Self assembled TiO2 with 5-sulfosalicylic acid for improvement its surface properties and photodegradation activity of dye

A new photocatalyst, 5-sulfosalicylic acid grafted TiO2 (5-SA-TiO2) was synthesized by a chemical adsorption-based self assembly technique, and its surface properties were characterized by means of XRD, BET, IR, and UV–vis spectra. After self assembly, a stable, yellow complex was formed quickly on TiO2 surface and then its UV–vis wavelength response range was expanded from 375 nm to 600 nm. The band gap of 5-SA-TiO2 was 2.95 ev, less than that of TiO2 (3.10 ev). The crystalline structure of TiO2 could be adjusted by self assembly, i.e., anatase was transformed into brookite and the proportion between brookite and anatase was increased. After self assembly, the adsorption ratio of acid violet 43 (AV 43) was enhanced from 13.56% to 52.36%, because the crystallite size of both anatase and brookite was smaller, the surface areas were larger, and the affinity of between AV 43 and the catalyst was enhanced for the interactions between phenyl groups. The visible light degradation ratio of TiO2 was increased by self assembly from 36.60% to 97.01% and 82.65% removal of total organic carbon was achieved.

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► A chemical adsorption-based self assembly technique for TiO2 was established.
► Crystalline structure and crystallite size of TiO2 was adjusted by self assembly.
► UV–vis wavelength response range was expanded to 600 nm.
► Adsorption ratio of acid violet 43 was improved 3.86 times than that of unmodified TiO2.
► Photodegradation ratio of acid violet 43 was improved 2.65 times than that of unmodified TiO2.