Efficient removal of Brilliant Blue G (BBG) from aqueous solutions by marine Aspergillus wentii: Kinetics, equilibrium and process design

Abstract

The sorption of Brilliant Blue G (BBG) by dead biomass of marine fungus Aspergillus wentii, which was chemically modified by esterification of the carboxylic acids (CB), or methylation of amine (NB), or raw biomass (RB) was studied with variation in the parameters of contact time (0–80min), initial concentration of dye (119.3–544.8mg/L) and solution pH (2–10). The contact time necessary to reach equilibrium was 180min. The BBG biosorption was strictly pH dependent, and maximum uptake capacity of all three biosorbents was observed at initial pH 2. The biosorption isotherm data were fitted well to the Langmuir isotherm and the monolayer sorption capacity was found to be 384.6, 370.4 and 312.5mg/g for CB, NB and RB, respectively. For each biosorbent-dye system, kinetic models were applied to the experimental data to examine the mechanisms of sorption and potential rate-controlling steps. The pseudo-second-order kinetic model described the biosorption kinetics accurately and the sorption process was found to be controlled by pore and surface diffusion. From the design of a single-batch biosorber it is predicted that the biosorbent, CB will require 20% less of the sorbent to treat certain volumes of wastewater containing 500mg/L of BBG when compared with the unmodified biosorbent (RB).