Enhanced photocatalytic degradation efficiency of ciprofloxacin by CuAl layered double hydroxide materials

Sets of nCuAl-LDH layered double hydroxide samples were successfully synthesized by the co-precipitation method, using precursors such as Al(NO 3 ) 3 , Cu(NO 3 ) 2 , and Na 2 CO 3 salts to provide <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline" overflow="scroll"> <mml:mrow> <mml:mi>C</mml:mi> <mml:msubsup> <mml:mi>O</mml:mi> <mml:mn>3</mml:mn> <mml:mrow> <mml:mn>2</mml:mn> <mml:mo>−</mml:mo> </mml:mrow> </mml:msubsup> </mml:mrow> </mml:math> ion in the interlayers. The synthesized material samples were characterized by modern physical analysis methods: XRD patterns, SEM images, EDX spectra, UV-Vis DRS spectra. The results of the characterization analysis showed that the 2CuAl-LDH, 3-CuAl-LDH samples had a lamellar structure similar to hydrotalcite. The synthesized samples with high Cu:Al molar ratio (4-CuAl-LDH, 5-CuAl-LDH, 6-CuAl-LDH) had a strong decrease in the layered double structure. The CuAl-LDH material samples had a strong shift to the visible light region, the band gap energy sharply reduced from 3.52 eV (MgAlH) to 1.44 eV (3CuAl-LDH) and 0.95 eV (2CuAl-LDH). The results of the investigation on the photocatalytic degradation of ciprofloxacin showed that two material samples 2CuAl-LDH and 3CuAl-LDH had the best CIP degradation ability. The CIP degradation efficiency with concentrations of 10, 25, 40, 50 ppm reached 93.3, 92.2, 90.2, 89.2% using a 30 W LED light source. In addition, the optimal environmental for CIP degradation was the initial pH value of the 50 ppm CIP solution (pH value as 5.8).