TiO2 and WO3 semiconductor particles in contact with fly ash for removal the pollutants from waste water

The goal of this paper is to develop a new material from fly ash which was further used for the advanced treatment of wastewaters with multiple pollutants load. The investigation of the effectiveness of the removal of cadmium, methylene blue and surfactant (sodium dodecylbenzenesulfonate) from wastewaters was studied. The photodegradation of organic pollutants by composite TiO2/WO3/FA was studied under irradiation with UV light. The composite used as a substrate in adsorption processes and as a photocatalyst was synthesized through hydrothermal method coated with two semiconductors: TiO2 and WO3 under alkaline conditions. The fly ash is of class “F”, regarding the fact that the sum of major oxides (SiO2: 53.32%, Al2O3: 22.05%) exceeds 70%. The obtained material was characterized by SEM and AFM for morphological characterization of the surface and X-ray diffraction for phase and crystalline analysis. Optical band gap was estimated based UV-VIS spectroscopy. The results show this combination as a viable, low cost, up-scalable and sustainable technology. The use of this combination must consider also the effect of the heavy metal on the TiO2 activity (as in situ surface doping), along with the parallel process involving the dye the surfactant and the fly ash. For obtaining a maximum efficiency during the adsorption and photocatalytic processes some parameters such as pH, contact time, the amount of substrate and the initial concentration of pollutants were optimized. Heavy metals concentration was measured using AAS, while the dyes quantitative analysis was done by UV-VIS spectroscopy.These parameters were further used in thermodynamic and kinetic studies.

Prof.Dr. Maria Visa, graduated in chemistry and physics at “Babes-Bolyai” University. She holds PhD in waste materials used for wastewater treatment as professor teach Recycling Materials and Processes of Treatment Water. She was manager of the national and international projects: New adsorbents of zeolite type obtained from fly-ash, System for simultaneous photocatalysis and adsorption applied in sustainable wastewater treatment, works in team of projects: (WaterSafe)-ERANET and Bio-Energy Train_H2020. She published more than 45 papers, (h-index=20) published in ISI Thomson Journals and got more than 10 of awards given by National Authority for Scientific Research. Since 2008 she participated in many International Conferences on materials, adsorption and photodegradation of the pollutants.