Using disposable iron oxide to adsorptive removal of phosphate from TFT-LCD factory

This study presents adsorptive removal of phosphate by using an amorphous iron oxide-BT-1. It is a granular (0.25 similar to 0.50 mm) byproduct which. is produced by the fluidized-bed reactor Fenton (FBR-Fenton) crystallization technology. Phosphate wastewater was obtained from the Al-etching procedure of a thin film transistor-liquid-crystal display (TFT-LCD) factory in Taiwan., X-ray powder diffraction (XRD), scanning electron microscopy (SEM), energy dispersive spectrometer (EDS), atomic adsorption spectrophotometer (AA), and surface area and porosity analyzer (BET-surface area analyzer) were used to characterize the BT-1. All the experiment trails were carried out in the nature pH of the diluted solution at 305K. Adsorption isotherm and desorptive ability were examined in this work. The equilibrium data were calculated by fitting Freundlish, Langmuir, and Temkin isotherm model. XRD analysis showed that BT-1 is an amorphous type iron oxide. The morphology was observed slightly smoother after adsorption by SEM. Phosphate adsorption has been proved by comparing with, the EDS data. It was found that most of phosphorus was adsorbed rapidly initially and then reached the thermodynamics equilibrium after 24 hours. The phosphate adsorptive capacity of BT-1 is 2.03 mmole/g at the PO43- equilibrium concentration 8.23mM. It shows that the adsorption process follows the Langmuir and Temkin adsorption isotherm. In the desorption test, it was found that less than 50% phosphate was desorpted at an optimum condition ranged from 6.45 to 12.9 wt% NaOH.