Removal of Congo red and malachite green from aqueous solution using heterogeneous Ag/ZnCo-ZIF catalyst in the presence of hydrogen peroxide

Abstract

The bimetallic Zn/Co zeolitic imidazole frameworks (ZnCo-ZIFs) were successfully synthesized by a simple solvothermal method at room temperature. Silver elements were afterward doped onto the bimetallic frameworks to form Ag/ZnCo-ZIFs via a facile impregnation method in acetone solvent. The as-synthesized material was used as a heterogeneous catalyst for the removal reaction of Congo red (CR) and malachite green (MG) in the presence of hydrogen peroxide (H2O2). Effects of catalyst dosage, H2O2 concentration, initial concentration of the contaminants, reaction temperature, and reaction time were conducted in this work. The results showed that more than 94% and 98% removal of CR and MG were, respectively, achieved within 45 and 30 min. The presence of Ag also enhanced the removal efficiency of CR and MG. The main mechanism of removal reaction of the organic contaminants could be oxidation via hydroxyl radicals. Moreover, the catalytic activity of the material remained over 90% after four recycling cycles. Due to the efficient reactivity as well as high stability, Ag/ZnCo-ZIFs can be a potential heterogeneous catalyst to remove hazardous dyes from aqueous solution.

Removal of Malachite Green Dye from Aqueous Solution by Catalytic Wet Oxidation Technique Using Ni/Kaolin as Catalyst

“…Due to the different experimental conditions used in prior investigations, a direct comparison of the adsorption capabilities investigated in this work with those previously published in the literature is challenging. However, an examination of Table 3 shows that Ni/kaolin catalyst used in this study exhibits a better MG removal rate than other catalysts [ 49 , 50 , 51 , 52 ], as listed in Table 3 .…”

Synthesis of zeolitic imidazole framework‐8 derived ZnCo layered double hydroxides for the removal of methylene blue from wastewater

“…There is a rapid increase in adsorption at an initial 30 min of contact because the adsorbent surface has more binding sites. However, up to 90 min of contact the adsorption rate gradually decreases in response to saturation of active sites of adsorbent with the ions of MB, and at the time interval between 90 and 120 min a slight desorption occurs which may be due to repulsive forces among them 49–51 …”

Influence of Cu doping on the functionality of spray coated SnS2 thin films and its photocatalytic degradation of dyes and antibacterial activity

“…Based on the results, it shows 2 at% Cu-doped SnS 2 can degrade MG easily eliminated when compared to CR. One possible explanation is that, as shown in figure 1, MG has a shorter chain of benzyl groups than CR [67]. Moreover, Cu-doped SnS 2 catalysts have significantly greater photocatalytic efficiency than pure SnS 2 catalysts.…”