Removal of organic dye compounds in water and wastewater samples based on covalent organic frameworks -titanium dioxide before analysis by UV-VIS spectroscopy

A simple and rapid microwave-assisted combustion method was developed to synthesize homogenous carbon nanostructures (HCNS). This research presents a new and novel nanocomposite structures for removal of methylene red (2-(4- Dimethylaminophenylazo) benzoic acid), methylene orange (4-[4-(Dimethylamino) phenylazo]benzenesulfonic acid sodium salt) and methylene blue (3,7-bis(Dimethylamino)phenazathionium chloride)with semi degradation-adsorption solid phase extraction (SDA-SPE) procedure before determination by UV-VIS spectroscopy. A covalent organic frameworks (COFs) with high purity were synthesized and characterized by X-ray diffraction (XRD) and scanning electron microscopy (SEM). The results indicated that the self-assembled carbon nanostructures (COFs) synthesized with the cost-effective method which was used as a novel adsorbent for adsorption of dyes after semi-degradation of methylene red, orange and blue (1-5 mg L-1) as an organic dye by titanium dioxide (TiO2) nanoparticales in presence of UV radiation. Based on results, the COFs/TiO2 has good agreement with the Langmuir adsorption isotherm model with favorite coefficient of determination (R2= 0.9989). The recovery of dye removal based on semi-degradation/adsorption of COFs/TiO2 and adsorption of COFs were obtained 98.7% and 48.3%, respectively (RSD less than 5%). The method was validated by spiking dye to real samples.