A self-prepared graphene oxide/sodium alginate aerogel as biological carrier to improve the performance of a heterotrophic nitrifier

Abstract

In order to enhance the resistance of microorganisms to toxic substance and adverse environment, graphene oxide/sodium alginate (GO/SA) aerogel was synthesized and used as adsorption material to immobilize heterotrophic nitrifier consortium FG-06. The aerogel showed the lamellar and network structure with a lot of oxygen-containing functional groups. Consortium FG-06 could be adsorbed and grow on the aerogel surface which was referred as GO/SA/FG-06. The NH4+-N adsorption capacity by the aerogel was very low, therefore, the NH4+-N removal in the degradation experiments should be attributed to the nitrification. GO/SA/FG-06 exhibited the better performance of the growth and pollutants removal than the suspend one. At 15 °C, 30 °C and 40 °C, the NH4+-N removal efficiencies by suspended FG-06 were 34.38 %, 90.20 % and 69.25 % in 24 h, respectively, which were increased to 83.4 %, 97.9 % and 97.6 % by GO/SA/FG-06. For the coking wastewater, the phenol degradation efficiency was 99.05 % by GO/SA/FG-06 at 72 h, whereas it was 86.98 % by suspended one at 96 h. Moreover, the final removal efficiencies of NH4+-N and COD were increased from 65.7 % and 81.21%–87.03% and 88.31 %, respectively, when FG-06 was immobilized. Therefore, the GO/SA aerogel was an ideal immobilization material.