Papers by Keyword: Sodium Tripolyphosphate

Abstract: The development of non-enzymatic glucose biosensor has been the concern of many researchers mainly because enzymes based sensor despite having excellent sensitivity and selectivity, has the limitations such as poor stability, complicated enzyme immobilization, critical operating conditions such as optimum temperature and reproducibility. This study developed a cheap biocompatible non-enzymatic glucose biosensor based on silver nanoparticle (AgNPs) stabilized with sodium tripolyphosphate (NaTPP) cross-linked chitosan. Direct electron transfer and electro-catalytic activity of the AgNPs modified glassy carbon electrode (AgNPGCE) was investigated using potentiometric and amperometric techniques. AgNPs was prepared and characterized by Fourier transform Infra-red spectroscopy (FTIR), X-ray diffractometry (XRD) and Scanning electron microscopy (SEM). The crystalline size of the AgNPs was revealed with XRD. However, the SEM micrograph of AgNPs revealed the spherical shape with a non-uniform granular shape attributed to bio-mediated ionic gelation process. The FTIR spectra of AgNPs shown peaks at 1054 – 1645 cm^-1 suggesting the presence of phosphonate linkages between ammonium, -NH₃⁺ of chitosan and -PO₃^2- moieties of NaTPP during cross linking process. Electro-catalytic oxidation of glucose at the AgNPGCE surface and the mechanism involved in glucose oxidation was revealed via cyclic voltammetry. The AgNPGCE showed a better electrochemical response towards glucose. This glucose sensor showed high sensitivity at +0.54 V. A low detection limit of 1.22 µM (the confident level κ = 3), and wide linear range of 2 to 24 µM with a correlation coefficient of 0.9987 were obtained. The calculated parameters revealed that AgNPGCE had shown better overall electrochemical performance and response than enzymatic biosensor.

Abstract: The transporting of sediments across watershed systems and their placement in reservoirs causes expensive issues for the operators of dams in many different nations throughout the world. In addition to the reservoir's functional capacity steadily decreasing as sediment settles in it, silt removal is a sensitive and challenging process that frequently necessitates taking the reservoir out of service, which is practically unachievable in dry and semi-arid regions. De-silting by hydraulic dredging has recently become a necessity to increase their longevity. But during this operation there are load loss exists so it is necessary to find solutions to reduce it. The present paper revealed that use the Sodium Tripolyphosphate as a reducing agent of the friction factor during the hydraulic dredging of dams. To carry out this study, a rheumatic characterization of dams sediments and dams sediments -sodium tripolyphosphate mixtures was carried out using a torque controlled rheometer (Discovery Hybrid Rheometer DHR2 from TA instrument). The flow curves as a function of dose of sodium tripolyphosphate added to dam sediments were analysed by the modified Cross model. It is clearly shown, in this work, when the quantity of sodium tripolyphosphate is less than of 0.4 % causes a decrease in the yield stress, the zero shear rate viscosity (lower Newtonian plateau) and the infinite shear rate viscosity (upper Newtonian plateau). However, when dose of sodium tripolyphosphate is greater than the critical dose, the the yield stress, the zero shear rate viscosity (lower Newtonian plateau) and the infinite shear rate viscosity (upper Newtonian plateau) are increased. As a result, this study find that the increase on thixotropic behavior of dams sediments is occurred by the addition of sodium tripolyphosphate in a concentration ranging between 0.2 wt% and 0.8 wt% to 40 wt% and 45 wt% of dams sediments. The study also demonstrated that adding of 0.4 wt% of sodium tripolyphosphate to 40 wt% and 45 wt% dam sediments decreased the friction factor by 96% and 25% respectively.

Abstract: The purpose of this study was to investigate the effect of polyanionsodium tripolyphosphate (STP) on color stability of the bleached enamel upon exposure to a staining agent-red wine. Thirty specimens were prepared and bleached with 35% hydrogen peroxide (HP). Then, they were divided into three groups and immersed in different experiment solutions, including distilled and deionized water (DDW, negative control), 2% STP (PH 9.0) and 1000 ppm NaF aq. (positive control), before and after red wine stain challenge, 3 times per day. The color of all specimens was measured before and after exposure to red wine with a spectrophotometer, and total color change (ΔE*) were calculated. The data were analyzed with a one-way ANOVA and the means were compared by Tukeys post hoc analysis (α=0.05). STP treatment group demonstrated significantly less color change than DDW and NaF groups (p<0.05). No significant difference was observed between DDW and NaF group. It can be concluded that the staining susceptibility of bleached enamel decreased after application of polyanion sodium tripolyphosphate.

Abstract: Aqueous dispersions of SiAlON forming powders (Si3N4, AlN and Y2O3) were obtained. Dispersibility of powders was found to be improved by addition of sodium tripolyphosphate. Stable aqueous suspensions of SiAlON forming powders were prepared by using a phosphate ester, sodium tripolyphosphate (STPP, Na5P3O10). Effect of the STPP on rheological properties of the powder mixture was investigated by zeta potential measurements, sedimentation and milling studies. It has been shown that addition of the STPP to the aqueous SiAlON forming powder mixture improves the dispersion behavior significantly. These results suggest that STPP can be utilized as a dispersant in such ceramic systems.

Abstract: Sodium silicate has been widely used as starting materials of chemical grout owing to its feasibility and short setting time with reasonable strength. Elution of sodium has been pointed out as the main reason of weak durability of homogel prepared with sodium silicate-cement grout. There are well known series of additives for controlling its setting time, fluidity, and compressive strength. We studied the structural change on the sodium silicate with additive of sodium tripolyphosphate (STPP) by 29Si nuclear magnetic resonance spectrum and viscosity. The homogel was prepared by mixing cement/water suspension and diluted sodium silicate/STPP mixtures, and aged in the water. The development of compressive strength and its structural change were observed using a universal test machine, X-ray diffraction, and scanning electron microscope. The additive changed the distribution of Si and rheological property of liquid sodium silicate, which caused more uniform distribution of Ca and Si in the homogel to lead to high initial strength and durability.