ADSORPTIVE REMOVAL OF INORGANIC POLLUTANTS FROM NUCLEAR POWER PLANT WASTEWATER USING A MODIFIED ZEOLITE NANOCOMPOSITE
A Major Qualifying Project Report
submitted to the Faculty
of the
WORCESTER POLYTECHNIC INSTITUTE
in partial fulfillment of the requirements for the
Degree of Bachelor of Science
By:
EDMUND CARL EDUAH
Date: March 7th, 2014
Approved by:
Professor Susan Zhou, Major Advisor
ACKNOWLEDGEMENT
I would like to first thank Worcester Polytechnic Institute and Shanghai Jiao Tong University for making this project and experience possible. I would also like to extend a special thank you to my advisors Professor Zhou and Professor Xu for their guidance and support and lastly to Timothy Wenzhong Zhang for assisting me throughout the experimental phase of the project.
ABSTRACT
This report focuses on the use of lab synthesized composite beads, made up of Xanthan Gum, Calcium Alginate and Na-A Zeolite, in adsorbing cobalt and nickel ions from nuclear power plant wastewater. The adsorption was investigated in a batch mode by changing relevant parameters including the adsorbent dosage, metal ions in solution, initial pH, temperature and salt concentration in the solution.
Optimal conditions for the adsorption process were found to be pH=5 and an adsorbent dosage of ~2.0 g L-1. The Pseudo-Second-order model best described the adsorption kinetics and the Langmuir isotherm model best fitted the adsorption process. Thermodynamically, the adsorption process was found to be spontaneous with a ΔG0 of -3237.45 KJ mol-1 for cobalt and -3494.93 KJ mol-1 for nickel, and endothermic, with ΔH0 being 5110.43 KJ mol-1 for cobalt and 8251.67 KJ mol-1 for nickel.
Finally, when tested in a synthesized solution of nuclear power plant wastewater, the XG-CA-Na-A composite beads showed encouraging results, removing 99.5% of the cobalt ions and 98.3% of the nickel ions in solution.
TABLE OF CONTENTS
ACKNOWLEDGEMENT 2
ABSTRACT 3
TABLE OF CONTENTS 4
LIST OF TABLES 6
LIST OF FIGURES 7
INTRODUCTION 8
BACKGROUND 9
Inorganic Pollutants of interest 9
Current Wastewater Treatment Methods for Inorganic Pollutants 10
Chemical Precipitation 10
Membrane Filtration 11
Ultrafiltration (UF) 11
Reverse Osmosis 12
Nanofiltration 12
Electrodialysis (ED) 13
Adsorption 14
Choosing a Wastewater Treatment Method 15
Adsorptive Removal of Wastewater Pollutants using XG-CA-Na-A composite Beads 15
Zeolites 15
Xanthan Gum and Calcium Alginate 16
PURPOSE OF THIS PROJECT 17
Objectives 17
METHODOLOGY 18
Materials and Instruments 18
Method 18
Preparation of XG-CA-Na-A Beads 18
Batch Adsorption Procedure 19
Optimal conditions for the adsorption process 19
Kinetic Study 20
Isotherms and Thermodynamic Study 21
Study of Competing Effects 23
RESULTS and DISCUSSION 25
Optimal Adsorption Conditions 25
Effect of XG-CA-Na-A composite beads dosage 25
Effect of pH 26
Adsorption Kinetics 29
Isotherm and Thermodynamic study 33
Adsorption isotherms and temperature effects 33
Thermodynamics Studies 35
Competing effects 37
The effect of ionic Strength 37
Competition due to presence of both Nickel and Cobalt ions 38
XG-CA-Na-A beads performance in synthesized nuclear wastewater 39
Comparisons between XG-CA-Na-A beads and other previously studied Adsorbents. 40
CONCLUSION 42
FUTURE PERSPECTIVES 42
REFERENCES 43
APPENDIX 46
Appendix A: pH of precipitation for 15 mg L-1 cobalt and nickel aqueous solutions. 46
Cobalt solution 46
Nickel solution 46
LIST OF TABLES
Table 1: Poisoning Effects and Groundwater QES for Co(II) and Ni(II) ions 10
Table 2: Composition of synthetic nuclear power plant wastewater 24
Table 3: Adsorption Capacity, Rate constant and regression values of the kinetic models 30
Table 4: Weber and Morris model constants for each adsorption step. 31
Table 5: Adsorption isotherm constants and the regression values for the three experimented temperatures 35
Table 6: Thermodynamic constant values for the
