Simultaneous Recovery of Display Panel Waste Glassand Wastewater Boron by Chemical Oxo-precipitation with Fluidized-BedHeterogeneous Crystallization

摘要

Silica-based carrier is a promising material for recovery of metal and nonmetal contaminants in chemical oxo-precipitation-fluidized bed crystallization (COP-FBC) system. Boron species are an essential element for plant growth and can cause health concerns in human beings at high concentrations in water environments. The composition of thin-film transistor liquid crystal display (TFT-LCD) contains a wide variety of metal oxides and can be tailored as promising functional mesoporous carriers for boron crystallization recovery in the presence of barium ions and hydrogen peroxide. In this study, waste-derived mesoporous aluminosilicate (MAS) nanomaterial in the presence of barium ions and hydrogen peroxide was used as a carrier for sustainable recovery of crystallized boron, a priority wastewaters pollutant. The MAS shows the hierarchically homogeneous distribution of nanostructured aluminosilicate particles with an average size of 12.8 ± 3.6 nm on the surface after the activation with Na2CO3 at 1000 °C. Moreover, the negatively charged surface and the mesoporous structureof MAS enhance the adsorption of Ba²⁺ onto MAS, and theLangmuir adsorption capacity of 105 mg/g is achieved, which is conduciveto the enhancement of the recovery of boron species. Moreover, therecovery efficiency and crystallization ratio of boron by MAS canbe up to 84.5 and 93.4%, respectively. The cross-sectional scanningelectron microscopy images and the high-temperature X-ray diffractionresults confirm the boron recovery mechanism that the negatively chargedfunctional group as well as the mesoporosity of MAS triggers the rapidformation of needle-shaped precipitates of barium peroxoborate, andthen converted to barium borate after calcination at 1050 °C.Results obtained in this study clearly demonstrate the possibilityof fabricating environmentally benign mesoporous aluminosilicate adsorbentsfrom TFT-LCD waste to sustainably recover and crystallize boron speciesfrom water and wastewater in COP-FBC.