TITLE:
Applicative Study (Part I): The Excellent Conditions to Remove in Batch Direct Textile Dyes (Direct Red, Direct Blue and Direct Yellow) from Aqueous Solutions by Adsorption Processes on Low-Cost Chitosan Films under Different Conditions
AUTHORS:
Vito Rizzi, Alessandra Longo, Paola Fini, Paola Semeraro, Pinalysa Cosma, Esther Franco, Rocío García, Marcela Ferrándiz, Estrella Núñez, José Antonio Gabaldón, Isabel Fortea, Enrique Pérez, Miguel Ferrándiz
KEYWORDS:
Chitosan Film, Textile Dyes, Adsorption Processes, Wastewater
JOURNAL NAME:
Advances in Chemical Engineering and Science,
Vol.4 No.4,
October
8,
2014
ABSTRACT: In
recent years the development of chitosan (CH) based materials as useful
adsorbent polymeric matrices is an expanding field in the area of adsorption
science. Even though CH has been successfully used for dye removal from aqueous
solutions due to its low cost, no considerations have been made about, for
example, the effect of changing the pH of chitosan hydrogelor about the
dehydrating effect of Ethanol (EtOH) treatment of chitosan film on the dyes
removal from water. Consequently in our laboratory we carried out a study
focusing the attention, mainly, on the potential use of CH films under
different conditions, such as reducing the intrinsic pH, increasing the
hydrophobic character by means of ethanol treatment and neutralization of CH
films to improve their absorption power. Textile anionic dyes named Direct Red
83:1, Direct Yellow 86 and Direct Blue 78 have been studied with the aim of
reducing the contact time of CH film in waste water improving the bleaching
efficiency. Neutralized acid CH film and longtime dehydrated one result to be
the better films in dye removal from water. Also the reduction of the CH
solution acidity during the film preparation determines the decreasing of the
contact time improving the results. The effect of initial dye concentration has
been examined and the amount of dye adsorption in function of time t, qt (mg/cm2), for each analyzed film has been evaluated comparing the
long term effect with the decoloration rate. A linear form of
pseudo-first-order Lagergren model has been used and described. The best
condition for removing all examined dyes from various dye solutions appears to
be the dehydration of a novel projected CH film obtained by means of the film
immersion in EtOH for 4 days. Also CH films prepared by well-known literature
procedure and neutralized with NaOH treatment appear having an excellent
behavior, however the film treatment requires a large quantity of water and
time.