Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
576090 | Journal of Hazardous Materials | 2015 | 9 Pages |
Abstract
Bioleaching by Aspergillus niger strain SY1 combined with Fenton-like reaction was optimized to improve trace metal removal and dewaterability of dredged sediments. The major optimized parameters were the duration of bioleaching and H2O2 dose in Fenton-like process (5 days and 2Â g H2O2/L, respectively). Bioleaching resulted in the removal of â90% of Cd, â60% of Zn and Cu, â20% of Pb, and in decrease of sediment pH from 6.6 to 2.5 due to organic acids produced by A. niger. After addition of H2O2, Fenton-like reaction was initiated and further metal removal occurred. Overall efficiency of the combined process comprised: (i) reduction of Cd content in sediment by 99.5%, Cu and Zn by >70% and Pb by 39% as a result of metal release bound in all mobilizable fractions; (ii) decrease of sediment capillary suction time (CST) from 98.2Â s to 10.1Â s (by 89.8%) and specific resistance to filtration (SRF) from 37.4Â ÃÂ 1012Â m/kg to 6.2Â ÃÂ 1012Â m/kg (by 83.8%), due to reducing amount of extracellular polymeric substances (EPS) by 68.7% and bound water content by 79.1%. The combined process was found to be an efficient method to remove trace metals and improve dewaterability of contaminated dredged sediments.
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Authors
Xiangfeng Zeng, Irena Twardowska, Shuhe Wei, Lina Sun, Jun Wang, Jianyu Zhu, Jianchao Cai,