Use of polyaniline coating on magnetic MoO3 and its effects on material stability and visible-light photocatalysis of tetracycline

A semiconducting material (polyaniline-coated magnetic MoO3) with photodegradative properties and low solubility was synthesized and assessed in the degradation of tetracycline (TC) to address the rising concern of antibiotics in water systems. Polyaniline (PANI) provided a protective coating, significantly reducing MoO3 dissolution across a wide pH range, while the Fe3O4 core facilitated photocatalyst extraction from water. Uncoated MoO3@Fe3O4 dissolution significantly increased with increasing pH (dissolved Mo percentage of 2.9% at pH 3 and 22.9% at pH 10). With the PANI coating, dissolution was reduced to 1.6% at pH 3 and 5.6% at pH 10. The TC removal by PANI@MoO3@Fe3O4 was 8.2 mg TC/g photocatalyst in visible light and 6.5 mg/g in dark within 35 min under optimum conditions. The degradative properties of PANI@MoO3@Fe3O4 toward TC were facilitated by reactive species produced from water oxidation by photogenerated holes (h+). This initial assessment of PANI@MoO3@Fe3O4 as a photocatalyst for pharmaceutical contaminant degradation indicates PANI@MoO3@Fe3O4 is a promising material useful for wider environmental applications. [Display omitted] •The high solubility of MoO3 makes it inefficient for water treatment.•Coating magnetic MoO3@Fe3O4 with polyaniline (PANI) reduces its dissolution.•MoO3@Fe3O4 coating with PANI increases photocatalytic activity by 20%.•PANI@MoO3@Fe3O4 degrades tetracycline by producing reactive oxygen species.•Mobile active sites of PANI promoted the oxidation of water by photogenerated h+.