Visual nickel(II) ions treatment in petroleum samples using a mesoporous composite adsorbent

Abstract

This study was considered as an effective application for visual nickel (Ni(II)) ion treatment in petroleum samples and contaminated wastewater using a ligand embedded novel composite adsorbent. The composite adsorbent was synthesized using dimethylglyoxime (DMG), which was successfully anchored onto the highly ordered mesoporous silica. The adsorbent was exhibited an easy accessibility of Ni(II) ions and generated an optical signal upon addition of Ni(II) even in the ultra-trace levels. The adsorbent was shown the ability to create Ni(II) ion capturing up to ∼0.22µg/L with the rapid response time. The colorimetric changes were extremely specific for the Ni(II) ions even in the trace concentration level. Therefore, The composite adsorbent was a simple, effective tool for the fast, sensitive, selective, inexpensive, and specific recognition of a broad range of Ni(II) ions optically. The data clearly clarified an interesting affinity between composite adsorbent and Ni(II) ions at neutral pH area. Due to the strong interaction between Ni(II) ions and the DMG ligand of the composite adsorbent surface, the adsorbent was exhibited high adsorption capacity and excellent selectivity towards the Ni(II) ions capturing. The adsorption capacity was determined and the data were well fitted by the Langmuir adsorption isotherm equation with a monolayer adsorption capacity of 198.41mg/g. The presence of competing ions did not interfere with Ni(II) detection, indicating the high selectivity towards the Ni(II) ion at optimum condition, and the adsorbent was successfully captured the Ni(II) ions even the petroleum samples of naphtha, jet fuel, gas oil, fuel oil. The elution study indicated that the adsorbent was effectively regenerated by dilute HCl acid, and the regenerated adsorbent was repeatedly used in several cycles without significant deterioration.