титану різного складу. Розроблено спосіб модифікації мікрофільтрів на основі композицій фосфат титану – пористий титан. В досліджені було використано сорбент на основі кислого фосфату титану (ФТ) складу Тi(НРО4)2-Н2О. Знайдено, що важливим є кількість просочень (імпрегнувань) модифікатором поверхні пористого мікрофільтра. Варіюючи іонну форму фосфат титану, пористість титану, кількість просочень (імпрегнувань), можна впливати на ступінь сорбції Fe(II) з розчинів під час фільтрації. Сорбційні властивості титантитанфосфатних мікрофільтрів досліджували шляхом потенціометричного титрування в системі NaCl-NaOH, а також сорбції іонів Fe(II). Ступінь очищення від Fe(II) розчинів, концентрація яких складала 10 мг/дм3 , становить 64 %. При накладанні електричного потенціалу до мікрофильтру пористий титан - фосфат титана, можна підвищити ступінь очищення Fe(II) до 88 %.

We designed pyrochlore-type potassium niobate (KN) and potassium tantalate (KT) by introducing silver ions to improve their antibacterial efficiency. KN and KT samples were used as ion-exchangeable parent compounds, and molten AgNO3 was used for the ion-exchange reaction. The formation of silver ion-exchanged compounds with various molar ratios, which was investigated by X-ray diffraction (XRD), indicated a clear structural transformation of KN after complete ion-exchange. The antibacterial efficacy of these samples was investigated using the colony count method, and the relative antibacterial activity was compared based on the area of the inhibition zone. The results indicated that silver ion-exchanged samples with molar ratios of Ag/Nb = 0.05, 0.44, 0.67, and Ag/Ta = 0.07, 0.44 0.64 exhibited complete (100%) antibacterial activity against Staphylococcus aureus (gram-positive) and Escherichia coli (gram-negative). Among the silver ion-exchanged samples, KAN1 and KAT1 exhibited the highest antibacterial activities because of the controlled release of Ag+ ions through their tunnel structure. In this study, it was found that tunable silver-release properties of pyrochlore-type niobate and tantalate enable the optimization of discharged Ag+ ions, which inhibits the bacterial efficacy in different extents, thus suggesting their use in various biomedical applications.

Here is described the preparation and characterization of iron oxide@silicon oxide-graphene oxide hybrid nanoparticles to remove and recover lead and cadmium from water samples. The high surface area from sorption capacity and low masses used for recovery and removal studies makes these particles attractive for preconcentration and water treatment. The results show that the method provided 97% recovery and 91% removal for lead and 78% recovery and 93% removal for cadmium from water at pH 8.0. Under the optimized conditions, the limits of detection were 37.0 mu g L-1 and 11.7 mu g L-1 and limits of quantification were 123.2 mu g L-1 and 45.0 mu g L-1 for lead and cadmium, respectively. The trueness of the method was confirmed by analyzing a certified reference material (BCR 715) with -11.0% and -15.0% relative error for lead and cadmium, respectively. The results from the certified reference material provided good accuracy (>85%). The method was employed to various water samples using the method of standard addition.

For the first time we show that the introduction of silver ions in the glass containing gold nanoparticles (NPs) and additional heat treatment of the glass in the air lead to the formation of Au/Ag alloy NPs. The proposed approach makes it possible to position localized surface plasmon resonance of the NPs by selecting the heat treatment temperature, which determines the silver proportion in the alloy NPs. This allows for expanding customizability of NPs for applications in surface-enhanced Raman scattering spectroscopy, catalysis and biochemistry. Developed technique benefits from the presence of silver in the glass in ionic form, which prevents the oxidation of silver and provides stable preparation of Au/Ag alloy NPs.

The design and fabrication of rare earth ions incorporated into the inorganic/organic hybrid materials have attracted growing attention for seeking improved optical properties and photofunctional performances. In this paper, a novel hybrid composite based on the layered rare earth hydroxides was successfully prepared by the ion-exchange and intercalation chemical process. The rare earth elements in the composite contain gadolinium (Gd) and europium (Eu) and the molar ratio of Gd to Eu is kept constant at 1.9 : 0.1. Organic sodium dodecyl sulfonate and dye coumarin-3-carboxyllc acid are simultaneously incorporated into the layered rare earth hydroxides as supporting agent and light-harvesting antenna, respectively. The resulting hybrid layered rare earth hydroxides exhibit the enlarged interlayer distance with about 2.60 nm, and the chemical composition was confirmed through X-ray diffraction, carbon, hydrogen and nitrogen (CHN) elemental analysis, infrared spectroscopy, and thermogravimetric analysis. The layered solid compound shows the characteristic red emission corresponding to the 5D0→7F2 transition of Eu3+ ion, and the luminescence intensity of the optimized compound is greatly enhanced as compared to its corresponding nitrate and the hybrid composite without the introduction of dye molecule. The hybrid layered rare earth hydroxides can be exfoliated into bright colloidal solution, which show superior recognition capability to Cu2+ ion with the distinct luminescence quenching. The large quenching constant (1.4 × 104 L/mol) and low detection limit (0.35 μmol/L) are achieved for Cu2+ ion, implying a “turn-off” fluorescent sensor for Cu2+ detection. Moreover, a transparent film was prepared based on the colloidal solution and displays the typical red emission in folded shape. The new hybrid compound with enhanced luminescence and excellent photofunctional performances is expected to be applied in the fields of fluorescent sensing and flexible optical devices. published

Natural zeolite, as an abundant aluminosilicate mineral with a hierarchically porous structure, has a strong affinity to ammonium in solutions. Adsorption mechanism of high-concentration ammonium (1000~4000 mg-N/L) in an aqueous solution without pH adjustment onto Chinese natural zeolite with the dosage of 5 g/L was revealed by the strategy of experimental optimization integrated with Molecular Dynamics (MD) simulation, and found the maximum ammonium adsorption capacity was 26.94 mg/g. The adsorption kinetics and isotherm analysis showed that this adsorption process fitted better with descriptions of the pseudo-second-order kinetics and Freundlich model. The theoretical calculations and infrared-spectrum characterization results verified the existence of hydrogen bonds and chemisorption. Therefore, the adsorption mechanism by natural zeolites of high-concentration NH4+ is defined as a process under the joint influence of multiple effects, which is mainly promoted by the synergy of the ion exchange process, electrostatic attraction, and chemisorption. Meanwhile, the hydrogen bond also plays an auxiliary role in this efficient adsorption. This study presents important theoretical significance for enriching the mechanism of zeolites adsorbing NH4+ from water, and provides reference and theoretical guidance for further exploring the potential application of natural zeolites.

Synthetic 11 Å tobermorite (Ca5Si6O16(OH)2.4H2O) and its Al-substituted analogue are layer-lattice ion-exchangers with potential applications in nuclear and hazardous wastewater treatment. The present study reports the facile one-pot hydrothermal synthesis of an Al-tobermorite-rich cation-exchanger from a combination of paper recycling ash, post-consumer container glass, and lime, with compositional ratios of [Ca]/[Si + Al] = 0.81 and [Al]/[Si + Al] = 0.18. The reaction products were characterized by powder X-ray diffraction analysis, 29Si magic angle spinning nuclear magnetic resonance spectroscopy, and scanning electron microscopy. Hydrothermal processing in 4 M NaOH(aq) at 100 °C for 7 days yielded an Al-tobermorite-rich product that also contained katoite (Ca3Al2SiO12H8), portlandite (Ca(OH)2), calcite (CaCO3), and amorphous silicate gel. The hydrothermal product was found to have a Cs+ cation exchange capacity of 59 ± 4 meq 100 g−1 and selective Cs+ distribution coefficients (Kd) of 574 ± 13 and 658 ± 34 cm3 g−1 from solutions with molar ratios [Cs+]:[Na+] and [Cs+]:[Ca2+] of 1:100. In a batch sorption study at 20 °C, the uptakes of Pb2+, Cd2+, and Cs+ were determined to be 1.78 ± 0.04, 0.65 ± 0.06, and 0.36 ± 0.03 mmol g−1, respectively. The kinetics of Pb2+, Cd2+, and Cs+ removal were described by the pseudo-second-order rate model, which gave respective rate constants (k2) of 0.010, 0.027, and 1.635 g mmol−1 min−1, and corresponding correlation coefficients (R2) of 0.997, 0.996, and 0.999. The metal ion sorption properties of the tobermorite-rich product compared favorably with those of other waste-derived tobermorites reported in the literature. Potential strategies to improve the yield, crystallinity, and sorption characteristics of the product are discussed.

In this study, strengthening of machinable zirconia/mica composites was attempted by exchanging interlayer ions of mica in composites for larger ions, like chemically strengthened glasses. So the sintering behavior and ion-exchange of the composites fabricated using swelling mica and the mechanical properties of the ion-exchanged composites were investigated. The dense composite was obtained by sintering at 1200°C for 1 min and was ion-exchanged in molten potassium salts at 800°C. Na+ ions in the interlayer of mica near surface of the composites were exchanged for K+ ions. However, K+ ions were not inserted in the interlayer of mica. Mica reacted with molten salts to form an amorphous phase near surface of the composites. Simultaneously with the reaction, Na+ ions in mica were discharged into molten salts and K+ ions in molten salts were penetrated into the amorphous phase. Then other crystalline phases were formed in the amorphous phase. By the ion-exchange, the cracks developed from Vickers indentation corners were obviously shortened, which is one of the evidence that the compressive stress was generated near surface. By the compressive stress, the fracture toughness (3.5 MPa・m0.5) and the bending strength (322 MPa) of the composites were increased to 5.6 MPa・m0.5 and 447 MPa, respectively.

Recent works have established bio-based carboxylic acids as adaptable precursors to renewable biofuels and chemicals. However, the separation of carboxylic acids is a major energy and cost driver, accounting for 20-40% of the entire processing cost. Improved downstream separation technologies that reduce operating costs compared to conventional approaches are needed, particularly to enable bio-based commodity fuels and chemicals. Here, we combine techno-economic analysis (TEA) and an energy and environmental assessment with experimental results to compare weak-base adsorption (WBA) processes with the conventional strong ion exchange (IX) process for the recovery of the exemplary product, butyric acid. TEA indicates that WBA has the potential to reduce operating expenses from 34% to 6% relative to the selling price of butyric acid ($1.8 kg(-1)). Our energy analysis shows that the WBA process has 12.2-fold energy reduction and 9.2-fold GHG emission reduction compared to the conventional IX process.

Simple, binder free, low-cost chemical route has been employed to design CdSe@PbS core-shell surface architecture in thin film form towards electrochemical supercapacitor application. Horizontal chemical bath deposition (H-CBD) was used to grow one-dimensional (1D) Cd(OH)2 nanowires (NWs) template followed by ion exchange to get 1D CdSe NWs. Further, PbS nanoparticles were encapsulated on the surface of CdSe nanowires by using successive ionic layer adsorption and reaction (SILAR) method. Structural, compositional, and morphological studies have been used to confirm and investigate obtain surface architecture. Interestingly, design CdSe@PbS core-shell surface architecture not only offer maximum active sites but also provide smooth and fast electron transfer path exhibiting significant electrochemical performance with a specific capacity of 82 mAh g-1 and improved long-term stability. Additionally, symmetric electrochemical supercapacitor device of CdSe@PbS exhibits noticeable energy density of 16.14 Wh kg-1 at the power density of 288 W/kg.

International audience; A variety of 0-20 mol% of molybdenum ions (Mo 3+) doped sodium Rare-Earth (RE) fluoride upconversion nanowires (UCNW) were prepared by Coprecipitate-Solvothermal Ion-Exchange (CSIE) method. In this study, the Mo 3+ doped rare-earth hydroxide [REMo(OH)3] precursors were synthesized by the coprecipitation-solvothermal method. Following, the hexagonal phase of the Mo 3+ doped sodium rare-earth fluoride (β-NaGdF4: Yb 3+ /Tm 3+ /Mo 3+) nanowires were successfully prepared by ion-exchange reaction, and checked by XRD data analysis. As shown in the EDS results, Mo 3+ was uniformly distributed in the β-NaGdF4: Yb 3+ /Tm 3+ /Mo 3+. The controlled diameter (20-50 nm) and aspect ratio (20-500) values of β-NaGdF4: Yb 3+ /Tm 3+ /Mo 3+ nanowires strongly depend on the amount of Mo doping according to TEM images. The upconversion luminescence intensity (UC) of 10 mol% Mo 3+ doped β-NaGdF4: Yb 3+ /Tm 3+ /Mo 3+ nanowires was increased by one order of magnitude under the 980 nm near-infrared (NIR) excitation in regard to the undoped sample. Onedimensional (1D) upconversion nanowires (UCNW) with 10 mol% Mo 3+ doping gives the upconversion polyurethane (UCPU) excellent luminescent performance and about 99 % of enhanced tensile strength.

Natural zeolite and bentonite were utilized as mineral additives in the mix-design of environmentally safe cement-based building materials. The adsorptive abilities of these two clayey raw materials, i.e. their affinity to immobilize heavy metal ions Zn2+, Ni2+, Pb2+ and Cu2+ were investigated. Singleand multi-solutions of Zn2+, Ni2+, Pb2+ and Cu2+ were prepared for the experiment. The obtained results were submitted to analysis via pseudo-first and pseudo-second order kinetic models. Langmuir and Freundlich isotherms were analyzed. Bentonite exhibited better adsorption affinity than zeolite towards all four investigated cations. As a proof, a leaching test was conducted on seven different cement binders with different mineral additives (fly ash, zeolite, bentonite). The leachates obtained on the samples of cement with addition of fly ash and clay (either zeolite or bentonite) contained lower concentrations of Zn2+, Ni2+, Pb2+ and Cu2+ ions than leachates obtained on the samples of cement binder with fly ash solely as a result of adsorption and hydration mechanisms that immobilized heavy metals within cementitious composites. Prirodni zeolit i bentonit korišćeni su kao mineralni dodaci u mešavinskom dizajnu ekološki sigurnih građevinskih materijala na bazi cementa. Ispitane su adsorptivne sposobnosti ove dve glinene sirovine, tj. njihov afinitet da imobiliziraju jone teških metala Zn2+, Ni2+, Pb2+ i Cu2+. Za eksperiment su pripremljeni pojedinačni i multi-rastvori Zn2+, Ni2+, Pb2+ i Cu2+ . Dobijeni rezultati su analizirani pomoću kinetičkih modela pseudo prvog i pseudo drugog reda. Analizirane su izoterme Langmuira i Freundlicha. Bentonit je pokazao bolji adsorpcioni afinitet od zeolita prema sva četiri ispitivana katjona. Kao dokaz, ispitano je ispitivanje ispiranja na sedam različitih veziva za cement sa različitim mineralnim dodacima (leteći pepeo, zeolit, bentonit). Eluati dobijeni na uzorcima cementa sa dodatkom letećeg pepela i gline (bilo zeolita ili bentonita) sadržavale su niže koncentracije jona Zn2+, Ni2+, Pb2+ i Cu2+ u odnosu na eluat dobijen na uzorcima cementnog veziva sa letećim pepelom. Razlog za dobijanje ovakvih rezultata su adsorpcioni i hidratacioni mehanizmi koji imobiliziraju teške metale u cementnim kompozitima.

Relatively easy treatment of glass aggregates can lead to the formation of a highly porous zeolite aggregate. This study focuses on the possibility of using such an aggregate as an active additive to a gypsum binder. The physical properties of hardened gypsum composites with zeolite fillers doped with various metal ions (Ni2+, Cu2+, and Zn2+) have been compared. In addition to studies of the basic physical properties of the composites, structural and microstructural studies as well as antimicrobial tests were performed. It was found that the parameters of the composites with the addition of various ions do not differ significantly from the reference but modifies the microstructure. Among other things, the ions analyzed reduce the microporosity of gypsum composites. Using all aggregates, a product with adequate strength (above 2 MPa) and thermal conductivity (about 0.35 W/m·K) appropriate for typical lightweight gypsum composites can be obtained. The bacteriostatic effect of formulations with copper and zinc against Escherichia coli and with copper against Staphylococcus aureus was found.

The production of electrolytic nickel includes the stage of leaching of captured firing nickel matte dust. The solutions formed during this process contain considerable amounts of Pb, which is difficult to extraction due to its low concentration upon the high-salt background. The sorption of lead from model solutions with various compositions by synthetic and natural titanosilicate sorbents (synthetic ivanyukite-Na-T (SIV), ivanyukite-Na-T, and AM-4) have been investigated. The maximal sorption capacity of Pb is up to 400 mg/g and was demonstrated by synthetic ivanyukite In solutions with the high content of Cl− (20 g/L), extraction was observed only with a high amount of Na (150 g/L). Molecular mechanisms and kinetics of lead incorporation into ivanyukite were studied by the combination of single-crystal and powder X-ray diffraction, microprobe analysis, and Raman spectroscopy. Incorporation of lead into natural ivanyukite-Na-T with the R3m symmetry by the substitution 2Na+ + 2O2− ↔ Pb2+ + □ + 2OH− leds to its transformation into the cubic P−43m Pb-exchanged form with the empirical formulae Pb1.26[Ti4O2.52(OH)1.48(SiO4)3]·3.32(H2O).

This work examines in silico the dominant geochemical processes that control inorganic nutrients (Ca, Mg, Na, K) availability in irrigated agricultural soil amended with potassium-enriched biochar (from olive mill wastes) at mass doses of 0.5%, 1%, 2% and 10%. The geochemical modelling step was supported by analytical measurements regarding the physicochemical characteristics of the irrigation water, the agricultural soil and the biochar. Two geochemical approaches, namely equilibrium exchange (E.E.) and kinetic exchange (K.E.) models were applied and compared to assess nutrient release with an emphasis on potassium availability. Equilibrium exchange perspective assumed that nutrient release is controlled by ion-exchange reactions onto the biochar surface, whilst kinetic exchange perspective assumed the contribution of both ion-exchange and dissolution of salts. Results indicated that for the E.E. model, the soluble amount of potassium is readily available for transport within the pores of the porous media, and therefore is leached from the column within only 10 days. For the K.E. model that assumes a kinetically controlled release of potassium due to interactions occurring at the solid-solution interface, the assessed retention times were more realistic and significantly higher (up to 100 days). Concerning the applied doses of biochar, for a 2% biochar fraction mixed with soil, for example, the available K for plants doubled compared with the available K in the soil without biochar. In any case, the use of numerical modeling was proven helpful for a quick assessment of biochar performance in soil, by avoiding time-consuming and laborious experimental set-ups. Validation of the models by experimental data will further establish the proposed mechanisms.

In this study, the layer-lattice calcium silicate hydrate mineral, tobermorite, was synthesized from waste green or amber container glass and separately ion-exchanged with Ag+ or Zn2+ ions under batch conditions. Hydrothermal treatment of stoichiometrically adjusted mixtures of waste glass and calcium oxide in 4 M NaOH(aq) at 125 °C yielded tobermorite products of ~75% crystallinity with mean silicate chain lengths of 17 units after one week. Maximum uptake of Zn2+ ions, ~0.55 mmol g−1, occurred after 72 h, and maximum uptake of Ag+ ions, ~0.59 mmol g−1, was established within 6 h. No significant differences in structure or ion-exchange behavior were observed between the tobermorites derived from either green or amber glass. Composite membranes of the biopolymer, chitosan, incorporating the original or ion-exchanged tobermorite phases were prepared by solvent casting, and their antimicrobial activities against S. aureus and E. coli were evaluated using the Kirby–Bauer assay. S. aureus and E. coli formed biofilms on pure chitosan and chitosan surfaces blended with the original tobermorites, whereas the composites containing Zn2+-substituted tobermorites defended against bacterial colonization. Distinct, clear zones were observed around the composites containing Ag+-substituted tobermorites which arose from the migration of the labile Ag+ ions from the lattices. This research has indicated that waste glass-derived tobermorites are functional carriers for antimicrobial ions with potential applications as fillers in polymeric composites to defend against the proliferation and transmission of pathogenic bacteria.

The mining industry is a significant contributor to the Canadian economy. However, the mining activities can be detrimental to the environment due to the release of pollutants. Ammonia is one of the noxious and toxic contaminants associated with mining, ammonia contamination is created by the oxidizing agent in explosives. The explosives impacted mining wastewater (EIMWW) usually contains ammonia and other metal ions. The ammonia in EIMWW could harm the aquatic environment by the depletion of oxygen and its lethal toxicity to aquatic organisms. Before release to environment, EIMWW needs to be treated with an easy-to-operate method for ammonia removal at the remote mining sites. Ion-exchange (IE) with zeolite is an effective method for ammonia removal that is easy-to-operate, is not significantly impacted by cold temperature or toxicity effects. However, the traditional IE regeneration approach of using high concentration NaCl solutions creates a secondary polluting stream. Chlorine regeneration of ammonia-loaded zeolite appears to be a promising option, an evaluation of this option is the main topic of this thesis. This thesis includes three initiatives. The first is a set of multi-cycle batch loading-regeneration tests to assess the viability of ammonia removal with a commercial zeolite (SIR-600) for the treatment of a synthetic EIMWW (containing total ammonia nitrogen (TAN), K, and Ca) and to examine the performance of different ion-exchange regeneration solutions. The long-term TAN uptake of SIR-600 regenerated using a NaOCl (100 mg free Cl2/L) solution was 0.24 meq/g, which was approximately 20% lower than that after a NaCl regeneration. However, chlorine regeneration is promising because the selectivity of SIR-600 for TAN over Ca and K increased after the chlorine regeneration. To simulate recycling of the NaOCl regenerants, K and Ca were added to the NaOCl solution, it did not substantially affect the subsequent SIR-600���s ion uptake. This initiative represents a significant contribution since the earlier studies into chlorine regeneration did not investigate the impact of competing ions. The second initiative addressed concerns regarding the long-term integrity of SIR-600 arising from its exposure to high chlorine concentrations during the regeneration. The five-week long chlorine batch exposure tests with solutions of up to 1000 mg free Cl2/L showed that chlorine exposure did not significantly affect the SIR-600���s characteristics in terms of particle size distribution, surface area, FTIR spectra and ion uptake. Thus, SIR-600 has the potential for long-term use in field applications. The final initiative evaluated the feasibility of chlorine regeneration for continuous flow IE column systems used for ammonia removal from a synthetic EIMWW. Continuous flow column systems are important because these are the standard IE units used in full-scale applications. Multi-cycle column loading-regeneration tests were performed to compare the zeolite performance using a NaOCl (1000 ppm as free Cl2) solution with that using a 5% NaCl regeneration. The influence of loading duration was also assessed. The use of 6-hr loading cycles were shown to be preferable to 23-hr loading cycles because it had lower effluent concentrations and they could achieve higher overall TAN mass removals per unit time. After three operational cycles, the SIR-600 had similar TAN uptake performances (0.21 meq/g Vs. 0.21 meq/g) after NaOCl regeneration and after salt (NaCl) regeneration. This is in contrast to the lower TAN uptakes for the NaOCl regeneration in the batch tests, this indicates that batch tests are not always representative of full-scale applications. Compared to NaCl regenerated SIR-600, SIR-600 after NaOCl regeneration had a higher preference for TAN over Ca and K, which makes this type of regeneration very promising. Its only apparent limitation is that the NaOCl regeneration required a longer duration. During the NaOCl regeneration, the main mechanism appears to be the oxidation of ammonia to nitrogen gas and hydrogen ions, however the Na in the NaOCl solution also seems to have a role in the regeneration.

Electrochemical ion separation is a promising technology to recover valuable ionic species from water. Pseudocapacitive materials, especially 2D materials, are up-and-coming electrodes for electrochemical ion separation. For implementation, it is essential to understand the interplay of the intrinsic preference of a specific ion (by charge/size), kinetic ion preference (by mobility), and crystal structure changes. Ti3C2Tz MXene is chosen here to investigate its selective behavior toward alkali and alkaline earth cations. Utilizing an online inductively coupled plasma system, it is found that Ti3C2Tz shows a time-dependent selectivity feature. In the early stage of charging (up to about 50 min), K+ is preferred, while ultimately Ca2+ and Mg2+ uptake dominate; this unique phenomenon is related to dehydration energy barriers and the ion exchange effect between divalent and monovalent cations. Given the wide variety of MXenes, this work opens the door to a new avenue where selective ion-separation with MXene can be further engineered and optimized.

Background: Cellulose is one of the most abundant, non-toxic, and renewable natural biopolymers. The presence of hydroxyl groups in cellulose leads to further modification of it. Preparation and modification of cellulose-based sorbents and their applications on water treatment gained traction in recent years. Objective: A low-cost and eco-friendly biosorbent was designed and fabricated by introducing the acetate functional groups into cellulose for removing Beryllium (Be2+) from an aqueous solution. The sorption of Be2+ on acetate containing cellulose was evaluated for varying sorbent doses and initial solution pH values. Methods: The sorbent was prepared by a two-step oxidation process. In the initial step, cellulose reacted with NaIO4 and aldehyde groups were introduced to the cellulose. In the second step, newly obtained aldehyde groups were oxidized to create acetate groups. Results: The kinetics of the sorption process showed that Be2+ uptake reached equilibrium in 3 minutes. The sorption isotherm was well fitted in the Langmuir model, and the maximum sorption capacity was 4.54 mg/g. Moreover, the thermodynamic studies demonstrated that Be2+ sorption was spontaneous and exothermic. Furthermore, the prepared sorbent can be regenerated by using 0.1 M HCl or H2SO4 solutions. Conclusion: It is concluded that the removal of Be2+ is pH-dependent and it is favorable at high solution pH. The kinetics of the prepared sorbent were rapid and equilibrium attained in 3 minutes. The prepared sorbent can be regenerated with 0.1 M acid solution with > 99% efficiency., Ege University Scientific Re-search Projects Coordination Unit [FLP-2018-20310], This study is supported by Ege University Scientific Re-search Projects Coordination Unit (Project Number: FLP-2018-20310) .

The aim of this study was to investigate the response of different alumina types modified by cooper. Two alumina oxyhydrates with different water content, 3mol H2O/ mol Al2O3 (gibbsite) 0.6 mol H2O/ mol Al2O3 (α,γ-alumina phase), were used in this study. Copper modified alumina samples were prepared by ion exchange with a solution of CuSO4*5H2O. Cu-alumina samples were dried at at 110 o C overnight. The obtained samples were used as modifiers of the carbon paste electrode. Their electrochemical response toward ferricyanide/ferrocyanide redox probe was evaluated by cyclic voltammetry and correlated with the type of alumina and the amount of copper in impregnated alumina. The possibility of the application of Cu-alumina as an electrochemical sensor was tested.

Polymer-enhanced ultrafiltration (PEUF) is widely used to remove toxic metal ions due to its low operating cost and high removal rate. This study presents an efficient removal of beryllium (Be2+) in aqueous solutions using the polymer-enhanced ultrafiltration (PEUF) method. An environmentally friendly, water-soluble biopolymer, sodium lignosulfonate, was used for the experiments. The sorption of Be2+ depends on the pH of the initial solution. It was found that the Be2+ rejection rate increased with an increase in the pH of the solution. The ion exchange process between Be2+ and the sulphonate group of the polymer is so fast that the ion exchange reaction takes place within 15 minutes. The presence of interfering ions on the elimination rate of Be2+ was also tested. K+, Ca2+, and Mg2+ did not affect the elimination rate of Be2+, but the presence of Na+ decreased the elimination rate of Be2+. © 2022 Nova Science Publishers, Inc.

International audience; In this study, new experimental data for the adsorption of lead onto a swelling clay mineral with a tetrahedral charge (beidellite) at the ultratrace level (

Alkali-activated (or geopolymer) membranes have emerged recently as an alternative for conventional ceramic membranes. Their main benefit is the simple and low-energy manufacturing not requiring sintering, and thus potential for clearly lower costs, while having largely similar performance as conventional ceramic materials. In this work, metakaolin, blast furnace slag, and their mixture (representing typical low, high, and medium Ca-content raw materials, respectively) were compared as aluminosilicate precursors for the preparation of self-supporting membrane disks (diameter 75 mm, height 3 mm). A thorough material characterization was performed to evaluate mechanical strength, shrinkage, microstructure, chemical composition, pore size distribution, specific surface area, zeta potential, and water flux at different temperatures (20–60 °C) and pressures (200–1000 kPa). Based on this screening, metakaolin-based membrane (i.e., the low-calcium system) indicated overall better performance than the two others based on blast furnace slag or their mixture. As a final part of the study, ammonium-containing model effluent ([NH4+] = 50 mg L⁻¹) was distributed through the membrane (using 200 kPa pressure at 25 °C) to evaluate the potential for nitrogen removal and recovery. The mass balance examination indicated that ammonium was retained in the membrane matrix (i.e., not concentrated in the retentate fraction), and thus the likely removal mechanism was via ion-exchange. The obtained results provide interesting insights for the further development of alkali-activated membranes for applications requiring ammonium nitrogen removal, such as membrane bioreactors in municipal wastewater treatment.

Разработана лабораторная установка для получения концентрированных композиций на основе наноразмерных частиц диоксида кремния, в которой используется ионообменная технология. Исследованы структурно-реологические свойства полученных композиций. Установлены температурные зависимости плотности и рН композиций. Методом атомно-силовой микроскопии определены размеры частиц диоксида кремния в композициях. Проведены производственные испытания композиций в процессе химико- механической полировки пластин монокристаллического кремния. A laboratory plant has been developed for producing concentrated compositions based on nanoscale particles of silicon dioxide, which uses ion-exchange technology. Structural and rheological properties of the obtained com positions were investigated. Temperature dependencies of density and pH of compositions are established. The size of silicon dioxide particles in the compositions was determined by atomic force microscopy. Production tests of compositions in the process of chemical-mechanical polishing of single-crystal silicon plates were carried out.

Solute carrier (SLC) transporters are membrane transport proteins, which catalyse the movement of nutrients, ions, and drugs across cell membranes. Here, I will present our contribution to understanding the mechanism of the sodium/proton exchangers (NHE), belonging to the SLC9 family of membrane transporters. NHEs exchange sodium ions for protons across biological membranes, which is a critical reaction for the fine-tuning of cytoplasmic and organelle pH, sodium levels and volume homeostasis. Dysfunction of NHE members has been linked to a number of diseases and disorders, such as hypertension, heart failure, autism spectrum disorder, epilepsy and the susceptibility of long COVID. Protein structures are important for developing mechanistic models, but due to technical challenges only bacterial homologue structures of NHE proteins were previously available. Accumulating many years of effort, we were able to determine the first structure of a mammalian Na+/H+ exchanger, the endosomal isoform NHE9 by single-particle cryo-EM. The structure of NHE9 demonstrated that NHE proteins are architecturally most similar to bacterial homologues with 13-TM segments and likely operated by a similar elevator mechanism (I). Interestingly, native MS and thermal-shift assays indicted that the NHE9 homodimer is stabilized by the binding of a rare lipid only found in late endosomes, which implies the cell may use this lipid as means to switch-on NHE9 activity once it reaches its correct functional localization. We further provided evidence that the large cytoplasmic tail in NHE proteins likely acts in an auto-inhibitory manner. It is only removed upon the binding of extrinsic proteins (II). Indeed, the first structure of a potassium specific K+/H+ exchanger KefC reveals how its cytoplasmic tail restricts movement of the ion-transporting domain to directly inhibit transport. The structure of KefC is also the first ion-bound state seen for this family and, unlike to the modeled Na+/H+ exchanger sites with a hydrated Na+ ion, coordinates K+ as a dehydrated ion (IV). Lastly, we determining the structure of a bacterial Na+/H+ exchanger NhaA to high-resolution at an active pH of 6.5. With this structure we demonstrated how a cytoplasmic “pH gate” controlled by the pH activated NhaA (III).

Complexes of Co(II) and Ni(II) with 2,6-pyridine dicarboxylic acid (PydcH2) have been synthesized in the NaX (zeolite-X) nanopores. The formation of zeolite X encapsulatedCo(II) and Ni(II) complexes ([M(pydcH)2]-NaX, [M = Co(II) and Ni(II])] were confirmed using spectroscopic methods of FT-IR, elemental analysis, XRD, FE-SEM, and TEM. It was affirmed that the encapsulation of complexes in NaX pores was formed without changes in the structure and shape of the zeolite. The oxidative degradation reaction of atenolol with hydrogen peroxide as an oxidant was performed in the presence of synthesized [M(pydcH)2]-NaX nanocomposites to study their catalytic activity. Therefore, oxidation of atenolol was performed under different conditions of catalyst, temperature, and time. Under optimal conditions, catalysts [Co(pydcH)2]-NaX and [Ni(pydcH)2]-NaX showed 82.3% and 71.1% activity of atenolol oxidation, respectively. These catalysts were stable after recovery and were used three more times. The results showed that these catalysts were reusable and had a reduction in the catalytic activity of less than ten percent. KEY WORDS: Zeolite-X, Nano porosity, Ion-exchange, Degradation of atenolol, 2,6-Pyridine dicarboxylic acid Bull. Chem. Soc. Ethiop. 2023, 37(3), 611-622. DOI: https://dx.doi.org/10.4314/bcse.v37i3.6

Inorganic sorbents are more selective in comparison with commercial ion exchange resins towards of metal ions. However, inorganic sorbents characterized not high kinetic properties. One of the way to increase the kinetic rate of inorganic sorbents is to reduce the particle size of these materials, other way is synthesizing inorganic sorbents as porous products from powder materials. A sample of such inorganic sorbents is titanium phosphate of various compositions. Studying the properties of microfilters based on composition titanium phosphate - porous titanium has been developed. The sorbents based on acidic titanium phosphate Ti(HPO4)2∙H2O were used for filtering solution with Fe(II) content. It is found that the number of impregnations with inorganic sorbent modificator is important and influence filtration process. The obtained results demonstrated that after the first impregnation of porous material with a smaller pore size, it is possible to obtain such sorbent as a mass content of powder material. By varying the ionic form of titanium phosphate, the porosity of titanium, the amount of impregnation, it could be possible effect on the sorption Fe(II). The sorption properties of titanium-titanium phosphate microfilters were studied by potentiometric titration in the NaCl-NaOH system, as well as the sorption of Fe2+ ions. The degree of purification for Fe(II) from solution with a concentration of 10 mg/l is 64 %. Application an electric potential to the microfilter of porous titanium - phosphate titanium increases the degree of purification of Fe(II) to 88 %., По відношенню до іонів металів неорганічні сорбенти є селективнішими порівняно з промисловими іонообмінними смолами, але ці сорбенти характеризуються невисокими кінетичними властивостями. Одним із способів підвищення кінетичної швидкості неорганічних сорбентів є зменшення розміру частинок цих матеріалів, іншим способом є синтез неорганічних сорбентів у вигляді пористих продуктів на основі порошкових матеріалів. Зразком таких неорганічних сорбентів є фосфат титану різного складу. Розроблено спосіб модифікації мікрофільтрів на основі композицій фосфат титану – пористий титан. В досліджені було використано сорбент на основі кислого фосфату титану (ФТ) складу Тi(НРО4)2·Н2О. Знайдено, що важливим є кількість просочень (імпрегнувань) модифікатором поверхні пористого мікрофільтра. Варіюючи іонну форму фосфат титану, пористість титану, кількість просочень (імпрегнувань), можна впливати на ступінь сорбції Fe(II) з розчинів під час фільтрації. Сорбційні властивості титан-титанфосфатних мікрофільтрів досліджували шляхом потенціометричного титрування в системі NaCl-NaOH, а також сорбції іонів Fe(II). Ступінь очищення від Fe(II) розчинів, концентрація яких складала 10 мг/дм3, становить 64 %. При накладанні електричного потенціалу до мікрофильтру пористий титан - фосфат титана, можна підвищити ступінь очищення Fe(II) до 88 %.

In this study, the acidity of urazole (pKa 5–6) was exploited to fabricate a hydrogel in two simple and scalable steps. Commercially available poly(hexamethylene)diisocyanate was used as a precursor to synthesize an urazole containing gel. The formation of urazole was confirmed by FT-IR and1 H-NMR spectroscopy. The hydrogel was characterized by microscopy imaging as well as spectroscopic and thermo-gravimetric analyses. Mechanical analysis and cell viability tests were performed for its initial biocompatibility evaluation. The prepared hydrogel is a highly porous hydrogel with a Young’s modulus of 0.91 MPa, has a swelling ratio of 87%, and is capable of exchanging ions in a medium. Finally, a general strategy was demonstrated to embed urazole groups directly into a crosslinked material. 2-s2.0-85121419582 34940320

We investigated the stability of silver nanoisland films, which were formed on glass surface by the method of out-diffusion, in biocompatible buffers and the applicability of the films in surface enhanced Raman scattering (SERS). We have shown that silver nanoisland films are stable in one of the most widespread in biological studies buffer—phosphate buffer saline (PBS), and in 1:100 water-diluted PBS, in the PBS-based buffer, in which NaCl is replaced by the same amount of NaClO4, and in acidic phosphate buffer. At the same time, the replacement of NaCl in PBS by N(CH3)4Cl leads to the degradation of the nanoislands. It was shown that after exposure to PBS the nanoisland films provided a good SERS signal from a monolayer of 1,2-di(4-pyridyl)ethylene (BPE), which makes silver nanoisland films promising for biosensor applications. Additionally, in our experiments, we registered for the first time that silver nanoparticles formed in the bulk of the samples dissolved after exposing to PBS, while nanoislands on the glass surface stayed unchanged. We associate this phenomenon with the interaction of ions contained in PBS solution with silver, which results in the shift of corresponding chemical equilibrium.

One of the foremost missions in restorative dentistry is to discover a suitable material that can substitute lost and damaged tooth structure. To this date, most of the restorative materials utilized in dentistry are bio-inert. It is predicted that the addition of nano-HA-SiO2 to GIC matrix could produce a material with better ion-exchange between the restorative material and natural teeth. Therefore, the aim of the current study was to synthesize and investigate the transfer of specific elements (calcium, phosphorus, fluoride, silica, strontium, and alumina) between nano-hydroxyapatite-silica added GIC (nano-HA-SiO2-GIC) and human enamel and dentine. The novel nano-hydroxyapatite-silica (nano-HA-SiO2) was synthesized using one-pot sol-gel method and added to cGIC. Semi-quantitative energy dispersive X-ray (EDX) analysis was carried out to determine the elemental distribution of fluorine, silicon, phosphorus, calcium, strontium, and aluminum. Semi-quantitative energy dispersive X-ray (EDX) analysis was performed by collecting line-scans and dot-scans. The results of the current study seem to confirm the ionic exchange between nano-HA-SiO2-GIC and natural teeth, leading to the conclusion that increased remineralization may be possible with nano-HA-SiO2-GIC as compared to cGIC (Fuji IX).

The exchange of Ca2+ ions in hydroxyapatite (HAp) with Zn2+ ions into Zn-HAp is of interest for applications ranging from bone tissue engineering to the use as a precursor in subsequent ion-exchange reactions. Previous studies, using direct synthesis, showed that ~ 20 mol% Zn2+ ions can be incorporated into HAp, before byproducts are observed. However, this is realized at the cost of a loss in crystallinity and control over crystal size and shape with increasing amounts of Zn2+ ion incorporation. In this work a simple post-synthetic ion-exchange strategy for the formation of Zn-HAp has been investigated. By merely exposing HAp to high concentrations of zinc nitrate in water, up to 22 mol% of the Ca2+ ions can displaced by Zn2+ ions without any measured loss in crystallinity and preservation of crystallite size and shape. It was found that the incorporation of Zn2+ ions destabilizes the HAp crystals resulting in their gradual dissolution and reprecipitation. Consequently, promoting the exchange of Ca2+ with Zn2+ions using increased reaction times, sonication and increased temperature results in an increased dissolution of HAp and precipitation of hopeite crystals, thereby preventing the formation of more zinc rich Zn-HAp.

This study investigated the one-pot hydrothermal synthesis of mixed-phase ion-exchangers from waste amber container glass and three different aluminium sources (Si/Al = 2) in 4.5 M NaOH(aq) at 100 °C. Reaction products were characterised by X-ray diffraction analysis, Fourier transform infrared spectroscopy, 27Al and 29Si magic angle spinning nuclear magnetic resonance spectroscopy and scanning electron microscopy at 24, 48 and 150 h. Nitrated forms of cancrinite and sodalite were the predominant products obtained with reagent grade aluminium nitrate (Al(NO3)3∙9H2O). Waste aluminium foil gave rise to sodalite, tobermorite and zeolite Na-P1 as major phases, and the principal products arising from amorphous aluminium hydroxide waste were sodalite, tobermorite and zeolite A. Minor proportions of the hydrogarnet, katoite, and calcite were also present in each sample. In each case, crystallisation was incomplete and products of 52, 65 and 49% crystallinity were obtained at 150 h for the samples prepared with aluminium nitrate (AN-150), aluminium foil (AF-150) and amorphous aluminium hydroxide waste (AH-150), respectively. Batch Pb2+-uptake (~100 mg g−1) was similar for all 150-hour samples irrespective of the nature of the aluminium reagent and composition of the product. Batch Cd2+-uptakes of AF-150 (54 mg g−1) and AH-150 (48 mg g−1) were greater than that of AN-150 (36 mg g−1) indicating that the sodalite- and tobermorite-rich products exhibited a superior affinity for Cd2+ ions. The observed Pb2+- and Cd2+-uptake capacities of the mixed-product ion-exchangers compared favourably with those of other inorganic waste-derived sorbents reported in the literature.

Lithium aluminosilicate glass-ceramics (LAS GCs) are ideal shell materials for mobile phones, however, the mechanical properties of LAS GCs are comparatively lower than that of other shell materials. In this work, the impact of TiO2/(TiO2 + ZrO2) ratio on properties of LAS GCs was studied and the ion-exchange methods were applied to improve the mechanical properties of LAS GCs. The results show that LAS GCs with TiO2/(TiO2 + ZrO2) = 1/2 exhibit the best flexural strength (109 MPa) and Vickers hardness (525 Kg/mm2). The as-prepared glass was nucleated at 560 °C for 1 h and crystallized at 720 °C for 0.5 h. The main crystalline phases of LAS GCs are β-quartz solid solution, β-spodumene solid solution, and Li2SiO3. Moreover, the flexural strength and Vickers hardness of LAS GCs with TiO2/(TiO2 + ZrO2) = 1/2 further increased to 356 MPa and 838 Kg/mm2 after an ion-exchange at 420 °C for 6 h in pure KNO3 molten salt. The LAS GCs with enhanced mechanical strength have the potential to be applied as mobile phone back panels.

In the cement system, hydrocalumite is a candidate adsorbent for low-level 129I anionic species. However, the stability of hydrocalumite after immobilizing I− is unclear when they are exposed to pedosphere characterized by organic substances derived from living organisms. In the present work, five amino acids were selected as simplified models of natural organic substances under alkaline conditions. L-cysteine (H2Cys) and L-aspartic acid (H2Asp) accelerated the release of I− from I-hydrocalumite through ion-exchange. Ion-exchange of Cys2− with I− in I-hydrocalumite was faster than Asp2−, and the interlayer spacing (d003) of Cys-hydrocalumite was smaller than that of Asp-hydrocalumite. DFT simulations not only supported the above results but also predicted that there was a positive correlation between the formation energies and interlayer spacings of amino acids intercalated hydrocalumite, depending on the configurations. Moreover, in the DFT predictions, the interaction between amino acids and metallic hydroxide layers was responsible for the formation of hydrogen bonds and Ca-O chemical bonds between the -COO− groups and [Ca2Al(OH)6]+. The other three amino acids did not show intercalation through ion-exchange. The stability of I-hydrocalumite is influenced differently by coexisting amino acids, depending on the ionic sizes, charge numbers, and hydrophilicity, which cause the second contamination.

Zeolites are nanoporous alumina silicates in a framework with cations, exhibiting ion-exchange properties with metal ions making them possible antimicrobial materials. The aim of this study was to evaluate the antimicrobial activity of ion-exchanged zeolites and the toxic potential of these materials. Zeolite-Co2+ and Li+ exhibited the most effective inhibition on Staphylococcus aureus growth than in other microorganisms (Escherichia coli and Pseudomonas aeroginosa) in low concentrations. Zeolite-Cu2+ presented higher zone of inhibition when tested against Candida albicans, while Zeolite-Zn2+ showed similar effectiveness among all the microorganisms. When ion-exchanged zeolites were used in effective concentrations to achieve antimicrobial activity, no alterations against bioindicators organisms as Artemia sp. and L. sativa were found and, in addition, they have non-significant result in terms of DNA cleavage activity. Zeolites have advantage of releasing slowly the metals loaded and this characteristic can to be considered promising as potential antimicrobial materials in concentrations safe for use.

A polymeric hybrid nanocomposite, namely polythiophene tin(IV)phosphate (PTh–SnP), was expediently synthesized by incorporating polythiophene (PTh) in tin phosphate (SnP) to enhance the conducting behavior and sorption of heavy metal ions by porous polymeric cation exchanger. Composite was characterized by Fourier Transform-Infra Red and Transmission Electron Microscopy. The dc electrical conductivity studies carried out on the composite, showed conductivity within the range of 4.0 × 10−2–1.0 × 10−3 S/cm−1; measured by a 4-in line-probe dc electrical conductivity measuring technique. Ion-exchange kinetics for few divalent metal ions was evaluated by particle diffusion-controlled ion-exchange phenomenon at four different temperatures. The particle diffusion mechanism is confirmed by the linear τ (dimensionless time parameter) vs t (time) plots. The exchange processes thus controlled by the diffusion within the exchanger particle for the systems studies herein. Some physical parameters like self-diffusion coefficient (D0), energy of activation (Ea) and entropy (ΔS°) have been evaluated under conditions favoring a particle diffusion-controlled mechanism. Keywords: Nanotetrapod, Hybrid, Electrically conducting, Diffusion coefficient, Ion-exchange, Kinetics

Sulfonated hyper-cross-linked polymers based on 4,4′-bis(chloromethyl)-1,1′-biphenyl (BCMBP) were synthesized via metal-free (SHCP-1) and conventional Lewis acid-catalyzed (SHCP-2) Friedel–Crafts alkylation routes. The sulfonated polymers possessed BET surface areas in excess of 500 m2·g–1. SHCP-1 was investigated for its ability to extract Sr and Cs ions from aqueous solutions via the ion-exchange reaction of the sulfonic acid moiety. Equilibrium uptake data could be accurately modeled by the Dubinin–Radushkevich isotherm, with maximum calculated loading values of 95.6 ± 2.8 mg·g–1 (Sr) and 273 ± 37 mg·g–1 (Cs). Uptake of both target ions was rapid, with pseudo second-order rate constants calculated as 7.71 ± 1.1 (×10–2) for Sr and 0.113 ± 0.014 for Cs. Furthermore, the polymer was found to be highly selective toward the target ions over large excesses of naturally occurring competing metal ions Na, K, Mg, and Ca. We conclude that hyper-cross-linked polymers may offer intrinsic advantages over other adsorbents for the remediation of aqueous Sr and Cs contamination.

In the Saharan regions of southern Algeria, sand winds are very harmful to fragile materials, particularly glass (house glazing, windshields, etc.). Sand impacts cause upward damage generated by erosive wear. Glass is very sensitive to superficial defects. The latter become unstable under repeated stresses and lead to catastrophic failure of the material. The reinforcement of its surface is, therefore, more than necessary. In this work, two thermochemical strengthening methods were proposed to improve the mechanical strength of glass without altering its optical properties. Reinforcement by chemical modification of the surface layer of the glass by ion exchange and the deposition of a thin layer of ZnO by the method of spray pyrolysis to maintain the transparency of the material. The purpose of this work is to study the influence of the technological parameters of the two reinforcement methods on the effectiveness of the treatment obtained. For the chemical toughening the effect of the immersion temperature and the ion exchange treatment time in a bath of molten salt of KNO3 on soda lime glass was studied. The thin film deposition parameters were modified in order to monitor their impact on the mechanical properties of the coated glass, in particular its resistance to erosion by natural sand from the Sahara and by abrasive grains of alumina. EDS analysis showed that the depth of penetration of K+ into glass increases as temperature and processing time increase. The effect of ion exchange temperature and time on mechanical reinforcement was studied by micro-indentation, scratch test, bending test, wear and erosion test. All of these mechanical properties are improved after ion exchange treatments. The increase in the ion exchange time induces an increase in Vickers hardness of about 15 to 40% compared to untreated glass. Samples processed at 520°C for a short period of 2 hours show better mechanical properties compared to samples processed at 480°C for longer times. In this case, the sample has a higher surface density which made the glass lattice in compression not only because the potassium ions occupy the ionic substitution spaces but also the free spaces. This treatment has no effect on the optical properties of glass. Erosion and wear resistance behave the same, either by using natural abrasives such as Sahara sand or by using an aggressive abrasive as alumina grits. The surface is damaged more with these grains than with the grains of sand. Different thin films have been produced under different conditions by the spray pyrolysis technique. The DRX analysis shows that the obtained ZnO layers are of the Zincite structure. These layers are removed after aging in water or NaCl.; Dans les régions sahariennes du sud l’Algérie, les vents de sable sont très néfastes pour les matériaux fragiles, particulièrement le verre (vitrages d’habitations, parebrises, …). Les impacts de sable provoquent un endommagement ascendant généré par l’usure érosive. Le verre est très sensible aux défauts superficiels. Ces derniers deviennent instables sous des sollicitations répétées et conduisent à la rupture catastrophique du matériau. Le renforcement de sa surface est de ce fait plus que nécessaire. Dans ce travail, deux méthodes de renforcement thermochimiques ont été proposées afin d’améliorer la résistance mécanique du verre sans altérer ses propriétés optiques. Le renforcement par modification chimique de la couche superficielle du verre par échange ionique et le dépôt d’une couche mince de ZnO pour conserver la transparence du matériau par la méthode de spray pyrolyse. Le but de ce travail de thèse est d'étudier l'influence des paramètres technologiques des deux méthodes de renforcement sur l’efficacité du traitement obtenu. Pour la trempe chimique l’effet de la température d'immersion et du temps de traitement de l'échange ionique dans un bain de sel fondu de KNO3 sur du verre sodocalcique a été étudié. Les paramètres de dépôt de couche mince ont été modifiés afin de suivre leur incidence sur les propriétés mécaniques du verre revêtu, en particulier sa résistance à l'érosion par du sable naturel du Sahara et par des grains abrasifs d’alumine. L'analyse EDS a montré que la profondeur de pénétration du K+ dans le verre augmente avec l'augmentation de la température et du temps de traitement. L'effet de la température et du temps d'échange ionique sur le renforcement mécanique a été étudié par la micro-indentation, l’essai de rayure, l’essai de flexion, l’essai d'usure et d'érosion. Toutes ces propriétés mécaniques sont améliorées après le traitement avec l’échange ionique. L'augmentation du temps d'échange ionique induit une augmentation de la dureté Vickers d'environ 15 à 40% par rapport au verre non traité. Les échantillons traités à 520°C pendant une courte période de 2 heures présentent les meilleures propriétés mécaniques par rapport aux échantillons traités à 480 ° C pendant des temps plus longs. Dans ce cas, l'échantillon a une densité de surface plus élevée qui rend le réseau des couches superficielles du verre en compression non seulement parce que les ions potassium occupent les espaces de substitution ionique mais également les espaces libres. Ce traitement n’a aucun effet sur les propriétés optiques du verre. L'érosion et la résistance à l'usure se comportent de la même manière, soit en utilisant des abrasifs naturels tels que le sable du Sahara, soit en utilisant un abrasif agressif comme les grains d'alumine. L’endommagement de la surface est plus accentué après son érosion avec les abrasifs d’alumine qu’avec les grains de sable. Différents films minces ont été déposés dans différentes conditions par la technique de la spray pyrolyse. L’analyse de DRX montre que les couches obtenues de ZnO sont de la structure de Zincite. Ces couches sont éliminées après un vieillissement en eau ou en NaCl.

This work aims to explore the interaction between water and ion-exchanged aluminosilicate glass. The surface mechanical properties of ion-exchanged glasses after different hydration durations are investigated. The compressive stress and depth of stress layer are determined with a surface stress meter on the basis of photo-elasticity theory. The hardness and Young’s modulus are tested through nanoindentation. Infrared spectroscopy is used to determine the variation in surface structures of the glass samples. The results show that hydration has obvious effects on the hardness and Young’s modulus of the raw and ion-exchanged glasses. The hardness and Young’s modulus decrease to different extents after different hydration times, and the Young’s modulus shows some recovery with the prolonging of hydration time. The ion-exchanged glasses are more resistant to hydration. The tin side is more resistant to hydration than the air side. The results are expected to serve as reference for better understanding the hydration process of ion-exchanged glass.

Bio-based and degradable polymers such as poly(lactic acid) (PLA) have become prominent. In spite of encouraging features, PLA has a low melt strength and melt elasticity, resulting in processing and application limitations that diminish its substitution potential vis-a-vis classic plastics. Here, we demonstrate a large increase in zero shear viscosity, melt elasticity, elongational viscosity and melt strength by random co-polymerization of lactide with small amounts, viz. 0.4–10 mol%, of diethylglycolide of opposite chiral nature. These enantiomerically pure monomers can be synthesized using one-step zeolite catalysis. Screening of the ester linkages in the final PLA chains by the ethyl side groups is suggested to create an expanding effect on the polymer coils in molten state by weakening of chain–chain interactions. This effect is suspected to increase the radius of gyration, enabling more chain entanglements and consequently increasing the melt strength. A stronger melt could enable access to more cost-competitive and sustainable PLA-based biomaterials with a broader application window. Amongst others, blow molding of bottles, film blowing, fiber spinning and foaming could be facilitated by PLA materials exhibiting a higher melt strength., Melt strength improvements of PLA by co-polymerizing lactide with co-monomers of opposite chirality were discovered. Stronger melts can translate in less plastic usage, paving the way towards more sustainable bioplastics with broader applicability.