Abstract:
The release of hazardous synthetic dyes into industrial effluents has emerged as an
environmental problem requiring remediation. The present study focused on the preparation
of a new and environmentally-friendly material for the remediation of hazardous dyes from
aqueous solution. The low cost adsorbents were prepared from industrial by products
including, brewery spent grain, brewery sewage sludge, municipal sewage sludge and metal
processing sludge, which accumulated the industrial waste on disposal places collected in the
Bedele town and Addis Ababa City, Ethiopia. The preliminary screening studied for
evaluations performance of each biochar variant in removing methylene blue dye, then, the
unmodified BSG biochar was selected. The comprehensive characterization studies were
carried out on the biochar such as proximate analyses, point of zero charge, BET, FTIR, XRD
and SEM analyzed. The batch adsorption experiments were conducted for optimizing
parameter such as the pH, contact time, initial dye concentration and adsorbent dose in
removing methylene blue dye. The selected unmodified biochar‖s removal efficiency 99.8%
and the maximum adsorption capacity of methylene blue dye was 34.5 mg/g, the parameters
optimized at the 3 h, pH 10, initial MB concentration 20 mg/L and adsorbent dose 2 g/L. The
kinetic studies revealed that the adsorption process was the best fit by pseudo-second-order
model, it indicated that the chemisorption mechanism and the adsorption process was the best
fit by Freundlich isotherm model, it suggested that the multilayer adsorption on surface of
biochar. The study demonstrated that the industrial waste biochar could be employed as an
effective and eco-friendly alternative for the cleanup of dye in aqueous solution. The studies
should be improve the regeneration efficiency of BSG biochar for enhance its long-term
applicability in wastewater treatment.
