Photocatalytic degradation of tetracycline antibiotic using new calcite/titania nanocomposites

A new efficient photocatalyst consisting of Calcite/TiO2 system was synthesized using Sol-Gel process and applied to the degradation of tetracycline antibiotic (TC). The CAL/TiO2 system at various TiO2 content was characterized using XRD, ATR, BET, SEM-EDX and TGA techniques. Photocatalytic activities of synthesized materials were evaluated through TC degradation under UV-light in aqueous solution. The results indicate that the raw material consists mostly on calcite carbonate and palygorskite clay, while TiO2 crystallized mostly in anatase phase. The specific surface area increases from 26 to 130 m(2). g(-1) with the content of TiO2. TiO2 nanoparticles are distributed between the pores of palygorskite clay and its surface. While all CAL/TiO2 configurations were active toward the degradation of TC molecules, CAL30 composites give the best results. The photocatalytic process was optimized according to the catalyst content, TC initial concentration, pH of the solution and the irradiance type. A content of 1.5 g.L-1 of the catalyst, 50 mg.L-1 of TC, and pH approximate to 7 are the best conditions for effective TC removal under UV-light. When the photocatalytic system reached 90% of TC removal, the TOC attained 50%.