Luận án tiến sĩ: Nonequilibrium transport of heavy metals in soils and its influence on soil remediation

NONEQUILIBRIUM TRANSPORT OF HEAVY METALS IN SOILS AND ITS INFLUENCE ON SOIL REMEDIATION by TSANG Chiu Wa A Thesis Submitted to The Hong Kong University of Science and Technology in Partial Fulfillment of the Requirements for : the Degree of Doctor of Philosophy in Civil Engineering August 2006, Hong Kong UMI Number: 3245372 INFORMATION TO USERS The quality of this reproduction is dependent upon the quality of the copy submitted. Broken or indistinct print, colored or poor quality illustrations and photographs, print bleed-through, substandard margins, and improper alignment can adversely affect reproduction. In the unlikely event that the author did not send a complete manuscript and there are missing pages, these will be noted. Also, if unauthorized copyright material had to be removed, a note will indicate the deletion.

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Box 1346 Ann Arbor, MI 48106-1346 Authorization I hereby declare that I am the sole author of the thesis. I authorize the Hong Kong University of Science and Technology to lend this thesis to other institutions or individuals for the purpose of scholarly research. I further authorize the Hong Kong University of Science and Technology to reproduce the thesis by photocopying or by other means, in total or in part, at the request of other institutions or individuals for the purpose of scholarly research. TSANG Chit Wa ˆ i NONEQUILIBRIUM TRANSPORT OF HEAVY METALS IN SOILS AND ITS INFLUENCE ON SOIL REMEDIATION by TSANG Chiu Wa This is to certify that I have examined the above PhD thesis and have found that it is complete and satisfactory in all respects, and that any and all revisions required by the thesis examination committee have been made.

S“ CHEUNG,ĐAU Department Department of Civil Engineering August 2006 11 ACKNOWLEDGEMENTS I would like to bow my thanks to Prof. LO for her continual encouragement, wisdom, and support in ways too numerous to recount here. Her heuristic teaching has expedited my growth. She is an understanding mentor who has been sensible of the demoralizing struggles that I was swamped.

When I hung my head from time to time, she came to show me her concern and back me up. What she cares more is my personal development than the tasks I can finish. She constantly puts her faith in me that I can rise above mediocrity with endeavor and vision and always encourage me to perform at full stretch whenever and whatever. For countless times, I was much moved and speechless.

I am more than obliged that Prof. LO has been my supervisor. She has guided me to develop as a person with her big-hearted tolerance of my strong and willful character, and she has always been by my side to help me get through the past three and a half years. I owe a great deal to Prof.

She is a mentor second to none for my life. With her enlightenment and nurturing, I have the heart to confront any challenges in future. Guanghao CHEN, Prof. Xiangdong LI, Prof.

Gordon MCKAY, and Prof. Chii SHANG for serving on my committee and offering their thoughtful advice and help. My gratitude also goes to Prof. Kwing Lam CHAN who kindly assisted in mathematical modeling of the transport of metal-EDTA complexes.

Thanks are also extended to technical staff, Mr. Shing Tak LUI and Mr. Johnson YAU, who continuously provided assistance in experimental setup, instrumentation and routine maintenance. I personally learnt a lot from the firsthand experience of Mr.

IV Special thanks must be given to my research teammates: Dr. Keith LAI, Weihua ZHANG, Agnes TONG, Kelvin NG, Chester LAM, Dr. Jing HU, and Tony LIU, who offered me many critical comments and suggestions im our regular group meeting, and what is more, we have got over many ups and downs together in these years. Also, I am grateful to have the support and company of many friends over the course of my study: Angel WONG, Yinan QI, Qian FANG, Davy LAU, Cyrus LEUNG, Will NIXON, Ying Yin CHAN, Ronald SIU, John LAI, Fancy CHEUNG, Chi Kin WAN, Karen HO, Kin Ming WONG, Bartek BACZKOWSKI, Li XIE, Sally LEE, Hexin ZHANG, Xin YANG, Ken CHAN, and what not.

Above all, I would like to dedicate this thesis to my mother as a token of love. She has raised me up by herself for over twenty years since my dad passed away. My mother always gives me the best. She is my role model all the time, showing me what perseverance, integrity, and responsibility are.

Although I find my affection unspeakable at times, I hope she would always be happy with me and my accomplishment. I know I still have a long way to go in academia. I wish to be an honor to her one day. I cannot imagine that this thesis can be finished without the generous help offered by a lot of people.

Credit for my work, if any, goes straight to Prof. LO and my mother. Responsibility for any errors is, of course, my own. TABLE OF CONTENTS ¡055.

i AUTHORIZA TION PAGE. Q1 HH KH re H S6 0/.cccccessscecsessneceeesssseeesessueeeseeseeseesecsseeseeneseeesteenenesensaes iv IV. 1X LIST OF TABLES. Xvi Chapter 1 Introduction 1 1.

--- 5S Ăn SH HT Khen 1 1.2 Scope and ObJ€CfIV€S.--- Ăn HH HH tờ 4 Chapter2 Literature Review 6 2.1 Heavy Metals and SOiÌS.1 Heavy Metal Contaminations. Subsurface Solute TTanSDOF.--- Ăn re 44 VI <ENH Co co.2 Iniial and Boundary CoOndifIOTIS. Equilibrium Transport Model. Nonequilibnum Transport Model.

Heavy Metal Transport Behavior and Soil Remediation.1 Pore-Water Velocity and Temp€ratUTe. HH KH HH 63 2. sọ HH nọ HH 65 PM V na e.5 Transport Behavior of Metal-EDFA Complexes. 68 Chapter 3 Materials and Methods 71 côn 9c.

- -- - - - - nh 84 Chapter 4 Influences of Pore-Water Velocity and Temperature. Transport Behavior at Different Pore-Water Velocities.4 Sorption Rate Coefficient and Fraction of Instantaneous Sorption at Different Pore-Water VeÌOCi{I€S .- LG HH ng v 96 4.5 Retardation of Transport at Different Pore-Water Velocities.6 Transport Behavior at Different 'ermperatur€s.7 Sorption Rate Coefficient and Fraction of Instantaneous Sorption at Different Temperatures PP .8 Retardation of Transport at Different 'ÏemperafUT€S.--- ---sc se 108 “Ta. 111 Chapter 5 Competitive Effects on Heavy Metal TTransporf.2 Competitive Heavy Metal Transport in SOIÌ. Batch Sorption Kinetics 200.

118 Sao 8s co on. 126 Chapter 6 Nonlinear and Rate-limited Sorption Effects on Heavy Metal Transport 127 G.2 Sorption Kinetics and IsOthe€rTmS.4 Cd Transport Behavior 1n SOI̧. 140 Chapter 7 EDTA-Flushing Effectiveness and EmpaCÉS.----ceesss<ssssssse 141 Noi.2_ Copper Distribution in Soils before EDTA Flushing. Copper Extraction EfÍ€CtIV€T€SS.QQ SH HH ngư.

Tron, Aluminium, and Calcium Dissolution.5 SoIl Organic Matter DIssoÌution.- -QQ ung 156 rZh. 158 Chapter 8 Transport of Metal-EDTA Complexes 160 8. Simulation of Transport of Metal-EDFA Complexes. Gà 176 CB an.

180 Chapter 9 Conclusions and Recommendations 181 9. -G SG Họ He 181 9.2 Recommendations for Future WOFK. -- Go HH re 184 References 189 Appendix A — Two-Region (Physical) Nonequilibrium Model. — 207 Appendix B - EDTA Properties 210 Appendix C — Proposed Model for Metal-EDTA Complex Transport.

213 Appendix D — Preliminary Spectroscopic Results 226 Vill LIST OF FIGURES FIGURE 1.1 Contaminant concentration versus pumping volume showing tailing and rebound €ff€C(S. - -- - HH nh 2 FIGURE 2.1 Heavy metal dynamics in soil environmert .2 Surface charge of colloidal materiaÌS .- ----- 5< ssss+essseeereee 13 FIGURE 2.3 Extent of tropicaÏ SOIÌS. - - - - s 93112 231119 HH3 HH ngư 16 FIGURE 2.4 Schematic diagram depicting four mechanisms for the formation of SUTÍaC€ DF€CIDIẨA{C.5 A hypothetical interfacial structure demonstrating the three mechanisms (diffuse ion swarm, outer-sphere surface complex, and inner-sphere surface complex) of cation adsorption on a surface .6 Possible sorption complexes at the mineral/water interface: (a) surface complexes formed between inorganic ions and hydroxyl groups of an oxide surface; (b) surface precipitation phenomena.7 Regions of stability for the products of sorption reactions with natural particles, defined by the quantity of sorbate and the sorption TE ACTION CHIME «22. ee ee ceeeceeceecssceceeeeeccceccceceeeceneceeeeeeeceseeeseeseneeteneseeeseceseeegs 28 FIGURE 2.8 Possible fates of ionic adsorbates in soils as dependent on concentration and time.

- - - HH TH 10 nếp 29 FIGURE 2.9 Time ranges required for attaining equilibrium by different types of TEACTIONS in SOIÌ ©€IVITOTIT€TIES. - G G5 SH ng 30 FIGURE 2.10 Classification of some metals according to ionic potential and L€WIS acid SOÍt€SS.- QQ HHng nh 42 FIGURE 2.11 Breakthrough curves for ideal and nonideal transport.12 Transport processes ¡in solid-liquid soil reactions.13 Breakthrough curves for ideal and nonideal transport.1 Soil column and setup for a series of column experiments .1 Breakthrough curves of Br in UST, TMS and CWB soils: at 58.2 cm h” and 21 °C; (b) at 6.2 Breakthrough curves of Cd in UST soil: (a) 8. ccsvc t1 nh ng gcec 93 FIGURE 4.3 Breakthrough curves of Cd in TMS soil: (a) 7.4 Breakthrough curves of Cd in CWB soil: (a) 6.5 Effects of pore-water velocity on (a) sorption rate coefficient (cx); (b) fraction of instantaneous sorption (F); (c) retardation factor (R).6 Observed and simulated breakthrough curves of Cd in UST soil at different temperatures: (a) 10 °C; (b) 21 °C; (c) 35 °C.7 Observed and simulated breakthrough curves of Cd in TMS soil at different temperatures: (a) 10 °C; (b) 21 °C; (c) 35 °C.8 Observed and simulated breakthrough curves of Cd in CWB soil at đifferent temperatures: (a) 10C; (b) 21 °C; (c) 35 °C.9 Batch sorption isotherms of Cd at different temperatures: (a) UST soil; (b) TMS soil; (Cc) CWB SOI]. ec ce cececceeccesetensssssecceseceneneseeeeseees 110 FIGURE 5.1 Experimental data and optimized simulations for Cu or Cd transport in the soil: (a) 10 mg L” Cu; (b) 100 mg L" Cu; (c) 10 mg L' Cd; (A) 100 mg e.2 Experimental data and optimized simulations for competitive Cu and Cd transport in the soil: (a) 10 mg L7! Cu & 10 mg L’! Cd; (b) 100 mg L7! Cu & 100 mg LÌ Cd; (c) 10 mg L7! Cu & 100 mg L” Cd; (đ) 100 mg L7! Cu & 10 mg L7” Cd.-- 7-5 S2 se cecxeereseeexes 116 FIGURE 5.3 Sorption kinetics of (a&b) 10 mg L"! and 100 mg L" Cu in the presence/absence of Cd; (c&d) 10 mg L and 100 mg L" Cd in the presence/absence Of (Êu.

cọ nhe 120 FIGURE 5.4 Distribution of Cu and Cd in soil samples of batch kinetics experiment after four reaction durations (1 min, 30 min, 1 day, and 7 day): (a&b) 10 mg L" and 100 mg L'! Cu alone; (c&d) 10 mg L! and 100 mg L Cu in the presence of Cd of equal concentration; (e&f) 10 mg L7” and 100 mg L7” Cd alone; (g&h) 10 mg LỶ and 100 mg L' Cd in the presence of Cu of equal concentration.5 Distribution of sorbed Cu and Cd in the soil after heavy metal breakthrough in column experiments using various heavy metal loadings: (a&b) 10 mg L" and 100 mg L” Cu in the presence/absence of Cd; (c&d) 10 mg L"' and 100 mg L" Cd in the presence/absenc€ Of (CU. -- HH re 124 FIGURE 6.1 Sorption kinetics of Cd of UST, TMS, and CWB soils at: (a) 105M; ()5 05.2 Sorption isotherms of Cd (log scale) of UST, TMS, and CWB ˆ91 10.3 Experimental data and optimized simulations for Cd transport in UST soil at four input concentrations of: (a) 10° M; (b) 5x10° M; (c) 10% Ms (d) 10% M voce ccccccsceccecsccscececesscsccesvevscecessvecsesecsceevanaveees 137 FIGURE 6.4 Experimental data and optimized simulations for Cd transport at two input concentrations in TMS soil: (a) 10° M; (b) 10° M; and CWB soil: (c) 10 M; (dđ) 10 ỔM.