Corrosion behavior of mild steel and SS 304L in presence of dissolved nickel under aerated and deaerated conditions

In dual purpose water/power co-generation plants, the presence of high concentration of Cu and Ni in the re-circulating brine/condensate as a result of condenser tubes corrosion has been attributed as one of the several causes of corrosion damage of flash chamber materials and water touched parts of the boilers. The present investigation deals with the effect of dissolved nickel in the concentration range of 10 ppb to 100 ppm on the corrosion behavior of mild steel and SS 304L in two aqueous medium namely, distilled water and artificial seawater. The effect of pH, dissolved oxygen and flow condition of aqueous medium on the corrosion behavior was also monitored. The experimental techniques include immersion test and electrochemical tests which include free corrosion potential measurements and potentiodynamic polarization measurements. The corrosion rate of mild steel and SS 304L under different experimental conditions was determined by weight loss method and spectrophotometric determination of iron ion entered into the test solution during the period of immersion. The pH of the test solution was also monitored during the entire period of immersion. The left over nickel ions present in the test solution after completion of immersion was also estimated using Atomic Absorption Spectrophotometer. The surface morphology of the corroded steel surface was also examined using scanning electron microscopy (SEM). The results of the studies show that SS 304L largely remains unaffected in both distilled water and artificial seawater under different experimental conditions. However, the effect of nickel on the corrosion behavior of mild steel is quite pronounced and follows interesting trends

PBPK modelling of ceftriaxone Na-loaded starch-sodium alginate polymeric blend prepared by water-in-oil emulsification for oral delivery

Ceftriaxone is a third-generation cephalosporin antibiotic effective against many bacterial infections. However, owing to its instability in the gastrointestinal tract (GIT), it is administered by injections, which is an unfavourable route of administration. Therefore, the aim of this study was to formulate ceftriaxone into biodegradable and thermally stable polymeric blend microparticles that are suitable for oral delivery. The drug-loaded microparticles were prepared by the water-in-oil (W/O) emulsion method and consisted of starch and sodium alginate (NaAlg) as a polymeric matrix and glutaraldehyde (GA) as a cross-linking agent. Characterization of these particles using scanning electron microscopy (SEM) showed that the particles were spherical in shape with a smooth surface. Differential scanning calorimetry (DSC) and X-ray diffraction (XRD) of these particles showed no drug-polymer interactions. The highest percentage yield of particles was obtained at 3% polymer concentration. The particle size increased slightly after drug loading. The drug loading and entrapment efficiency appeared to increase with increasing polymer concentration. In vitro drug release at pH 1.2 and pH 7.4, revealed that drug release was below 20% at the acidic pH, while at pH 7.4, drug release of up to 85% was observed. The release mechanism followed first-order and Fickian diffusion patterns. Plasma concentration-time profiles were simulated for subcontinental Asian populations using commercial PBPK software, and the results suggest that microencapsulation of ceftriaxone sodium in a polymeric blend could represent a promising approach for controlled oral delivery of the drug, with enhanced absorption and bioavailability of the drug