Electrochemical Treatment of Textile Dye Wastewater by Aluminium and Stainless-Steel Electrodes
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Date
2020-11
Authors
Ndambo, Michael Mwashighadi
Journal Title
Journal ISSN
Volume Title
Publisher
Kenyatta University
Abstract
Pollution of water resources due to the increasing growth in industrialization
continues to pose a great challenge to the rapidly growing population. Textile
industries are among the principal polluters of surface water. The development of
these textile industries has resulted in severe water pollution due to discharge of dye
wastewaters to natural water courses. This laboratory scale study was aimed at
establishing an eco-friendly wastewater treatment method dubbed electrocoagulation
(EC) method. The main objective of the study was to establish an
electrochemical and efficient method that would effectively remove COD and colour
from azo dye wastewater using aluminium (Al) and stainless steel (SS) electrodes.
Increasing current density and contact time significantly increased the removal of
colour and COD. Increase in current density increased both COD and colour
removal. When current density was increased from 15 to 47 A/m2 the colour
removal increased from71 to 99 % for the case of disperse blue with SS electrode.
Increase in contact time 5- 20min. caused increase in colour and COD removal from
below 50 to 98 and 78 % respectively for disperse blue with SS. When interelectrode
distance (IED) and dye concentration was increased the colour and COD
removal declined significantly. As the IED increased from 1-3cm the percentage
removal of colour decreased from 99 to 45 % for the case of disperse blue with SS.
Addition of sodium chloride enhanced the electrocoagulation process. Addition of
NaCl from 0 - 0.4g enhanced colour removal from 15 to 80% for disperses black
with SS. Under optimum operating conditions (current density 47.2 A/m2, Interelectrode
distance 1cm, SE 0.2 g/L, 0.1 g/L dye concentration and 25 minutes
contact time) the performance of stainless steel on removal of colour recorded the
highest removal at 97% compared to that of aluminium of 90%.the physio-chemical
parameters where reduced to NEMA disposable levels making it possible for treated
water fit for re-use. COD reduced by 81%, conductivity by 89% and turbidity by
88%. Operating cost was evaluated by adding cost of electrode per Kg at the market
price and the cost of electricity per (kWh/m3) for SS= 50.56 KES/m3 and Al =50.55
KES/m3. This confirms the viability and a cost-effectiveness of the process.
Description
A Thesis Submitted in Partial Fulfilment of the Requirements for the Award of the Degree of Masters of Science (Chemistry) in the School of Pure and Applied Science Kenyatta University
Keywords
Electrochemical, Treatment, Textile Dye Wastewater, Aluminium, Stainless, Steel Electrodes