H3PO4 Concentration Research Articles

Process Optimization of High Surface Area Activated Carbon Prepared from Cucumis Melo by H3PO4 Activation for the Removal of Cationic and Anionic Dyes Using Full Factorial Design

In this study, Chemical activation was used to prepare a low-cost activated carbon (AC) from agricultural waste material: Cucumis melo. It was used as a green biosorbent for the removal of cationic and anionic dyes from aqueous solutions (Methylene blue (MB) and Acid orange 7 (AO7)).A full factorial 24 experimental design was used to optimize the preparation conditions. The factors and levels included are activation temperature (300 and 500ºC), activation time (1 and 3 h), H3PO4 concentration (1.5 and 2.5 mol/L), and contact time (60 and 90 min). The surface area of the activated carbons and high removal efficiency of MB and AO7 was chosen as a measure of the optimization. The activated carbon prepared at 500 °C, for 3 hours with an H3PO4 concentration of 2.5 mol/L and a contact time of 90 min, have the largest specific surface area (475 m2/g) and the percentage of discoloration of methylene blue (99.4%). Furthermore, the greater value of AO7 removal (94.20%) was obtained at 3h - activation time, 500°C - activation temperature, 1.5 mol/L - H3PO4 concentration with a 90 min contact time.

Optimization of preparation conditions of highly efficient activated carbon for use in water treatment – experimental design approach

ABSTRACT The objective of this study was the utilisation of Cucumis melo biomass as a new precursor to produce highly efficient activated carbons by chemical activation method using phosphoric acid (H3PO4) as the activating agent and their evaluation with high removal efficiency (%) values of SN, BPA and Cr (VI). The effects of four factors controlling the activation process, such as time of activation (1–3 h), the temperature of activation (300–500°C), the concentration of H3PO4 (1.5–2.5 mol/L) and contact time (60–90 min) were used. In order to reduce the number of experiments, full factorial experimental design at two levels (24) were carried out in order to achieve simultaneously optimal preparation conditions and high removal of SN, BPA and Cr (VI). The experimental results showed that the removal efficiency of SN and BPA onto activated carbons was more influenced by the temperature of activation and time of activation with a positive effect. Further, and in same as, the interaction between time of activation and temperature of activation had a negative effect on the SN and BPA removal. While the factors influenced the chromium removal are the H3PO4 concentration and the temperature of activation with a positive effect. Moreover, the interaction between the temperature of activation and H3PO4 concentration had a negative impact for chromium ions removal. Based on the statistical data, the best conditions for the removal of SN, BPA and Cr (VI) by the prepared activated carbon samples were investigated. The maximum removal efficiency of SN, BPA and Cr (VI) obtained under these experimental conditions were 94.20%, 94.14% and 96.80% respectively. Thus, the characterisation results showed that the surface of cucumis melo activated carbon has acidic nature and have a large amount of acidic functional groups with a BET surface area of 407.94 m2/g.

Phosphoric Acid: A Key Role in Control of Structure and Properties of Vanadium Phosphorus Oxide Catalysts During Synthesis

AbstractThe catalytic performance of vanadium phosphorus oxide (VPO) catalysts is closely related to the synthetic conditions of precursors. Herein, the role of phosphoric acid during VPO precursors synthesis process was thoroughly studied by investigating the morphology, crystal phase composition, and surface chemical property of VPO catalysts and their precursors. The H3PO4 concentration, the temperature of reaction system at the time of H3PO4 adding, and H3PO4 adding speed were optimized to prepared efficient VPO catalysts which applied in selective oxidation of n‐butane to produce maleic anhydride (MA). The obtained VPO catalyst by adding 85 % H3PO4 at or above 110 °C with the speed of approximate 1.1 mL/min could exhibit promising catalytic performances, which are 93.8 % of n‐butane conversion and 62.4 % of MA yield at 420 °C. Thus, this study emphasized the role of H3PO4 adding during VPO synthesis process, which is favorable to understand and fabricate the compositional, structural, and morphological properties of VPO catalysts.

Ammonia capture from human urine to harvest liquid N-P compound fertilizer by a submerged hollow fiber membrane contactor: Performance and fertilizer analysis

In this study, we developed a submerged hollow fiber membrane contactor (HFMC) to recover ammonia from human urine to get compound N-P fertilizers. The ammonia capture performance, water vapor transmembrane performance, ion rejection performance and the liquid fertilizer components using 1–4 mol/L H3PO4 as the stripping solution was comprehensively investigated. Increasing H3PO4 concentration did not significantly affect the ammonia capture performance but the water vapor transfer and fertilizer components. The ammonia mass transfer coefficients were in a range of 1.95×10−6±4.77×10−8 to 2.28×10−6±6.71×10−8 m/s and the ammonia flux fluctuated between 17.80 and 20.80 g/m2·h. The water vapor flux increased with the increase of stripping solution concentration and the time elapsed. The N content (21.29–55.24 g/L) was in the range of the commercial products while the P2O5 content (99.41–281 g/L) was slightly higher, which can be used in the soils or plants with a high demand for phosphorus. The liquid fertilizers were all mixtures of (NH4)2HPO4 and NH4H2PO4, but the distribution ratio slightly changed with the different initial H3PO4 concentration. The economic assessment showed that harvesting liquid N-P fertilizer from human urine using HFMC can make a profit of $7.089/L.

Physics and chemical activation to produce activated carbon from empty palm oil bunches waste

This research was conducted by laboratory-scale trials to make activated carbon from empty oil palm bunches. Empty bunches were palm oil processing industrial waste. This research was an effort to optimize waste management. Empty palm oil bunches were studied to become carbon active. Activated carbon is needed to meet the needs of the food industry and non-food industries. This research aimed to determine the appropriate method, optimal operating condition, and get the specification of standard carbon active. Making activated carbon was carried out by multiple activations; chemical and physical. The feed carbonation process was conducted at 400° C for 4 hours with N2 gas flow. After the charcoal is formed, chemical activation is carried out using an H3PO4 activator with a concentration of 9-15% wt. Physical activity was conducted by heating the activated carbon method in 700°C for an hour. The result of the study showed that multiple activations produced activated carbon, and the quality filled the standard. H3PO4 concentration of 13% was the most appropriate concentration to provide activated carbon with the best quality. The best quality activated carbon, which has produced of this research has complied with Indonesian National Standards 06-3730-1995 with parameters: 3% moisture content, 3.92% ash content, 0.7% volatile matter, 95.38% bonded carbon, iodine number 945.47 mg / g, and surface area of 272.9 m2/g.

New insights for titanium(iv) speciation in acidic media based on UV-visible and 31P NMR spectroscopies and molecular modeling.

Titanium chemistry in aqueous acidic media has been extensively investigated over the last decades. Hydrolyzed species such as Ti(OH)3+, TiO2+, Ti(OH)22+ or Ti(OH)3+ have been identified and their equilibria have been studied in nitric and perchloric acid. A predominance of the divalent cations was found for low pH (i.e., pH <2). Nonetheless, recent literature reports the existence of small titanium oxo-clusters in aqueous acidic media for large titanium(iv) concentration (typically., >0.1 mol L−1), as stable precursors for the formation of condensed titanium dioxide. The present paper reconsiders firstly previous knowledge about the speciation of titanium(iv) in non-complexing acidic media by giving evidence for the presence of polynuclear hydrolyzed species, even at very low Ti(iv) concentration (i.e., typically <0.1 mmol L−1). UV-visible absorbance spectra recorded for diluted nitric acid solutions (a model of non-complexing acidic medium) containing titanium(iv) were compared to time-dependent density functional theory (TD-DFT) predicted excitation energies. Experimental and predicted maximal absorbance wavelengths showed significantly improved matches when polynuclear species were considered in TD-DFT calculation. Then, 0.1–12.7 mol L−1 phosphoric acid solutions containing titanium(iv) were studied by means of spectroscopic techniques (UV-visible, NMR) in order to identify qualitatively the presence of titanium(iv) complexes and to link this speciation to the acid concentration. Two different titanium(iv) orthophosphate complexes, potentially polynuclear, were detected, and the presence of free titanium(iv) is also expected for low phosphoric acid concentration (i.e., <0.1 mol L−1). A general complexation scheme for a large range of H3PO4 concentration was thus formulated.

Synthesis of Biomaterial Hydroxyapatite from Limestone by Using Two-Step Conversion

Hydroxyapatite [Ca10(PO4)6(OH)2] is natural ceramic material which is often used for artificial bone reconstruction. In this research, hydroxyapatite was synthesized from mineral of Calcite (CaCO3) which obtained from the Campurdarat, Tulungagung. The hydroxyapatite synthesis steps are encompassed by the preparation of precursors and the synthesis process by using wet chemical manipulation or routes. The XRF characterization shows that the percentage of calcium from the raw material is around 99%. This study succesfully obtains the compound of Ca(OH)2as a source of hydroxyapatite. The concentration of H3PO4 in hydroxyapatite synthesis process influences the synthesis results. For the concentration of H3PO4 0.6 M is still found the compound of Ca(OH)2. The difference result is shown H3PO4 with concentration 0.8 M which the total synthesis product is hydroxyapatite.

Biomass waste conversion into low-cost carbon-based materials for supercapacitors: A sustainable approach for the energy scenario

Biomass upgrading is a promising approach to face the current energy consumption and chemicals production. Lignocellulosic biomass residues have taken the lead in this field. In this study, hemp residue-based activated carbons (ACs) were prepared by H3PO4-assisted hydrothermal carbonization (HTC) using a low concentration of H3PO4 (25 wt%). ACs with a high porosity development were obtained (SBET > 1200 m2 g−1), and they were subsequently functionalized with nitrogen groups using mild conditions. As-synthesized ACs were also heat-treated to enhance the electrical conductivity, improving the electrochemical performance. As a proof of concept, electrochemical capacitors (ECs) based on as-prepared ACs in aqueous and organic electrolytes, showing energy densities comparable to those of a capacitor based on an AC used in commercial capacitors. The most attractive outcome of this study is the straightforward, cost-effective, and sustainable methodology to prepare high added-value functional ACs with great potential for energy and environmental applications.

Understanding the setting and hardening process of wollastonite-based brushite cement. Part 2: Influence of the boron and aluminum concentrations in the mixing solution

The mixing solution of wollastonite-based brushite cement is a phosphoric acid solution containing metallic cations and borax. This work complements a previous study devoted to the influence of the H3PO4 concentration, Ca/P and liquid-to-solid (l/s) ratios on the setting and hardening process of the binder by providing new insight into the role of aluminum and boron.Boron retards the setting and decreases the heat released during the process. It also contributes to reduce the macroporosity of the hardened material but yields to poor compressive strength. With aluminum in the mixing solution, the mechanical properties are greatly improved thanks to the precipitation of an amorphous aluminophosphate which increases the density of the cement matrix. But aluminum alone leads to fast setting. A joint addition of boron and aluminum to the mixing solution makes it possible to get a material with optimized properties both in fresh and hardened states.

The effect of chemical refining process on the physicochemical and fatty acid composition of water melon seed oil (Citrulus lanatus L.)

A lot of watermelon seed waste is wasted, generally its only used to make “kuaci”, a kind of salted saline a snack made from watermelon seeds. As a member of Cucurbitaceae family, watermelon seeds can be used as a source of vegetable oil that predicted contains squalene inside like other Cucurbitaceae members. This study aims to determine the effect of refining process on the physicochemical properties and composition watermelon seed oil. Watermelon seed oil which is obtained by using Soxhlet extractor in n-hexane solvent was refined in 3 steps, which was degumming, neutralization, and bleaching, respectively. Degumming process used 3 concentrations of H3PO4, which were 0,15%; 0,20%; and 0,25%, respectively; whereas 3 zeolit concentrations of 2%; 4%; and 8%, respectively were used in bleaching steps. Data were analyzed by using 3x3 Factorial design and it was laid out with Randomized Completely Block Design, 3 replications and as the block is time analysis. The optimum yield of the watermelon (C. lanatus L.) seed oil is obtained in the amount of 48.47±0.91 % at 0.25% phosphoric acid concentration and 4% Zeolite concentration. The result of physicochemical analysis before and after the refining process have changed. The density, peroxide value and acid value show a significantly decrease, while only the saponification value shows an increase. Fatty acid composition (profile) of WSO before and after refining process does not change, comprises linoleic acid, palmitic acid, stearic acid and squalene (unsaturated hydrocarbon). Linoleic acid is the main compound of WSO (76.69%), followed by palmitic acid (14.60%), stearic acid (6.53%) and squalene (2.18%), respectively.

Use of H3PO4/ZrO2–TiO2–surfactant mixed oxide for catalytic vapor-phase dehydration of 1-octanol

Catalytic dehydration of 1-octanol over H3PO4/ZrO2–TiO2–surfactant (H3PO4/ZTS) mixed oxides at 350 °C for production of 1-octene was investigated. ZrO2–TiO2 (ZT) with Zr:Ti molar ratio = 1:1 was prepared with and without cetylpyridinium bromide surfactant and modified by different concentration of H3PO4. These catalysts were characterized by several methods such as XRD, BET, pyridine adsorption, and NH3-TPD. The prepared catalysts with surfactant showed better selectivity and activity than the prepared catalysts without surfactant for 1-octene synthesis. Maximum selectivity to 1-octene in 1-octanol dehydration was attained over 15 wt% H3PO4/ZTS, while maximum conversion of 1-octanol with lower selectivity to 1-octene was achieved over 35 wt% H3PO4/ZTS. At 350 °C and with WHSV 1.978 h−1, the maximum conversion of 1-octanol over 15 wt% H3PO4/ZTS was 68.8%, with 48.3% selectivity to 1-octene.

Production of renewable jet fuel and gasoline range hydrocarbons from catalytic pyrolysis of soapstock over corn cob-derived activated carbons

Selective production of jet fuel and gasoline range hydrocarbons from waste soapstock was achieved for the first time by catalytic pyrolysis over activated carbon catalyst that was prepared via pyrolysis of H3PO4-impregnated corn cob pyrolysis. Experimental results exhibited that the concentration of H3PO4 played an important role in acid groups and porous properties of prepared activated carbon catalyst. The obtained catalyst had a remarkable catalytic performance for C8–C16 aromatics formation with the highest selectivity of 89.97% in the bio-oil. In the meantime, the selectivities of jet fuel and gasoline range hydrocarbons could reach up to 98.78% and 91.03%, respectively. The bio-gas yield was improved with the increase in H3PO4 concentration, pyrolysis temperature and feedstock/activated carbon catalyst ratio, and the highest concentration of H2 (69.90 vol%) was achieved. The optimal reaction condition was at a pyrolysis temperature of 500 °C with a soapstock/ACC4 ratio of 1:1.5. In addition, a possible reaction mechanism was proposed for catalytic pyrolysis of soapstock over activated carbon catalyst. The current work might provide a novel, facile and efficient pathway to directly convert waste soapstock into valuable drop-in jet fuel and gasoline together with production of H2-rich syngas.

Leaching tungsten and rare earth elements from scheelite through H2SO4–H3PO4 mixed acid decomposition

Rare earth elements (REEs) possess distinctivephysicalandchemical properties and are mainly extracted from several rare earth (RE) and ion-absorbing type RE ores. Traditional RE sources are unable to meet the global demand, making it necessary to explore other resources for the extraction of rare REEs. While this is possible, the recovery of REEs from the leach residue of such resources is uneconomical due to the enormous consumption of mineralacids. H2SO4–H3PO4 mixed acid decomposition is an effective method for leaching tungsten from scheelite and is evaluated in this study for its efficient extraction of tungsten and REEs from the same mineral. The scheelite used in this study contains REEs such as lanthanum, cerium, and neodymium. The properties of the REs in the leaching system are used to evaluate our method. Additionally, the effects of the reaction conditions on the leaching of tungsten and REEs are investigated. The results show that increasing the reaction temperature and H2SO4 concentration favors the leaching process. However, high H2SO4 concentration also promotesthetransformationof gypsumfromCaSO4·2H2OtoCaSO4, which affects the leaching process negatively. Further, excessive H3PO4 concentration increases the viscosity of the leaching solution. Increasing the liquid–solid ratio is beneficial for the dissolution of scheelite. The addition of an appropriate amount of CaSO4·2H2O promotes the leaching of tungsten and REEs but the addition of PEG-400 does not. In terms of the experimental conditions used in this study, the leaching efficiency of W, La, Ce, and Nd can reach approximately 100%, 96.6%, 66.6%, and 57.1%, respectively. After the circulationleaching process, the concentrations of tungsten and the REEs in the leach liquor are increased, which proves these materials can be efficiently leached from scheelite using the H2SO4–H3PO4 mixed acid.

Removal of iron from wet process phosphoric acid using ion exchange method by Puromet MTS9570 resin

ABSTRACT In this paper, batch experiments were performed to study the effect of Puromet MTS9570 resin on the removal process of iron from wet process phosphoric acid (WPPA). Various parameters such as effect of initial iron concentration, effect of resin amount of addition, effect of phosphoric acid redox potential, effect of stirring time and effect of temperature were investigated to determine the optimum conditions required for iron removal. The numerical results obtained support the experimental data on removal of iron value where 12.0 g Puromet MTS9570 resin could remove 70.0% of already present iron with very small negative effect on the H3PO4 concentration. The adsorption isotherms were studied to evaluate the maximum sorption capacity of Puromet MTS9570 resin. The experimental results were found to fit with Langmuir isotherm model (R 2 = 0.9927), the experimental data fitted well with Langmuir than Freundlich.

Understanding the setting and hardening process of wollastonite-based brushite cement. Part 1: Influence of the Ca/P ratio and H3PO4 concentration of the mixing solution

Wollastonite-based brushite cement is prepared by mixing wollastonite with a phosphoric acid solution containing metallic cations and boric acid. This work investigates simplified systems comprising wollastonite and H3PO4 solutions only, in order to clarify the influence of the H3PO4 concentration, Ca/P and l/s ratios (this latter parameter being correlated to the two others) on the setting and hardening process.At constant H3PO4 concentration, increasing the Ca/P ratio, and decreasing the l/s ratio, accelerates the early stages of hydration but limits its progress at 7 d. At high Ca/P ratio, more basic calcium orthophosphates form in addition to dicalcium phosphate.At constant l/s ratio, increasing the H3PO4 concentration in the range 7–10 mol·L−1 retards cement hydration, and inhibits the setting at concentrations ≥12 mol·L−1. A good compromise is obtained for H3PO4 concentrations between 9 and 10 mol·L−1: hydration is not too fast and yields the maximum amount of dicalcium phosphate.

Selective transportation of molybdenum from model and ore through poly inclusion membrane

The extraction of molybdenum from the aqueous solution through poly inclusion membrane (PIM) containing tri-caprylylmethylammonium chloride (Aliquat-336) as a carrier has been investigated. A solution of molybdenum in phosphoric acid was used as a feed side while sodium hydroxide was used as stripping reagent. The results indicate that maximum flux value was obtained at 0.16 M Aliquat-336. Increase in H3PO4 concentration from 0.05 to 1.5 M results into an increase in molybdenum ions. The maximum flux of 3.00×10−6 mol/m2s through PIM was found at 1.5 M H3PO4. The optimized conditions were applied for removal of Mo(VI) from ore and more than 97 % Mo(VI) was extracted.&#x0D; &#x0D; Bull. Chem. Soc. Ethiop. 2020, 34(1), 93-104.&#x0D; DOI: https://dx.doi.org/10.4314/bcse.v34i1.9

Dissolution Behavior of Rare-Earth Metal in H2SO4-H3PO4-H3PW12O40 Solution

The dissolution behavior of a rare-earth element in H2SO4-H3PO4-H3PW12O40 solution has been investigated. The results showed that La2(SO4)3 dissolution increased with increasing H3PO4 or H3PW12O40 concentration in single H3PO4 or H3PW12O40 solution. The presence of H3PW12O40 can improve La2(SO4)3 dissolution owing to its coordination toward La3+ in H3PO4-H3PW12O40 mixed solution. However, La2(SO4)3 dissolution decreased gradually with increasing H2SO4 concentration in H2SO4-H3PW12O40 mixed solution. In these solutions, increasing the temperature showed an adverse effect on La2(SO4)3 dissolution. In H2SO4-H3PO4-H3PW12O40 solution, when the concentration of H2SO4 or/and H3PO4 was lower, increasing the H3PO4 concentration or decreasing the temperature was beneficial to La2(SO4)3 dissolution. However, when H2SO4 or H3PO4 reached a certain concentration, some H3PW12O40 precipitated from the mixed solution. Furthermore, increasing the H3PO4 concentration was found to be harmful, while increasing the temperature could increase La2(SO4)3 dissolution. Nevertheless, increasing the H2SO4 concentration showed an adverse effect on La2(SO4)3 dissolution regardless of the H3PO4 concentration.

Oil palm empty fruit bunch (OPEFB) (Elaeis guineensis Jacq.) cellulose conversion into levulinic acid using hierarchical Mn/ZSM-5 heterogeneous catalyst

Oil palm empty fruit bunch (OPEFB) is one of the potential biomasses containing cellulose that can be used as a source for renewable energy. However, the cellulose is tightly connected with lignin in lignocellulose system, which needs to be separated, so called delignification, before being used. To investigate the effect of delignification on conversion reaction, the pretreated cellulose was treated with different delignification processes, i.e. alkali delignification using 10 % NaOH (w/v) and oxidative delignification using 2 % NaOCl (v/v). Furthermore, cellulose conversion from OPEFB into levulinic acid was performed using hierarchical Mn/ZSM-5 (Mn/Hi_ZSM-5) heterogeneous catalyst with various reaction times and concentration of H3PO4. The cellulose conversion into levulinic acid in the absence of catalyst was also conducted to study the effect of catalyst. High Performance Liquid Chromatography (HPLC) analysis showed the highest cellulose conversion into levulinic acid was achieved using cellulose from alkali delignification (28.08 % yield) in optimum reaction condition of 40 % H3PO4 (v/v), 30 % H2O2 (v/v), and 0.1 g of Mn/Hi_ZSM-5 at 100 °C for 10 h. Mn/Hi_ZSM-5 revealed good selectivity for levulinic acid with the absence of 5-HMF as an intermediate compound in conversion reaction.

Preparation of FePO4 and LiH2PO4 from cathode mixture materials of scrapped LiFePO4 batteries

Typically, LiFePO4 batteries (LFPBs) contain a shell, cathode mixture materials, anode mixture materials, current collector, electrolyte, separator, and other components. Cathode mixture materials are composed of a binder, conductive additive, and LiFePO4/C. After LFPBs are scrapped, their appropriate disposal is necessary to avoid pollution. This study investigated the recovery of Li, Fe, and P by hydrometallurgy from scrapped LFPBs. To remove the binder, conductive additive, and carbon coating layer, recycled cathode mixture materials are oxidized to Li3Fe2(PO4)3 and Fe2O3 at 600 °C. Using H3PO4 as a leaching agent, the optimal leaching efficiencies, i.e., 99.2% and 97.68% for Li and Fe, respectively, can be achieved when the reaction time, temperature, Li in the Li3Fe2(PO4)3 and Fe2O3 mixture materials to the H3PO4 molar ratio (L/P ratio), and H3PO4 concentration are 12 h, 95 °C, 1:5, and 0.5 mol/L, respectively. Moreover, Li can be leached into a solution efficiently and recovered as LiH2PO4, while Fe and P can be selectively precipitated as FePO4·xH2O. FePO4 is prepared by a heat treatment. Furthermore, LiFePO4/C is re-synthesized by FePO4, LiH2PO4, Fe2O3, LiOH, and sucrose.

Nghiên cứu trích ly hydroxyapatite từ xương cá tra (Pangasianodon hypophthalmus)

Hydroxyapatite (HA) is a calcium phosphate mineral that exists in animal bones and it has good biological compatibility. Therefore, this study was conducted to produce hydroxyapatite (HA) from striped catfish (Pangasianodon hypophthalmus) bone. After pre-treatment in dilute NaOH solution and ethanol, the striped catfish bone was calcined at high temperature to burn all organic compounds and then grinded by ball mill machine to obtain powder of striped catfish bone. The powder was used to react with H3PO4 solution to produce HA. Some important factors affecting HA formation such as concentration of H3PO4, reaction temperature, pH value, calcinating time and temperature were investigated. Experimental results showed that it could be produced HA in crystal size of 100 nm and particle size of 1,100 nm when reaction was carried out in solution of H3PO4 60 mM, reaction temperature 90 ℃, pH 11 and calcinating at 1,000℃ in 2 hours. Hydroxyapatite (HA) là một loại khoáng calcium phosphate tồn tại trong xương động vật và có tính tương hợp sinh học tốt. Vì thế, nghiên cứu được tiến hành nhằm sản xuất hydroxyapatite từ xương cá tra (Pangasianodon hypophthalmus). Sau khi được xử lý với dung dịch NaOH loãng và cồn, xương cá được nung ở nhiệt độ cao nhằm loại bỏ các hợp chất hữu cơ và được nghiền thành bột bằng máy nghiền bi. Bột xương cá sau đó được chuyển hóa thành HA. Các yếu tố ảnh hưởng đến sự hình thành của HA như nồng độ H3PO4, nhiệt độ phản ứng, pH dung dịch phản ứng, nhiệt độ nung và thời gian nung HA được tiến hành khảo sát. Kết quả cho thấy, có thể sản xuất HA dạng hạt với kích thước tinh thể khoảng100 nm và kích thước hạt khoảng 1.100 nm khi phản ứng chuyển hóa bột xương cá được thực hiện ở điều kiện H3PO4 60 mM, nhiệt độ phản ứng 90℃, pH 11 và nung ở 1.000 ℃ trong thời gian 2 giờ.