Adsorption of arsenic from aqueous solution using a zero-valent iron material modified by the ionic liquid [Hmim]SbF

The environmental and health impacts caused by arsenic (As) in wastewater make it necessary to carefully manage As wastes. In the present work, a composite of the ionic liquid [Hmim]SbF 6 and nano-iron (H/Fe) was used as an adsorbent to remove As( v ) from aqueous solution. To better understand the removal effect of H/Fe on As( v ) in aqueous solution, the reaction parameters of pH, reaction temperature, time and H/Fe dosage were systematically analyzed in detail. The results show that H/Fe has significant removal efficiency toward As( v ), and that the adsorption of As( v ) by 0.5 g H/Fe reaches its maximum adsorption capacity within 2 h. The adsorption of As( v ) on H/Fe is a non-linear, time-varying process. The initial adsorption reaction is fast; however, unlike at the beginning, the later reaction involves sustained slow absorption, resulting in a distinct two-phase adsorption characteristic. Redox reaction may be one of the mechanisms responsible for the slow adsorption of As( v ) on H/Fe. At the same time, the As( v ) removal effect of H/Fe is greatly restricted by the pH. Electrostatic adsorption, adsorption co-precipitation and redox reactions act together on H/Fe in the As( v ) removal process. This study provides a basis for further clarifying the adsorption, adsorption rules and mechanism of As( v ) on H/Fe and a feasible method for the improvement of As( v ) removal efficiency of zero-valent iron materials. The environmental and health impacts caused by arsenic (As) in wastewater make it necessary to carefully manage As wastes.