Functionalized polystyrene beads as carriers in release studies of two herbicides: 2,4-dichlorophenoxyacetic acid and 2-methyl-4-chlorophenoxyacetic acid

Abstract

The extensive usage of pesticides in agriculture has adverse effect on the quality of water and soil; therefore, the proper dosage is of great concern. The aim of this study was to use the functionalized polystyrene beads (QuadraPure™) as a reservoir for the storage and controlled release of two herbicides: 2,4-dichlorophenoxyacetic acid and 2-methyl-4-chlorophenoxyacetic acid. It was proved that desorption of herbicides was strongly affected by the surface properties of polystyrene beads characterized by different pore size distributions and modified with various functional groups. We suggest that the optimal hybrid systems are the mixtures that are able to release the high amount of herbicides for a long time. For 2,4-dichlorophenoxyacetic acid, these conditions were fulfilled by polystyrene beads with the attached imino diacetate or thiourea functional groups. For 2-methyl-4-chlorophenoxyacetic acid, the appropriate results were obtained when polystyrene beads with the thiourea functional groups were applied. Additionally, QuadraPure™ scavengers could form stable complexes with copper and nickel ions, and therefore, the pesticide release was limited. The application of a hybrid system permitted to control the distribution of the herbicide by the formation of complexes between metal ions and organic groups of QuadraPure™ materials. The results proved that by using the polystyrene beads the release of herbicide could be controlled.

Design of Paracetamol Delivery Systems Based on Functionalized Ordered Mesoporous Carbons

“…The paracetamol release data were fitted to kinetic models including zero-order (percentage of acetaminophen release versus time), first-order (log of the percentage of acetaminophen remaining versus time), Higuchi’s model (percentage of acetaminophen release versus square root of time), the Korsmeyer–Peppas model (log of the percentage of acetaminophen release versus log time), and the Hixson–Crowell model (cube root of the percentage of acetaminophen remaining versus time) [ 35 , 36 ]. Additionally, R 2 was calculated to determine which model follows the selected release profile.…”

Injectable, self-healing and degradable dynamic hydrogels with tunable mechanical properties and stability by thermal-induced micellization

“…In the Ritger–Pappas model, the n value indicates the release mechanism. 47 At 37 °C, the n value for DOX release at pH 2.0 and pH 7.4 (0.303 and 0.204, respectively) was less than 0.45, indicating that the release of DOX from H4 was controlled by the Fickian diffusion mechanism. 48 However, the n value (0.454) for DOX release at pH 2.0 at 5 °C decreased in the range of 0.45 < n < 0.89, which can be classified as non-Fickian or anomalous transport 47 owing to the combination diffusion and swelling.…”

“… 48 However, the n value (0.454) for DOX release at pH 2.0 at 5 °C decreased in the range of 0.45 < n < 0.89, which can be classified as non-Fickian or anomalous transport 47 owing to the combination diffusion and swelling. 47 …”

The Electrospray (ESI) and Flowing Atmosphere-Pressure Afterglow (FAPA) Mass Spectrometry Studies of Nitrophenols (Plant Growth Stimulants) Removed Using Strong Base-Functionalized Materials

“…The controlled release of bioactive compounds from hybrid materials or functionalized polymers is studied not only in the field of biomedicine [ 13 , 14 , 15 ] but also in agriculture [ 16 , 17 , 18 , 19 ]. In the case of nitrophenols, there are no sufficient studies on their controlled delivery using hybrid materials as transporting platforms.…”