Assessment of the phytoremediation potential of Panicum maximum (guinea grass) for selected heavy metal removal from contaminated soils

Soil contaminated with Cd and Pb has caused sharp decrease of cultivatable soil and has been attracting increasing attention. Biosurfactants are efficient in solving the problem. However, little information is available about the influence of sophorolipids (SLs) on the remediation of Cd- or Pb-contaminated soil. The sophorolipids produced by Starmerella bombicola CGMCC 1576 were used to study the effects of Cd and Pb removal in batch soil washing from artificially contaminated soil. The removal efficiency of crude total SLs was better than both distilled water and synthetic surfactants. Furthermore, 83.6% of Cd and 44.8% of Pb were removed by 8% crude acidic SLs. Acidic SLs with high water solubility were more effective than lactonic SLs in enhancing remediation of heavy metal-contaminated soils. The complexation of Cd with the free carboxyl group of the acidic SLs was observed by Fourier-transform infrared spectroscopy study, and this complexation was effective in heavy metal removal from the soil. The fermentation broth of S. bombicola, without further preparation, removed 95% of Cd and 52% of Pb. These results suggested that SLs produced by S. bombicola could function as potential bioremediation agents for heavy metal-contaminated soil.

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New-Generation Washing Agents in Remediation of Metal-Polluted Soils and Methods for Washing Effluent Treatment: A Review

International Journal of Environmental Research and Public Health ◽

10.3390/ijerph17176220 ◽

2020 ◽

Vol 17 (17) ◽

pp. 6220 ◽

Cited By ~ 2

Author(s):

Zygmunt M. Gusiatin ◽

Dorota Kulikowska ◽

Barbara Klik

Keyword(s):

Heavy Metals ◽

Heavy Metal ◽

Contaminated Soils ◽

Metal Removal ◽

Heavy Metal Removal ◽

Soil Washing ◽

Effluent Treatment ◽

Chemical Pollution ◽

Polluted Soils ◽

Soil Flushing

Soil quality is seriously reduced due to chemical pollution, including heavy metal (HM) pollution. To meet quality standards, polluted soils must be remediated. Soil washing/soil flushing offers efficient removal of heavy metals and decreases environmental risk in polluted areas. These goals can be obtained by using proper washing agents to remove HMs from soil. These washing agents should not pose unacceptable threats to humans and ecosystems, including soil composition. Currently, it is desirable to use more environmentally and economically attractive washing agents instead of synthetic, environmentally problematic chemicals (e.g., ethylenediaminetetraacetic acid (EDTA)). The usefulness of novel washing agents for treatment of heavy metal-contaminated soils is being intensively developed, in terms of the efficiency of HM removal and properties of washed soils. Despite the unquestionable effectiveness of soil washing/flushing, it should be remembered that both methods generate secondary fluid waste (spent washing solution), and the final stage of the process should be treatment of the contaminated spent washing solution. This paper reviews information on soil contamination with heavy metals. This review examines the principles and status of soil washing and soil flushing. The novel contribution of this review is a presentation of the sources and characteristics of novel washing agents and chemical substitutes for EDTA, with their potential for heavy metal removal. Methods for treating spent washing solution are discussed separately.

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Can Microbially Induced Calcite Precipitation (MICP) through a Ureolytic Pathway Be Successfully Applied for Removing Heavy Metals from Wastewaters?

Crystals ◽

10.3390/cryst8110438 ◽

2018 ◽

Vol 8 (11) ◽

pp. 438 ◽

Cited By ~ 12

Author(s):

Álvaro Torres-Aravena ◽

Carla Duarte-Nass ◽

Laura Azócar ◽

Rodrigo Mella-Herrera ◽

Mariella Rivas ◽

...

Keyword(s):

Heavy Metals ◽

Heavy Metal ◽

Contaminated Soils ◽

Metal Removal ◽

Metal Tolerance ◽

Heavy Metal Removal ◽

Heavy Metal Tolerance ◽

Successful Implementation ◽

Calcite Precipitation ◽

Microbially Induced Calcite Precipitation

Microbially induced calcite precipitation (MICP) through a ureolytic pathway is a process that promotes calcite precipitation as a result of the urease enzymatic activity of several microorganisms. It has been studied for different technological applications, such as soil bio-consolidation, bio-cementation, CO2 sequestration, among others. Recently, this process has been proposed as a possible process for removing heavy metals from contaminated soils. However, no research has been reported dealing with the MICP process for heavy metal removal from wastewater/waters. This (re)view proposes to consider to such possibility. The main characteristics of MICP are presented and discussed. The precipitation of heavy metals contained in wastewaters/waters via MICP is exanimated based on process characteristics. Moreover, challenges for its successful implementation are discussed, such as the heavy metal tolerance of inoculum, ammonium release as product of urea hydrolysis, and so on. A semi-continuous operation in two steps (cell growth and bio-precipitation) is proposed. Finally, the wastewater from some typical industries releasing heavy metals are examined, discussing the technical barriers and feasibility.

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