Novel adsorbent of removal phosphate from TFT LCD wastewater

In this study, a waste iron oxide material (BT-1), which is a by-product of the fluidized-bed Fenton reaction (FBR-Fenton), was thermally treated between 200 and 900 °C and was used as an efficient adsorbent for the removal of phosphate in an aqueous system. The wastewater was discharged from a real TFT-LCD plant in Taiwan and diluted to 10.51 mM phosphate before experiments. The XRD and SEM analyses indicated that BT-1 was mainly composed of the poorly crystallized goethite (α-FeOOH). After adsorption, the phosphate surface was occupied on BT-1 using EDS and FTIR analysis. The adsorption isotherms are consistent with Temkin, Langmuir, and Freundlich models and indicated the BT-1 was a suitable adsorbent for the removal of phosphate. The maximum adsorption capacity of BT-1 was 2.32 mmol-P/g (72 mg-P/g). The coexisting anions affected the phosphate adsorption capacity of BT-1 at pH 2.11 ± 0.2 in this order: SO42− > NO3− > Cl− > F−. The coexisting anions F− and Cl− did not influent the adsorption capacity significantly, but SO42− and NO3− affected the phosphate adsorption capacity of BT-1. Finally, there are almost 48% phosphate desorption form the adsorbed BT-1 in the NaOH alkaline solution.

► In Taiwan, phosphate cause serious the eutrophication, if excessive in water bodies.
► The study applied the new catalyst, which is the waste material, is form industrial FBR reactors.
► The optimal removal efficiency of phosphate reached 96.1% in 480 min using a BT-1 dosage of 20 g/L.
► The maximum adsorption capacity of BT-1 was 2.32 mmol-P/g (72 mg-P/g) which was better than previous research.