A Guide to the Economic Removal of Metals from Aqueous Solutions

Provides public health, sanitary and water engineers baselinedata for designing plants for the treatment of industrial effluentsrich in the metallic species in general and that of nickel andchromium in particular.

DescriptionWater pollution is a topic of immense and commonconcern throughout the world. With a rapidly escalating globalpopulation and increased industrial development in a growing numberof countries, the world′s freshwater resources have becomestressed. One way to get more out of less is ′treatment and reuse′.Nickel and chromium are toxic metals and they are used extensivelyin numerous industries such as textiles, beverages, steel, pulp andpaper, and electroplating. Their industrial effluent contains largemeasures of non–biodegradable traces that are harmful to flora,fauna, and human beings. Although there are a number ofmethodologies used for treatment of metal–containing industrialeffluents and waste water, there is not one up to now that offers ahigh capacity removal rate at an economical cost.

This book presents the results and data from research andadsorption experiments carried out on the removal of nickel andchromium (as well as other metals) from aqueous solutions usingmodified silica sand. The data resulting from detailed kinetic,equilibrium and thermodynamic studies, show that the removalcapacity is increased so the treated water has a higher quality orpurity. It also demonstrates that the extraction of metals isachieved at a significant lower cost because the treated wateradsorption is a simple process with less maintenance, and becausesilica is a nontoxic natural material widely available in all partsof the world.

1. Introduction 1

1.1 Environment 1

1.2 World Water Distribution 2

1.3 Environmental Pollution 5

1.4 Chromium 11

1.5 Nickel 16

1.6 Objectives 20

1.7 Literature Review 20

1.8 Adsorption 31

1.9 Adsorption Forces 35

1.10 Adsorption Theories 36

2. Material and Methods 39

2.1 Adsorbent Collection and Storage 39

2.2 Adsorbent Modification 39

2.3 Preparation of Adsorbate Cr (VI) and Ni (II) Solution 40

2.4 Instrumentation 40

2.5 Batch Adsorption Experiment 41

3. Results and Discussions 45

3.1 Characterization of Silica Sand 45

3.2 Effect of Contact Time and Initial Concentration of Cr (VI)and Ni (II) 52

3.3 Effect of pH on the Removal of Cr (VI) and Ni (II) 56

3.4 Effect of Temperature on the Removal of Cr (VI) and Ni (II)60

3.5 Effect of Adsorbent Dosage on the Removal of Cr (VI) and Ni(II) 66

3.6 Adsorption Isotherm 73

3.7 Adsorption Kinetics 79

3.8 Thermodynamic Studies 86

4. Conclusions 91

References 94 

Yogesh Sharma is a professor in the Department of Applied Chemistry, Institute of Technology, Banaras Hindu University. Prior to this he was at the National Institute of Foundry and Forge Technology, Ranchi, where he was involved with consultancy and testing of metals and alloys, drinking water, and industrial effluents. Dr. Sharma has published widely on the removal of metallic species from aqueous solutions.