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Frontiers of Environmental Science & Engineering >> 2017, Volume 11, Issue 2 doi: 10.1007/s11783-017-0917-7

Chemical additives affect sulfate reducing bacteria biofilm properties adsorbed on stainless steel 316L surface in circulating cooling water system

Research Center for Aqueous Organic Pollutants Control and Water Quality Security, Beijing Key Laboratory Beijing Jiaotong University, Beijing 100044, China

Available online: 2017-04-07

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Abstract

There are more polysaccharides than proteins in EPS on SS316L surface. NaClO cuts down more protein, while 1227 reduced more polysaccharides in EPS. HEDP slightly eased the corrosion, NaClO and 1227 inhibited the microbial corrosion. NaClO still performed pitting corrosion properties to some extent. 1227 changed the C:O and NaClO decreased the amidogen in SS316L surface film. This paper studied the biofilm properties and corrosion behavior of sulfate reducing bacteria (SRB) on stainless steel 316L (SS316L) surface in circulating cooling water system with and without additives including hydroxy ethyl fork phosphonic acid (HEDP), dodecyl dimethyl benzyl ammonium chlotide (1227) and NaClO. Biochemical technique, electrochemical technology, X-ray photoelectron spectroscopy (XPS) and scanning electron microscope (SEM) were used. The results show that the extracellular polymeric substance (EPS) in biofilm attached on the SS316L surface mainly contain proteins and polysaccharides, the contents are 98 ug·cm and 635ug·cm , respectively. The polysaccharides were cut by 1227 about 80%, while 55% by NaClO. The proteins were reduced by NaClO about 53%, while only 30% by 1227. The potentiodynamic polarization shows that the corrosion potential of SS316L was enhanced from −0.495 V to −0.390 V by the chemical additives, delaying the occurrence of the corrosion. And the corrosion rate was also reduced from 5.19 × 10 mm·a to 2.42 × 10 mm·a . But NaClO still caused pitting corrosion after sterilizing the bacteria, while 1227 can form a protective film on the surface of SS316L. Though HEDP contribute to the bacteria activity, it can enhance the breakdown potential. XPS results confirmed that 1227 can change the value of C:O in the biofilm attached on metal surface, and NaClO can eliminate the existence of amidogen. This study would provide some recommendations for the selection of chemical additives in the thermal power plant.

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