Assessment of soil washing for simultaneous removal of heavy metals and low-level petroleum hydrocarbons using various washing solutions

Abstract

Bench-scale soil washing experiments were conducted to remove both heavy metals (Pb, Cu, Zn) and petroleum from contaminated soils. Diverse washing solutions including hydrochloric acid (HCl), nitric acid (HNO3), sulfuric acid (H2SO4), tartaric acid (C4H6O6) and ethylenediaminetetraacetic acid (C10H16N2O8, EDTA) were used. The concentration of the washing solutions used in this study ranged from 0.1 M to 3 M with a liquid to solid ratio of 10. The soil washing results showed that hydrochloric acid (HCl) was the best washing solution at 3M for heavy metals removal. Other washing solutions also showed a significant removal of heavy metals, except for sulfuric acid (H2SO4). Sulfuric acid (H2SO4) had the worst performance of all the washing solutions with respect to removing Pb. 1M HCl and HNO3 were sufficient for effective Pb and Cu removal and all of the tested washing solutions at a concentration of 0.1 M were able to pass the Korean warning standard for Zn removal. In the case of TPH removal, tartaric acid (C4H6O6) was the best washing solution for the removal of TPH from contaminated soil. Overall, tartaric acid (C4H6O6) could be a viable washing solution for the removal of both heavy metals (Pb, Cu, Zn) and TPH from contaminated soils.

Oyster Shell as a Low-Cost Adsorbent for Removing Heavy Metal Ions from Wastewater

“…Copper, cadmium, and lead solutions were prepared by dissolving Cu(NO 3 grade heavy metal nitrates were produced by the Junsei Chemical Company (Japan). A batch adsorption experiment was undertaken to investigate effects of temperature, contact time, pH value, and initial concentration on adsorption of heavy metal ions from an aqueous solution by OSP.…”

Washing and Extraction of Metals from Contaminated Soil Constituents: Implications for Contaminated Simulated Soil and Metallurgical Wastes with Different Reagents

“…To determine the equation(s) that best described the leaching process, a standard error of estimate (SE) was calculated for each equation to determine their spread or variability with experimental data. A relatively high value of the correlation coefficient (R 2 ) and low SE were used as criteria for the best fit [50]. The experimental profile data was fitted to the various kinetic equations discussed above to obtain the respective rate constants a, b, k 1 , and 1/β.…”

Enhancement of tartaric acid modified washing solutions for lead decontamination of tropical soils

“…Toxic trace metals undoubtedly have continued to raise attention due to greater understanding of their toxicological importance in the environment [1][2][3]. Particularly, soil-Pb content has dramatically increased in recent decades and often anthropogenically derived and non-biodegradable [4][5][6][7].…”

“…Greater emphases have now been placed on the use of low molecular weight organic acids (LMWOAs) which are more biodegradable and have less secondary ecological risk, because they can be produced by plant roots or microorganisms [20,21]. Some LMWOAs such as acetic, citric, oxalic and tartaric acids have recently been used for soil washing [3,13,[22][23][24]. However, their removal efficiency is not as effective as inorganic acids or chelating agent.…”