Chemically treated carbon black waste and its potential applications.
In this work, carbon black waste - a hazardous solid residue generated from gasification of crude oil bottom in refineries - was successfully used for making an absorbent material. However, since the carbon black waste also contains significant amounts of heavy metals (especially nickel and vanadium), chemical leaching was first used to remove these hazardous impurities from the carbon black waste. Acid leaching with nitric acid was found to be a very effective method for removal of both nickel and vanadium from the carbon black waste (i.e. up to 95% nickel and 98% vanadium were removed via treatment with 2M nitric acid for 1h at 20°C), whereas alkali leaching by using NaOH under the same condition was not effective for removal of nickel (less than 10% nickel was removed). Human lung cells (MRC-5) were then used to investigate the toxicity of the carbon black waste before and after leaching. Cell viability analysis showed that the leachate from the original carbon black waste has very high toxicity, whereas the leachate from the treated samples has no significant toxicity. Finally, the efficacy of the carbon black waste treated with HNO3as an absorbent for dye removal was investigated. This treated carbon black waste has high adsorption capacity (∼361.2mgdye/gcarbonblack), which can be attributed to its high specific surface area (∼559m2/g). The treated carbon black waste with its high adsorption capacity and lack of cytotoxicity is a promising adsorbent material. Moreover, the carbon black waste was found to show high electrical conductivity (ca. 10S/cm), making it a potentially valuable source of conductive material.
NUS Environmental Research Institute, National University of Singapore, 1 Create Way, Create Tower #15-02, 138602, Singapore.
Pengwei
P
Dong
NUS Environmental Research Institute, National University of Singapore, 1 Create Way, Create Tower #15-02, 138602, Singapore.
Thawatchai
T
Maneerung
NUS Environmental Research Institute, National University of Singapore, 1 Create Way, Create Tower #15-02, 138602, Singapore.
Wei Cheng
WC
Ng
NUS Environmental Research Institute, National University of Singapore, 1 Create Way, Create Tower #15-02, 138602, Singapore.
Xu
X
Zhen
School of Mechanical Engineering, Shanghai Jiao Tong University, Shanghai 200240, China.
Yanjun
Y
Dai
NUS Environmental Research Institute, National University of Singapore, 1 Create Way, Create Tower #15-02, 138602, Singapore; Department of Chemical and Biomolecular Engineering, National University of Singapore, 4 Engineering Drive 4, 117585, Singapore.
Yen Wah
YW
Tong
Department of Chemical and Biomolecular Engineering, National University of Singapore, 4 Engineering Drive 4, 117585, Singapore.
Yen-Peng
YP
Ting
Sembcorp Industries Ltd., 30 Hill Street #05-04, 179360, Singapore.
Shin Nuo
SN
Koh
Department of Chemical and Biomolecular Engineering, National University of Singapore, 4 Engineering Drive 4, 117585, Singapore. Electronic address: chewch@nus.edu.sg.
Chi-Hwa
CH
Wang
Department of Chemical and Biomolecular Engineering, National University of Singapore, 4 Engineering Drive 4, 117585, Singapore. Electronic address: chenkg@nus.edu.sg.
Koon Gee
KG
Neoh
D000327:Adsorption; D002460:Cell Line; D002470:Cell Survival / Q000187:drug effects; D005347:Fibroblasts / Q000187:drug effects; D006256:Hazardous Waste / Q000032:analysis*; D006801:Humans; D008168:Lung / Q000166:cytology / Q000187:drug effects; D009532:Nickel / Q000302:isolation & purification*; D010316:Particle Size; D012037:Refuse Disposal / Q000379:methods*; D053260:Soot / Q000737:chemistry* / Q000633:toxicity; D013499:Surface Properties; D014639:Vanadium / Q000302:isolation & purification*
D006256:Hazardous Waste; D053260:Soot; D014639:Vanadium; D009532:Nickel
Adsorption; Carbon black; Chemical leaching; Cytotoxicity; Dye removal