Factors affecting the leaching behaviours of magnesium phosphate cement-stabilised/solidified Pb-contaminated soil, part 1: water-to-solid ratio and Pb concentration

2018 ◽  
Vol 63 (1/2) ◽  
pp. 89 ◽  
Author(s):  
Ping Wang ◽  
Qiang Xue ◽  
Jiang Shan Li ◽  
Ting Ting Zhang ◽  
Shan Yong Wang ◽  
...  
Keyword(s):  
Contaminated Soil ◽  
Magnesium Phosphate ◽  
Factors Affecting ◽  
Solid Ratio ◽  
Pb Concentration

Factors affecting the leaching behaviors of magnesium phosphate cement-stabilized/solidified Pb-contaminated soil, part II: Dosage and curing age

2017 ◽  
Vol 36 (5) ◽  
pp. 1351-1357 ◽  
Author(s):  
Ping Wang ◽  
Qiang Xue ◽  
Zhenning Yang ◽  
Jiangshan Li ◽  
Tingting Zhang ◽  
...  
Keyword(s):  
Contaminated Soil ◽  
Magnesium Phosphate ◽  
Factors Affecting ◽  
Curing Age

scholarly journals Application of nanoscale zero-valent iron in hexavalent chromium-contaminated soil: A review

2020 ◽  
Vol 9 (1) ◽  
pp. 736-750
Author(s):  
Xilu Chen ◽  
Xiaomin Li ◽  
Dandan Xu ◽  
Weichun Yang ◽  
Shaoyuan Bai
Keyword(s):  
Heavy Metal ◽  
Hexavalent Chromium ◽  
Contaminated Soil ◽  
Zero Valent Iron ◽  
Toxic Heavy Metal ◽  
Factors Affecting ◽  
Metal Pollutants ◽  
Nanoscale Zero Valent Iron ◽  
Low Toxicity ◽  
Heavy Metal Pollutants

AbstractChromium (Cr) is a common toxic heavy metal that is widely used in all kinds of industries, causing a series of environmental problems. Nanoscale zero- valent iron (nZVI) is considered to be an ideal remediation material for contaminated soil, especially for heavy metal pollutants. As a material of low toxicity and good activity, nZVI has been widely applied in the in situ remediation of soil hexavalent chromium (Cr(vi)) with mobility and toxicity in recent years. In this paper, some current technologies for the preparation of nZVI are summarized and the remediation mechanism of Cr(vi)-contaminated soil is proposed. Five classified modified nZVI materials are introduced and their remediation processes in Cr(vi)-contaminated soil are summarized. Key factors affecting the remediation of Cr(vi)-contaminated soil by nZVI are studied. Interaction mechanisms between nZVI-based materials and Cr(vi) are explored. This study provides a comprehensive review of the nZVI materials for the remediation of Cr(vi)-contaminated soil, which is conducive to reducing soil pollution.

Factors affecting the extraction of alkylamides and cichoric acid during ethanolic processing of Echinacea purpurea (L.) Moench.

2000 ◽  
Vol 40 (6) ◽  
pp. 873 ◽  
Author(s):  
D. L. Stuart ◽  
R. B. H. Wills
Keyword(s):  
Particle Size ◽  
Echinacea Purpurea ◽  
Acid Extraction ◽  
Cichoric Acid ◽  
Factors Affecting ◽  
Water Solutions ◽  
Solid Ratio ◽  
Ethanolic Extracts ◽  
Pharmacologically Active

Factors generic to the manufacture of ethanolic extracts of Echinacea purpurea (L.) Moench were evaluated for their ability to extract the pharmacologically active alkylamides and cichoric acid in roots and shoots. Extraction of alkylamides and cichoric acid was differentially affected by ethanol composition, with 60 : 40 mixture of ethanol : water giving the maximum overall yield of both constituents. Elevated solvent temperature enhanced cichoric acid extraction but was detrimental for the alkylamides. A reduction in particle size and a high solvent : solid ratio resulted in a marked increase in extraction of both constituent groups. Both constituent groups were found to be stable in ethanol : water solutions held at 20˚C for 4 months.

Study on Renovation of Heavy Metal Pb (II)-Contaminated Soil

2012 ◽  
Vol 518-523 ◽  
pp. 1800-1803
Author(s):  
Xiao Jiao Yu ◽  
Lin Zhu Huang ◽  
Qian Yang ◽  
Fan Zhang ◽  
Jian Zhang
Keyword(s):  
Heavy Metal ◽  
Contaminated Soil ◽  
Extraction Efficiency ◽  
Removal Rate ◽  
Polluted Soil ◽  
Extraction Rate ◽  
Extraction Time ◽  
Regeneration Medium ◽  
Solid Ratio ◽  
Edta Concentration

To remedy polluted soil, EDTA is choosen when seeing metal Pb (Ⅱ) as target pollutant. There has been a focus on discussion about the infuencs of liquid-solid ratio, EDTA concentration and extraction time on Pb (Ⅱ) extraction rate. And attention is being paid to study the effect of Na2S concentration and pH on Pb (Ⅱ) removal rate with Na2S as EDTA regeneration medium. The results obtained demonstrate that when the liquid-solid ratio is 10, EDTA concentration is 0.5 mol/L, extraction time is 24 h, extraction efficiency can reach 66.67 %. When the concentration of Na2S is 0.5 mol/L, pH is 10, the 96.67 % Pb (Ⅱ) removal rate can be achieved.

scholarly journals Leaching characteristics and curing mechanism of magnesium phosphate cement solidified zinc-contaminated soil in an acid rain environment

2020 ◽  
Vol 26 (4) ◽  
pp. 200256-0
Author(s):  
Zhe Wang ◽  
Hangjun Zhu ◽  
Xuehui Wu ◽  
Binpin Wei ◽  
Hongli Zhou ◽  
...  
Keyword(s):  
Heavy Metal ◽  
Acid Rain ◽  
Contaminated Soil ◽  
Water Glass ◽  
Ph Value ◽  
Strong Acid ◽  
Magnesium Phosphate ◽  
Leaching Characteristics ◽  
Curing Mechanism ◽  
Acid Environment

A semi-dynamic leaching test was used to simulate the erosion effect of acid rain on magnesium phosphate cement (MPC)-stabilized/solidified zinc-contaminated soil. The leaching characteristics and curing mechanism were studied with a combination of X-ray diffraction (XRD) and scanning electron microscopy (SEM). Influences of the initial pH value of the simulated acid rain, the ratio of the curing agent (MgO/KH2PO4, abbreviated M/P), and the mass of water glass on the leaching characteristics of Zn<sup>2+</sup> and conductivity in the leachate of the sample were studied. It is shown that the curing effect of the cement component on Zn<sup>2+</sup> is better for M/P = 6 when compared to M/P = 4 in a strong acid environment. While in a weak acid environment, it is observed that the curing effect is superior when M/P = 4. Also it is observed that 4% water glass content can effectively improve the cement curing effect of heavy metal Zn in an acid rain environment. These results indicate that water glass can be effectively applied to MPC solidified heavy metal Zn.

Utilisation of Magnesium Phosphate Cements to Facilitate Biodegradation within a Stabilised/Solidified Contaminated Soil

2010 ◽  
Vol 216 (1-4) ◽  
pp. 411-427 ◽  
Author(s):  
Reginald B. Kogbara ◽  
Abir Al-Tabbaa ◽  
Srinath R. Iyengar
Keyword(s):  
Contaminated Soil ◽  
Magnesium Phosphate

scholarly journals Leachate Characteristics of Contaminated Soil Containing Lead by Stabilisation/Solidification Technique

2015 ◽  
Vol 773-774 ◽  
pp. 1443-1447 ◽  
Author(s):  
Mohamed Nur Shafiq Mohamed Hanif ◽  
Saiful Azhar Ahmad Tajudin ◽  
Aeslina Abdul Kadir ◽  
Aziman Madun ◽  
Mohamad Azim Mohammad Azmi ◽  
...  
Keyword(s):  
Developing Countries ◽  
Soil Remediation ◽  
Contaminated Soil ◽  
Clay Soil ◽  
Partial Replacement ◽  
Leachate Characteristics ◽  
Leaching Procedure ◽  
Pb Concentration ◽  
Cockle Shell

Contaminated soil is often a problem and typical concern in the developing countries due to the lack of clean soil for development, such as in Malaysia. The objective of this study is to investigate the performance of the available techniques for soil remediation contaminated with lead (Pb) through Stabilisation/Solidification (S/S) technique. In this study, cockle shell powders at different percentages (2.5%, 5% and 7.5%) were added as a partial replacement of cement. Toxicity Characteristics Leaching Procedure (TCLP) was conducted to determine the effectiveness of the S/S technique to treat the contaminated soil. The results showed a 99% reduction of Pb concentration after the contaminated clay soil was treated with S/S technique. The combination of cement and cockle shell powders is very effectively used in the remediation of lead contaminated soil and reducing the amount of cement usage for sustainability approaches.

The Application of XRF in Field Monitoring on Digging Pb-Contaminated Soil

2012 ◽  
Vol 500 ◽  
pp. 24-28 ◽  
Author(s):  
Xiao Nan Sun ◽  
An Ping Liu ◽  
Xiao Song Sun
Keyword(s):  
Heavy Metal ◽  
Contaminated Soil ◽  
Field Monitoring ◽  
Contaminated Site ◽  
Full Time ◽  
Portable Xrf ◽  
Monitoring Method ◽  
X Ray ◽  
Limit Value ◽  
Pb Concentration

In this paper, a portable X-ray fluorescence (XRF) is designed to monitor the digging process of Pb contaminated soil based on contaminated site remediation. This field monitoring method is applied to the project of Pb contaminated restoration site K. A full time program is designed for XRF to monitor the exceeded standard regions of Pb pollution during the digging contaminated soil. The acceptance monitoring results show that the Pb concentration of all original exceeded points are under the limit value 260mg/kg, and reach the requirement of environmental protection. This application results show that the portable XRF was designed effectively in field monitoring on heavy metal such as Pb, which realize the purpose of quickly identification and digging of contaminated soil.

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