Related Experiment Video
Updated: Jun 25, 2025
11:14
Two-way Valorization of Blast Furnace Slag: Synthesis of Precipitated Calcium Carbonate and Zeolitic Heavy Metal Adsorbent
Published on: February 21, 2017
12.4K
Solidification/stabilization of lead-contaminated soil using alkali-activated volcanic ash
Mohammad Amin Molaei1, Hania Miraki1, Mohsen Morovati1
1School of Civil Engineering, Iran University of Science and Technology, Tehran, Iran.
Summary
Alkali-activated volcanic ash effectively immobilizes lead in contaminated soil, significantly increasing strength and reducing lead leaching. This eco-friendly alternative offers a promising solution for soil remediation.
Area of Science:
- Environmental Science
- Geotechnical Engineering
- Materials Science
Background:
- Lead bioaccumulation in soil presents a significant human health risk.
- Traditional soil remediation using Portland cement has adverse environmental impacts.
- Alkali-activated materials (AAMs) offer eco-friendly alternatives for soil stabilization and solidification (S/S).
Purpose of the Study:
- To assess the efficacy of AAMs, specifically volcanic ash (VA), in the S/S of lead-contaminated soil.
- To investigate the influence of VA content, lead concentration, curing temperature, and time on soil remediation.
- To elucidate the mechanisms responsible for lead immobilization.
Main Methods:
- Soil samples were treated with varying percentages of VA.
- Specimens were subjected to oven curing (OC) and ambient curing (AC).
- Evaluated properties included unconfined compressive strength (UCS), lead leaching (TCLP), and microstructural analysis (XRD, FTIR, FESEM/EDS/mapping).
Main Results:
- UCS increased significantly with 15% VA (OC) and 10% VA (AC), reaching up to 600% and 458% respectively.
- Lead leaching reduced by 87% (OC) and 91% (AC) for high contamination levels.
- Effective lead immobilization was achieved through chemical bonding, physical encapsulation, and insoluble silicate formation.
Conclusions:
- Alkali-activated volcanic ash demonstrates excellent performance in remediating lead-contaminated soil.
- The formation of N-A-S-H and hydroxy sodalite structures is crucial for the S/S mechanisms.
- This study highlights VA-based AAMs as a sustainable and effective alternative to conventional cement-based remediation.
Keywords:
Alkali-activated volcanic ashGeopolymerHeavy metalLeadSoil remediationSolidification/stabilizationMore Related Videos
07:32Monitoring Pedogenic Inorganic Carbon Accumulation Due to Weathering of Amended Silicate Minerals in Agricultural Soils.
Published on: June 4, 2021
5.1K
05:52Resource Recycling of Red Soil to Synthesize Fe2O3/FAU-type Zeolite Composite Material for Heavy Metal Removal
Published on: June 2, 2022
2.9K
Related Concept Videos
01:26Alkali Aggregate Reaction in Concrete
93
The alkali-aggregate reaction in concrete involves natural siliceous minerals in aggregates reacting with alkaline hydroxides derived from cement alkalis. This reaction forms an alkali-silica gel that absorbs water, swells, and increases in volume, which is confined by the surrounding cement paste, creating internal pressures that crack and disrupt the concrete. The extent of expansion and damage can be partly attributed to the alkali-silica reaction's osmotic hydraulic pressure and the...
93
01:21Pozzolans
111
Pozzolans are siliceous or aluminous materials blended with Portland cement. They interact with the calcium hydroxide produced during the hydration of Portland cement and contribute to improved strength and durability of concrete. The pozzolanic activity, a measure of a pozzolan's effectiveness, is typically assessed using the strength activity index, as defined in ASTM C 618-93, which calculates the ratio of the compressive strength of cement mixtures with and without pozzolan.
Fly ash is...
Fly ash is...
111
01:08Sample Preparation for Analysis: Advanced Techniques
326
Accurate analysis of complex samples often requires advanced preparation techniques to achieve reliable and reproducible results. Samples containing inorganic or organic materials can be challenging to dissolve or decompose effectively. Standard sample preparation methods include acid digestion, fusion, dry ashing, and wet digestion.
Acid digestion with strong acids is commonly used to dissolve inorganic materials that are insoluble (do not dissolve) in water. This method can be useful for...
Acid digestion with strong acids is commonly used to dissolve inorganic materials that are insoluble (do not dissolve) in water. This method can be useful for...
326
00:52Washing, Drying, and Ignition of Precipitates
908
After filtration, the precipitate is washed to remove coprecipitated impurities and any remaining mother liquor. Colloidal precipitates, such as silver chloride, are washed with an electrolyte (such as dilute nitric acid) to prevent the peptization of the precipitate. In the case of slightly soluble precipitates, the wash solution contains a common ion to reduce solubility. Lead sulfate, which is slightly soluble in water, is washed with dilute sulfuric acid. Similarly, wash solutions may be...
908
01:25Deleterious Substances in Aggregate
166
Deleterious substances in aggregates can be detrimental to the quality and durability of concrete. These substances include organic impurities like loam, which interfere with cement hydration and are usually present in the sand. These prevent a good bond between aggregate and cement paste. Organic impurities can be detected using the colorimetric test, where the darkness of a solution after agitation indicates the level of organic content.
Another type of impurity is clay and fine material that...
Another type of impurity is clay and fine material that...
166
01:14Design Example: Managing Concrete Workability
80
This example deals with managing the workability of concrete for a raft foundation project under hot weather conditions. Workability is crucial for ensuring the concrete is easy to place, compact, and finish. In this scenario, a slump test — a common method to measure the workability of fresh concrete — initially indicated low workability. This was attributed to the rapid water loss from the concrete mix, exacerbated by the high temperatures causing the course aggregates to heat up.
80