scholarly journals Mechanical Properties and Leaching Characteristics of Geopolymer-Solidified/Stabilized Lead-Contaminated Soil

2019 ◽  
Vol 2019 ◽  
pp. 1-8 ◽  
Author(s):  
Yuan-Yuan Li ◽  
Ting-Ting Zhang ◽  
Shi-Bo Jia ◽  
Jiang Liu ◽  
Xian-Hao Quan ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Contaminated Soil ◽  
Contaminated Soils ◽  
Extraction Procedure ◽  
Fine Aggregate ◽  
Limited Information ◽  
Granulated Blast Furnace Slag ◽  
Leaching Characteristics ◽  
Stabilized Soil ◽  
Synthetic Precipitation

Ordinary Portland cement (OPC) is widely used in the solidification/stabilization of Pb-contaminated soils. However, many studies have suggested that the high content of Pb would degrade the mechanical properties of OPC-solidified/stabilized soils. This paper presents a new binder, geopolymer fine aggregate (GFA), composed of ground granulated blast furnace slag, fly ash, CaO, and Na2SiO3. For comparison, OPC was used as a conventional binder. Mechanical properties and leaching characteristics are typically used to evaluate the effects of binders on solidified/stabilized soils. Nevertheless, limited information on the mechanical properties and leaching characteristics of the GFA-solidified/stabilized soils is available. This study thus investigated the mechanical properties and leaching characteristics of geopolymer-solidified/stabilized Pb-contaminated soil. Unconfined compressive strength test, permeability test, synthetic precipitation leaching procedure, simplified bioaccessibility extraction, phytoavailability extraction (with diethylene-triamine penta-acetic acid), sequential extraction procedure, mercury intrusion porosimetry, and scanning electron microscopy (SEM) were performed on OPC- and GFA-solidified/stabilized soil. The results showed that the GFA presented a better effect on the mechanical properties and leachability of the solidified/stabilized soils than the OPC-solidified/stabilized soils. The GFA-solidified/stabilized soil displayed considerably lower leachability, bioaccessibility, and phytoavailability of Pb and higher mechanical properties and chemical stability than the OPC counterpart. This study demonstrated that GFA had a better effect than OPC on the solidification/stabilization of Pb-contaminated soils.

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 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 Environmental Impacts and Immobilization Mechanisms of Cadmium, Lead and Zinc in Geotechnical Composites Made from Contaminated Soil and Paper-Ash

2021 ◽  
Vol 11 (24) ◽  
pp. 11822
Author(s):  
Marija Đurić ◽  
Primož Oprčkal ◽  
Vesna Zalar Serjun ◽  
Alenka Mauko Pranjić ◽  
Janez Ščančar ◽  
...  
Keyword(s):  
Contaminated Soil ◽  
Contaminated Soils ◽  
Methodological Approach ◽  
Extraction Procedure ◽  
Water Soluble ◽  
Mineral Phases ◽  
Lead And Zinc ◽  
Remediation Efficiency ◽  
Cadmium Lead ◽  
One Year

Paper-ash is used for remediation of heavily contaminated soils with metals, but remediation efficiency after longer periods has not been reported. To gain insights into the mechanisms of immobilization of cadmium (Cd), lead (Pb), and znic (Zn), a study was performed in the laboratory experiment in uncontaminated, artificially contaminated, and remediated soils, and these soils treated with sulfate, to mimic conditions in contaminated soil from zinc smelter site. Remediation was performed by mixing contaminated soil with paper-ash to immobilize Cd, Pb, and Zn in the geotechnical composite. Partitioning of Cd, Pb, and Zn was studied over one year in seven-time intervals applying the sequential extraction procedure and complementary X-ray diffraction analyses. This methodological approach enabled us to follow the redistribution of Cd, Pb, and Zn over time, thus, to studying immobilization mechanisms and assessing the remediation efficiency and stability of newly formed mineral phases. Cd, Pb, and Zn were effectively immobilized by precipitation of insoluble hydroxides after the addition of paper-ash and by the carbonization process in insoluble carbonate minerals. After remediation, Cd, Pb, and Zn concentrations in the water-soluble fraction were well below the limiting values for inertness: Cd by 100 times, Pb by 125 times, and Zn by 10 times. Sulfate treatment did not influence the remediation efficiency. Experimental data confirmed the high remediation efficiency and stability of insoluble Cd, Pb, and Zn mineral phases in geotechnical composites.

scholarly journals Evaluation of Zero-Valent Iron for Pb(II) Contaminated Soil Remediation: From the Analysis of Experimental Mechanism Hybird with Carbon Emission Assessment

2021 ◽  
Vol 13 (2) ◽  
pp. 452
Author(s):  
Junfang Sun ◽  
Angran Tian ◽  
Zheyuan Feng ◽  
Yu Zhang ◽  
Feiyang Jiang ◽  
...  
Keyword(s):  
Soil Remediation ◽  
Contaminated Soil ◽  
Contaminated Soils ◽  
Carbon Emission ◽  
Physical Adsorption ◽  
Extraction Procedure ◽  
Economic Benefits ◽  
Zero Valent Iron ◽  
Order Kinetic ◽  
Low Carbon

Carbon emission is one of the main causes of global climate change, thus it is necessary to choose a low-carbon method in the contaminated soil remediation. This paper studies the adsorption ability of ZVI on Pb(II) contaminated soils under different working conditions. The removal efficiency of Pb(II) was 98% because of the suitable ZVI dosage, log reaction time and low initial solution concentration. The whole balancing process was much fast according to the pseudo-second-order kinetic and Freundlich isothermal model. Moreover, sequential extraction procedure (SEP) showed Pb(II) was transformed from Fe/Mn oxides-bound form to residual form in Pb(II) contaminated soils. From scanning electron microscopy (SEM), Brunauer-Emmett-Teller method (BET) and X-ray diffraction (XRD) results, it was confirmed that zero-valent iron (ZVI) stabilizes Pb(II) pollutants mostly through the combination of chemical adsorption and physical adsorption. The economic and carbon emission assessments were used to compare the cost and carbon emissions of different methods. The results show that ZVI adsorption has excellent economic benefits and low carbon emission.

scholarly journals Influence of GGBS and Marble Dust on Mechanical Properties of Concrete

2020 ◽  
Vol 9 (7) ◽  
pp. 1037-1039
Keyword(s):  
Mechanical Properties ◽  
Research Work ◽  
Literature Survey ◽  
High Tech ◽  
Fine Aggregate ◽  
Split Tensile Strength ◽  
Conventional Concrete ◽  
Granulated Blast Furnace Slag ◽  
Marble Dust ◽  
Furnace Slag

Concrete is a extensively used material in construction. Due to high tech upgrading, the concrete have been matured to augment the equity of concrete. Now a day’s various studies have been conducted to make concrete with waste materials with the intension of reducing cost and demand of materials. This paper investigates the mechanical goods of concrete using Ground Granulated Blast furnace Slag (GGBS) and Marble Dust (MD) as a limited replacement of cement and fine aggregate respectively. Based on previous literature survey, 40% of GGBS and 10, 20 and 30% of MD are taken for the present study. The present research work is aimed at studying the mechanical properties of M20 grade concrete using GGBS and MD. Compressive strength and Split tensile strength were carried out for 7, 28 and 56 days and insignificant increases in the strength were observed for concrete specimens admixed with GGBS and MD when compared with conventional concrete

Sequential extraction procedure for fractionation of Pb and Cr in artificial and contaminated soil

2016 ◽  
Vol 39 (1-2) ◽  
Author(s):  
Sadia Qayyum ◽  
Ibrar Khan ◽  
Yangguo Zhao ◽  
Farhana Maqbool ◽  
Changsheng Peng
Keyword(s):  
Contaminated Soil ◽  
Contaminated Soils ◽  
Extraction Procedure ◽  
Chemical Properties ◽  
Absorption Spectrometry ◽  
Water Soluble ◽  
Residual Fraction ◽  
Exchangeable Fraction ◽  
Fraction Bound

AbstractMetal contamination of soil is due to mining, manufacturing and use of synthetic products (e.g. pesticides, paints, batteries, industrial waste and industrial or domestic sludge) which is a serious environmental problem. Hence, determining chemical forms of metals in soils is important to evaluate their mobility or bioavailability. Both artificial and contaminated soils were sequentially extracted to fractionate metals into the water soluble fraction (WSF), exchangeable fraction (EF), bound to carbonate fraction, bound to metal oxide fraction, organically bound fraction (OBF) and residual fraction (RF). In the case of contaminated soil, Pb and Cr are found to be associated with the carbonate fraction while in artificial soil, Pb bound to WSF and Cr with the Fe/Mn fraction. Chemical properties such as pH, electrical conductivity (EC) and textural classification of concerned soils were also analyzed. Percentage recovery was calculated to check the reliability of processes both in Pb and Cr, and it was found to be more in Cr (66% and 84%) in both artificial and contaminated soil than Pb (5% and 34%) in both soils. Analyses of extracts were carried out by atomic absorption spectrometry (AAS). Results were interpreted in terms of environmental mobility or bioavailability of metals.

scholarly journals Characteristics and Applications of Sewage Sludge Biochar Modified by Ferrous Sulfate for Remediating Cr(VI)-Contaminated Soils

2020 ◽  
Vol 2020 ◽  
pp. 1-10
Author(s):  
Yuan-Yuan Li ◽  
Ting-Ting Zhang ◽  
Zhi Ning ◽  
Jin-Hong Chen ◽  
Kirk Hatfield
Keyword(s):  
Sewage Sludge ◽  
Sequential Extraction ◽  
Environmental Quality ◽  
Contaminated Soil ◽  
Contaminated Soils ◽  
Extraction Procedure ◽  
Quality Standards ◽  
British Geological Survey ◽  
Environmental Quality Standards ◽  
Us Epa

Background. Soil contamination by hexavalent chromium is becoming a main environmental concern in China. This study developed a sewage sludge biochar modified by FeSO4 (CHBC) as a new reductant for Cr(VI)-contaminated soil. The effectiveness of CHBC-stabilized Cr(VI)-contaminated soil was investigated. Methods. Typical industrial Cr(VI)-contaminated soil in China was chosen as the medium. The total and Cr(VI) contents of the contaminated soil were 1014.6 and 973.5 mg/kg, respectively. The effectiveness of the Cr(VI)-contaminated soil stabilized by CHBC was investigated by the leaching test (US EPA method 1312), the simplified bioaccessibility extraction test (US EPA 2007 protocol and British Geological Survey), alkaline digestion (US EPA method 3060A), sequential extraction (BCR sequential extraction procedure), X-ray diffraction, and the risk assessment code test. Results. Results show that CHBC substantially reduced the leachability and Cr(VI) content of the contaminated soil. The leachability and content of Cr(VI) were lower than the thresholds of the Environmental Quality Standards of Soil in China for civil reuse and the China Environmental Quality Standards of surface water for civil use when the soil was stabilized with 10% dosage of CHBC. Conclusion. CHBC is highly efficient in stabilizing Cr(VI) and can effectively reduce the leachability and bioavailability of Cr in contaminated soil and thus feasible for stabilizing Cr(VI)-contaminated soil and shows potential for application in the field.

scholarly journals Diminishing Heavy Metal Hazards of Contaminated Soil via Biochar Supplementation

2021 ◽  
Vol 13 (22) ◽  
pp. 12742
Author(s):  
Mahrous Awad ◽  
Mahmuod M. El-Sayed ◽  
Xiang Li ◽  
Zhongzhen Liu ◽  
Syed Khalid Mustafa ◽  
...  
Keyword(s):  
Heavy Metal ◽  
Contaminated Soil ◽  
Contaminated Soils ◽  
Pyrolysis Temperature ◽  
Block Design ◽  
Extraction Procedure ◽  
Application Rate ◽  
Mn Oxide ◽  
Randomized Block Design ◽  
Different Temperatures

Depending on the geochemical forms, heavy metal (HM) accumulation is one of the most serious environmental problems in the world and poses negative impacts on soil, plants, animals, and humans. Although the use of biochar to remediate contaminated soils is well known, the huge quantities of waste used and its recycling technique to sustain soil in addition to its use conditions are determinant factors for its characteristics and uses. A pot experiment was conducted in a completely randomized block design to evaluate metal forms and their availability under the application of garden waste biochar (GB) pyrolyzed at different temperatures, and a sequential extraction procedure was designed to fractionate Pb, Cd, Zn, and Cu of the contaminated soil. The results show that the TCLP-extractable Pb, Cd, Zn, and Cu were significantly decreased depending on the biochar addition rate, pyrolysis temperature, and tested metal. The acid extractable fraction was significantly decreased by 51.54, 26.42, 16.01, and 74.13% for Pb, Cd, Zn, and Cu, respectively, at the highest application level of GB400 compared to untreated pots. On the other hand, the organic matter bound fraction increased by 76.10, 54.69, 23.72, and 43.87% for the corresponding metals. The Fe/Mn oxide bound fraction was the predominant portion of lead (57.25–62.84%), whereas the acid fraction was major in the case of Cd (58.06–77.05%). The availability of these metals varied according to the application rate, pyrolysis temperature, and examined metals. Therefore, the GB is a nominee as a promising practice to reduce HM risks, especially pyrolyzed at 400 °C by converting the available fraction into unavailable ones.

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