Fe‐modified Clinoptilolite is Effective to Recover Plant Biosurfactants Used for Removing Arsenic From Soil

Kaal²,

Wasilewska

et al. 2021

Self Cite

Cadmium, Cu, Ni, Pb, and Zn removal via soil flushing with tannic acid (TA) as a plant biosurfactant was studied. The soil was treated for 30 h in a column reactor at a constant TA concentration and pH (3%, pH 4) and at variable TA flow rates (0.5 mL/min or 1 mL/min). In the soil leachates, pH, electrical conductivity (EC), total dissolved organic carbon, and metal concentrations were monitored. Before and after flushing, soil pH, EC, organic matter content, and cation exchange capacity (CEC) were determined. To analyze the organic matter composition, pyrolysis as well as thermally assisted hydrolysis and methylation coupled with gas chromatography-mass spectrometry were used. Metal fractionation in unflushed and flushed soil was analyzed using a modified sequential extraction method. The data on cumulative metal removal were analyzed using OriginPro 8.0 software (OriginLab Corporation, Northampton, MA, USA) and were fitted to 4-parameter logistic sigmoidal model. It was found that flushing time had a stronger influence on metal removal than flow rate. The overall efficiency of metal removal (expressed as the ratio between flushed metal concentration and total metal concentration in soil) at the higher flow rate decreased in this order: Cd (86%) > Ni (44%) > Cu (29%) ≈ Zn (26%) > Pb (15%). Metals were removed from the exchangeable fraction and redistributed into the reducible fraction. After flushing, the soil had a lower pH, EC, and CEC; a higher organic matter content; the composition of the organic matter had changed (incorporation of TA structures). Our results prove that soil flushing with TA is a promising approach to decrease metal concentration in soil and to facilitate carbon sequestration in soil.

Section: Resultsmentioning

confidence: 99%

Short-Term Soil Flushing with Tannic Acid and Its Effect on Metal Mobilization and Selected Properties of Calcareous Soil

Kaal²,

Wasilewska

et al. 2021

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“…Commercial plant biosurfactants after soil washing could be recovered by separation of pollutants from the effluent prior to reutilization. The recovery and reuse of biosurfactants make soil washing more environmentally friendly and cost-effective [ 61 ]. Thus, in practice, the cost of using biosurfactants in soil remediation could be much lower than the relative cost indicated in the present study.…”

Section: Resultsmentioning

confidence: 99%

Remediation of Smelter Contaminated Soil by Sequential Washing Using Biosurfactants

Kumpienė

Carabante

et al. 2021

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This paper presents experimental results from the use of biosurfactants in the remediation of a soil from a smelter in Poland. In the soil, concentrations of Cu (1659.1 mg/kg) and Pb (290.8 mg/kg) exceeded the limit values. Triple batch washing was tested as a soil treatment. Three main variants were used, each starting with a different plant-derived (saponin, S; tannic acid, T) or microbial (rhamnolipids, R) biosurfactant solution in the first washing, followed by 9 different sequences using combinations of the tested biosurfactants (27 in total). The efficiency of the washing was determined based on the concentration of metal removed after each washing (CR), the cumulative removal efficiency (Ecumulative) and metal stability (calculated as the reduced partition index, Ir, based on the metal fractions from BCR sequential extraction). The type of biosurfactant sequence influenced the CR values. The variants that began with S and R had the highest average Ecumulative for Cu and Pb, respectively. The Ecumulative value correlated very strongly (r > 0.8) with the stability of the residual metals in the soil. The average Ecumulative and stability of Cu were the highest, 87.4% and 0.40, respectively, with the S-S-S, S-S-T, S-S-R and S-R-T sequences. Lead removal and stability were the highest, 64–73% and 0.36–0.41, respectively, with the R-R-R, R-R-S, R-S-R and R-S-S sequences. Although the loss of biosurfactants was below 10% after each washing, sequential washing with biosurfactants enriched the soil with external organic carbon by an average of 27-fold (S-first variant), 24-fold (R first) or 19-fold (T first). With regard to environmental limit values, metal stability and organic carbon resources, sequential washing with different biosurfactants is a beneficial strategy for the remediation of smelter-contaminated soil with given properties.

“…For treatment of SWSs, different physico-chemical methods can be used, including adsorption [ 81 , 82 , 83 , 84 ], precipitation [ 85 , 86 , 87 , 88 , 89 ], advanced oxidation processes [ 90 , 91 , 92 , 93 , 94 , 95 ], and membrane technology [ 96 , 97 , 98 ]. Although the latest soil remediation tests were focused on the suitability of novel WAs (DOM, HLS, and SHS from different organic wastes), data about their treatment after soil washing/soil flushing are missing.…”

Section: Treatment Of Swss After Soil Washing/soil Flushingmentioning

confidence: 99%

“…Gusiatin [ 84 ] demonstrated effective recovery of saponin from SWSs after washing of soils contaminated by As ore processing with clinoptilolite modified by FeCl 3 . Depending on the As content in treated soils (4294–7598 mg/kg), concentration of As removed with saponin varied between 9.5 and 54.6 mg/L.…”

Section: Treatment Of Swss After Soil Washing/soil Flushingmentioning

confidence: 99%

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

Kulikowska

Klik

2020

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.