Remediation of Chromium-Contaminated Soil: ​Theory and Practice​ (Environmental Science and Engineering)

Preface
Contents
1 Contamination Characteristics of Soils and Biological and Chemical Behavior of Chromium in Soil
	1.1 Sources of Soil Chromium
		1.1.1 Chromium Pollution from the Chromium Salt Industry
		1.1.2 Chromium Pollution in the Electroplating Industry
		1.1.3 Chromium Pollution in the Tanning Industry
		1.1.4 Chromium Pollution from Other Industries
	1.2 Characteristics of Chromium Pollution in Soil
		1.2.1 Chromium Concentrations in Chromium Pollution in Soil
		1.2.2 Vertical Distributions of Total Cr and Water-Soluble Cr(VI) in the Soil Profiles
		1.2.3 Chromium Fractions in the Contaminated Soils
	1.3 Microbial Communities in Chromium-Contaminated Soil
		1.3.1 Bacterial Structural Diversity in the Contaminated Soils
		1.3.2 Isolation and Identification of Hexavalent Chromium-Resistant Bacteria
		1.3.3 Bacterial Genetic Diversity on the Basis of Rep-Polymerase Chain Reaction Fingerprints
		1.3.4 Hexavalent Chromium Reduction by Cr(VI)-Reducing Bacterial Strains
	1.4 Adsorption of Cr(VI) on Soils
		1.4.1 Adsorption Kinetics of Cr(VI)
		1.4.2 Adsorption Thermodynamics of Cr(VI)
	1.5 Cr(VI) Migration in Chromite Ore Processing Residue (COPR)-Soil
		1.5.1 Diffusion of Cr(VI) in Chromium-Containing Slag
		1.5.2 Cr(VI) Migration in Soils
	References
2 Mechanisms of Cr(VI) Reduction by Microorganisms
	2.1 Cr(VI)-Reducing Bacteria Pannonibacter Phragmitetus BB Isolated from Chromium-Contaminated Soil
		2.1.1 Isolation and Identification of Cr(VI)-Reducing Bacterial Strain
		2.1.2 Cr(VI) Reduction by Pannonibacter Phragmitetus BB
		2.1.3 Morphology of Pannonibacter Phragmitetus BB
		2.1.4 Elemental Composition of the Cr(VI)-Reduction Product
		2.1.5 Identification of Cr(VI)-Reduction Product
	2.2 The Cr(VI)-Reducing Bacteria Leucobacter sp. CRB1 Isolated from Chromium-Containing Slag
		2.2.1 Physiological and Biochemical Characteristics of the Strain
		2.2.2 The Phylogenetic Tree of Strain
		2.2.3 Evaluation of Chromium Tolerance
		2.2.4 Identification of Cr(VI)-Reduction Product
	2.3 Behavioral Characteristics of Cr(VI) Reduction by Bacteria
		2.3.1 Cr(VI) Reduction Characteristics of Pannonibacter Phragmitetus BB
		2.3.2 Cr(VI) Reduction Characteristics of Leucobacter sp. CRB1
	2.4 Electrochemical Characteristics of Cr(VI) Reduction by Leucobacter sp. Ch-1
		2.4.1 Effect of Initial pH Values on the Growth of Leucobacter sp. Ch-1 and Reduction of Cr(VI)
		2.4.2 Effect of Applied Potentials on the Growth of Leucobacter sp. Ch-1
		2.4.3 Effect of Applied Potentials on the Reduction of Cr(VI)
		2.4.4 The Range of Initial pH and Eh for Leucobacter sp. Ch-1 Growth and Cr(VI) Reduction
		2.4.5 Potential-pH Diagram for “Leucobacter sp. Ch-1-Cr-H2O” System
	2.5 Molecular Mechanisms of Bacterial Reduction of Cr(VI)
		2.5.1 Multiomics Response of Pannonibacter Phragmitetus BB to Hexavalent Chromium
		2.5.2 Discerning Chromate Reduce and Transport Genes of Highly Efficient Pannonibacter Phragmitetus BB
		2.5.3 Dynamic Proteome Responses to Sequential Reduction of Cr(VI) and Removal of Coexisting Heavy Metals by Pannonibacter Phragmitetus BB
	References
3 Microbial Remediation of Chromium-Polluted Soil
	3.1 The Microbial Remediation Efficacy of Soil Contaminated with Chromium
		3.1.1 Microbial Remediation of Cr(VI) in Soil
		3.1.2 Kinetics of Cr(VI) Microbial Reduction
		3.1.3 Changes in pH and φh During Cr(VI) Microbial Reduction
		3.1.4 Changes in Concentrations of Fe2+, Mn2+, SO42− and NO3−
	3.2 Optimization of Cr(VI) Bioremediation in Polluted Soil
		3.2.1 Effect of Particle Size
		3.2.2 Effect of Spray Intensity
		3.2.3 The Impact of the Initial Cr(VI) Content
		3.2.4 Effect of Depth
		3.2.5 Effect of Circulation Mode
	3.3 Stability of Chromium in the Microbial Remediation Soil Under Simulated Acid Rain Leaching
		3.3.1 The pH Values of the Leachate in the Soils Subjected to Simulated Acid Rain Leaching Exhibited Variations
		3.3.2 Releases of Chromium in Soils Under Simulated Acid Rain Leaching
		3.3.3 Risk to Groundwater
	3.4 Changes in the Bacterial Community During the Bioremediation of Cr(VI)-Contaminated Soil
		3.4.1 Phylogenetic Analysis of 16 rRNA Clone Libraries
		3.4.2 Real-Time Quantitative PCR Analysis
	3.5 The Impact of Microbial Remediation on the Physicochemical and Biological Qualities of Cr(VI)-Contaminated Soils
		3.5.1 Chemical Characteristics of Soils After Remediation
		3.5.2 Changes in Enzyme Activity in Soils After Remediation
		3.5.3 Quality of Soil Assessment
	References
4 Mechanism of Chemical Reduction of Cr(VI)
	4.1 Chemical Reductive Materials for Cr(VI)
		4.1.1 Organic Amendments
		4.1.2 Iron-Bearing Reductants
		4.1.3 Sulfur-Based Compounds
	4.2 Enhanced Cr(VI) Removal by an “In Situ Synthesized” Iron-Based Bimetal Material
		4.2.1 Activity Toward Cr(VI) Removal
		4.2.2 Enhancement of Coexisting Cations on Cr(VI) Removal
		4.2.3 In Situ Synthesized Fe-Cu Bimetal During Cr(VI) Removal
		4.2.4 Electrochemical Behaviors and Contribution of in Situ Synthesized Fe–Cu Bimetal on Cr(VI) Removal
		4.2.5 Enhanced Cr(VI) Removal Mechanism by in Situ Synthesized Fe–Cu Bimetal
	4.3 Interaction Between Pyrite and Zerovalent Iron that Has a Higher Ability to Reduce Through Fe(II) Regeneration
		4.3.1 Incorporation of Sulfur into Fe0
		4.3.2 Removal Activity of FeS2/ZVI Toward Cr(VI)
		4.3.3 Mechanism of Cr(VI) Removal by FeS2/ZVI
		4.3.4 Sulfur Speciation Affects the Electron Transfer of FeS2/ZVI
	4.4 Synergistic Cr(VI) Reduction and Organic Pollutant Oxidative Degradation
		4.4.1 Simultaneous Cr(VI) Reduction and Phenol Oxidation
		4.4.2 The Evolution of Cr(VI) in the FeS2/Fe0 + PS System
		4.4.3 The Roles of Surface-Bound Fe2+
		4.4.4 The Roles of SO42− in the FeS2/Fe0 + PS System
		4.4.5 Reactive Species for Phenol Degradation
		4.4.6 Synergistic Redox Conversion Mechanism
	References
5 Chemical Remediation of Chromium-Contaminated Soil
	5.1 Kinetics, Thermodynamics And Long-Term Effects in Remediation of Cr(VI)-Contaminated Soil
		5.1.1 Factors Affecting Remediation of Cr(VI)-Contaminated Soil
		5.1.2 Kinetics and Thermodynamics
		5.1.3 Soil pH Variation
		5.1.4 Soil Cr Speciation Change
		5.1.5 Long-Term Stability of Cr in Remediated Soil
	5.2 Remediation of Cr(VI) and Organic Pollutant Cocontaminated Soil
		5.2.1 Factors Affecting the Remediation of Cr(VI) and Organic Pollutants
		5.2.2 Remediation Performance Comparison of Different Reaction Systems
		5.2.3 Soil Cr(VI) Speciation
	5.3 Synergistic Remediation of Cr(VI) and Cationic Metal Co-contaminated Soil
		5.3.1 Factors Affecting the Remediation of Cr–Cu–Ni–Co–Contaminated Soil
		5.3.2 Sequential Extraction, Followed by an Evaluation of Risk Reduction
	5.4 Chemical-Microwave Combined Remediation of Strongly Alkaline High Cr(VI)-Contaminated Soil
		5.4.1 Comparison of Remediation Effect by Various Amendments
		5.4.2 Factors Affecting Microwave Irradiation-Assisted Reduction
		5.4.3 Mechanism of Microwave Irradiation Accelerating Cr(VI) Reduction
		5.4.4 Cr Speciation and Phase Transformation Under Microwave Irradiation
		5.4.5 Long-Term Stability of Cr in Remediated Soil
	References
6 Case of Chrome-Contaminated Site Remediation Project
	6.1 Project Overview
	6.2 Remediation Technology and Route
	6.3 Project Photos
	6.4 Remediation Effects