The Preparation Of Organic Pre-treated Titanium Dioxide Pillared Clay And Application In The Degradation Of Organic Pollutants In Solution

Pillared clay materials, which are prepared by introducing cationic pillars into the layer structure of clays and achieve different functions after particular treatments, have developed into a leading advancement in geological environmental chemistry.Nowadays, the study of pillared clays is mainly focused on the single inorganic or organic ions treatment, indicating the resulted clay materials have lower adsorption capability. In our research work, the different clays were used as matrix to synthesize novel hydrophobic nano-scale Titanium Dioxide pillared materials with the organic surfactants pre-treatment. The prepared pillared clays showed good adsorption ability and photoactivity. The component, texture, surface area and titanium dioxide pillar of the prepared materials were investigated by many spectra analysis technologies, such as thermogravimetric (TG) analysis, X-ray powder diffraction (XRD) , scanning electron microscope (SEM), Energy Dispersive Spectroscopy (EDS) and steam adsorption capacity etc. Organic model pollutants, Methyl orange (MO), Dimethyl phthalate ester (DMPE) and 4-Nonyphenol (4-NP) were employed to test the adsorption and photocatalytic degradation performance of synthesized materials. The photocatalytic degradation mechanisms of these organic pollutants were investigated by GC/MS and HPLC/MS/MS techniques. The experimental results have shown the resulted hydrophobic pillared clay catalysts exhibited much higher adsorption capability and good photoactivity to organic pollutants due to the enhancement of the surface area and total organic carbon concentration. The anatase titanium dioxide pillar in the synthesized clays can photodegrade the adsorbed organics, which realized the in-situ regeneration. The photocatalytic degradation of the organics was also induced by the attack of free hydroxyl radicals generated by TiO₂ pillars. According to the intermediates observed during the photodegradation reaction, the different degradation mechanisms were supposed and the dominant degradation pathways were suggested at same time. The recycling experiments were also carried out to show the hydrophobic pillared clays remained good adsorption capacity and photoactivity after five times reuse. The excellent sendimentation performance of synthesized catalysts, when compared to the commercial TiO₂ catatlyst P25, also means that the pillared photocatalyst prepared in the paper can be much more easier to recover and reuse at the post-run in wastewater treatment.