Keywords: 2,4-dichlorophenoxyacetic acid; interleave; intercalation; co-precipitation; ion-exchange; LDH-Calcium-Aluminium

Abstract

Herbicide 2,4-dichlorophenoxyacetic acid, or also known as 2,4-D, was studied for the comparison between two methods, namely ion exchange and co-precipitation methods, for intercalating with the Ca-Al-Layered Double Hydroxide (LDH) host in this research. Based on PXRD results, 2,4-D anions were successfully intercalated into the interlayer of Calcium-Aluminium-Layered Double Hydroxide (Ca-Al-LDH) with the co-precipitation method compared to the ion-exchange method. The interleaving of the former occurred with the optimum concentration at 0.05 M and with basal spacing increased from 8.67 to 17.59 Å, compared with the latter. From the attenuated total resonance fourier transform infrared (ATR- FTIR) observation, the nitrate peak at 1350.01 cm^-1 disappeared and a new peak which represents the carboxylic ion at 1726.41 cm^-1 was observed, with Carbon, Hydrogen, Nitrogen, and Sulphur analysis (CHNS) showed a percentage of loading of 92.78% (w/w) estimated from the percentage of carbon. The Barret, Joyner and Halenda (BJH) average pore diameter of the synthesized nanocomposite was 136.1 Å, which shows a mesoporous-type material that was confirmed with Brunauer-Emmett-Teller surface area analysis (BET). This research demonstrated that the 2,4-D-Ca-Al-LDH nanocomposite was suitable using direct co-precipitation method compared to ion-exchange method.