Feasibility of micellar-enhanced ultrafiltration (MEUF) or the heavy metal removal in soil washing effluent

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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Comparative Heavy Metal Removal Efficiencies of Biosurfactants Produced by Odoribacter Splanchnicus DSM 20712, Bacterium Clone JX981747 and Soil Washing Agents

10.21203/rs.3.rs-26833/v1 ◽

2020 ◽

Author(s):

TOOCHUKWU Ekwutosi Ogbulie ◽

Chioma Chimezie Okore ◽

Agunna Everest Ejele

Keyword(s):

Heavy Metal ◽

Metal Removal ◽

Heavy Metal Removal ◽

Soil Washing ◽

Acid Methyl Ester ◽

Lead Removal ◽

Test Soil ◽

Gas Chromatography Mass Spectroscopy ◽

Set Up ◽

The One

Abstract The application of two biosurfactants in the removal of copper, zinc, and lead from waste metal dumpsite soil with their efficiencies was compared to soil washing agents as KNO3, Ca(NO3)2 and NaOH. The test soil samples were also spiked separately with different concentrations (50 mg/L, 250 mg/L, 750 mg/L and 1500 mg/L ) of CuSO4, ZnSO4 and Pb(NO3)2. The biosurfactants used were produced by Odoribacter splanchnicus DSM 20712 (WBS1) and an unidentified bacterium clone JX981747 (CMS). Five different treatment set up comprising of different ratios (20:1, 15:1, 10:1, 5:1, and 1:1) with the soil solution constant was respectively used. The heavy metal contents were measured using Atomic Absorption Spectrophotometer and the percentage heavy metal removal efficiency was calculated. The highest concentrations of biosurfactant (20:1) at different spiked concentrations of metallic salts recorded the highest values of copper (95.47%, 95.73%, 91.69%, 78.82%); zinc (97.98%, 98.98%, 97.29%, 96.78%) and lead (97.68%, 93.09%, 88.12%, 84.98%) removal. The percentage metal removed in each treatment increased with increasing concentration of the biosurfactants and washing agents (1:1 to 20:1). The chemical structure of the two biosurfactants analyzed using Gas Chromatography Mass Spectroscopy (GC-MS) depict the major component of biosurfactants produced from Odoribacter splanchnicus DSM 20712 to be Di-n- amyl phthalate while 9, Octadecanoic acid, methyl ester was from unidentified bacterium clone JX981747. The one dimensional paper chromatography showed presence of galactose/glucose, mannose, ribose, rhamnose in the biosurfactants produced from Odoribacter splanchnicus DSM 20712 whereas the unidentified bacterium clone JX981747 produced biosurfactants that contained all sugars except mannose. The test biosurfactants studied showed high levels of copper and lead removal than zinc when compared with the test soil washing agents (KNO3), Ca(NO3)2 and NaOH used in this study. Biosurfactants have thus shown to have the ability to remove metals hence its use requires scaling up for environmental applications.

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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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