Synthesis of Atmospherically Stable Zero-Valent Iron Nanoparticles (nZVI) for the Efficient Catalytic Treatment of High-Strength Domestic Wastewater

Afzal Ansari,Mahmoud A Hussein,Weqar Ahmad Siddiqi,Madhu Puttegowda,Abeer Nasser Al-Romaizan,Anish Khan,Vasi Uddin Siddiqui,Md Khursheed Akram

doi:10.3390/catal12010026

Abstract

Here, we report the fabrication of nZVI by the wet chemical technique in the presence of ethanol using ferric iron and sodium borohydride as the reducing agents under ambient conditions. The obtained nZVI particles are mainly in a zero-valent oxidation state and do not undergo significant oxidation for several weeks. The structural and morphological parameters of nZVI were investigated by using UV, XRD, SEM, EDX, TEM, and DLS analysis. The optical nature, bandgap energy, and absorption edge were all revealed by the UV–visible spectrum. The phase development and crystallinity of nZVI particles were shown by the XRD pattern. The morphological investigation revealed that the nanoparticles were spherical with an average size of 34–110 nm by using ImageJ software, and the elemental analysis was analyzed using EDX. Furthermore, the catalytic treatment performance of domestic wastewater was evaluated in terms of pH, COD (chemical oxygen demand) solubilization, total solids (TS), volatile solids (VS), phosphorous, and total nitrogen (TN) reduction under aerobic and anaerobic operating conditions. The effluent was subjected to a process evaluation with a different range (100–500 mg/L) of nZVI dosages. The COD solubilization and suspended solids reduction were significantly improved in the anaerobic condition in comparison to the aerobic condition. Furthermore, the effect of nZVI on phosphorous (PO43−) reduction was enhanced by the electrons of iron ions. The high concentration of nZVI dosing has a positive impact on COD solubilization and phosphorous removal regardless of the aeration condition with 400 mg/L of nZVI dosage.

Highlights

The activation of surface plasmon vibrations in the nZVI solution results in two absorption peaks at 216 and 264 nm, which are identical to the UV–visible spectrum of metallic iron and indicate the fabrication of nZVI particles
The synthesis of nZVI was facilitated by infiltration of nZVI particles with a ferric chloride solution and reduction with sodium borohydride, as revealed by UV, XRD, SEM, EDS, and TEM studies
The results of this study showed that nZVI nanoparticles can successfully treat domestic wastewater with and without oxygen

Summary

Introduction

Wastewater is one of the most serious concerns of the world, caused by industrial/domestic waste or human-made sources [1,2]. Pollutants are discharged into the water by the industry without any prior treatment, resulting in significant water pollution, environmental and human health risks [3,4]. The primary sources of water contamination have been industrial and residential waste, mining, oil spills, nuclear waste, and pesticides [5,6,7,8]. Domestic and municipal wastewater is generally 99% water and

Methods

Results

Conclusion