Treatment and characterization of phosphorus from synthetic wastewater using aluminum plate electrodes in the electrocoagulation process

Dessie Tibebe,Ashok N Bhaskarwar,Yezbie Kassa

doi:10.1186/s13065-019-0628-1

Dessie Tibebe, Ashok N Bhaskarwar + Show 1 more

Open Access

https://doi.org/10.1186/s13065-019-0628-1

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Abstract

The main objective of this study is treatment and characterization of phosphorus from synthetic wastewater using aluminum electrodes in the electrocoagulation process. EC experimental setups were designed and different parameters were optimized. The maximum amounts of phosphorus removal efficiencies were observed at pH 7. The phosphorus removal efficiency increases from 85.16 to 97.65% as the temperature increases from 15 to 45 °C, beyond this temperature, there is small effect on removal efficiency. Pollutant removal efficiency increases with an increase in the electrolysis time. At lower initial concentrations the removal efficiencies reached to their maximum values while at the highest initial concentration, the phosphorus removal efficiency was decreased. The increase of current density improves the efficiency of phosphorus removal. Energy and aluminum consumption decreases with increasing initial concentration of phosphorus. Field Emission Scanning Electron Microscope (FESEM) image analysis demonstrated very fine structures for aluminum hydroxide/oxyhydroxides and aluminum phosphate. The existence of the different elemental composition in the sludge was proved by the help of Energy Dispersive X-ray Analysis (EDXS), indicating that the aluminum, oxygen and phosphorus were present in the product. From X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FT-IR) and Raman analyses of the sludge product, it is concluded that the chemical speciation of the by-products can be mostly aluminum hydroxide and aluminum phosphate.

Highlights

One of the main problems in the twenty-first century is the provision of adequate treated water free from pollutants
Negative side, aluminum plate electrode surface was cracked because the release of too much hydrogen bubbles which help flocculated particles to float out of the aqueous solution and there were basic media around this electrode
There were three layers formed in the beaker after the electrocoagulation process (Fig. 2)

Summary

Introduction

One of the main problems in the twenty-first century is the provision of adequate treated water free from pollutants. The precipitation is governed by the integrated particles giving the formation of aluminium-hydroxylphosphate complexes, Al(OH)3-x(PO4)x, rather than the individual AlPO4 and Al(OH) species These complexes either adsorb onto positively charged aluminium hydrolysis species or act as further centers of precipitation or nucleation points for aluminum hydrolysis products [5, 6]. This technology is a promising technique for phosphorus removal from wastewater because it is simple, selective, effective, ability in multi-pollutant removal and economical, result in less sludge production and experience minimal disposal problems [7, 8]

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