Functionalization of Iron Nanoparticles with Linkers for Removal of Pollutants in Water

Today, quality monitoring of water resources played an influential role in its exploitation and use. Water sources usually contain heavy metals in minor concentrations. The research showed various methods of removing heavy metals in aqueous solutions, such as chemical reduction, ion exchange, adsorption, etc. Hence, the widespread applications of nanotechnology to remove toxic pollutants from different contaminated water sources are known. In this study, while the existence of other methods for pollutants elimination from water, the use of iron nanoparticles was investigated. Eco-friendly and cost-effective nanomaterials are vital to ultimately removing contaminants from water. Meanwhile, iron nanoparticles are available, cheap, and practical in water and wastewater treatment. Therefore, Nano Zero-Valeant Iron (nZVI) with high surface area, nanoscale particle size, unique catalytic activity, more reactivity than bulk iron, and mobility in the underground has attracted significant consideration due to their performance in removing pollutants from aqueous solutions. Since nZVI could have aggregated, various linkers have been used to stabilize these particles on the substrate, and the use of some linkers to support these nanoparticles was examined. The results showed that hydrophilic and biodegradable linkers such as Starch, Carboxymethyl cellulose (CMC), Polyethylene glycol (PEG), Polyacrylamide (PAM), and Polyvinylpyrrolidone (PVP) could increase the speed of chemical reaction in reducing pollutants from water. Because linkers often had different functional groups that could enhance the stabilizing of these particles on the substrate. Among these linkers, PVP, as a hydrophilic, cheap, and biodegradable polymer, has performed an excellent function in supporting nZVI

Photocatalytic application of a phosphonate-based metal-organic framework for the removal of bisphenol A under natural sunlight

Photocatalytic removal of bisphenol A, one of the most widely and emerging pollutants in the aquatic environment, was investigated by advanced oxidation process under natural sunlight. The removal process by a metal-organic framework, synthesized with phosphonic acid ligand, namely STA-12 (Fe) and hydrogen peroxide revealed excellent results. Therefore, the optimal conditions for the degradation of bisphenol A by the photo-Fenton mechanism were studied. The removal process follows the first-order kinetics with respect to the contaminant and a significant synergy was observed in the catalytic system of hydrogen peroxide/sunlight/STA-12 (Fe). The Optimal values for pH, irradiation time, catalyst amount and H2O2 dosage for oxidation of bisphenol A in 30 mg / l aqueous solution were determined to be 5, 90 minutes, 10 mg and 12 μl, respectively. Under these conditions, the best removal efficiency was 79.8%. Also, the mineralization value of organic pollutant was determined to equal 51% by measuring TOC. To determine the most important species that affected the photocatalytic reduction, trapping experiments were carried out, using various kinds of scavengers and the results showed that the hydroxyl radicals (•OH) are the main oxidizing agent in the photocatalytic system and superoxide radical and the holes in the photocatalyst surface are less involved in the process of contaminant degradation. Finally, a probable reaction mechanism has been investigated in detail. In addition, the catalyst has recyclability and stability in the photocatalytic reaction. This study is the first report for application of a phosphonate-based MOF for the removal of an emerging pollutant with a photo-Fenton mechanism and presents a new example of solar-driven advanced oxidation process for the treatment of aquatic sources and environmental protection

The Study of Silymarin Release Kinetic in Free and Hydrogel Bound Micellar Forms: Qualitative and Quantitative Analysis Using RPHPLC: The study of silymarin release kinetic

Silymarin is a safe herbal medicine; however, it has some undesirable properties such as short half-life and poor aqueous solubility. To the best of our knowledge, this study is the first to report utilizing a dual-drug delivery system (DDDS) to enhance the release profile of silymarin from both micelles and hydrogels. In this experimental study, the release profile of micellar silymarin and micelle-hydrogel bounded silymarin during 21 days was examined using Knauer K2600A liquid chromatography. The calibration curve was plotted using the peak-areas of the silymarin at different concentrations.The RP-C18 column allowed a good separation of the components of standard silymarin.LOD and LOQ were 16.5 and 55.02 μg/ml, respectively. The in vitro release profiles of the two compounds showed a rapid release of silymarin, especially in the absence of hydrogel. The cumulative release graph revealed that the hydrogel-bound form has more constant release kinetics than the free micelle form; this means that the hydrogel-bound form may sustain for longer durations.In this study, a dualdrug delivery system based on hydrogel/micelle composites was introduced. The results showed that the Puramatrix hydrogel plays an important role in the constant release of silymarin. Furthermore, the RP-HPLC method presented in this study can be used by other researchers to overcome the difficulties associated with the in vitro separation and quantification of silymarin