Activated carbon surface modifications by adsorption of bacteria and their effect on aqueous lead adsorption

Abstract

The adsorption of Escherichia coli on different activated carbons has been studied. The activated carbon samples used have been characterized, determining their surface area, pore size distribution, elemental analysis, mineral matter analysis and pH of the point of zero charge. The adsorption capacity of these carbons increased with their hydrophobicity and macropore volume. The number of bacteria adsorbed on the demineralized activated carbon in a solution of pH value equal to the iso-electric point of the carbon was negligible. However, in the presence of cations the proportions of bacterial cells adsorbed were 87.8% (Fe 3 ), 54.7% (Ca 2 ) and 24.8% (Mg 2 ) respectively. This increase in adsorption capacity in the presence of electrolytes has been explained on the basis of both the reduction in electrostatic free energy and the increase in cell surface hydrophobicity due to the metal bound by some compounds of the cell membrane. When the solution pH was intermediate between the pH values of the point of zero charge of the carbon and bacteria the number of bacteria adsorbed increased due to the attractive interactions between the carbon and bacteria. The adsorption of bacteria on activated carbons decreased the porosity and increased the negative charge density of the latter. Depending on the experimental conditions used, the presence of bacteria can enhance the capacity of activated carbons to adsorb lead.

Open circuit potential shifts of activated carbon in aqueous solutions during chemical and adsorption interactions

“…The influence of interaction of oriented water dipoles and adsorbate molecules on the mechanism of adsorption was developed by Bockris et al [9,10]. The electrochemical theory is still used today for adsorption studies on activated carbons [7,11,12] development of new electrosorption processes on activated carbon [13] and other porous carbon materials [14].…”

Interaction of Gram-Positive and Gram-Negative Bacteria with Ceramic Nanomaterials Obtained by Combustion Synthesis – Adsorption and Cytotoxicity Studies

“…The possibility of bacterial adsorption onto the surface of nanostructures has been presented, e.g., in the work of Kang et al (2007) and Singh et al (2011). Similarly, the ability to create a biofilm and the adsorption of bacterial cells onto the surface of mineral materials, including carbon materials and modified clay minerals, were also demonstrated (Yee et al, 2000;Rivera-Utrilla et al, 2001;Yamamoto et al, 2001;Jiang et al, 2007;Rong et al, 2008). These studies also indicated the important roles of pH and the ionic strength of the solution as significant factors affecting the adsorption of bacterial cells onto the surface of minerals.…”

“…Some of these studies are also related to the adsorption of bacteria onto the surface of such materials. This is an important aspect of the research that involves the potential applications of these methods for microbiological water treatment (Rivera-Utrilla et al, 2001;Savage and Diallo, 2005;Li et al, 2008;Qu et al, 2013;Hossain et al, 2014). Similar investigations have focused not only on…”

Evaluation of Sorption Mechanism of Pb (II) and Ni (II) onto Pea (<i>Pisum sativum</i>) Peels

“…Perhaps this may be due to formation of hydroxides of these metal ions. The zero point charge pH ZPC of the pea peels was determined to explain the effect of pH on sorption process of Pb II and Ni II in aqueous solution 21 . It has been given in the literature that favorable pH for adsorption of cation is greater than that of pH ZPC while …”