Biomass/adsorbent electrostatic interactions in expanded bed adsorption: a zeta potential study.
Expanded bed adsorption is an integrated technology that allows the introduction of particle-containing feedstock without the risk of blocking the bed. The biomass particles contained in the feedstock have to be treated as an integral part of the process and potential interactions between suspended biomass and the adsorbent must be excluded during process design. Because the electrostatic forces dominate the interactions between the biomass and adsorbent, the zeta potential has been studied as a tool to characterize biomass/adsorbent electrostatic interactions. The zeta potentials of four types of biomass (yeast intact cells, yeast homogenate, Escherichia coli intact cells, and E. coli homogenate) and two types of ion exchanger were measured systematically at varying process conditions. Using the cell transmission index from biomass pulse-response experiments as a parameter, the relations between zeta potential and the biomass/adsorbent interaction were evaluated. Combining the influences from zeta potential of adsorbent (zeta(a)), zeta potential of biomass (zeta(b)), and biomass size (d), parameter (-zeta(a)zeta(b)d) was found to be an appropriate indicator of the biomass/adsorbent interactions in expanded beds under various liquid-phase conditions for different types of biomass. The threshold value of parameter (-zeta(a)zeta(b)d) can be defined as 120 mV(2) microm for cell transmission of >90%, which means that systems with (-zeta(a)zeta(b)d) < 120 may have a considerable probability of forming stable expanded beds in a biomass suspension under the particular experimental conditions.
Lin
Dong-Qiang
DQ
Institut für Enzymtechnologie, Heinrich-Heine Universität Düsseldorf, im Forschungszentrum Jülich, 52426 Jülich, Germany.
Brixius
Peter J
PJ
Hubbuch
Jürgen J
JJ
Thömmes
Jörg
J
Kula
Maria-Regina
MR
D000327:Adsorption; D018533:Biomass; D004553:Electric Conductivity; D004926:Escherichia coli / Q000254:growth & development / Q000502:physiology; D006863:Hydrogen-Ion Concentration; D011199:Potentiometry; D012441:Saccharomyces cerevisiae / Q000254:growth & development / Q000502:physiology*; D055672:Static Electricity