▎ 摘　　要

NOVELTY - Strengthening iron reducing bacteria coupled passivation nano-zero-valent iron system comprises (i) adding graphene oxide, dissolving ferrous sulfate heptahydrate in a mixed solution of water and ethanol, ultrasonically processing on an ultrasound system, adding sodium borohydride solution, allowing to react, continuously passing nitrogen and stirring, collecting product, washing and drying, (ii) allowing to react graphene oxide-loaded nano-zero-valent iron with 4-chlorophenol, carrying out degradation, drying and storing, (iii) culturing Shewanella in Luria Bertani liquid medium, shaking, centrifuging and washing and (iv) carrying out graphene oxide-mediated reduction and passivation of nano-valent iron by Shewanella degraded 4-chlorophenol, adding graphene oxide loaded passivated nano-zero-valent iron, sodium lactate, enriched Shewanella and 4-(2-hydroxyethyl)-1-piperazineethanesulfonic acid (HEPES) and inorganic salt medium. USE - The method is useful in strengthening iron reducing bacteria coupled passivation nano-zero-valent iron system. ADVANTAGE - The method: strengthens the coupling system: reduces the formation of passivation layer; improves the reactivity of the system; overcomes the shortcoming of nano-zero-valent iron which can be easily deactivated. DETAILED DESCRIPTION - Strengthening iron reducing bacteria coupled passivation nano-zero-valent iron system comprises (i) using Hummers method to prepare graphene oxide, adding 200 mg graphene oxide into 250 ml three-necked flask, dissolving 0.496 g ferrous sulfate heptahydrate in a mixed solution of 60 ml water and 20 ml ethanol, adding the mixed solution into a three-necked flask and ultrasonically processing at 50 kHz for 30 minutes on an ultrasound system under stirring and nitrogen protection of a mechanical stirrer, adding 25 ml sodium borohydride solution into the three-mouth flask in a drop wise manner using a peristaltic pump, allowing to react for 30 minutes, continuously passing nitrogen and stirring for 20 minutes to allow the mixed solution to react completely, collecting the product by centrifugation at 5000 revolutions/minute for 5 minutes, washing with deionized water and absolute ethanol thrice in sequence and drying in a vacuum oven at 60 degrees C to obtain graphene oxide loaded nano-zero-valent iron, (ii) allowing to react graphene oxide-loaded nano-zero-valent iron with 4-chlorophenol, carrying out degradation batch reaction in a 100 ml serum bottle sealed with nitrile valgus rubber stopper to protect from light, where the initial concentration of 4-chlorophenol is 10 mg/l, collecting the passivated sample by centrifugation, drying at 60 degrees C in a vacuum drying oven and storing the dried sample, preferably graphene oxide loaded with passivated nano zero-valent iron in a 10 ml polyethylene (PE) tube, (iii) culturing Shewanella in Luria Bertani liquid medium, shaking at 30 degrees C at a speed of 200 revolutions/minute, centrifuging at the end of 16 hours log growth to collect bacterial suspension and washing with inorganic salt culture solution for 3 times to obtain final enriched bacterial solution and (iv) carrying out graphene oxide-mediated reduction and passivation of nano-valent iron by Shewanella degraded 4-chlorophenol in 100 ml nitrile rubber sealed serum bottle protected from light, where the concentration of 4-chlorophenol is controlled at 20 mu g/l, adding 150 mg graphene oxide loaded passivated nano-zero-valent iron to serum bottle, 20 mM sodium lactate as electron donor, 3 ml enriched Shewanella and 20 mM 4-(2-hydroxyethyl)-1-piperazineethanesulfonic acid (HEPES) as biological buffer to maintain the pH in the range of 6.9-7.1 and filling the remaining volume with inorganic salt medium, where the graphene oxide, passivated nano-zero valent iron and Shewanella are the coupling systems and sodium lactate is carbon source and controlling the concentration of bacterial suspension at optical density (OD) 600 is 1.2.