Catalytic Degradation of Diatrizoate by Persulfate Activation with Peanut Shell Biochar-Supported Nano Zero-Valent Iron in Aqueous Solution.

Jian Xu,Yusuo Lin,Yuxuan Dai,Shaogui Yang,Huan He,Qun Li,Xueliang Zhang,Xinhua Zhan,Cheng Sun,Yan Zhou

doi:10.3390/ijerph15091937

Abstract

An emerging pollutant, diatrizoate (DTZ) has been frequently detected in aqueous solution. Unique reticular peanut shell biochar (BC)-supported nano zero-valent iron (nZVI) composite (nZVI/BC) was successfully synthesized and used as a catalyst for activating persulfate (PS) to promote the removal of DTZ. The structure and morphology of the nanocomposite materials were characterized by scanning electron microscopy, X-ray diffraction, Brunauer-Emmett-Teller measurements, and Fourier transform infrared spectroscopy. The degradation of DTZ (20 mg L−1) was achieved by activating PS with the nanocomposite material. The removal of DTZ reached nearly 100% using 25 mM PS and 0.45 g L−1 nZVI/2BC (mass ratio of nZVI and BC at 1:2) nanocomposite material at pH 3.0 and 25 °C. Influencing factors, such as dosages of nZVI/2BC and PS, temperature, and pH were also investigated. The mechanisms of PS activation with nZVI/2BC were discussed, including BC property, electron transfer, and the identification of free radicals in the reaction. The findings demonstrated that nZVI/BC-PS (peanut shell BC-supported nZVI activating PS) is a promising material for the treatment of refractory organic pollutants.

Highlights

With the rapid development of medicine, considerable attention is being paid to pharmaceuticals and personal care products (PPCPs), which are emerging contaminants (ECs) [1,2]
With the assistance of Scanning electron microscopy (SEM), the morphologies of nano zero-valent iron (nZVI), BC, and nZVI/BC were clearly observed at a magnification of 10,000 (Figure 1)
The BC structure was well-preserved during the pyrolysis under 350 ◦ C, shown by how the branches of BC are neatly arranged and how each has enough space for nZVI adhesion

Summary

Introduction

Iodinated contrast media (ICM) is a typical PPCP, which is used to enhance organs and blood vessel image observation effects [3]. ICM was widely detected in hospital and domestic wastewater, treated wastewater effluent, groundwater, surface water, and even drinking water, ranging from ng L−1 to μg L−1 worldwide due to its abuse and improper disposal [4,5]. Previous studies reported that DTZ led to nephrotoxic effects and decreased thyroid homeostasis of organisms [9,10].

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