Abstract
The wide application of organic dyes in many industries has brought challenges to the effective treatment of organic wastewater. In this study, a series of ZrMOX (M: Fe, Co, Ni, Cu) particles were prepared by the coprecipitation method to adsorb methyl orange (MO) in aqueous solution. The adsorbents were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FT-IR), and N2 adsorption-desorption. The selected adsorbent with the best adsorption performance was ZrFeOX with a molar ratio of 1 : 1 and calcination temperature of 573 K; the maximum adsorption capacity was 138.95 mg·g-1. The adsorption behavior of MO onto the adsorbent was studied as a function of contact time, initial concentrations, adsorption temperature, and pH conditions. The analysis results showed that pseudo-second-order, Elovich, and Langmuir models were suitable to describe the adsorption behavior of MO on the adsorbent. In addition, regeneration experiments presented that the MO removal rate reached over 96% after repeated recycling for 5 times. The adsorbent developed in this work is not only simple to prepare and low cost but also green and energy-saving, which can make some contributions to environmental governance.
Highlights
Among the four ZrMOX adsorbents prepared by the coprecipitation method, through step-by-step screening, 1-573-ZFe showed best adsorption performance when the pH was between 4 and 6; this may be due to their high BET surface area (255.754 m2·g-1) and pore volume (0.218 cm3·g-1)
It can be seen from the X-ray diffraction (XRD) and scanning electron microscopy (SEM) characterization results that 1-ZFe is an amorphous composite metal oxide with irregular structure
The experimental data of kinetics and PSO and ELO can describe the dynamic adsorption process of methyl orange (MO) on 1-573-ZFe, indicating that the adsorption of MO on 1-573-ZFe was a chemical adsorption control process that occurs on a heterogeneous surface
Summary
More than 100 000 types have been discovered or invented, and over 7 000 tons of dyes are being manufactured and used yearly world widely [2]. There are about 100 tons of dye wastewater discharged into the water body every year in the process of using dyes [3]. Due to the existence of the −N=N− group and the benzene ring, MO and other azo dyes are highly toxic [4, 5]. They cause various diseases in humans and animals and cause harm to the environment. It is necessary to remove MO and other dyes before the dye wastewater is discharged
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