Proses elektro penggumpalan telah digunakan untuk mengatasi masalah
yang dihadapi oleh proses fiziko kimia konvensional dalam rawatan air sisa tekstil. Air
sisa tekstil sebenar mengandungi pencelup reaktif selalunya bersifat alkali. Bahanbahan
elektrod yang berbeza seperti zink dan keluli tahan karat boleh digunakan bagi
mengatasi prestasi lemah elektrod aluminium dalam medium beralkali untuk rawatan
air sisa tekstil sebenar. Prestasi proses elektro penggumpalan untuk rawatan air sisa
tekstil sintetik (disediakan menggunakan pencelup biru reaktif 261) dan air buangan
tekstil sebenar telah disiasat. Tiga jenis bahan elektrod iaitu aluminium, zink dan keluli
tahan karat telah digunakan dalam kajian ini. Parameter operasi terlibat dalam kajian
ini ialah ketumpatan arus (2-8 mA/cm2), kepekatan pewarna awal (20-100 mg/L) dan
nilai pH awal (5-9). Kajian permulaan telah dijalankan menggunakan air buangan
tekstil sintetik untuk menentukan keadaan operasi optimum yang memberikan
penyingkiran pencelup yang tinggi untuk setiap bahan elektrod. Keadaan-keadaan
optimum yang diperolehi ialah ketumpatan arus (4 mA/cm2 untuk semua elektrodelektrod),
kepekatan awal pencelup (50 mg/L untuk elektrod aluminium dan 100 mg/L
untuk elektrod zink dan keluli tahan karat) dan nilai awal pH (7 untuk elektrod
aluminium dan 9 untuk elektrod zink dan keluli tahan karat). Satu penyiasatan yang
menyeluruh dari segi penyingkiran pencelup, COD, kekeruhan, kehilangan berat
elektrod, dan penggunaan tenaga dijalankan di bawah keadaan optimum (ketumpatan
arus dan kepekatan pewarna yang awal) manakala nilai pH awal telah ditetapkan pada
9 bagi mewakili keadaan air sisa tekstil sebenar yang digunakan dalam kajian ini.
Penyingkiran pencelup, kehilangan berat elektrod, dan penggunaan kuasa telah
direkodkan sebagai 99.8%, 0.66 kWh/m3 dan 0.039% untuk elektrod zink, 99.1%, 0.70
kWh/m3 dan 0.066% untuk elektrod keluli tahan karat dan 75.8%, 0.50 kWh/m3 dan
0.41% untuk elektrod aluminium masing-masing. Rawatan air sisa tekstil yang sebenar
di bawah keadaan operasi optimum (ketumpatan arus dan kepekatan pewarna yang
awal) dan pada nilai pH semula jadi air sisa tekstil menunjukkan bahawa elektrod zink
memberikan penyingkiran pencelup yang tertinggi (83.7%), kehilangan berat elektrod
yang terendah (0.043%) dan penggunaan tenaga yang munasabah (0.69 kWh/m3). Kos
operasi duga dianggarkan lebih rendah untuk elektrod zink (MYR 3.93 setiap 1 m3 air
sisa terawat tekstil selama 10 minit) berbanding dengan elektrod aluminium dan keluli
tahan karat. Oleh itu, elektrod zink dianggap sebagai bahan elektrod paling berkesan
untuk rawatan air sisa tekstil yang mengandungi pencelup reaktif.
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Electrocoagulation process (EC) has been used to overcome the problems
related to the use of conventional physico-chemical process in treatment of textile
wastewater. Real textile wastewaters containing reactive dyes are often characterized
by their alkalinity. Different electrode materials such as zinc and stainless steel could
be used to tackle the low performance of aluminum electrode in alkaline medium for
treatment of a real textile wastewater. The performance of electrocoagulation process
for treatment of a synthetic textile wastewater (prepared using reactive blue 261 dye)
and a real textile wastewater was investigated. Three types of electrode material
namely aluminum, zinc and stainless steel were used in this study. The operating
parameters involved in this study were current density (2-8 mA/cm2), initial dye
concentration (20-100 mg/L) and initial pH (5-9). The preliminary study was
conducted using synthetic textile wastewater to determine the best operating
conditions that would lead to high dye removal for each electrode material. The best
conditions were current density (4 mA/cm2 for all electrodes), initial dye concentration
(50 mg/L for aluminum electrode and 100 mg/L for zinc and stainless steel electrode)
and initial pH (7 for aluminum electrode and 9 for zinc and stainless steel electrode).
A thorough investigation in terms of dye removal, COD, turbidity, energy
consumption and electrode weight loss was conducted under the best conditions
(current density and initial dye concentration) while the initial pH value was kept at 9
to represent the real textile wastewater condition as used in this study. Dye removal,
power consumption and electrode weight loss were found at 99.8%, 0.66 kWh/m3 and
0.039% for zinc electrode, 99.1%, 0.70 kWh/m3 and 0.066% for stainless steel
electrode and 75.8%, 0.50 kWh/m3 and 0.41% for aluminum electrode, respectively.
The treated real textile wastewater under the best operating conditions (current density
and initial dye concentration) and at original pH of textile wastewater demonstrated
that zinc electrode showed the highest dye removal (83.7%), lowest electrode weight
loss (0.043%) and reasonable energy consumption (0.69 kWh/m3). The estimated
operating cost of the EC process was lower for zinc electrode (MYR 3.9 per 1 m3 of
treated textile wastewater for 10 minutes) compared with aluminum and stainless steel
electrodes. Thus, zinc electrode could be an effective electrode material for treatment
of textile wastewater containing reactive dye.
Effect of operational parameters on treatment of textile wastewater by electrocoagulation process using different electrode materials / Marwa Ali Elajel