Removal of toxic organic compounds from synthetic wastewater by a solar photocatalysis system

摘要

The present study was aimed at investigating the feasibility of a solar photocatalytic system to degrade toxic materials generated from different activities (e.g., xylene from petroleum refineries, tetracycline from pharmaceuticals factories, and chloropyrifos from constructions and pesticides) using the coupled homogenous-heterogeneous solar photocatalytic process. The system consists of ten Pyrex tubes (25 mm inside diameter and 125 cm long) connected in series and mounted on a parabolic trough collector (PTC) with other associated facilities. Different operating variables were studied to predict the performance of the solar reactor like, pH of solution, loading of heterogeneous catalyst, loading of homogeneous catalyst, H2O2 concentration, and liquid flow rate. The maximum degradations obtained, using coupled heterogeneous-homogeneous solar photocatalytic process, were 100% within 30 min for tetracycline at (Fe2+= 50 mg/l, TiO2 = 100 mg/l, H2O2 = 200 mg/l, pH = 3 and liquid flow rate = 1000 l/min), 100% for xylene within 30 min at (100mg TiO2/l, 50mg Fe2+/l, 100 mg H2O2/l, pH = 3 and liquid flow rate = 1000 l/min), and for chlopyrifos, a maximum degradation of 100% was obtained within 1.5 h at (150 mg Fe2+/l, 250 mg H2O2/l, and 400 mg TiO2/l, pH = 3 and liquid flow rate = 1000 l/min). Results of this study confirmed the capability of the designed solar system to degrade different types of toxic organics.