Phosphoric Acid Solution Research Articles

Rapid synthesis of monocalcium phosphate using calcium carbonate extracted from green mussel shells and phosphoric acid solution

Ca-source of green mussel shells (Perna-Viridis) recovered into precipitated calcium carbonate (PCC) powders via a calcination-dissolution-precipitation pathway is a prospective feedstock for the rapid synthesis of monocalcium phosphate monohydrate (MCPM). In the study, a potential aqueous crystallization process was implemented for MCPM synthesis by blending PCC powders with vaterite (55.20 wt %) and calcite (44.80 wt%) in strongly phosphoric acid with a molarity of 85% (w/w) and varying amounts of water (2–6 mL), followed by rapid evaporation and drying. The resulting product contained at least 90 wt % MCPM and minor monetite according to XRD and FTIR analyses. The morphology of the MCPM product is a prismatic-like shape with grain sizes ranging from 3 to 9 μm, as observed using SEM techniques. DTA/DTG/TG analysis confirms the stability of MCPM products at temperatures up to 100 °C providing benefits for food industries and communities as a stable food additive commodity.

Understanding the fast formation mechanism of hard nanoporous alumina films on aluminum in acidic solutions containing nitric acid

Nanoporous alumina films formed on aluminum via anodization are widely used for scientific and technical purposes owing to their various advantageous properties, including excellent corrosion and wear resistance, good thermal and electrical insulation, and facile producibility at low cost. Herein, we report a novel approach to fabricate hard porous anodic alumina (PAA) films by adding an appropriate amount of nitric acid to sulfuric-, oxalic-, and phosphoric-acid solutions at critical high current densities. The effects of the nitric additives on the anodizing behavior, film growth mechanism, microstructure, chemical composition, film thickness, microhardness, and appearance of the PAA films formed from various solutions were systematically investigated. The addition of nitric acid enhanced the formation of alumina and resulted in fast growth rates of 196 μm/h and 166 μm/h for sulfuric- and oxalic-based solutions, respectively, while maintaining high hardness of approximately 380 and 430 HV0.1, respectively. The surface hardness of the films decreased to some extent with the increase in nitric acid concentration and/or film thickness owing to the strong corrosive nature of nitric acid during prolonged anodization, although nitrogen inclusion in anodic alumina films was not detected through X-ray photo-electron spectroscopy, which differs from the other acidic anions. In particular, the barrier layer thickness and pore intervals of PAA films increased with the nitric concentration in the aforementioned solutions, leading to a fast growth rate and high hardness inside the films.

Multi-component content determination of Dracocephalum tanguticum by quantitative analysis of multi-components by single-marker

This study aims to establish a method for the simultaneous determination of 7 active components in Dracocephalum tanguticum and to evaluate the quality of medicinal materials from different habitats. The method was established with high performance liquid chromatography(HPLC) and the gradient elution was performed with the mobile phase of acetonitrile-methanol-0.2% phosphoric acid solution at a column temperature of 35 ℃, an injection volume of 15 μL, and a flow rate of 0.6 mL·min~(-1). The detection wavelength was set as 215 nm. With rosmarinic acid as the internal reference, the relative correction factors and the content of other 6 components were calculated. The results were compared with those obtained with the external standard method. The results showed that the samples from Huangzhong county, Qinghai province had the best quality, with the highest content of p-hydroxybenzoic acid, cosmosiin, rosmarinic acid, oleanolic acid, and ursolic acid(9.29, 12.14, 6.02, 3.11, 17.67 mg·g~(-1) respectively). The samples from Chaya county, Tibet autonomous region ranked the second, with the highest content of betulin and betulinic acid(15.53, 7.17 mg·g~(-1), respectively). The method is accurate, reliable, and repeatable and suitable for the simultaneous determination of multiple components in D. tanguticum. The content of functional components varied in the samples from different producing areas and can be used as the indicator for the quality evaluation of medicinal materials.

A comparative study of compressed lateritic earth bricks stabilized with natural pozzolan-based geopolymer binders synthesized in acidic and alkaline conditions

Two geopolymer binder systems made under alkaline and acidic conditions have been evaluated for the stabilization of compressed lateritic earth bricks (CEBs) using natural pozzolan as aluminosilicate precursor. The preparation of alkaline and acidic activators involved the combination of sodium silicate and 10 mol/L sodium hydroxide solutions, as well as 10 mol/L phosphoric acid solutions, respectively. CEBs were prepared to comprise different proportions of natural pozzolan of 5, 10, 15, and 20 %. The physico-mechanical and mineralogical properties of compressed earth bricks were studied using the compressive strength, the dry and wet bulk density, the water absorption rate, Fourier transform infrared spectroscopy (FTIR), powder X-Ray Diffraction (PXRD) and optical microscopy (OM).The results showed that in the acid environment, the mechanical performance increased considerably with the pozzolan content and slightly with the curing time, whereas in the alkaline environment these performance decrease for the sample with 0 to 10 % of pozzolan and remain constant for the sample with 15 to 20 % of pozzolan after 14 days of curing. The utilization of acid-activated geopolymer binder in the production of laterite-based compressed earth bricks has been shown to be more effective compared to the utilization of an alkali-activated geopolymer binder. The high performance of acid-stabilized CEBs is related to the best reactivity of natural pozzolan in acid medium allowing the formation of Al-O-P bonds.

Activation of natural manganese oxide material: reduction of cadmium from phosphoric acid solutions

Activation of natural manganese oxide material: reduction of cadmium from phosphoric acid solutions

Separation and fractionation of glutamic acid and histidine via origami isoelectric focusing

We demonstrated the fractionation of two amino acids, glutamic acid and histidine, separated via isoelectric focusing (IEF) on filter paper folded and stacked in an origami fashion. Channels for electrophoresis were fabricated as circular zones acquired via wax printing onto the filter paper. An ampholyte solution with amphiphilic samples was deposited on all the circle zones, which was followed by folding to form the electrophoresis channels. IEF was achieved by applying an electrical potential between the anodic and cathodic chambers filled with phosphoric acid and sodium hydroxide solutions, respectively. A pH gradient was formed using either a wide-range ampholyte with a pH of 3 to 10 or a narrow-range version with a pH of 5 to 8, which was confirmed by adding pH indicators to each layer. The origami IEF was used to separate the amino acids, glutamic acid and histidine, by mixing with the ampholytes, which were deposited on the layers. The components in each layer were extracted with water and measured by high-performance liquid chromatography using pre-column derivatization with dansyl chloride. The results indicated that the focus for glutamic acid and that for histidine were at different layers, according to their isoelectric points. The origami isoelectric focusing achieved the fractionation of amino acids in less than 3 min using voltage as low as 30 V.

Scholastic modeling of pH and redox potential changes in olive tree leaf alcohol and acids containing incubation media designed for the steady growth of Acetobacter aceti and Saccharomyces cerevisiae

Modeling of pH and redox potential changes was investigated instructionally in incubation media designed for a stable growth of Acetobacter aceti and Saccharomyces cerevisiae. Olive tree leaf, phosphoric acid, vinegar, acetic acid and ethyl alcohol were used in incubation for extraction and symbiotic purposes. Structure imaging of olive tree leaf powder was performed using the Field Emission Gun – Scanning Electron Microscope (FEG-SEM). The incubation experiments were carried out at initially lowest pH and high temperatures of 30oC and 35oC for eight days in liquid state fermentation process. A steady A. aceti and S. cerevisiae growth was observed during the incubation. Increase in pH value displayed increase in redox potential in water+ phosphoric acid, vinegar+A. aceti+phosphoric acid, S. cerevisiae+A. aceti+acetic acid+phosphoric acid and S. cerevisiae+A. aceti+phosphoric acid solution processes at 30oC, and acetic acid+phosphoric acid and vinegar+phosphoric acid solution processes at 35oC. Decrease in pH value displayed decrease in redox potential in A. aceti+alcohol+phosphoric acid, vinegar+phosphoric acid, S. cerevisiae+A. aceti+acetic acid+phosphoric acid and S. cerevisiae+A. aceti+phosphoric acid solution processes at 30oC, and vinegar+A. aceti+phosphoric acid, S. cerevisiae+A. aceti+acetic acid+phosphoric acid and S. cerevisiae+A. aceti+phosphoric acid solution processes at 35 oC.

Adsorption of chromium from electroplating wastewater using activated carbon developed from water hyacinth

Industrial wastewater polluted with high concentrations of Cr is commonly discharged into water resources without proper treatment. This gives rise to the deterioration of water quality and imposes adverse effects on public health. Therefore, this study is aimed at removing Cr from electroplating wastewater using activated carbon produced from water hyacinth under a full factorial experimental design with three factors and three levels (pH,2,5 and 8, adsorbent dose 0.5,1and1.5 in 100 mL and contact time 30, 60 and120 min). A phosphoric acid solution of 37% was used to activate the carbon, which was then subjected to thermal decomposition for 15 min at 500 °C. The activated carbon was characterized by the presence of a high surface area (203.83 m2/g) of BET, cracking of adsorbent beads of SEM morphology, amorphous nature of XRD, and many functional groups of FTIR such as hydroxyl (3283 cm−1), alkane (2920 cm−1), nitrile (2114 cm−1) and aromatics (1613 cm−1). The minimum Cr adsorption performance of 15.6% was obtained whereas maximum removal of 90.4% was recorded at the experimental condition of pH 2, adsorbent dose of 1.5 g/100 mL, and contact time of 120 min at a fixed value of initial Cr concentration of 100 mg/L. Similarly, the maximum Cr removal from real electroplating wastewater was 81.2% at this optimum point. Langmuir's model best described the experimental value at R2 0.96 which implies the adsorption is chemically bonded, homogeneous, and monolayer. Pseudo-second-order model best fits with the experimental data with R2 value of 0.99. The adsorbent was regenerated for seven cycles and the removal efficiency decreased from 93.25% to 21.35%. Finally, this technology is promising to be scaled up to an industrial level.

Analytical Method Development and Validation of Ubrogepant and their Degradation Studies in Bulk and Pharmaceutical Dosage form by RP-HPLC

An accurate, rapid economical and straight forward, reliable new analytical method was developed and validated for the quantification of Ubrogepant and their degradation studies by using RP-HPLC.In the proposed method efficient chromatographic separation was achieved by using Ammonium aecetate buffer with pH adjusted to 5.0 with dilute Orthophosphoric acid solution and methanol (30:70 v/v) as a mobile phase with a flow of 1 ml/min and Water and Acetonitrile(30:70) is used as a diluent, the wave length was observed at 280 nm with isocratic mode at ambient temperature and run time was approximately 10 min and the retention time (Rt) of Ubrogepant was observed as 4.570 min. The method validated as per ICH guidelines. System suitability parameters were studied by injecting six standard solutions of Ubrogepant and results were well under acceptance criteria. Linearity study was administered between 25% to 150% levels, Regression coefficient value was observed as 0.999. LOD and LOQ were observed as 0.02 ug/ml and 0.2 ug/ml, respectively. Precision was found to be 0.54 for repeatability and 0.33 for intermediate precision. Recovery of the drug was found to be 100.86% indicates that the recovery is in the acceptable limit. Stress conditions of degradation in Acidic, Alkaline, Peroxide and Thermal were studied for Ubrogepant and validation results were found to be satisfactory and the proposed method was suitable for regular analysis and quality control of pharmaceutical preparations.

Process and corrosion property of laser-chemical hybrid polishing of TC4 alloy

In order to reduce the adverse effects of recast layer and heat-affected zone during laser polishing of titanium alloys, a novel laser-chemical hybrid polishing method was proposed. The surface of TC4 alloy in phosphoric acid solution was irradiated by nanosecond laser for polishing experiments. White light interferometer was used to measure the surface roughness at different number of laser scanning times. The surface composition was analyzed by XPS. The results showed that the surface roughness of the substrate was reduced from 304 nm to 59 nm, and the corrosion resistance of the polished substrate were significantly improved compared with the original substrate. Local electrochemical effects occur on the substrate surface due to thermal difference caused by uneven energy distribution of the laser beam on the substrate. Under the continuous irradiation of the laser, further corrosion under the electrochemical effect gradually reduced the surface roughness of the substrate. After laser-chemical hybrid polishing, the surface roughness of the titanium alloy substrate was reduced, and no recast layer and heat-affected zone were found on the surface of the substrate.

Analysis of the properties of chemically bound phosphate ceramics (CBPCs) produced from metakaolin with various acid phosphates

In this study, chemically bound phosphate ceramics (CBPCs), a type of geopolymer, were synthesized by reacting metakaolin (MK) with acidic solutions of phosphoric acid (PA), potassium dihydrogen phosphate (KDP), calcium dihydrogen phosphate (CDP), and aluminum dihydrogen phosphate (ADP). The obtained CBPCs were characterized using thermal analysis (DTA-TG), X-ray diffraction, dilatometry, and scanning electron microscopy and by their real density, porosity, water absorption, and compressive strength. The analyses revealed that the used acid phosphate type strongly influenced the properties of the resulting CBPCs. The best compressive strength results were found in CBPCs obtained using ADP, with an average value of 34.50 MPa and average porosity of 23.21%. For CBPCs obtained from PA, CDP, and KDP, the average compressive strength values were 14.18, 8.17, and 2.84 MPa, respectively; their average porosities were 18.79%, 36.23%, and 37.90%, respectively. The results demonstrate that CBPCs produced with MK can be cured at room temperature and that CBPCs obtained with ADP have higher compressive strength values than these of the other acids.

Surface modification of lithium metal anode with lithium silicate-lithium phosphate composite layer for enhanced cycling stability

Lithium metal anode with exceptionally high capacity is very attractive for next-generation anode material of lithium rechargeable batteries, but the safety problems and low Coulombic efficiency have retarded its commercialization. Despite the enormous efforts made to solve the problem of lithium metal anode, its practical use still appears to have a long way to go. In this study, to expedite the problem-solving, we suggest the use of a lithium silicate-lithium phosphate (SP) composite layer to suppress the dendritic growth of lithium and the formation of dead lithium. The composite layer is formed by simply dipping lithium metal in a mixed solution of tetraethyl orthosilicate and phosphoric acid. The synergistic effect of lithium silicate and lithium phosphate – high Li-ion conductivity and high Young's modulus of the inorganic layer – results in enhanced cycling stability of Li || Li symmetric cell and LiFePO4 || Li cell. The change in morphology of the lithium metal anode surface after cycling confirms that the SP layer mitigates the excessive dendritic growth of lithium and dead lithium formation, stabilizing the interface of lithium metal anode/electrolyte.

Changes in solubility and chemical speciation of potassium, calcium, and silicon in wood ash by acid treatment

ABSTRACT This study investigated the relationship between the solubility and the chemical speciation of plant nutritional elements (K, Ca, and Si) in wood ash treated with a dilute solution of sulfuric acid or phosphoric acid. The diluted acid solutions were added to fly ash (FA) collected from a power plant, and the untreated and acid-treated FAs were analyzed for their contents of K, Ca, and Si. The crystalline phases of the untreated and acid-treated FAs were identified using X-ray diffraction (XRD), and the Si species were determined using X-ray absorption near-edge structure (XANES) spectroscopy. Sulfuric acid and phosphoric acid treatments did not affect the solubility of K in FA. Water soluble and citrate soluble K in FA were decreased by the addition of these acids. The water soluble Ca content in FA treated with phosphoric acid did not show a significant change compared to that in the untreated FA, but it increased up to 65 times in FA treated with sulfuric acid. It is suggested that CaCO3, which was the main Ca species in the untreated FA, was transformed into syngenite and gypsum by the sulfuric acid treatment. Hydrochloric acid soluble Si in the acid-treated FA decreased compared to that in the untreated FA. In contrast, the NaOH-soluble Si fraction, a method for selectively extracting silica gel, increased especially in the phosphoric acid-treated FA. The results of XANES analysis showed that the FA samples treated with 10–30% sulfuric acid or 10–30% phosphoric acid had a lower degree of Si polymerization than the untreated FA, which corresponded generally to the increased Si solubility in FAs. However, FA treated with 30% sulfuric acid had lower soluble Si despite a lower degree of polymerization than FA, which was attributed to a lower pH. These results suggest that the change in solubility of Si in the acid-treated FA was influenced by the degree of polymerization and the decrease in pH. From the viewpoint of a fertilizer use of FA, sulfuric acid-treated ash, which consists of both water soluble Ca and citrate soluble Ca, is suitable for Ca fertilizer, and phosphoric acid-treated ash, which has high NaOH-soluble Si, is suitable for Si fertilizer

Electrochemical Separation of Porous Anodic Aluminum Oxide with Thick Barrier Layers

We investigated an electrochemical separation method for anodic aluminum oxide (AAO) films possessing thicker barrier layers by electrolysis in sodium chloride (NaCl) and ethylene glycol (EG) solution and subsequent fabrication of through-hole AAO membranes by immersion in phosphoric acid (H3PO4) solution. The AAO films with different barrier layer thicknesses were formed on the aluminum surface by anodizing in sulfuric, oxalic, and H3PO4 solutions at up to 130 V. The AAO-covered aluminum specimens were immersed in NaCl/EG solution, and then constant voltage electrolysis at 10 V higher than the anodizing voltage was performed for the separation of AAO from the aluminum surface. Many nanoscale paths were formed throughout the barrier alumina layer in the initial stage of electrolysis, and then the aluminum substrate electrochemically dissolved through these narrow paths during electrolysis. Although the AAO film formed by anodizing at 130 V was partially fractured by electrolysis, the AAO films formed at up to 80 V were uniformly separated from the aluminum surface. As the separated AAO membrane was immersed in H3PO4 aqueous solution after electrolysis, the barrier layer with narrow paths preferentially dissolved into the solution, and a through-hole AAO membrane could be successfully obtained.

Biosorption of aqueous Pb(II) by H3PO4-activated biochar prepared from palm kernel shells (PKS)

The conversion of palm kernel shells (PKS), a major agricultural waste from the palm oil sector, into a potentially high-value biosorbent for heavy metals-contaminated wastewater treatments was explored in this work. Following carbonization, the activated PKS was chemically activated by soaking the biochar in a phosphoric acid (H3PO4) solution at 25 °C. The low-temperature approach benefits from less dangerous acid fume production and operational challenges when compared to the high-temperature procedure. The properties of the biochar were characterized by BET, FTIR, and SEM. The effects of H3PO4 dosage, initial Pb(II) concentration, and adsorbent dosage on removing Pb(II) from synthetic wastewater were investigated in the adsorption study. The activation of PKS biochar with high H3PO4 concentrations led to enhanced removal efficiency. The pseudo-second-order (PSO) kinetic model fitted the experimental data well (R2 0.99), indicating that chemisorption was likely involved in the adsorption of Pb(II) onto activated PKS. Pb(II) sorption was possibly promoted by the presence of phosphate moieties on the adsorbent surface. The Langmuir isotherm best described the sorption of Pb(II) onto the activated PKS (R2 0.97), giving the calculated maximum adsorption capacity (qm) of 171.1 μg/g. In addition to physical sorption, possible adsorption mechanisms included functional group complexation and surface precipitation. Overall, activating PKS biochar with H3PO4 at room temperature could be a promising technique to improve the adsorbent's adsorption efficiency for Pb(II) removal from wastewater.

Corrosion of Low-Carbon Steel in a Flow of Phosphoric Acid Solution Containing Iron(III) Phosphate

Corrosion of Low-Carbon Steel in a Flow of Phosphoric Acid Solution Containing Iron(III) Phosphate

Corrosion of Low-Carbon Steel in a Flow of Phosphoric Acid Solution Containing Iron(III) Phosphate

Theoretical aspects of low-carbon steel corrosion in H3PO4 solutions containing FePO4 are considered. In the system under study, reactions of iron with the acid solution and Fe(III) salt are thermodynamically allowed. The oxidizing power of this medium, characterized by the Fe(III)/Fe(II) couple redox potential, is mainly determined by its anionic composition. Phosphate anions of a corrosive medium bind Fe(III) cations into complex compounds, reducing their oxidizing ability. In H3PO4 solutions containing FePO4 and Fe3(PO4)2, the dependence of the system’s redox potential on the Fe(III) and Fe(II) cation relative content is poorly described by the Nernst equation, which is due to the nonequivalent complex formation of these cations with phosphate anions. Analysis of the effect of the studied media convection on the low-carbon steel electrode reactions allowed revealing some of their features. In a FePO4-containing H3PO4 solution, kinetically controlled partial reactions of iron anodic ionization and H+ cathodic reduction, as well as diffusion-controlled Fe(III) cation cathodic reduction, occur on the steel. The FePO4 accelerating effect on the steel corrosion in H3PO4 solution is due only to the Fe(III) reduction but does not affect the H+ reduction and the iron ionization. The value of the Fe(III)-cation diffusion coefficient in the studied corrosive medium was experimentally determined from the data of cyclic voltammetry of the Pt electrode therein and the results of the studying of the cathodic reaction of a steel disk electrode at different rotation velocities. The data on the low-carbon steel corrosion in the flow of the studied media, obtained from the metal samples mass loss, are in full agreement with the results of the study of the electrode partial reactions. An accelerating effect of FePO4 on the steel corrosion in H3PO4 solutions is observed. In this environment, steel corrosion is determined by the convective factor, which is typical of processes with diffusion control. The empirical dependence of the steel corrosion rate on the medium flow intensity is described by the linear dependence k = kst + λw1/2, where kst is the steel corrosion rate in a static medium, w is the rotation velocity of the propeller stirrer that creates the medium flow, λ is the empirical coefficient.

Electron Emission from High-Purity Copper Wires

Abstract: Field electron emission measurements were carried out on copper of 99.95% purity emitters, with apex radii in the nano and micrometer range. Samples have been prepared by electrochemical etching using phosphoric acid (H3PO4) solution. Measurements have been carried out under high vacuum environments with a base pressure of 10-7 mbar. Samples were installed in a field electron microscope (FEM) with an anode (tip)-to-cathode (screen) distance of 10 mm. Scanning electron microscope images, electrons spatial distribution behavior, and the current-voltage characteristics (I-V) have been studied and analyzed. Copper emitters have been prepared as electron sources and tested. The results showed a typical current-voltage characteristic from a coat emitter. The scanning electron microscope showed the sample geometry and cleanness. These copper electron emitters have been found to have significant aspects (high voltage breakdown mechanism) affecting the performance of advanced systems such as the electronic accelerator of The European Organization for Nuclear Research, known as CERN. This work aims to study this type of material to understand the high voltage breakdown phenomena in copper and the reasons behind it to provide a solution to such phenomena. Keywords: Field electron emission, Current-voltage characteristics, Copper tips, High vacuum.

Treatment of an industrial wastewater for phosphorus and fluoride recovery by a process coupling block freeze concentration and precipitation

The work aims at developing a process for treating industrial wastewater from phosphoric acid and fertilizer production units by a coupled block freeze concentration-precipitation process. First, the block freeze concentration study, carried out on synthetic phosphoric acid solutions of concentrations ranging between 1.31 wt% 29.93 wt%, has shown that the purity of the ice block is strongly dependent on the initial concentration, the freeze duration, the thawing rate and the ice block temperature. Second, the block freeze concentration study, performed on a solution containing an orthophosphate-fluoride mixture, showed that the process increased the purity of the ice by the migration of occluded fluoride and orthophosphate ions until reaching a removal efficiency of F− and PO43− upper than 94 %. Further treatment by precipitation was studied on the first thawed fraction resulting from the freezing step. The results of the recovered liquid confirmed that, in the pH range between 2.4 and 12.73, the removal of fluoride and orthophosphate increased from 9.8 % to 96 % and from 6.3 % to 99 %, respectively. Precipitates characterization using methods such as X-ray diffraction, Fourier transform infrared spectroscopy, and scanning electron microscopy combined with energy dispersive X-ray analysis, indicated that CaF2, Ca5(PO4)3(OH)F and Ca5(PO4)3(OH) were successfully produced.

Preparing of Nano-Hydroxyapatite from Seashell and Mixed with Gold to Repair Bony Defect of Mandibular Bone in Rabbits

The objectives of the present study were undertaken to prepared hydroxyapatite powder from seashell and convert this to nano size and then added to gold nanoparticles. Materials and Methods: The seashells was cleaned and the phosphoric acid was added. The product was inserted in oven then calcined in the muffled furnace, to evaporate CO2 and getting the white crystalline powder which indicated presence of hydroxyapatite. This powder was converted to nanoparticle. Gold 1% mixed with prepared seashell nano hydroxyapatite. The characteristics of the prepared nano hydroxyapatite from seashell, were studied by the FTIR infrared spectrophotometer. The most biocompatible nano hydroxyapatite estimation by chemical test and examine prepared nano hydroxyapatite from seashell alone or when mixed with gold 1% in vivo to detect the effectiveness on reparing bone defect in mandibulare rabbits. Results: The results of an infrared measurement (FTIR Spectroscopy) for prepared nano hydroxyapatite showed that the chemical structure and band have the same FTIR spectrum of standard nano hydroxyapatite and have the same nano traits as the chemical test showed a yellow precipitation consisting in the nHA seashells. As an indication of biocompatibility and increase Bone Mineral Density by repairing bone defect in rabbits. And when added gold to nano hydroxyapatite, increased the efficacy of bone remodeling and repair bone. Conclusions: The possibility of preparing nanoparticles for hydroxyapatite from seashell are simple and inexpensive feedstock's and can be successfully produced by chemical precipitation technology from seashells with a phosphoric acid solution.