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Removal of dyes by adsorption on magnetically modified activated sludge
Maderova, Z.; Baldikova, E.; Pospiskova, K.; Safarik, I. & Safarikova, M.
Abstract
The ability of magnetically modified activated
sludge affected by thermal treatment to remove watersoluble
organic dyes was examined. Twelve different dyes
were tested. Based on the results of the initial sorption
study, four dyes (namely aniline blue, Nile blue, Bismarck
brown Y and safranin O) were chosen for further experiments
due to their promising binding onto magnetic activated
sludge. Significant factors influencing adsorption
efficiency such as dependence of contact time, initial pH or
temperature were studied in detail. The adsorption process
was very fast; more than 88 % of dye content (55 mg/L)
was adsorbed within 15 min under experimental conditions
used. The equilibrium adsorption data were analyzed by
Freundlich, Langmuir and Sips adsorption isotherm models,
and the fitting of each isotherm model to experimental
data was assessed on the basis of error functions. The
maximum adsorption capacities of magnetic activated
sludge were 768.2, 246.9, 515.1 and 326.8 mg/g for aniline
blue, Bismarck brown Y, Nile blue and safranin O,
respectively. The kinetic studies indicated that adsorption
of all selected dyes could be well described by the pseudo-second-order kinetic model, and the thermodynamic data
suggested the spontaneous and endothermic process.
Keywords
Biosorption; Dyes; Magnetic adsorbent; Magnetic modification; Microwave-assisted synthesis
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