Electrochemical Degradation of Crystal Violet Using Ti/Pt/SnO2 Electrode

Rachid El Brychy,Nadia Rhazzane,Mhamed Abali,Souad El Issami,Mohamed Moutie Rguiti,Mustapha Hilali,Lahcen Bazzi,Moulay Driss Mellaoui,Khalid Abbiche,Karine Groenen-Serrano,Hanane Zejli

doi:10.3390/app11188401

Abstract

Today, organic wastes (paints, pigments, etc.) are considered to be a major concern for the pollution of aqueous environments. Therefore, it is essential to find new methods to solve this problem. This research was conducted to study the use of electrochemical processes to remove organic pollutants (e.g., crystal violet (CV)) from aqueous solutions. The galvanostatic electrolysis of CV by the use of Ti/Pt/SnO2 anode, were conducted in an electrochemical cell with 100 mL of solution using Na2SO4 and NaCl as supporting electrolyte, the effect of the important electrochemical parameters: current density (20–60 mA cm−2), CV concentration (10–50 mg L−1), sodium chloride concentration (0.01–0.1 g L−1) and initial pH (2 to 10) on the efficiency of the electrochemical process was evaluated and optimized. The electrochemical treatment process of CV was monitored by the UV-visible spectrometry and the chemical oxygen demand (COD). After only 120 min, in a 0.01 mol L−1 NaCl solution with a current density of 50 mA cm−2 and a pH value of 7 containing 10 mg L−1 CV, the CV removal efficiency can reach 100%, the COD removal efficiency is up to 80%. The process can therefore be considered as a suitable process for removing CV from coloured wastewater in the textile industries.

Highlights

The protection of the environment and the problem of cleaning up contaminated water and soil require a rapid response worldwide
After only 120 min, in a 0.01 mol L−1 NaCl solution with a current density of 50 mA cm−2 and a pH value of 7 containing 10 mg L−1 crystal violet (CV), the CV removal efficiency can reach 100%, the chemical oxygen demand (COD) removal efficiency is up to 80%
CV is an organic compound of the raw formula C25N3H30Cl (Figure 1) soluble in water, with a molar mass equals to 407.979 g mol−1, it is widely used as dye for food and textile industry [6,42,43,44,45,46]

Summary

Introduction

The protection of the environment and the problem of cleaning up contaminated water and soil require a rapid response worldwide. The textile industry is one of the industrial poles, it produces an enormous quantity of waste loaded with non-biodegradable dye stuffs [5,6,7,8] These discharges contribute to the degradation of the quality of surface water and groundwater by their harmful and toxic side effects [9,10,11]. The annual world production of dyes is about 7 × 105 tons, of which 5–10% is discharged into water by the textile industry [14] They can be carcinogenic and toxic and their intensive use in everyday life can have harmful consequences on the environment and food [15,16,17]. Most of the dyes used are synthetic products, with an often-complex molecular structure, which makes them stable and difficult to degrade by conventional treatment processes [18,19]

Methods

Results

Conclusion