Zero-valent iron supported by dendritic mesoporous silica nanoparticles to purify dye wastewater

The presence of different types of organic dyes in water stream will clearly give rise to unexceptional side effects on living organisms. Emerging physical or chemical methods have been developed for the treatment of dye-involving water, but the exploration for adequate design strategy and technique available is still ongoing. Here, zero-valent iron (ZVI) was prepared by a liquid phase sodium borohydride reduction approach and then integrated with dendritic mesoporous silica nanoparticle (DMSN) to construct Janus magnetic adsorbent (denoted as ZVI-DMSN), which could be employed to purify dye wastewater. The structure, magnetic properties and dye adsorption results of ZVI-DMSN were systematically investigated. The ZVI component can enable efficient solid-liquid separation through magnetic separation route, and, more importantly, provided additional binding sites for adsorption process to increase the adsorption capacity. The thermodynamic analysis of adsorption indicated that the adsorption of typical organic dyes was an irreversible, spontaneous and endothermic process. Moreover, ZVI-DMSN adsorbent was recyclable, showing a regeneration efficiency of more than 80% after 5 cycles. We believe that ZVI-DMSN, as an inexpensive adsorbent material with excellent adsorption properties, e.g., short time, high efficiency and large capacity, will host vast potential for removal of dyes in water bodies.