Facile integration of FeS and titanate nanotubes for efficient removal of total Cr from aqueous solution: Synergy in simultaneous reduction of Cr(VI) and adsorption of Cr(III)

[Display omitted] •A novel FeS-TNTs was integrated for the first time through a facile synthesis.•Simultaneous removal of total Cr by FeS-TNTs was achieved.•Outperformance of FeS-TNTs under wide pH range and high oxygen level was obtained.•Synergies in reduction of Cr(VI) and adsorption of Cr(III) between FeS and TNTs were identified. In this study, a novel composite composed of iron monosulfide nanoparticles (FeS NPs) and titanate nanotubes (TNTs) was hydrothermally synthesized. Characterizations revealed the encapsulation and homogenous dispersion of FeS NPs into the interlayers of TNTs. Significant performance in removal of aqueous total Cr was acquired by efficient conversion of Cr(VI) to Cr(III) on FeS and simultaneous adsorption of Cr(III) on TNTs. Moreover, the high activity of FeS-TNTs in reduction of Cr(VI) can maintain at high oxicity or alkalinity of its solution. The synergistic effect between FeS and TNTs was derived from sheltering of FeS NPs from their self-aggregation, O2-oxidation and the affinity of Cr(III) to TNTs. The unique properties, e.g. the solid acidity, the hollow and interlayered configuration of TNTs played important roles in high activity, good stability and reusability of FeS-TNTs.