Abstract
Based on the Fe0/H2O2 heterogeneous Fenton system, the degradation of rhodamine B (RhB, an organic dye pollutant) was researched in this paper. The effects of initial pH value, concentration of H2O2, dosage of zero-valent iron (ZVI), and initial RhB concentration on RhB degradation by Fe0/H2O2 were studied. The results showed that when the initial pH = 4, dosage of ZVI was 9 mM, and concentrations of H2O2 and RhB were 8 mM and 0.1 mM, respectively, the color of RhB could be completely faded within 30 min, and the total organic carbon (TOC) removal percentage was about 63% after 120 min. The dissolved oxygen (DO) content and oxidation–reduction potential (ORP) were monitored during the reaction. Quenching experiments with methanol confirmed that the degradation of the dye was mainly due to oxidation by the ˙OH radical. Besides, the results from UV-Vis spectroscopy showed that the degradation of RhB was mainly due to the destruction of the conjugated oxygen hetero-anthracene in the RhB molecule. The solid-phase characterization of the ZVI samples after reaction confirmed that the original regular and slippery ZVI samples finally were corroded into rough and irregular lepidocrocite and magnetite. Two possible competitive reaction pathways for the degradation of RhB by Fe0/H2O2 were proposed by GC-MS analysis, which were attributed to the dissociation of ethyl radicals and the degradation of chromophore radicals.
Highlights
In 2015, Chinese industry wastewater treatment capacity reached 20.0 billion tons, and the discharge wastewater from the manufacture of textiles, clothing, and apparel was estimated to be 2.0 billion tons.[1]
The effects of pH on Rhodamine B (RhB) removal by Fe0/H2O2 were studied in the pH range of 3.0–4.5
RhB removal by the heterogeneous Fenton reaction was obviously limited by the range of pH.[31]
Summary
In 2015, Chinese industry wastewater treatment capacity reached 20.0 billion tons, and the discharge wastewater from the manufacture of textiles, clothing, and apparel was estimated to be 2.0 billion tons.[1]. Most dyestuffs present in dye and textile wastewater possess complicated chemical structures, such as hydroxytriarylmethanes, xanthene, and aminotriarylmethanes, which are difficult to destroy by biological or photolytic processes. Rhodamine B (RhB), as an important aminoxanthene dye, is widely used as a textile, biological and uorescent stain, in the colored glass industry, and in reworks.[2,3] RhB is used as a food additive in some developing countries, such as India,[4] Vietnam,[5] and Argentina.[6] RhB has been listed as a carcinogenic chemical (Group 3) by the IARC (International Agency for Research on Cancer) since 1987.7 many developed countries and regions such as Japan, the EU, and the United States have forbidden the use of RhB.[8] Besides, RhB has toxic effects on animals and humans, inducing teratogenicity, carcinogenicity and mutagenicity.[9] RhB is frequently present in dye wastewater due to the wide application of RhB in the textile industry. RhB in wastewater accumulates, but it can be effectively degraded in an oxidation system.[10,11] it is very important to nd a suitable oxidation system to treat wastewater
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
