Biosorption of Cr(VI) by a Bacillus coagulans biofilm supported on granular activated carbon (GAC)

Abstract

The ability of a biofilm of Bacillus coagulans supported on granular activated carbon (GAC) to biosorb Cr(VI) was investigated in batch and column studies so it may be applied to low metal concentration wastewater treatment. The quantification of polysaccharides and polymeric net revealed a value of 9.19 mg/g biosorbent for the polysaccharides and 75 mg/g biosorbent , for the polymeric net. The results obtained with open systems showed uptake values of 1.50, 1.98 and 5.34 mg/g biosorbent , respectively, for initial concentrations of 10, 50 and 100 mg/L of Cr(VI). Column studies performed with an industrial effluent showed values of Cr uptake of 0.090 mg/g biosorbent , for an initial concentration of 4.2 mg/L. The presence of functional groups on the cell wall surface of the biomass that may interact with the metal ion, was confirmed by FTIR. The equilibrium studies in batch systems were described by Freundlich, Langmuir, Reddlich-Peterson, Dubinin-Radushkevich, Sips and Toth model isotherms. Best fit was obtained with Toth model isotherm. Data from column studies were described by Adams-Bohart and Wolborska models. These models were found suitable for describing the dynamic behaviour of the columns with respect to the inlet chromium concentration. The whole study showed that the biofilm tested is very promising for the removal of Cr(VI) in industrial wastewater.

Mathematical modeling of Fe(II), Cu(II), Ni(II) and Zn(II) removal in a horizontal rotating tubular bioreactor

“…Therefore, values of the q max,L and b L (or K F,L and h L ) in this research were attributed to higher adsorption activity in the column than in the tank bioreactor systems. Quintelas et al [47] arrived at similar conclusions during their study of chromium adsorption properties in tank and column bioreactor system. Sensitivity analysis was also preformed for adsorption model parameters for all metal ions and following impact on the integral model prediction efficiency was observed: show higher impact on the model prediction efficiency than parameters related to the adsorption process in the suspended biomass, which is expected because adsorption process mostly occurs in the microbial biofilm.…”

“…For the description of metal ions adsorption in the suspended biomass, Freundlich and Langmuir isotherms were selected due to the fact that these two isotherms were the most often used adsorption isotherms in biotechnology [46,47]. The measured equilibrium concentration of metal ions (c M,L ) in the multi-metals solution along the HRTB was used for the determination of the suspended biomass adsorption capacity (q x,L ) presented as points in Fig.…”

Removal of Cr(VI) from Aqueous Solutions by a Bacterial Biofilm Supported on Zeolite: Optimisation of the Operational Conditions and Scale‐Up of the Bioreactor

“…Recently, biosorption of heavy metals by microbial cells has been recognised as a potential alternative to the traditional treatment technologies for waste streams and natural waters [7,8]. The ability of Cr(VI) anions to overcome the permeability barrier of a prokaryotic cell, such as a bacterium, can be attributed to the chemical similarity between CrO 4 2-and SO 4 2-ions [9].…”

Tratamiento de disoluciones que contienen cromo hexavalente mediante electrocoagulación con ánodos de hierro

“…La biosorción consiste en varios mecanismos, principalmente intercambio iónico, lixiviación, adsorción y difusión a través de las paredes de una célula, los cuales se diferencian dependiendo de la especie usada, el origen y el proceso de la biomasa [86,87].…”

“…Los resultados obtenidos han demostrado valores de adsorción de 1.50, 1.98 y 5.34 mg/g de biosorbente, para concentraciones iniciales de 10, 50 y 100 mg/L de Cr(VI), respectivamente [86].…”