Removal of microplastics in food packaging industry wastewaters with electrocoagulation process: Optimization by Box-Behnken design.

Currently, the vast majority of studies on microplastics (MPs) focus on determining the quantity and presence of these particles in various receiving environments and their treatment in domestic wastewater treatment plants. However, little research has been conducted on the treatment of microplastics in industrial effluent. Therefore, in this study, effluent samples from the cooling water tank of a local food packaging manufacturing company were analyzed to determine the presence and quantity of MPs for the first time. MPs removal from industrial wastewater using the electrocoagulation (EC) method was optimized using the Box Behnken Design (BBD). A second-order model was developed to estimate the microplastic removal efficiency, and the R2, adjusted R2, and predicted R2 of the model were 0.9994, 0.9985, and 0.9962, respectively. The optimal reaction parameters resulting in the maximum removal rate of microplastics (99 %) were determined to be pH 6.74, current density of 3.16 mA cm-2, and duration of 13.58 min. The cost of microplastic treatment per m3 of wastewater in the EC system, operated under optimal conditions, was calculated as 0.125 $. In this study, it was concluded that the EC process is a highly efficient technique for the removal of MPs from industrial wastewater at a low cost. Determining the most favorable conditions with BBD for the EC process at the feasibility stage of treatment plants will provide economic benefits and increase treatment efficiency during the installation of large-scale plants.

Pure ZnO and composite ZnO/TiO2 catalyst plates: a comparative study for the degradation of azo dye, pesticide and antibiotic in aqueous solutions.

Photocatalytic degradations of azo dye (RR 180), pesticide (2,4-D) and antibiotic (enrofloxacin) in aqueous solutions were performed and compared by using pure ZnO and ZnO/TiO2 composite (at 1:1 ZnO to TiO2 mole ratio) catalysts in a self-supporting plate form. The plates were produced by tape casting of the constituent powder slurries and sintering at 600°C. Photocatalytic degradations of these pollutants were carried out under UVA and UVC irradiations for 120 min. Maximum degradation was obtained for 2,4-D solution using pure ZnO plates under UVC. Due to the photolysis effect, UVC wavelength yielded higher efficiency values for all the chemicals than UVA. The discrepancy in the photocatalytic performances of the pure ZnO and the ZnO/TiO2 composite plates were not found to be significant. The plates were found to be effective for the consecutive degradation tests which indicated their potentiality in extended applications.