Phosphate ion sensor fabrication based on conductive polymer polypyrrole film coatings in doped phosphate using thick film technology

This study describes the development of chemical sensors to detect polypyrrole (PPy) based phosphate sensors in doped di-ammonium hydrogen phosphate (DAP) with thick film technology (TFT). Manufacturing screen-printed carbon electrode (SPCE) with thick film uses alumina substrate provided a more portable, miniature, inexpensive, and reduced use of samples and reagents. Polymer polypyrrole and di-ammonium hydrogen phosphate as sensitive membranes are electrodeposition on carbon electrodes. Characterization has been conducted to see the electrode morphology in scanning electron microscopy (SEM) test, which showed that sensitive material particles were distributed evenly on the surface of the sample and spherical. The energy dispersive spectroscopy (EDS) experiment results showed the atomic composition respectively carbon 86.95 %, nitrogen 6.94 %, oxygen 5.9 %, and phosphate 0.21 %, which were exposed to the electrode. The performance test of electrodes with a phosphate standard solution has proceeded at a concentration between 5 to 100 mg/l, which is measured using the galvanostatic method. The voltage range was from 0.252 to 0.957 V with R2 at approximately 90.265 %. The results of sensor performance were concluded that the electrode was able to detect phosphate ions.

Synthesis of sodium ammonium hydrophosphate and sodium dihydrophosphate based on extraction phosphoric acid from Central Kyzylkum phosphorites

The aim of the research is the synthesis of sodium ammonium hydrogen phosphate and sodium dihydrogen phosphate based on purified extraction phosphoric acid. The acid was purified from accompanying impurities by precipitation methods using sodium carbonate and metasilicate, washed burnt phosphoconcentrate, barium carbonate, acid neutralization with gaseous ammonia. Pre-neutralization of the purified solution of monoammonium phosphate with sodium carbonate to the ratio Na2O:P2O5 = 0.44 and subsequent drying at a temperature of 50 °С allows to obtain sodium ammonium hydrogen phosphate tetrahydrate, and at 100 °С sodium dihydrogen phosphate monohydrate. The individuality and purity of the synthesized substances was established by the methods of X-ray diffraction, IR spectroscopy, thermogravimetry and scanning electron microscope.

Sorption of ions of some metals on synthesized weakly basic ion exchangers

The aim of the research is the synthesis of sodium ammonium hydrogen phosphate and sodium dihydrogen phosphate based on purified extraction phosphoric acid. The acid was purified from accompanying impurities by precipitation methods using sodium carbonate and metasilicate, washed burnt phosphoconcentrate, barium carbonate, acid neutralization with gaseous ammonia. Pre-neutralization of the purified solution of monoammonium phosphate with sodium carbonate to the ratio Na2O:P2O5 = 0.44 and subsequent drying at a temperature of 50 °С allows to obtain sodium ammonium hydrogen phosphate tetrahydrate, and at 100 °С sodium dihydrogen phosphate monohydrate. The individuality and purity of the synthesized substances was established by the methods of X-ray diffraction, IR spectroscopy, thermogravimetry and scanning electron microscope.

Synthesis of bioactive calcium phosphate from cockle shell for biomedical applications

The present work reports the synthesis of bioactive calcium phosphate from cockle shell via the combination of calcination and hydrothermal process. The raw cockle shells were pre-treated with 30 % of hydrogen peroxide for 4 days to eliminate the impurities. Afterward, the dried cockle shells were crushed and calcined at various temperatures ranging from 300 to 1100 °C. Subsequently, the calcined powders underwent hydrothermal process in di-ammonium hydrogen phosphate and distilled water at pH of 10.5 for 30 minutes. Lastly, the hydrothermal treated powders were dried in oven at 50 °C for 3 days. The results showed that the mixture of aragonite, calcite, hydroxyapatite, and calcium hydroxide was successfully synthesized at a calcination temperature of 900 °C and 1100 °C. In addition, the nanorods in the length of 80-300 nm were formed. The findings of this work indicate that the cockle shell could be transformed into valuable bioactive materials for biomedical applications.