The release of 3,4-D into SO4 2−, CO3 2−, PO4 3−, and Cl− aqueous solutions was formed to follow the pseudo-second-order kinetic models with r 2 close to 1. The t ½ values, the time it takes for the concentration of 3,4-D to be at half of the accumulated saturated release, were found to be 39, 56, 74, and 78 min for 3,4-D release in phosphate, carbonate, sulfate, and chloride aqueous solutions, respectively. The t ½ values are in the order of phosphate < carbonate < sulfate < chloride which followed the release rate of
the organic moieties in the aqueous solution mentioned above, as t ½ is inversely proportional to the release rate [27]. Figure 8 Release profiles of 3,4-D. Fitting the release data of selleck chemicals llc 3,4-D from the nanohybrid into various aqueous media (Na3PO4, Na2CO3, Na2SO4, and NaCl (0.005 M)) using first-order,
parabolic diffusion, and pseudo-second-order kinetic models. Table 2 Rate constant, half time, and correlation coefficient ( r 2 ) value Aqueous solution (0.005 M) Zeroth-order r 2 First-order r 2 Parabolic diffusion Pseudo-second-order (3,000 min) (3,000 min) r 2 k (×10−3) c r 2 t 1/2 (min) k (×10−4) c Na3PO4 0.315 0.549 0.390 15.50 0.797 1.000 39 2.458 0.698 Na2CO3 0.567 0.621 0.738 5.99 0.254 0.999 66 2.424 0.391 Na2SO4 0.215 0.228 0.340 4.32 0.717 0.999 74 2.235 1.360 NaCl 0.322 0.336 0.494 5.90 1.640 0.959 Blebbistatin cell line 78 2.146 1.470 Obtained from the fitting of the data from 0 to 3,000 min of 3,4-D in the LDH interlayer into the aqueous solution containing various anions, phosphate, carbonate, sulfate, and chloride, by first-order, parabolic diffusion, and pseudo-second-order kinetics models. Conclusions A herbicide compound, 3,4-D, was successfully intercalated into the layer of ZAL for the formation of a new organic–inorganic hybrid nanocomposite, N3,4-D, which shows a potential to be used as a
Amylase controlled-release formulation in agrochemicals. The interlayer spacing of LDH increased from 8.9 to 18.72 Å in the N3,4-D due to the inclusion of 3,4-D into the Zn-Al-LDH interlayer space. Release of 3,4-D from the Zn-Al-layered inorganic host follows pseudo-second-order kinetic models with regression values of 0.959 to 1. This study suggests the possibility of zinc-aluminum-layered double hydroxide to be used as a carrier host for 3,4-D for the generation of environmentally friendly agrochemicals. Acknowledgements This research was funded by the Ministry of Higher Education Malaysia (MOHE) under the Fundamental Research Grant Scheme (FRGS) grant no. 600RMI/ST/FRGS/FST (194/2010). References 1. Johnson RM, Pepperman AB: Release of atrazine and alachlor from clay-oxamide controlled release formulations. Pestic Sci 1998, 53:233–240.CrossRef 2. Gish TJ, Scoppet MJ, Helling CS, Schirmohammadi A, Schenecher MM, Wing RE: Transport comparison of AG-120 technical grade and starch-encapsulated atrazine. Trans ASAE 2011, 34:1738–17444. 3.