The Mechanism Of Bacteria Adhesion On Modified Carbon Felt Electrode And Its Electrochemical Performance

Surface properties of electrode are critical for electroactive microorganism initial adhesion and biofilm formation in electrochemical system.In this study,three modified electrode materials(CF-GO,CF-NH2,CF-GO-NH2)were prepared based on a blank carbon felt electrodes(CF),which was modified by a graphene oxide(GO)impregnation or amination reaction or both.And the GO impregnation made surface more hydrophilic and amination reaction made it more positively charged.Then we explored the effect of hydrophilicity and the charge property of the electrode surface on the initial adhesion kinetics and mechanism as well as electrochemical performance of Shewanella xiamenensis BC01(S.xiamenensis)and Escherichia coli DH5a(E.coli),and gained the conclusions as follows:(1)The adhesion kinetic behavior on the four material surfaces was shown that the initial adhesion of S.xiamenensis and E.coli on the negatively charged CF and CF-GO surfaces conformed to pseudo-first-order kinetic and Freundlich isothermal;the initial adhesion on the positively charged CF-NH2 and CF-GO-NH2 conformed to the pseudo-second-order kinetic and Langmuir isothermal.(2)The adhesion mechanism interpreted by the XDLVO model showed that S.xiamenensis and E.coli formed reversible adhesion on the negatively charged CF and CF-GO surfaces,where the dominant adhesion mechanism is LW and AB force;on the positively charged CF-NH2 and CF-GO-NH2 surface formed irreversible and strong adhesion,where the dominant adhesion mechanism is EL force.(3)The electrochemical performace test indicated that both hydrophilic modification(CF-GO)and positively charged modification(CF-NH2)were effective,but the effect of the latter was much better than the former.The material CF-GO-NH2 had the best electrochemical performance and the cumulative charge amount(S.xiamenensis,0.028 C/mg·cm-2;E.coli,0.0024 C/mg·cm-2),which the optimization experiment found that the material CF-GO-NH2-10 has the largest charge amount.The modified carbon felt prepared in this paper enhanced the efficiency of initial bacterial adhesion and improved the electrochemical performance.At the same time,this paper also deeply studied the typical adhesion behavior and dominated adhesion mechanism of electroactive microorganism that provides useful tool of the targeted electrode materials modifications.