Enhanced Electrokinetic Remediation for the Removal of Heavy Metals from Contaminated Soils

The electrokinetic remediation of an agricultural soil contaminated with heavy metals was studied using organic acids as facilitating agents. The unenhanced electrokinetic treatment using deionized water as processing fluid did not show any significant mobilization and removal of heavy metals due to the low solubilization of metals and precipitation at high pH conditions close to the cathode. EDTA and citric acid 0.1 M were used as facilitating agents to favor the dissolution and transportation of metals. The organic acids were added to the catholyte and penetrated into the soil specimen by electromigration. EDTA formed negatively charged complexes. Citric acid formed neutral metal complexes in the soil pH conditions (pH = 2–4). Citric acid was much more effective in the dissolution and transportation out of the soil specimen of complexed metals. In order to enhance the removal of metals, the concentration of citric acid was increased up to 0.5 M, resulting in the removal of 78.7% of Cd, 78.6% of Co, 72.5% of Cu, 73.3% of Zn, 11.8% of Cr and 9.8% of Pb.

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Removal of heavy metals from sewage sludge by extraction with organic acids

Water Science & Technology ◽

10.2166/wst.1999.0029 ◽

1999 ◽

Vol 40 (1) ◽

pp. 129-136 ◽

Cited By ~ 52

Author(s):

A. H. M. Veeken ◽

H. V. M. Hamelers

Keyword(s):

Heavy Metals ◽

Citric Acid ◽

Organic Acids ◽

Waste Water Treatment ◽

Economic Valuation ◽

Complexing Agents ◽

Citric Acid Concentration ◽

Sludge Compost ◽

Removal Of Heavy Metals ◽

Increasing Temperature

Waste water treatment in activated sludge plants results in the production of large amounts of surplus sludge. After composting the sludge can be reused as fertiliser and soil conditioner in agriculture. Compared to landfilling and incineration, utilisation of sludge-compost is a more sustainable treatment because it recycles both nutrients and organic matter. However the high levels of heavy metals in sludge frequently prevent the reuse of sludge compost in agriculture. The extraction of heavy metals from the sludge before composting is therefore a necessary step to achieve a more sustainable sludge treatment. Extraction of heavy metals by inorganic acids and complexing agents has severe drawbacks. Organic acids could be an attractive extracting agent because the extraction can be performed at mildly acidic conditions (pH 3-5) and they are biologically degradable. The extraction was studied for heavy metals Cu and Zn and for competing metals Ca and Fe. The rate of extraction increases for increasing temperature and citric acid concentration. Cu can be extracted for 60-70% and Zn for 90-100% by citric acid at pH 3-4. A first economic valuation of the extraction and subsequent composting process showed that the total costs of the treatment process are below the costs of incineration.

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Synergistic Effect of Rhamnolipid and Saponin Biosurfactants on Removal of Heavy Metals from Oil Contaminated Soils

Tenside Surfactants Detergents ◽

10.3139/113.110672 ◽

2020 ◽

Vol 57 (2) ◽

pp. 109-114

Author(s):

Amirhossein Dolatzadeh khiyavi ◽

Reza Hajimohammadi ◽

Hossein Amani ◽

Hadi Soltani

Keyword(s):

Heavy Metals ◽

Synergistic Effect ◽

Contaminated Soils ◽

Removal Of Heavy Metals

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Feasibility of a counter-current extraction procedure for the removal of heavy metals from contaminated soils

Water Air & Soil Pollution ◽

10.1007/bf00171639 ◽

1996 ◽

Vol 89 (3-4) ◽

pp. 317-335 ◽

Cited By ~ 6

Author(s):

P. H. Masscheleyn ◽

F. M. Tack ◽

M. G. Verloo

Keyword(s):

Heavy Metals ◽

Contaminated Soils ◽

Extraction Procedure ◽

Removal Of Heavy Metals ◽

Counter Current

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Selection and test of effective chelators for removal of heavy metals from contaminated soils

International Journal of Rock Mechanics and Mining Sciences & Geomechanics Abstracts ◽

10.1016/s0148-9062(97)87333-0 ◽

1996 ◽

Vol 33 (8) ◽

pp. A347

Keyword(s):

Heavy Metals ◽

Contaminated Soils ◽

Removal Of Heavy Metals

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Effect of Soil Washing Solutions on Simultaneous Removal of Heavy Metals and Arsenic from Contaminated Soil

International Journal of Environmental Research and Public Health ◽

10.3390/ijerph17093133 ◽

2020 ◽

Vol 17 (9) ◽

pp. 3133 ◽

Cited By ~ 1

Author(s):

Kanghee Cho ◽

Eunji Myung ◽

Hyunsoo Kim ◽

Cheonyoung Park ◽

Nagchoul Choi ◽

...

Keyword(s):

Heavy Metals ◽

Sulfuric Acid ◽

Phosphoric Acid ◽

Contaminated Soil ◽

Contaminated Soils ◽

Soil Washing ◽

Metal Extraction ◽

Simultaneous Removal ◽

Removal Of Heavy Metals ◽

Removal Efficiencies

In this study, we investigated the feasibility of using a solution of sulfuric acid and phosphoric acid as an extraction method for soil-washing to remove Cu, Pb, Zn, and As from contaminated soil. We treated various soil particles, including seven fraction sizes, using sulfuric acid. In addition, to improve Cu, Pb, Zn, and As removal efficiencies, washing agents were compared through batch experiments. The results showed that each agent behaved differently when reacting with heavy metals (Cu, Pb, and Zn) and As. Sulfuric acid was more effective in extracting heavy metals than in extracting As. However, phosphoric acid was not effective in extracting heavy metals. Compared with each inorganic acid, As removal from soil by washing agents increased in the order of sulfuric acid (35.81%) < phosphoric acid (62.96%). Therefore, an enhanced mixture solution using sulfuric acid and phosphoric acid to simultaneously remove heavy metals and As from contaminated soils was investigated. Sulfuric acid at 0.6 M was adopted to combine with 0.6 M phosphoric acid to obtain the mixture solution (1:1) that was used to determine the effect for the simultaneous removal of both heavy metals and As from the contaminated soil. The removal efficiencies of As, Cu, Pb, and Zn were 70.5%, 79.6%, 80.1%, and 71.2%, respectively. The combination of sulfuric acid with phosphoric acid increased the overall As and heavy metal extraction efficiencies from the contaminated soil samples. With the combined effect of dissolving oxides and ion exchange under combined washings, the removal efficiencies of heavy metals and As were higher than those of single washings.

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Use of citric acid for heavy metals extraction from contaminated sewage sludge for land application

Water Science & Technology ◽

10.2166/wst.2006.764 ◽

2006 ◽

Vol 54 (9) ◽

pp. 129-135 ◽

Cited By ~ 19

Author(s):

D. del Mundo Dacera ◽

S. Babel

Keyword(s):

Heavy Metals ◽

Citric Acid ◽

Land Application ◽

Metal Extraction ◽

Lead Removal ◽

Inorganic Matter ◽

Highly Effective ◽

Removal Of Heavy Metals ◽

Anaerobically Digested Sludge ◽

Extracting Agents

Recent studies revealed that organic acids such as citric and oxalic acids seemed to be more promising as chemical extracting agents for removal of heavy metals from contaminated sludge, since they are biodegradable and can attain a higher metal extraction efficiency at mildly acidic pH compared to other extracting agents. Results of a lab-scale study on the efficiency of citric acid in the extraction of chromium (Cr), copper (Cu), lead (Pb), nickel (Ni) and zinc (Zn) from anaerobically digested sludge, revealed that citric acid seemed to be highly effective in extracting Cr (at 100%), Cu (at 88%), Ni (at 98%) and Zn (at 100%) at pH 2.33, mostly at 5 days leaching time except for Cu and Zn, which are at 1 day and 2 h contact times respectively. Lead removal at the same pH was also high at 95% but at a longer leaching time of 11 days. At pH 3, citric acid seemed to be highly effective in extracting Pb (at 100%) at 1 day leaching time, although higher removals were also attained for Ni (70%) and Zn (80%) at only 2 h leaching time. Chemical speciation studies showed that Cr, Cu and Ni in the sludge sample seem to predominate in residual fractions, while Pb and Zn were found mostly bound to organic and inorganic matter forms, hence the potential of the sludge for land application.

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Organic acids effects on desorption of heavy metals from a contaminated soil

Scientia Agricola ◽

10.1590/s0103-90162006000300010 ◽

2006 ◽

Vol 63 (3) ◽

pp. 276-280 ◽

Cited By ~ 36

Author(s):

Clístenes Williams Araújo do Nascimento

Keyword(s):

Heavy Metals ◽

Molecular Weight ◽

Citric Acid ◽

Organic Acids ◽

Low Molecular Weight ◽

High Biomass ◽

High Concentration ◽

Accumulation Of Metals ◽

Pb Concentration ◽

Oxalic Acids

Phytoremediation of heavy metals is a biotechnology that extracts metals from soils and transfer them to plant. As hyperaccumulator species have demonstrated low potential for commercial phytoextraction, synthetic chelates have been successfully used to induce accumulation of metals by high-biomass plants. However, they pose serious environmental drawbacks regarding excessive amount of metals solubilized. In search for synthetic chelate-alternatives, this paper evaluate the performance of DTPA, EDTA, citric acid, oxalic acid, vanillic acid, and gallic acid in desorbing Cd, Pb, Zn, Cu, and Ni from soil. DTPA and EDTA were highly effective in desorbing Cd, Pb, Zn, Cu, and Ni from soil. However, the excessively high concentration of metals brought in solution by such chelates limits their application in the field. Citric and oxalic acids desorbed substantial quantities of Zn, Cu, and Ni if applied at 10 or 20 mmol kg-1. At the 20 mmol kg-1 dose, vanillic and gallic acids solubilized significant amounts of Zn, Ni, and Cd from soil. None of the tested low molecular weight organic acids substantially increased the Pb concentration in soil solution.

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Removal of heavy metals from green mussels (Perna viridis) using pineapple (Ananas comosus) solution as a source of citric acid

IOP Conference Series Earth and Environmental Science ◽

10.1088/1755-1315/919/1/012041 ◽

2021 ◽

Vol 919 (1) ◽

pp. 012041

Author(s):

F Swastawati ◽

S R Rizkirana ◽

Romadhon ◽

M Muniroh ◽

Mulyono ◽

...

Keyword(s):

Heavy Metals ◽

Citric Acid ◽

Metal Content ◽

Ananas Comosus ◽

Perna Viridis ◽

Green Mussel ◽

Icp Ms ◽

Removal Of Heavy Metals ◽

Excessive Consumption ◽

Ph Level

Abstract Green mussel is a type of shellfish that is widely consumed by humans. Excessive consumption of green mussels can be harmful to health because they are prone to contain heavy metals. One of the methods to reduce the heavy metal content of green mussels is to use citric acid in the pineapple solution. The Green mussel was soaked in pineapple solution for 30 min, 60 min and 90 min. The content of heavy metals such as Pb, Cd, and As was analyzed by ICP-MS. The results showed that after soaking green mussels in pineapple solution for 30 minutes, they reduced 85% Pb, 80,95% Cd, and 53,23% As. The duration of soaking green mussels in pineapple solution for 30 minutes overall had a better quality than soaking for 60 and 90 minutes, with a moisture content of 74,43 + 0,39 (%), protein content 15,21 + 0,35 (%), pH level 6,74 + 0,10, organoleptic with a confidence interval of 7,48<μ< 7,54.

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