Bacterial remediation from effluent containing multi-walled carbon nanotubes

Multi-wall carbon nanotubes (MWCNT) were functionalized with functional groups containing oxygen, mainly carboxylic groups (-COOH), through reaction with a mixture of H sub(2)SO sub(4)/HNO sub(3 ) (3:1 v/v). The oxidized multi-wall carbon nanotubes (MWCNTOOH) were used to prepare an effluent, 2 mg L super(-1) in a saline solution of NaCl (0.9%), to study of remediation of MWCNTOOH in aqueous suspension by utilization of Escherichia coli. The suspensions of E. coli (4.5 x 10 super(5) CPU mL super(-1) and 4.5 x 10 super(8) CPU mL super(-1)) in test tubes with MWCNTOOH effluent caused the precipitation of a large amount of MWCNTOOH and supernatant clearing. The scanning electron microscopy (SEM) analysis of the precipitate and supernatant showed the adhesion and interlace of MWCNTOOH in bacteria surface. Although the precipitate consist of a large quantity of MWCNTOOH and bacteria, it was verified their presence in the supernatant. The spread plate technique showed that MWCNTOOH caused no cellular death of E. coli in the supernatant.