scholarly journals Physical Separation of Contaminated Soil Using a Washing Ejector Based on Hydrodynamic Cavitation

2021 ◽  
Vol 14 (1) ◽  
pp. 252
Author(s):  
Kanghee Cho ◽  
Hyunsoo Kim ◽  
Oyunbileg Purev ◽  
Nagchoul Choi ◽  
Jaewon Lee
Keyword(s):  
Heavy Metals ◽  
Removal Efficiency ◽  
Contaminated Soil ◽  
Contaminated Soils ◽  
Fine Particles ◽  
Soil Aggregates ◽  
Hydrodynamic Cavitation ◽  
Toxic Heavy Metals ◽  
Treatment Technology ◽  
Physical Separation

A washing ejector is a pre-treatment technology used to remediate contaminated soil by separating fine particles. The washing ejector developed in this study is a device that utilizes fast liquid jets to disperse soil aggregates by cavitation flow. The cavitation phenomenon is affected by the Bernoulli principle, and the liquid pressure decreases with the increase in kinetic energy. The cavitating flow of the fluid through the Ventrui nozzle can remove surface functional groups and discrete particles. The main methodology involves the removal of small particles bound to coarse particles and the dispersion of soil aggregates. Particle collisions occur on the surface soil, such as the metal phase that is weakly bound to silicate minerals. It was observed that the dispersed soil affected the binding of toxic heavy metals and the mineralogical characteristics of the soil. The quantity of oxides, organic matter, and clay minerals affected the properties of the soil. An almost 40–60% removal efficiency of total metals (As, Zn, and Pb) was obtained from the contaminated soils. After treatment by a washing ejector, the volume of fine particles was reduced by 28–47%. When the contaminants are associated with particulates, separation using a washing ejector can be more effective. Therefore, physical separation improves the removal efficiency of heavy metals from soil aggregates.

scholarly journals Remediation of Toxic Heavy Metal Contaminated Soil by Combining a Washing Ejector Based on Hydrodynamic Cavitation and Soil Washing Process

2022 ◽  
Vol 19 (2) ◽  
pp. 786
Author(s):  
Hyunsoo Kim ◽  
Kanghee Cho ◽  
Oyunbileg Purev ◽  
Nagchoul Choi ◽  
Jaewon Lee
Keyword(s):  
Heavy Metals ◽  
Phosphoric Acid ◽  
Contaminated Soil ◽  
Fine Particles ◽  
Soil Washing ◽  
Hydrodynamic Cavitation ◽  
Metal Phase ◽  
Toxic Heavy Metals ◽  
Physical Separation ◽  
Washing Process

Based on the features of hydrodynamic cavitation, in this study, we developed a washing ejector that utilizes a high-pressure water jet. The cavitating flow was utilized to remove fine particles from contaminated soil. The volume of the contaminants and total metal concentration could be correlated to the fine-particle distribution in the contaminated soil. These particles can combine with a variety of pollutants. In this study, physical separation and soil washing as a two-step soil remediation strategy were performed to remediate contaminated soils from the smelter. A washing ejector was employed for physical separation, whereas phosphoric acid was used as the washing agent. The particles containing toxic heavy metals were composed of metal phase encapsulated in phyllosilicates, and metal phase weakly bound to phyllosilicate surfaces. The washing ejector involves the removal of fine particles bound to coarse particles and the dispersion of soil aggregates. From these results we determined that physical separation using a washing ejector was effective for the treatment of contaminated soil. Phosphoric acid (H3PO4) was effective in extracting arsenic from contaminated soil in which arsenic was associated with amorphous iron oxides. Thus, the obtained results can provide useful information and technical support for field soil washing for the remediation of soil contaminated by toxic heavy metals through emissions from the mining and ore processing industries.

scholarly journals Fractionation of Heavy Metals in Multi-Contaminated Soil Treated with Biochar Using the Sequential Extraction Procedure

Biomolecules ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 448
Author(s):  
Mahrous Awad ◽  
Zhongzhen Liu ◽  
Milan Skalicky ◽  
Eldessoky S. Dessoky ◽  
Marian Brestic ◽  
...  
Keyword(s):  
Heavy Metals ◽  
Organic Matter ◽  
Soil Organic Matter ◽  
Soil Ph ◽  
Contaminated Soil ◽  
Contaminated Soils ◽  
Extraction Procedure ◽  
Sequential Fractionation ◽  
Relationship Of ◽  
The Relationship

Heavy metals (HMs) toxicity represents a global problem depending on the soil environment’s geochemical forms. Biochar addition safely reduces HMs mobile forms, thus, reducing their toxicity to plants. While several studies have shown that biochar could significantly stabilize HMs in contaminated soils, the study of the relationship of soil properties to potential mechanisms still needs further clarification; hence the importance of assessing a naturally contaminated soil amended, in this case with Paulownia biochar (PB) and Bamboo biochar (BB) to fractionate Pb, Cd, Zn, and Cu using short sequential fractionation plans. The relationship of soil pH and organic matter and its effect on the redistribution of these metals were estimated. The results indicated that the acid-soluble metals decreased while the fraction bound to organic matter increased compared to untreated pots. The increase in the organic matter metal-bound was mostly at the expense of the decrease in the acid extractable and Fe/Mn bound ones. The highest application of PB increased the organically bound fraction of Pb, Cd, Zn, and Cu (62, 61, 34, and 61%, respectively), while the BB increased them (61, 49, 42, and 22%, respectively) over the control. Meanwhile, Fe/Mn oxides bound represents the large portion associated with zinc and copper. Concerning soil organic matter (SOM) and soil pH, as potential tools to reduce the risk of the target metals, a significant positive correlation was observed with acid-soluble extractable metal, while a negative correlation was obtained with organic matter-bound metal. The principal component analysis (PCA) shows that the total variance represents 89.7% for the TCPL-extractable and HMs forms and their relation to pH and SOM, which confirms the positive effect of the pH and SOM under PB and BB treatments on reducing the risk of the studied metals. The mobility and bioavailability of these metals and their geochemical forms widely varied according to pH, soil organic matter, biochar types, and application rates. As an environmentally friendly and economical material, biochar emphasizes its importance as a tool that makes the soil more suitable for safe cultivation in the short term and its long-term sustainability. This study proves that it reduces the mobility of HMs, their environmental risks and contributes to food safety. It also confirms that performing more controlled experiments, such as a pot, is a disciplined and effective way to assess the suitability of different types of biochar as soil modifications to restore HMs contaminated soil via controlling the mobilization of these minerals.

scholarly journals Heavy metal composition of maize and tomato grown on contaminated soils

2018 ◽  
Vol 3 (1) ◽  
pp. 414-426
Author(s):  
A.O. Adekiya ◽  
A.P. Oloruntoba ◽  
S.O. Ojeniyi ◽  
B.S. Ewulo
Keyword(s):  
Heavy Metals ◽  
Heavy Metal ◽  
Contaminated Soils ◽  
Heavy Metal Contamination ◽  
Mining Area ◽  
Atomic Absorption Spectrophotometry ◽  
Toxic Heavy Metals ◽  
Mining Site ◽  
Solanum Lycopersicum L ◽  
Sources Of Pollution

Abstract The study investigated the level of heavy metal contamination in plants {maize (Zea mays) and tomato (Solanum lycopersicum L.)} from thirty soil samples of three locations (Epe, Igun and Ijana) in the Ilesha gold mining area, Osun State, Nigeria. Total concentrations of As, Cd, Co, Cr, Cu, Ni, Pb and Zn were determined using atomic absorption spectrophotometry. Spatial variations were observed for all metals across the locations which was adduced to pH and the clay contents of the soils of each location. The results showed that heavy metals are more concentrated in the areas that are closer to the mining site and the concentrations in soil and plants (maize and tomato) decreased with increasing perpendicular distance from the mining site, indicating that the gold mine was the main sources of pollution. The mean concentrations of heavy metals in plants (tomato and maize) samples were considered to be contaminated as As, Cd and Pb respectively ranged from 0.6 - 2.04 mg kg-1, 0.8 - 5.2 mg kg-1, 0.8 - 3.04 mg kg-1 for tomato and respectively 0.60 - 2.00 mg kg-1, 1.50 - 4.60 mg kg-1 and 0.90 - 2.50 mg kg-1 for maize. These levels exceeded the maximum permissible limits set by FAO/WHO for vegetables. In conclusion, monitoring of crops for toxic heavy metals is essential for food safety in Nigeria.

scholarly journals Researches on the accumulation and transfer of heavy metals in the soil in tomatoes -Solanum lycopersicum

2019 ◽  
Vol 112 ◽  
pp. 03020
Author(s):  
Mihaela Niţu ◽  
Augustina Pruteanu ◽  
Despina Maria Bordean ◽  
Carmen Popescu ◽  
Gyorghy Deak ◽  
...  
Keyword(s):  
Heavy Metals ◽  
Transfer Coefficient ◽  
Human Body ◽  
Contaminated Soil ◽  
Contaminated Soils ◽  
Tomato Fruit ◽  
Human Consumption ◽  
Tomato Fruits ◽  
Lead And Zinc ◽  
Copper Lead

Heavy metals in contaminated soils have benefited from a considerable attention due to the possible risks for the human body. The current study has investigated the accumulation and transfer coefficient for three heavy metals (Cu, Pb, Zn) found in the contaminated soil with three concentrations (c1=1.5%, c2=3.0%, c3=4.5%, c4=6.0%), obtained by mixing the three metals, in the tomato fruit. The highest accumulation in the tomato fruits was recorded for zinc, then copper and the smallest for lead, for all four concentrations used. The transfer coefficient decreases as the concentration of heavy metals increases, so that for high heavy metals concentrations, the values of the transfer coefficient are very low, and for small heavy metals concentrations in the soil, the values for the transfer coefficient are higher. The assessment of accumulation and transfer of heavy metals in the fruits of tomatoes grown in the contaminated soil has concluded that all concentrations of the copper, lead and zinc mix have shown a low risk for human consumption.

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

2020 ◽  
Vol 17 (9) ◽  
pp. 3133 ◽  
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.

Batch and column tests for the development of an immobilization technology for toxic heavy metals in contaminated soils of closed mines

1998 ◽  
Vol 37 (8) ◽  
pp. 81-88 ◽  
Author(s):  
A. Jang ◽  
Y. S. Choi ◽  
In S. Kim
Keyword(s):  
Heavy Metals ◽  
Heavy Metal ◽  
Contaminated Soils ◽  
Mine Drainage ◽  
Fine Sand ◽  
Design Parameters ◽  
Batch Adsorption ◽  
Toxic Heavy Metals ◽  
Chemical Additives ◽  
Column Tests

Laboratory tests of various chemical treatments for the immobilization of copper, nickel, and lead in soils typically found at mine facilities were evaluated. A series of batch, adsorption tests, and lab-scale continuous column tests were conducted to optimize the design parameters for the full-scale immobilization processes. The laboratory test program consisted of batch and column experiments to measure the leachability and subsequent immobilization of the single heavy metal, Cu2+, Pb2+, and Ni2+ in an artificial soil which was composed of bentonite and quartz fine sand. Batch equilibrium methods were used to test the ability of a large number of chemical additives to react with heavy metals in contaminated soil. The two best treatment chemicals (CaO and Na2S) for each soil-metal combination were selected for more detailed columns studies. The column tests were carried out in the acidic pH range. According to the results of the column leaching test, it was found that the degree of heavy metal leaching is highly dependent on pH. An adsorption test was performed under acidic conditions (pH 4) to evaluate bentonite as an additive to treat acid mine drainage (AMD).

scholarly journals Evaluation of Acid Leaching on the Removal of Heavy Metals and Soil Fertility in Contaminated Soil

2018 ◽  
Vol 2018 ◽  
pp. 1-8 ◽  
Author(s):  
Chen-Yao Chu ◽  
Tzu-Hsing Ko
Keyword(s):  
Heavy Metals ◽  
Heavy Metal ◽  
Seed Germination ◽  
Soil Fertility ◽  
Sequential Extraction ◽  
Contaminated Soil ◽  
Contaminated Soils ◽  
Germination Rate ◽  
Extraction Procedure ◽  
Acid Leaching

Heavy metal-contaminated soils were leached with various acid reagents, and a series of treatments was assessed to understand soil fertility after acid leaching. Aqua regia digestion and a five-step sequential extraction procedure were applied to determine heavy metal distribution. The average total concentrations of Zn, Cd, Cu, and Pb for contaminated soil were 1334, 25, 263, and 525 mg·kg−1 based on the ICP/AES quantitative analysis. Other than Pb extracted by H2SO4, over 50% removal efficiency of other heavy metals was achieved. A five-step sequential extraction revealed that the bound-to-carbonate and bound-to-Fe-Mn oxides were the major forms of the heavy metals in the soil. The addition of organic manure considerably promoted soil fertility and increased soil pH after acid leaching. Seed germination experiments demonstrated that after acid leaching, the soil distinctly inhibited plant growth and the addition of manure enhanced seed germination rate from 35% to 84%. Furthermore, the procedure of soil turnover after acid leaching and manure addition greatly increased seed germination rate by 61% and shortened the initial germination time. Seed germination in untreated soil was superior to that in acid-leached soil, illustrating that the phytotoxic effect of acid leaching is more serious than that of heavy metals.

scholarly journals Modern environmental technologies of healthy soils contaminated by heavy metals and radionuclides

2020 ◽  
Vol 166 ◽  
pp. 01007
Author(s):  
Vasyl Savosko ◽  
Aleksandr Podolyak ◽  
Irina Komarova ◽  
Aleksey Karpenko
Keyword(s):  
Heavy Metals ◽  
Contaminated Soil ◽  
Contaminated Soils ◽  
Chemical Elements ◽  
Soil Layer ◽  
Ex Situ ◽  
Soil Restoration ◽  
Mission Strategy ◽  
Environmental Technologies

Object of research: to systematize (taking into account the possible consequences to biosphere) the known technologies for ecological restoration of soils contaminated by heavy metals and radionuclides. Only a healing technology should be recognized as one possible methodology for solving any soil problems. For soils contaminated by heavy metals and radionuclides healing patterns is conceptually ordered into the following levels: mission, strategy, technology. The mission of healthy soil should be aimed at maintaining the chemical elements content within the optimum interval. The strategy of healthy soil involves the regulation of individual elements content in the soil. Ex-situ a soil healing technology is implemented outside the original pollution site. In-situ, a soil healing technology is carried out directly on the original pollution site. Excavation of the contaminated soil layer is the first stage for ex-situ soil restoration. In the future it will be possible: 1) storage of contaminated soil at special landfills, 2) treatment of contaminated soil at a special reactor. All technologies for in-situ healthy of heavy metals contaminated soils can be ordered as: 1) localization, 2) deconcentration, 3) inactivation, 4) extraction.

scholarly journals Identification of Microbial Profiles in Heavy-Metal-Contaminated Soil from Full-Length 16S rRNA Reads Sequenced by a PacBio System

2019 ◽  
Vol 7 (9) ◽  
pp. 357 ◽  
Author(s):  
Moonsuk Hur ◽  
Soo-Je Park
Keyword(s):  
Heavy Metals ◽  
Heavy Metal ◽  
Community Structure ◽  
16S Rrna ◽  
Microbial Communities ◽  
Contaminated Soil ◽  
Contaminated Soils ◽  
Full Length ◽  
Rrna Gene ◽  
Microbial Composition

Heavy metal pollution is a serious environmental problem as it adversely affects crop production and human activity. In addition, the microbial community structure and composition are altered in heavy-metal-contaminated soils. In this study, using full-length 16S rRNA gene sequences obtained by a PacBio RS II system, we determined the microbial diversity and community structure in heavy-metal-contaminated soil. Furthermore, we investigated the microbial distribution, inferred their putative functional traits, and analyzed the environmental effects on the microbial compositions. The soil samples selected in this study were heavily and continuously contaminated with various heavy metals due to closed mines. We found that certain microorganisms (e.g., sulfur or iron oxidizers) play an important role in the biogeochemical cycle. Using phylogenetic investigation of communities by reconstruction of unobserved states (PICRUSt) analysis, we predicted Kyoto Encyclopedia of Genes and Genomes (KEGG) functional categories from abundances of microbial communities and revealed a high proportion belonging to transport, energy metabolism, and xenobiotic degradation in the studied sites. In addition, through full-length analysis, Conexibacter-like sequences, commonly identified by environmental metagenomics among the rare biosphere, were detected. In addition to microbial composition, we confirmed that environmental factors, including heavy metals, affect the microbial communities. Unexpectedly, among these environmental parameters, electrical conductivity (EC) might have more importance than other factors in a community description analysis.

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