Kinerja Fotokatalis CU/TIO2 Nanotube (CU/Tnt) Terhadap Naphtol Blue Black Dye Dengan Pengaruh Variasi Massa Dopan CU2+

Abstract

Titanium dioxide (TiO₂) is a semiconductor material that has found widespread use as a photocatalyst, a material that can be used to accelerate reactions involving light. In particular, TiO₂ is used to degrade organic pollutants, which are chemicals that have been used in large quantities and have become a significant environmental concern. However, its photocatalytic activity is constrained by a substantial bandgap and expeditious electron-hole recombination. The modification of TiO₂ into a nanotube structure (TNT) and subsequent doping with copper (Cu) has been demonstrated to enhance visible light absorption and photocatalytic efficiency. Naphthol Blue Black (NBB) is an azo dye that is frequently utilized in the textile and batik industries. It is regarded as an environmental contaminant due to its persistence and resistance to natural degradation. The objective of this study is to examine the impact of varying Cu dopant mass fractions on the photocatalytic performance of Cu/TiO2 nanotubes (Cu/TNT) in NBB degradation processes. Additionally, the study seeks to ascertain the optimal pH, catalyst dosage, and catalyst reusability for maximized efficiency. The Cu dopant mass utilized in this study ranged from 0% to 3%, with increments of 0.1%. The precursors employed were TiO2 micropowder and CuCl2·2H2O. Cu/TNT was synthesized using the hydrothermal method at 130°C for 24 hours and applied for the photocatalytic degradation of a 25 ppm NBB solution under visible light irradiation. Photocatalytic performance was evaluated through a series of analytical tests, including adsorption tests, irradiation time tests, pH variation tests, catalyst dosage tests, and reusability tests. These evaluations were conducted using UV-Vis spectrophotometry, a method of optical analysis that quantifies the absorption and emission of light by a sample. The results demonstrated that an augmentation in the mass of the Cu dopant enhanced both adsorption and photocatalytic activity. Cu/TNT 3% demonstrated the optimal performance, exhibiting an adsorption value of Ct/C₀ of 0.4935 and a removal efficiency of 50.91% after 60 minutes of irradiation. The optimal degradation conditions were obtained at a pH of 3 and a catalyst dose of 5 g/L, yielding removal efficiencies of 53.34% and 59.15%, respectively. Reusability tests demonstrated that the 3% Cu/TNT catalyst exhibited excellent stability for up to five cycles and attained a removal efficiency of 49.34% in the sixth cycle. These findings suggest that Cu/TNT is a promising visible-light photocatalyst for the treatment of wastewater containing dyes.