Batch removal of manganese from acid mine drainage using bone char

Abstract

-The present study investigated batch kinetics and the batch equilibrium of manganese removal from acid mine drainage (AMD) using bone char as an adsorbent. Equilibrium tests revealed that the Langmuir-based maximum manganese uptake capacity was 22 mg g -1 for AMD effluents and 20 mg g -1 for laboratory solutions at a pH ranging from 5.5 to 5.7. The pseudo-second order model best described the manganese kinetics within bone char. Manganese removal was mainly influenced by the operating variables of the solid/liquid ratio and the pH of the aqueous phase. In fact, metal uptake was favored at nearly neutral pH values. The effect of particle size and temperature proved to be insignificant for the investigated operating range. This work also evaluated the mechanism for manganese removal using bone char. Results showed that intraparticle diffusion is the main rate-limiting step; however, additional contributions from boundary layer diffusion may well affect this removal when particles of smaller sizes are used. The final concentration of fluoride and other metals present in the AMD effluent was in agreement with the concentration limit set forth by Brazilian legislation. The present study demonstrated that bone char is a suitable material to be used for the removal of manganese from AMD effluents.

Mathematical modeling of manganese adsorption onto bone char in a continuous fixed bed column incorporating backmixing and shriking core approaches

“…The characteristic parameters of the column are listed in Table 1; given by Sicupira et al (2014) and were kept constant in the simulations (a = 0.7 L mg -1 and q m = 18.8 mg g -1 ). Hydrodynamic parameters were investigated and simulation results of the output column concentrations (step curve F(t/τ), where τ is the mean residence time of fluid in the column) are shown in Figure 3.…”

“…The condition of equilibrium is given by the Langmuir isotherm, as assessed by Sicupira et al (2014), while the chemical reaction between manganese and bone char is irreversible according to the following stoichiometric equation:…”

“…e) The pH of the aqueous phase is kept constant overtime and along the length of the column, due to the buffering effect of the calcite dissolution present in the bone char (Sicupira et al, 2014);…”

Cinética De Adsorção De Manganês Em Zeólitas Exauridas

“…Os principais métodos para a remoção de manganês de efluentes incluem precipitação como hidróxido ou MnO 2 , além de adsorção ou biossorção, bem como osmose reversa [8]. Um exemplo de estudos de adsorção é o trabalho de Sicupira et al [9] que investigaram a remoção de manganês por carvão de osso e observaram carregamentos da ordem de 20mg.g -1 do sólido em condições de equilíbrio e soluções monoelementares [10]. A adsorção em zeólitas também tem sido alvo de várias pesquisas devido ao seu baixo custo e sua alta disponibilidade, que compete com os métodos de adsorção em carvão ativado [11] ou de biossorção [12].…”

Biosorption of Mn (II), Co (II) and Cr (VI) in a horizontal rotating tubular bioreactor: experiments and evaluation of the integral bioprocess model

“…As an alternative, different biological methods could be applied because they do not destroy metals, but concentrate and immobilize them (Gavrilescu, 2004;Vieira et al, 2012;Michalak et al, 2013;Sicupira et al, 2014;Vieira et al, 2014). Biosorption is the removal of metals and their complexes by biological materials such as active or inactive microorganisms, microbial aggregates or biofilms (Singh et al, 2006;Baysal, et al, 2009;Xie, et al, 2013).…”