Kinetic, Isotherm and Thermodynamic Analysis on Adsorption of Cr(VI) Ions from Aqueous Solutions by Synthesis and Characterization of Magnetic-Poly(divinylbenzene-vinylimidazole) Microbeads

The magnetic-poly(divinylbenzene-1-vinylimidazole) [m-poly(DVB-VIM)] microbeads (average diameter 53–212 μm) were synthesized and characterized; their use as adsorbent in removal of Cr(VI) ions from aqueous solutions was investigated. The m-poly(DVB-VIM) microbeads were prepared by copolymerizing of divinylbenzene (DVB) with 1-vinylimidazole (VIM). The m-poly(DVB-VIM) microbeads were characterized by N2 adsorption/desorption isotherms, ESR, elemental analysis, scanning electron microscope (SEM) and swelling studies. At fixed solid/solution ratio the various factors affecting adsorption of Cr(VI) ions from aqueous solutions such as pH, initial concentration, contact time and temperature were analyzed. Langmuir, Freundlich and Dubinin–Radushkvich isotherms were used as the model adsorption equilibrium data. Langmuir isotherm model was the most adequate. The pseudo-first-order, pseudo-second-order, Ritch-second-order and intraparticle diffusion models were used to describe the adsorption kinetics. The apparent activation energy was found to be 5.024 kJ mol−1, which is characteristic of a chemically controlled reaction. The experimental data fitted to pseudo-second-order kinetic. The study of temperature effect was quantified by calculating various thermodynamic parameters such as Gibbs free energy, enthalpy and entropy changes. The thermodynamic parameters obtained indicated the endothermic nature of adsorption of Cr(VI) ions. Morever, after the use in adsorption, the m-poly(DVB-VIM) microbeads with paramagnetic property were separeted via the applied magnetic force. The magnetic beads could be desorbed up to about 97% by treating with 1.0 M NaOH. These features make the m-poly(DVB-VIM) microbeads a potential candidate for support of Cr(VI) ions removal under magnetic field

Ipomoea triloba: an alien plant threatening many habitats in Turkey

Ipomoea triloba is a plant native to tropical America and has been observed in cotton fields in Antalya Province, Turkey. Ipomoea triloba was identified in 2014 after a warning from the Centre of the Farmers’ Union (Antbirlik). Subsequent field surveys showed that this plant has been considered as a weed by farmers in this region for the last two decades; it has spread in non-agricultural habitats but due to its limited presence did not receive much attention. The spread of I. triloba has increased over the last 5 years to such an extent that it cannot be controlled by existing methods including herbicides. It has established not only in agricultural areas but also in other habitats such as roadsides, irrigation channel edges and coastal regions. This paper provides the first botanical description report of I. triloba in the defined area, an evaluation of environmental and socioeconomic impacts, current status and management activities. Based on all available information the authors concluded that pest risk analysis should be conducted on I. triloba. Furthermore, it should be regarded not only as an environmental weed but also as an agricultural weed and kept under surveillance in Turkey. © 2018 The Authors. Journal compilation © 2018 OEPP/EPP