INDUSTRIAL WASTE WATER TREATMENT USING NATURAL ADSORBENTS

Abstract

The textile dye industry is the largest consumer of dye stuffs. During the coloring process a large amount of
synthetic dye does not bind and is lost to the waste system. These dyes are difficult to remove in conventional wastewater
treatment processes and can be transported easily through sewers and rivers especially because they are designed to have
high water solubility. The effluent streams from these textile industries leads to serious water pollution problems. For
separation of dyes from these effluent streams, adsorption technique is used in this study. Adsorption is a surface
phenomenon in which the liquid phase solutes in gas or liquid phase are adsorbed on the surface of the adsorbents.
Adsorption using natural adsorbents is more feasible and economical as the natural adsorbents are available in bulk and
majorities are usually waste products. Adsorption can bedone using two methods, primarily on lab scale, using lab apparatus
such as beaker with constant stirring where the adsorbent and dye solutions are intimated for a specific period; secondly it
can also be done in a packed bed in which packing is made up of the adsorbents. Adsorbent used in this study is Banana
peels. Different parameters were altered during the experimentation such as adsorbent dosage, concentration of adsorbent
solution, time of contact and keeping temperature constant. Adsorption is a low-cost waste water treatment process and is
comparatively economical than advanced oxidation processes and filtration processes. The optimum adsorbent dosage was
4-5 grams in 100ml dye sample for time 60mins.Adsorption using banana peels has achieved up to 92% removal of methyl
red as per the experimentation at 50ppm dye concentration. The equilibrium adsorption behavior was carried out by plotting
Freundlich’s adsorption isotherm. Adsorption of Methyl Red dye on the banana peels is quite low but comparable to
activated carbon.