Optimization of electrocoagulation process for fluoride removal: a blending approach using gypsum plaster rich wastewater

Virendra K Jadhao,Shyam Kodape,Kunjan Junghare

doi:10.1186/s42834-019-0002-y

Virendra K Jadhao, Shyam Kodape + Show 1 more

Open Access

https://doi.org/10.1186/s42834-019-0002-y

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Abstract

A novel blending approach has been introduced for fluoride removal by means of electrocoagulation. A blend was prepared by mixing synthetic phosphoric acid plant wastewater and gypsum plaster (GP) rich wastewater. This study explores defluoridation of wastewater using the simultaneous effect of chemical precipitation and electrocoagulation. Fourier transform infrared spectroscopy analysis of sludge confirms the presence Ca-F bond, which proves that enhancement in fluoride removal with blending of GP rich wastewater is due to simultaneous action of chemical precipitation and electrocoagulation. Optimization and statistical modeling were done with the help of MINITAB 17 software. Response surface methodology was performed using Box-Behnken Design to predict the fluoride removal efficiency and energy consumption. R2 values of 0.9485 and 0.9998 shows a good agreement between experimental and predicted values of responses. Kinetic study was done to determine the rate constant and it is found out that fluoride removal follows second order kinetic model. Blending approach confirmed the assistive role of GP rich wastewater in the enhancement of fluoride removal efficiency.

Highlights

Water contamination of fluoride is an issue related to drinking water, as excess fluoride exhibits hazardous health effects like dental fluorosis, skeletal fluorosis etc
If we consider the wastewaters from semiconductor or phosphate fertilizer industries, excess fluoride from these waters acts as a source for drinking water contamination
Fourier transform infrared spectroscopy (FTIR) spectrum was recorded in the range of 4000–400 cm− 1

Summary

Introduction

Water contamination of fluoride is an issue related to drinking water, as excess fluoride exhibits hazardous health effects like dental fluorosis, skeletal fluorosis etc. [1]. Water contamination of fluoride is an issue related to drinking water, as excess fluoride exhibits hazardous health effects like dental fluorosis, skeletal fluorosis etc. Excess fluoride in water could be due to natural causes like volcanic ash, fluoride rich minerals etc. Anthropogenic causes like fly ash, fertilizer plant wastewater [2]. The majority of researcher’s work on defluoridation is about the treatment of target drinking water source. All these work have tried to remove fluoride from drinking water as per WHO norms, i.e., max 1.5 mg L− 1 of F− ion [3]. If we consider the wastewaters from semiconductor or phosphate fertilizer industries, excess fluoride from these waters acts as a source for drinking water contamination. According to Central Pollution Control Board of India, maximum fluoride limit for industrial wastewater is 15 mg L− 1 for discharge to public sewers or marine coastal areas [4]

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