Application of Plasma for the Removal of Pharmaceuticals in Synthetic Urine

Removal of pharmaceuticals in source-separated urine is an important step toward gaining acceptance of urine-derived fertilizers among important stakeholders such as consumers, farmers, and regulatory agencies. Advanced oxidation processes (AOPs)...

Comparative analysis of superabsorbent properties of PVP and PAA nanofibres

This study presents the comparative analysis of production, characterization and absorption properties of Polyvinylpyrrolidone (PVP) and Polyacrylic acid (PAA) nanofibres. Firstly, optimization studies about polymer (PVP and PAA), superabsorbent additive (waterlock)(WL) and crosslinker agent (sodium persulfate and glutaraldehyde)concentrations were achieved. Then solution properties such as conductivity, surface tension and viscosity were determined. Electrospinning was carried out under the optimum process parameters (voltage, distance between the electrodes, solution feed rate etc.) to obtain superabsorbent nanofibrous surfaces. Surface and fibre morphologies were analysed with Scanning Electron Microscopy (SEM) and thickness of nanoweb and weight in grams of nanofibres were also measured. Lastly, optimized PVP and PAA nanofibres were compared in terms of absorption properties with water and synthetic urine with various times from 5 to 86400 seconds. According to the results, generally fine, smooth and uniform nanofibres were obtained. It was observed that the solution viscosity, conductivity, and average fibre diameter increase with waterlock (WL) and cross-linker additions while surface tension was not change. In addition, PAA nanofibres’ absorption capacity with water and synthetic urine was higher than PVP nanofibres, while PVP nanofibres’ absorption rate is higher. It is possible to say that electrospun nanofibrous surfaces that are ultra-thin, light, porous and with high specific surface area to volume ratio are promising for new superabsorbent materials.

A Photomicroscopic Study on the Growth Rates of Calcium Oxalate Crystals in a New Synthetic Urine without Inhibitors and with Various Inhibitors

A photomicroscopic growth apparatus was used to study the growth rates of calcium oxalate crystals in a new synthetic urine without inhibitors and with various inhibitors, including magnesium ions, citrate ions, chondroitin sulfate ions, and phytate ions. The dependence of growth rates on supersaturation at different temperatures without inhibitors was investigated using a power law model in terms of the Arrhenius form. The effects of various inhibitors on the growth rates of calcium oxalate indicated that the inhibition of growth rates increases in the order magnesium ions < citrate ions < chondroitin sulfate ions < phytate ions. The polymorphic forms of calcium oxalate crystals without inhibitors and with various inhibitors were examined by scanning electron microscopy.