Heterogeneous Fenton and Photo-Fenton Reactions in Paraquat Removal Using Iron Nanoparticles

© 2016 Inderscience Enterprises Ltd. This work was aimed to investigate the ability of iron nanoparticles in paraquat degradation using heterogeneous Fenton and photo-Fenton processes. The iron nanoparticles were synthesised and their sizes are in the nanometre range of 10-30 nm. SEM, TEM, and XRD were used to characterise the obtained materials. From XRD analysis and the Fe(II)/Fe(III) ratio, the iron nanoparticles are predominantly of magnetite phase. Results from Fenton reaction at pH3 show that paraquat with initial concentrations in range of 60-100 ppm has been degraded with the removal percentages in the range of 43.7-75.8%. In photo-Fenton process at pH3, the paraquat removal percentages were 70.9-99.1% for initial paraquat concentrations as of 100-300 ppm. The photo-Fenton reaction using iron nanoparticles provided higher efficiency in paraquat removal than the Fenton process. Results from this work can benefit further for application of iron nanoparticles in pesticides removal from water and wastewater

Adsorption Isotherm and Kinetics of Paraquat Removal Using Activated Carbon/Iron Oxide Composite Material

© 2016 Inderscience Enterprises Ltd. A composite material between activated carbon (AC) and iron oxide in nanoscale was used to remove paraquat from contaminated water. The surface area of AC/iron oxide nanoparticles was in the range of 754.39 to 775.81 m2/g for the ratio 1:1 to 10:1 AC:iron oxide nanoparticles. The maximum adsorption capacity was found at pH 11. Adsorption of paraquat increases with increase in temperature indicating an endothermic process. Sorption behaviour of paraquat onto AC/iron oxide nanoparticles was evaluated using the Langmuir and Freundlich isotherm. The adsorption behaviour of paraquat was well described by Freundlich isotherm indicated that AC/iron oxide nanoparticles posed heterogeneous surface with heterolayer paraquat coverage on the surface of composite material. First and second order kinetic models were tested. The paraquat adsorption rate fits a pseudo-second-order kinetic model where the rate-limiting step is assumed to be chemical sorption between the adsorbate and adsorbent. The AC/iron oxide nanoparticles can readily be separated from the solution using a permanent magnet