The effect of ctab on bentonite for slow release fertilizer

Effect of CTAB (Cetyltrimethylammonium Bromide) surfactant concentration on synthesized CTAB modified bentonite and release of NPK has been studied. Besides, the release kinetic model was also determined. Characterizations of the modified bentonite were done using FTIR (Fourier Transform Infra-Red), XRD (X-Ray Diffraction), and SEM (Scanning Electron Microscope). The amount of released NPK was analyzed using Spectrophotometer UV-Visible and AAS (Atomic Absorption Spectrometer). The release kinetics of NPK were determined using zeroth, first, second, pseudo-first, pseudo-second order, and Korsmeyer-Peppas kinetics models. The result of the study showed that CTAB modified bentonite has been successfully synthesized for NPK slow-release fertilizer. The CTAB concentration in CTAB modified bentonite affects the amount of NPK released out of bentonite and also could reduce the release of NPK. Among modified bentonite synthesized, CMB-3 (bentonite modified by CTAB 2 times CEC of bentonite) could reduce NPK release rate in water very well. The release kinetic of NPK followed the pseudo-second order kinetics model, with the release rate constant (k) of N, P, and K were 0.0027, 0.0540, and 0.0169 g mg−1 day−1, respectively. © 2021 Trans Tech Publications Ltd, Switzerland.