Adsorption and photocatalytic degradation of tetracycline hydrochloride using a palygorskite-supported Cu2O–TiO2 composite

• A Cu2O–TiO2–Pal composite is prepared as a photocatalyst for tetracycline removal.
• The catalyst support, palygorskite, has a porous structure and large surface area.
• The catalyst has a maximum tetracycline adsorption capacity of 113.6 mg·g− 1 at 20 °C.
• The Cu2O–TiO2 heterostructure has enhanced solar-driven photocatalytic activity.
• The catalyst can be recycled more than three times by calcination.

A palygorskite (Pal)-supported Cu2O–TiO2 heterojunction composite (Cu2O–TiO2–Pal) was successfully prepared. The morphology, structure and chemical composition of the composite was characterized, and the adsorption and photocatalytic degradation of tetracycline hydrochloride using this composite was also investigated. The results showed that a layer of TiO2 − Cu2O was successfully loaded on the surface of Pal. The Cu2O–TiO2–Pal composite had a specific surface area of 93 m2·g− 1, mesoporous features, and a uniform slit channel. The composite possessed twofold removal ability to TC, including adsorptive capability for the separation and solar-light illuminate photocatalytic in degradation. The maximum adsorption capacity of Cu2O–TiO2–Pal for TC was 113.6 mg·g− 1 at 20 °C as calculated by the Langmuir model. The pseudo-first-order degradation rate constant of 50 mL of TC with an initial concentration of 30 mg·L− 1 reached 0.0129 min− 1 when the Cu2O–TiO2–Pal concentration was 1.0 g·L− 1. The total removal rate of TC reached 88.81% in the presence of Cu2O–TiO2–Pal. In addition, the composite could be regenerated by calcination at 400 °C and recycled more than three times, which is useful for practical applications.

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