Discoloration of Rhodamine B dyeing wastewater by schorl-catalyzed Fenton-like reaction

Abstract

As other natural iron-bearing minerals, schorl could be taken as an effective iron source for degradation of organic pollutants by mineral-catalyzed Fenton-like system. In our present study, the schorl-catalyzed Fenton-like system has been successfully developed for discoloration of an active commercial dye, Rhodamine B (RhB), in an aqueous solution. Through a number of batch discoloration experiments under various conditions, it was found that the reactivity of the system increased by, respectively, increasing schorl dosage, temperature, hydrogen peroxide starting concentration and by decreasing the pH. Over 90% of discoloration ratio could be gained in less than 30 min, and nearly 70% of total organic carbon (TOC) could be removed in less than 200 min. And, the schorl catalyst could be repeatedly used at least ten times, still with high catalytic activity. Comparative studies indicated that the RhB discoloration ratios were much higher in presence of schorl and H 2 O 2 than those in presence of schorl or H 2 O 2 only, which suggested that the schorl-catalyzed Fenton-like reaction governed the RhB discoloration process. The content of Fe ion leaching in the solution was also measured using inductively coupling plasma-atomic emission spectra (ICP-AES). A mechanism proposed herein suggested that adsorption and Fenton-like reaction (heterogeneous and homogeneous) were responsible for the discoloration of RhB.schorl, Rhodamine B, discoloration, Fenton-like reaction

Preparation of Fe3O4/TiO2/C Nanocomposites and Their Application in Fenton-Like Catalysis for Dye Decoloration

“…Another drawback is that the Fe 2+ -H 2 O 2 Fenton system requires a stoichiometric amount of iron. The iron ions are hard to remove and generate a high degree of sludge [4,5]. The iron containing sludge should be further treated to avoid environmental hazards.…”

Enhanced Removal of Phenol from Aquatic Solution in a Schorl-catalyzed Fenton-like System by Acid-modified Schorl

“…Similar result has been reported previously. 31,32 The existence of alkali group 35 and electrostatic field 30 on the surface of schorl may be contributed to its adsorption properties. Figure 3 shows the effect of modified schorl dosage on phenol removal.…”

“…However, the total concentration of iron ion is only 1.7 × 10 -3 mmol/L under similar conditions in the system of raw schorl and H2O2. Three processes occur in mineral-catalyzed Fentonlike system, the first is the adsorption of organic pollutants on the surface of mineral catalyst; the second is the oxidation of organic 31,32,36 Thus, more dissolved iron ions in solution make higher catalytic oxidant activity in the system of modified schorl and H2O2. At the same time, the results of XRD, FT-IR and SEM after phenol removal rule out the possibility of formation of new solid phases during phenol removal.…”

“…The physical properties and chemical compositions have been mentioned in previous work. 31,32 Characterization. XRD was employed to identify mineral phases of schorl before and after treatment with phenol solution.…”

“…31,32 But, according to previous experimental results, the efficiency of removal of phenol in water was not good. Hence, in this study, the attention has been paid to enhance the phenol removal by schorl-catalyzed Fenton-like system.…”