The Effects of Phosphonate-Based Scale Inhibitor on BrineâBiotite

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Energy and the Environment

The Effects of Phosphonate-Based Scale Inhibitor on Brine-Biotite Interactions under Subsurface Conditions Lijie Zhang, Doyoon Kim, and Young-Shin Jun Environ. Sci. Technol., Just Accepted Manuscript • DOI: 10.1021/acs.est.7b05785 • Publication Date (Web): 18 Apr 2018 Downloaded from http://pubs.acs.org on April 18, 2018

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Environmental Science & Technology

The Effects of Phosphonate-Based Scale Inhibitor on Brine−Biotite Interactions under Subsurface Conditions

Lijie Zhang, Doyoon Kim, and Young-Shin Jun* Department of Energy, Environmental and Chemical Engineering, Washington University, St. Louis, MO 63130

Address: One Brookings Drive, Campus Box 1180 E-mail: [email protected] Phone: (314)935-4539 Fax: (314)935-7211 http://encl.engineering.wustl.edu/ Submitted: November 2017 Revised: March 2018


*Corresponding Author

ACS Paragon Plus Environment


1

ABSTRACT

2

To explore the effects of scale inhibitors on subsurface water−mineral

3

interactions, here batch experiments on biotite dissolution (0-96 h) were conducted in

4

solutions

5

(DTPMP, a model scale inhibitor), at conditions simulating subsurface environments (95

6

°C and 102 atm CO2). The phosphonate groups in DTPMP enhanced biotite dissolution

7

through both aqueous and surface complexations with Fe, with more significant effects at

8

a higher DTPMP concentration. Surface complexation made cracked biotite surface

9

layers bend, and these layers detached at a later stage (≥ 44 h). The presence of DTPMP

10

also promoted secondary precipitation of Fe- and Al-bearing minerals both in the solution

11

and on the reacted biotite surfaces. With 1.0 mM DTPMP after 44 h, significant coverage

12

of biotite surfaces by precipitates and less detachment of cracked layers blocked reactive

13

sites and inhibited further biotite dissolution. Furthermore, adsorption of DTPMP made

14

the reacted biotite basal surfaces more hydrophilic, which may affect the transport of

15

reactive fluids. This study provides new information on the impacts of phosphonates in

16

brine−mineral interactions, benefiting safer and more environmentally sustainable design

17

and operation of engineered subsurface processes.

containing

0–1.0

mM

diethylenetriaminepenta(methylene)phosphonate

1 ACS Paragon Plus Environment

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INTRODUCTION

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Geologic CO2 sequestration (GCS) and CO2-enhanced oil/gas recovery (EOR) are

20

important engineered subsurface operations to mitigate global warming and meet energy

21

demands.1-3 The chemical and physical properties of rocks, such as their porosity,

22

permeability, surface chemistry, and wettability, greatly affect the engineered operations.

23

During these processes, scale formation of calcium carbonate, calcium sulfate, and

24

barium sulfate is a significant problem which can reduce the porosity and permeability of

25

reservoirs and block flow in production wells.4-7 To prevent the formation of mineral

26

scales, scale inhibitors have been used.8 In the course of scale inhibitor application,

27

interactions between rocks and minerals with the scale inhibitors determine their

28

retention and release, thus influencing their efficacy in inhibiting scale formation.

29

Wettability, an important rock property, largely determines the distribution and mobility

30

of reactive fluids, such as CO2 and oil/gas.9-10 It has been reported that mineral

31

wettability can be altered by chemical reactions of minerals.11-12 Based on the known

32

strong chelating capability of scale inhibitors and their chemical interactions with

33

minerals, one can expect that significant brine−mineral interactions can occur during

34

applications of scale inhibitors in subsurface operations.13-18 Therefore, for safer and

35

more efficient subsurface operations, it is important to understand how scale inhibitors

36

interact with rocks and minerals under relevant conditions.

37

Phosphonates, which contain one or more functional groups (-PO3H2) and P-C-N-

38

C-P or P-C-P bonds, are commonly used as scale inhibitors in engineered subsurface

39

operations.13-14,19-20 These compounds are strong chelating agents that can complex with

40

aqueous metal ions and metal sites at mineral surfaces, affecting mineral dissolution.16-17



41

It was reported that aqueous Fe (II/III) can complex strongly with phosphonate functional

42

groups.13-15 Yan et al. observed that iron was extracted from Marcellus shale by

43

phosphonates due to their strong chelating properties, and that a ferrous or ferric

44

phosphonate precipitate might form.18 However, the identity of the reaction products and

45

impacts of these unexpected and uncommon mineral scales on physicochemical

46

properties of rocks were not discussed.

47

The reported average concentration of phosphonates in subsurface operations,

48

such as in fracking fluids, is ~0.023 wt.% (~0.5 mM).21 They are applied under pressure

49

and then work at a concentration above a minimal inhibitor concentration by affecting

50

nucleation and growth of scale minerals.2,11,13,22 During subsurface operations,

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phosphonate concentrations can change due to interactions with rocks and minerals. They

52

will also vary from near the wellbore area to areas away from the wellbore. Recent

53

studies have reported phosphonate adsorption onto reservoir rocks at low concentrations

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(generally ˂ 0.06 mM)

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phosphonate) on mineral surfaces at higher phosphonate concentrations at 70 °C, with the

56

concentration threshold depending on mineralogy and CO2 pressures.18,23 However,

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information on the effects of different phosphonate concentrations on mineral dissolution

58

and secondary precipitation is lacking. In addition, if phosphonates precipitate as solid

59

forms, they will reduce the available inhibitor concentrations in solution and influence

60

their performance in scale inhibition. Thus, we need a better understanding of the effects

61

of different concentrations of phosphonates on the chemical processes of rocks and

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minerals under subsurface conditions.

and formation of precipitates (Ca-phosphonate or Fe-


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Shales are the main reservoirs for unconventional oil and gas recovery, led by

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new developments in horizontal drilling and hydraulic fracturing.24-25 They have also

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been evaluated as host rocks and caprocks for CO2 storage.26 Shales are mixtures of

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various clay minerals, with fine grains of quartz, feldspars, and calcite.27 Despite the

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important role of shales in engineered subsurface operations, previous studies have

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focused only on scale inhibitor–carbonate/sandstone interactions by investigating

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retention and release mechanisms of phosphonates.6, 23, 28 Only a few studies investigated

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the adsorption and precipitation of scale inhibitors on shale formations,18,29 and their

71

effects on the dissolution of shales and on secondary precipitation still remain poorly

72

understood. Moreover, the solubility of Fe-phosphonate mineral is many orders of

73

magnitude lower than that of Ca-phosphonate.6,13-14 Phosphonates may enhance

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secondary precipitation when they interact with Fe-bearing minerals, which can further

75

influence mineral dissolution in subsurface sites. Although phosphonates can much

76

differently affect the dissolution of Fe-bearing minerals and non-Fe-bearing minerals,

77

such as sandstone or carbonate minerals, studies on Fe-bearing shale minerals are very

78

limited.

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Therefore, using biotite as a model Fe-bearing clay mineral,30-31 this study

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investigated the effects of phosphonates on brine−biotite interfacial interactions and

81

mechanisms under conditions relevant to subsurface environments (95 °C and 102 atm

82

CO2). The results will improve our understanding of the impacts of phosphonate

83

additives on the geochemical processes of reservoir rocks and minerals and the

84

subsequent physicochemical property changes of mineral surfaces. The findings can



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provide new fundamental information that can benefit environmental safety and

86

efficiency of engineered subsurface operations.

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EXPERIMENTAL SECTION

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Minerals and Chemicals

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Biotite from Bancroft, Ontario, Canada (Ward’s Natural Science, NY) was used.

90

The

chemical

composition,

analyzed

by

X-ray

fluorescence

(XRF),

was

91

K0.91Na0.08Ca0.05Mg1.72Mn0.06Fe1.12Ti0.12Al1.00Si2.98O10(F0.51(OH)0.49)2 (Table S1). Biotite

92

flakes measuring 1.0 cm × 0.8 cm, with a thickness of 80 ±10 µm, were prepared by

93

cleaving specimens along the {001} basal planes. The biotite flakes were sonicated in

94

acetone, ethanol, and isopropanol successively for 5 min each to remove organic matter,

95

then rinsed with deionized (DI) water (resistivity > 18.2 MΩ·cm, Barnstead Ultrapure

96

Water Systems), and dried with high purity nitrogen gas. They were stored in dust-free

97

tubes for further dissolution experiments.

98

Diethylenetriaminepenta(methylene)phosphonate (DTPMP, Sigma-Aldrich) was

99

used as a model phosphonate scale inhibitor. To mimic the water chemistry in subsurface

100

environments, reaction solutions of 0 (control), 0.05, 0.5 (the reported average site

101

value), and 1.0 mM DTPMP were prepared, all with a salinity of 0.5 M NaCl.

102

High temperature and high pressure reaction systems

103

The temperature and pressure of engineered subsurface sites are generally in the

104

ranges of 35–110 °C and 73.6–600 atm, respectively.32-34 Biotite dissolution experiments

105

were conducted at 95 °C and 102 atm CO2, simulating CO2-involved GCS and EOR

106

operation conditions. The relatively high temperature was used (S2 in the Supporting

107

Information) to accelerate the reactions and make experimental observations available 5 ACS Paragon Plus Environment

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within reasonable time frames, and to compare them with previous studies.11-12,30-31 A

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benchtop reactor was used for the reaction, as described in our previous studies (Figure

110

S1).11,30 To control the initial pH values within a small range, the solutions of four

111

different DTPMP concentrations were adjusted to pH 5.6 with diluted hydrochloric acid

112

(HCl) under ambient conditions. Measured by a pH probe (Corr Instruments, TX) that

113

can work under 20–120 °C and 1–136 atm, the initial in situ pH values for all four

114

solutions were within a small range of 3.0–3.4 at 95 °C and 102 atm CO2. The

115

Supporting Information (S3) gives detailed information about in situ pH measurement

116

and thermodynamic calculation of the initial pH of the control system by Geochemist’s

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Work Bench (GWB, Release 8.0, RockWare, Inc). Triplicate PTFE tubes containing 4

118

mL of the prepared solutions and a piece of clean biotite flake were placed in a 300 mL

119

reactor. To mimic and investigate the effects of DTPMP on brine−biotite interactions in

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the early period of injection, at six elapsed times between 0–96 hours, the reactor was

121

cooled and slowly degassed, both within 30 min.

122

Analyses of aqueous samples

123

After degassing, the solutions were filtered through 0.2 µm polypropylene

124

membranes and then analyzed by ultraviolet-visible spectroscopy (UV-Vis, Thermo

125

Scientific Evolution 60S) in the 200–500 nm wavelength range for aqueous complexes.

126

Then, the solutions were acidified in 1% trace metal nitric acid (HNO3) to quantify the

127

concentrations of dissolved aqueous cations and total phosphorus using inductively

128

coupled plasma-optical emission spectrometry (ICP-OES, PerkinElmer Optima 7300

129

DV). The aqueous phosphate concentrations, which can be released by decomposition of



130

DTPMP, were measured with ion chromatography (IC, Thermo Scientific Dionex ICS-

131

1600).

132

Surface characterization and secondary mineral identification

133

The reacted biotite flakes were gently rinsed with DI water and dried with

134

nitrogen gas, and then analyzed for surface morphology and secondary mineral phases.

135

The surface morphology of biotite flakes was analyzed in contact mode with atomic force

136

microscopy (AFM, Nanoscope V Multimode SPS, Veeco) under ambient conditions.

137

Using nonconductive silicon nitride probe (tip radius of 10 nm, DNP-S10, Bruker) at a

138

rate of 0.999 Hz and with a deflection set point of 1.975 V, we scanned areas of 50 µm ×

139

50 µm. The obtained AFM images were analyzed with Nanoscope software (v7.20).

140

Scanning electron microscopy (SEM, Nova NanoSEM 230) was used to analyze

141

both the reacted biotite basal surfaces and the particles in the solutions. A 10.00 kV

142

electron accelerating voltage was used for imaging. To capture possible detached biotite

143

layers and any particles formed in the solutions, after the dissolution reactions, the

144

polypropylene membranes used for filtration were washed with DI water and examined

145

by SEM. SEM images were taken and energy dispersive X-ray spectroscopy (EDX) was

146

used to analyze the elemental compositions of the particles.

147

High resolution-transmission electron microscopy (HR-TEM, JEOL-2100F)

148

characterized the secondary mineral phases. To examine particles formed in solutions,

149

TEM samples were prepared in the following way: after reaction for 70 h, the solutions

150

were centrifuged at 5000 rpm for 5 min. The particles in the bottom were collected, 40

151

mL of DI water was added, and the suspension was centrifuged again. This process was

152

repeated for 5 times to remove ionic species and prevent unexpected precipitation during


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sample drying. After centrifugation, a droplet from the bottom of the solution (containing

154

only particles formed during the reactions) was placed on a Formvar/carbon coated-Cu

155

grid (Electron Microscopy Science, PA) and allowed to dry. To examine particles formed

156

on the reacted biotite surfaces, TEM samples were prepared by sonicating the reacted

157

biotite flake in ethanol for 5 min, detaching particles from the surface into ethanol, and

158

placing a droplet of the suspension on a TEM grid. Lattice fringes and electron

159

diffraction patterns were obtained to identify the secondary mineral phases. Elemental

160

compositions were also analyzed by energy dispersive X-ray spectroscopy during the

161

TEM measurements.

162

Contact angle measurements

163

Under ambient conditions, biotite flakes reacted at 95 oC and 102 atm CO2 were

164

analyzed for contact angles using a contact angle analyzer (Surface Electro Optics,

165

Phoenix 300). A droplet of DI water was generated by a syringe needle, placed on the

166

biotite basal surface, and imaged. Contact angles were then obtained by analyzing the

167

images (Figure S2). Six measurements were made on every biotite sample, and the

168

average contact angles were reported.

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RESULTS AND DISCUSSION

170

DTPMP promoted the dissolution of biotite

171

The effects of DTPMP on the evolution of aqueous cation concentrations varied

172

for different cations after biotite reacted under high temperature and high pressure

173

conditions. The release of interlayer K, mediated by ion-exchange reactions, from biotite

174

was not affected by the presence of DTPMP (Figure 1). Due to the controlled background

175

salinity and initial pH (Table S2), similar extents of ion-exchange reactions between 8 ACS Paragon Plus Environment


176

interlayer K and cations in the reaction solutions occurred at all DTMPM concentrations.

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However, the aqueous concentrations of framework cations (Si, Mg, Fe, and Al) were

178

dependent on DTPMP (Figure 1). The Si and Mg concentrations were higher with

179

DTPMP than in control experiments without DTPMP, indicating the promotion of biotite

180

dissolution by DTPMP. On the other hand, we observed that aqueous concentrations of

181

Fe and Al were lower with DTPMP than those in control experiments, especially after

182

longer reaction times (≥ 44 h). Note that the aqueous concentrations measured by ICP-

183

OES are the net results of biotite dissolution and secondary mineral precipitation. Fe- and

184

Al-bearing phosphonate/phosphate minerals are quite insoluble, with solubility product

185

constants (Ksp) lower than the order of 10-19.14,35-36 Therefore, we hypothesized that

186

DTPMP could promote biotite dissolution and the release of Fe and Al. Secondary

187

precipitation of Fe- or Al-bearing minerals then consumed Fe and Al released during

188

biotite dissolution, resulting in their lower aqueous concentrations as measured by ICP-

189

OES.

190

The effects of DTPMP on the evolution of framework cations were also

191

dependent on DTPMP concentrations. For Si and Mg, which were assumed not to have

192

significant secondary precipitation, their aqueous concentrations increased with

193

increasing DTPMP concentrations from 0 to 0.5 mM. Interestingly, however, the Si and

194

Mg concentrations in 1.0 mM DTPMP reaction system were lower than those in the 0.5

195

mM DTPMP systems. Because the initial and final pH values of the control and 1.0 mM

196

DTPMP systems were close (Table S2), the pH difference might not influence biotite

197

dissolution and secondary precipitation. To explain the observations, several possible

198

scenarios can be considered: First, aqueous complexation and surface complexation could 9 ACS Paragon Plus Environment

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affect biotite dissolution. With increasing DTPMP concentration, more significant

200

aqueous complexation could increase the apparent solubility of minerals, thus promoting

201

biotite dissolution.37 DTPMP adsorption onto biotite surfaces could either promote or

202

inhibit dissolution by forming different configurations of mono/bi/multi-dentate

203

mono/bi/multi-nuclear surface complexation.38-39 Second, more promoted dissolution and

204

even more significant secondary precipitation with 1.0 mM DTPMP could result in the

205

lower net aqueous concentrations. Third, if the secondary precipitation occurred on the

206

biotite surface, the precipitates might block reactive surface sites and even inhibit further

207

dissolution of biotite. To evaluate these three possible mechanisms, further studies were

208

conducted.

209

Aqueous complexation of DTPMP with ferric ions (Fe(III))

210

UV-Vis analyses of the reacted solutions after filtration were conducted to

211

characterize aqueous complexation, and the results are shown in Figure 2 and S5. As

212

reported by Matthijs et al., the maximum absorbance around 260 nm (Figure S3)

213

observed in this study corresponded to Fe(III)-DTPMP aqueous complexes.15 The UV-

214

Vis analyses showed increasing absorbance by Fe(III)-DTPMP aqueous complexes with

215

increasing DTPMP concentrations (Figure 2A). In the 0.05 mM DTPMP system,

216

although we observed higher aqueous Fe concentrations in the ICP-OES results than in

217

the 0.5 mM and 1.0 mM DTPMP systems (Figure 1), the aqueous Fe was not fully

218

complexed because of the low DTPMP concentration, showing lower absorbance in the

219

UV results. Therefore, aqueous complexation contributed to enhancing biotite dissolution,

220

and more significant promotion effects occurred at higher DTPMP concentrations. The

221

observation for DTPMP effects was different from the effects of phosphate ions on



222

biotite dissolution, where aqueous complexation was quite weak.12 The difference could

223

have resulted from the higher chelating capacity of DTPMP, with several phosphonate

224

functional groups.40 As the reaction continued, the absorbance decreased with time from

225

22 h to 44 h, indicating a decreasing aqueous complexation. The decreasing could result

226

from lower aqueous Fe or DTPMP concentrations caused by secondary precipitation or

227

DTPMP adsorption.

228

DTPMP promoted secondary precipitation and altered biotite surface morphology

229

The morphological evolution of the reacted biotite basal surface was dependent

230

on DTPMP concentrations, as shown in the AFM images in Figure 3. Compared with

231

control samples, increasing the concentration of DTPMP promoted the formation of

232

cracks (red to dark channels, indicated by arrows in Figure 3) and increased the crack

233

depth. Based on analyses of 12 regions of cracks from triplicate samples after 8 h

234

reaction, the crack depths reached to around 13 nm for the 0.5 mM DTPMP sample and

235

30 nm for the 1.0 mM DTPMP sample. This observation indicates that 1.0 mM DTPMP

236

promoted more biotite dissolution at early reaction times than 0.5 mM DTPMP,

237

consistent with UV-Vis analyses. Fibrous precipitates, identified as illite in previous

238

studies,30,41-42 were formed on all four biotite samples after 3 h reaction (yellow to pink

239

fibers, indicated by arrows in Figure 3). Then, rough biotite basal surfaces were observed

240

for 0.05 mM, 0.5 mM, and 1.0 mM DTPMP samples after 8 h, 22 h, and 44 h,

241

respectively, resulting from enhanced surface precipitation of fragile particles by the

242

presence of DTPMP. The first occurrence of significant surface precipitation was

243

increasingly delayed as the DTPMP concentrations increased from 0.05 mM to 1.0 mM.

244

This delay would have resulted from enhanced biotite dissolution by more significant


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aqueous complexation at higher DTPMP concentrations (Figure 2A), which could have

246

led to more homogeneous precipitation in the solutions than surface precipitation. At the

247

early reaction times (˂ 44 h), enhanced biotite dissolution at higher DTPMP

248

concentrations released more cations into the solutions, causing higher mineral

249

saturations and favoring homogeneous precipitation over heterogeneous precipitation on

250

the mineral surfaces.43-44 Notably, in the 1.0 mM DTPMP system, the greater

251

homogeneous precipitation in the solution even led to lower aqueous cation

252

concentrations than those in the 0.5 mM DTPMP system. In addition, the removed

253

aqueous P concentrations in the DTPMP systems over time were monitored by ICP-OES,

254

and the results are shown in Figure 2B. At the early times (< 44 h), P removal in the 1.0

255

mM DTPMP system was higher than that in the 0.5 mM DTPMP system. The P was

256

mainly removed by adsorption onto mineral surfaces or secondary precipitation.

257

Although we could not deconvolute the relative amounts of P removed by adsorption and

258

secondary precipitation, the evolution of aqueous P removal hinted at more secondary

259

precipitation in the 1.0 mM DTPMP system at an early time. This observation was

260

consistent with a recent report that a higher phytate (an organic phosphate) concentration

261

promoted more secondary precipitation.40 We initially assumed that there was no

262

significant secondary precipitation of Si and Mg, however, the formation of Fe- or Al-

263

bearing minerals could incorporate Si and Mg, and coprecipitation lowered the aqueous

264

Si and Mg concentrations.

265

On the 0.05 mM and 0.5 mM DTPMP samples, after longer reaction times (≥ 44

266

h), new layers on biotite surface were exposed due to detachment of the cracked biotite

267

surface layers together with secondary precipitates. The surfaces of 1.0 mM DTPMP



268

samples were significantly covered by secondary minerals. Because AFM tips are

269

sensitive to rough surfaces, to observe the features of reacted biotite surfaces, SEM

270

measurements were conducted for samples after 70 h reaction. In the SEM images

271

(Figure 4), cracks were observed on the surfaces of all four samples. Interestingly, some

272

cracked layers were bent outwards from the DTPMP samples (indicated by the yellow

273

dotted circles in Figure 4). Differently, in our recent study of the promotion effects of

274

inorganic phosphate on biotite dissolution, bent surface layers were not observed,12

275

probably because inorganic phosphate has a smaller molecular size than DTPMP.

276

Phosphorus in EDX was observed on the cracked biotite layer (Figure S4A), suggesting

277

surface complexation and adsorption of DTPMP. Therefore, although reference

278

information about DTPMP complexation with Fe or Al sites is not available to determine

279

the configuration of surface complexation by FTIR (Fourier-transform infrared

280

spectroscopy), it is clear that the adsorption of the large DTPMP molecules helped create

281

the cracks and resulted in the bent layers, both of which exposed reactive surface sites

282

and contributed to promoting the biotite dissolution. The bent cracked layers detached

283

from the reacted biotite basal surfaces, and obviously, the 0.5 mM DTPMP sample

284

showed the newly exposed layer and the remaining cracked layers. For the 1.0 mM

285

DTPMP sample, the peeling was not as significant as for the 0.5 mM DTPMP samples.

286

After 44 h reaction, the high coverage of the attacked biotite layer, together with DTPMP

287

coating and secondary precipitation on the surface of 1.0 mM DTPMP sample, could

288

block the reactive surface sites and inhibit further biotite dissolution, leading to lower

289

aqueous cation concentrations than those in the 0.5 mM DTPMP system.

290


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Identification of secondary minerals

292

The lower aqueous Fe and Al concentrations in the DTPMP systems were

293

hypothesized to be caused by both homogeneous precipitation in the reaction solution

294

and heterogeneous precipitation of Fe- and Al-bearing minerals on the biotite surfaces.

295

The hypothesis was supported by the both ICP and AFM observations. To further

296

identify the compositions and phases of the secondary minerals, SEM and TEM

297

measurements were conducted for samples collected after 44 and 70 h reactions.

298

After 44 h of reaction, homogeneous precipitates were observed in the DTPMP

299

reaction solutions (Figure 5A). The porous substrate shown in Figure 5A is the

300

membrane used for filtration. The filtration results showed that homogeneous

301

precipitation was more significant in the 1.0 mM DTPMP solution than in the 0.5 mM

302

DTPMP solution. The precipitates contained mainly Fe, Al, and P as well as

303

incorporations of Mg and Si as revealed by EDX measurements (Figures S4B). Therefore,

304

at this early reaction time of 44 h, the more significant homogeneous precipitation of Fe-,

305

Al-, Mg-, Si-, and P-bearing minerals could contribute to the lower aqueous cation

306

concentrations observed in the 1.0 mM DTPMP system than 0.5 mM DTPMP system

307

(Figure 1). The aqueous concentrations of Si and Mg were lower in the 1.0 mM DTPMP

308

system than 0.5 mM DTPMP system, but the aqueous Fe and Al concentrations were

309

similar between the two systems. This observation could result from the preferential

310

release of Fe and Al over Si and Mg by complexation with DTPMP. DTPMP could

311

strongly interact with Fe and Al,15,45 leading to higher promotion effect of Fe and Al

312

dissolution and secondary precipitation. Note that the ICP-OES results in Figure 1 show

313

net concentrations of dissolution and secondary precipitation. Considering the



314

disproportional DTPMP promotion effects on releases of different elements and

315

secondary precipitation, it is reasonable that the evolutions of aqueous Si and Mg

316

concentrations were different from those of Fe and Al in the 0.5 mM DTPMP and 1.0

317

mM DTPMP systems.

318

After 70 h reaction, regarding particles in control solution, flakes (Figure 5B1)

319

were observed with a composition similar to biotite, measured by EDX (Figure S4C). In

320

the 0.5 mM DTPMP solution, more flakes with a similar biotite composition at a size

321

around 10 µm were observed. The flakes were probably detached from the biotite

322

surfaces during the reactions. Phosphorus was also identified by EDX measurements in

323

the flakes (Figure S4C), which further supports the assumption of DTPMP adsorption

324

onto biotite surfaces. In addition to the flakes, abundant particles of several hundred

325

nanometers were formed in the 0.5 mM DTPMP solution (Figure 5B1). The EDX

326

measurements of the particles formed in solution showed they contained high amounts of

327

P, Fe, and Al, with incorporation of Si and Mg (Figure S4C). In TEM measurements, no

328

obvious electron diffractions were observed for those particles (Figure S5 and Figure 5B2)

329

formed in the 0.5 mM DTPMP solution, indicating amorphous phases of the secondary

330

particles.

331

On the other hand, the particles observed on biotite surfaces after reaction for 70 h

332

with 0.5 mM DTPMP were crystalized, showing strong electron diffraction patterns

333

(Figure 5C). The particles were also abundant in P, Fe, and Al (Figure S4A). The d-

334

spacings calculated from the electron diffraction patterns and the lattice fringes are

335

shown in Figure S6. Initially, it was anticipated that Fe- or Al-DTPMP minerals formed

336

on biotite surfaces during the reactions because they have quite low solubility.14,35-36 No


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references for d-spacings of Fe- and Al-DTPMP minerals are available. However, by

338

comparing the measured d-spacings with available reference information for Fe- or Al-

339

inorganic phosphate or (hydr)oxide minerals, we can suggest that the secondary phases

340

probably contained a mixture of minerals, including strengite (FePO4), gibbsite

341

(Al(OH)3), and berlinite (AlPO4).46 Furthermore, there was no d-spacing which did not

342

match these three mineral phases. The formation of the phosphate minerals is interesting,

343

but it is plausible because we observed up to 2.8 mM of phosphate as a degradation

344

product of DTPMP, based on IC measurements of solutions in the DTPMP systems after

345

high temperature and pressure experiments (Figure S7). While the degradation

346

mechanism of DTPMP is not the focus of the present study, it has been reported

347

previously that photodegradation of phosphonates or nonilluminated degradation of

348

phosphonates in the presence of transition metals and molecular oxygen can release

349

phosphate.16,

350

precipitation of released Fe and Al with phosphate. DTPMP could also serve as an

351

organic template, mediating the formation of these crystalized secondary precipitates.

352

Nonetheless, amorphous Fe- or Al-DTPMP minerals could still form on biotite surfaces,

353

which do not have obvious electron diffraction patterns. Thermodynamic calculations for

354

saturations of the secondary minerals were not possible in the DTPMP systems because

355

detailed thermodynamic data for DTPMP is not available and phosphonate can strongly

356

affect the apparent solubility by strong complexation with cations and protons.

47

Hence, the strengite and berlinite we found could have formed from

357

In summary, aqueous complexation and surface adsorption of DTPMP promoted

358

biotite dissolution, with more significant effects at higher DTPMP concentrations.

359

Moreover, the enhanced formation of Fe- and Al-bearing secondary minerals in the



360

DTPMP systems significantly consumed the released Fe and Al from biotite dissolution,

361

resulting in lower aqueous Fe and Al concentrations. However, based on the current

362

experimental results, we could not determine the extents of homogeneous precipitation

363

and heterogeneous precipitation and their relative contributions to the lower aqueous Fe

364

and Al concentrations. In the 1.0 mM DTPMP system, significant precipitation in the

365

solution at early reaction times (˂ 44 h) and inhibited dissolution by surface precipitation

366

at longer reaction times (≥ 44 h) occurred, leading to lower aqueous cation concentrations

367

than those in the 0.5 mM DTPMP system.

368

DTPMP enhanced biotite wettability

369

Wettability is an important parameter controlling the flow and distribution of

370

fluids during subsurface operations. The presence of DTPMP significantly affected

371

biotite wettability, given by contact angle, as shown in Figure 6. Even after just 3 h

372

reaction, lower contact angles (around 11º) were observed for biotite samples after

373

reaction with DTPMP than those for control samples (25º–28º) (Figure 6), indicating that

374

DTPMP enhanced biotite wettability. In our recent study,11 we found that increased

375

roughness, more negatively charged surfaces, and higher densities of hydroxyl groups on

376

biotite surfaces induced by dissolution can contribute to enhancing biotite wettability.

377

From the ICP and AFM results, after 3 h reaction, the reaction extents for all four

378

samples were similar, without significant differences in released cation concentrations

379

and surface morphology changes. Therefore, the current study shows that dissolution-

380

induced changes in surface roughness, surface charges, and hydroxyl groups were not the

381

main mechanisms leading to the enhanced wettability by DTPMP.


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382

In addition, the contact angles were close for all the DTPMP samples and they did

383

not change over time despite the significant differences in surface morphology after

384

reaction times longer than 3 h. The observation further rules out the contribution of

385

surface roughness to changes in surface wettability in this study. We considered that

386

adsorption of DTPMP contributed the most to the enhanced wettability of biotite samples

387

in the DTPMP systems. As discussed in our previous study,30 oxalate preferentially forms

388

complexes with biotite edge surface sites. By analogy, DTPMP, a strong chelating agent,

389

probably adsorbed onto edge surface sites. However, due to biotite dissolution, cracks

390

were formed, exposing edge sites on biotite basal planes. Therefore, DTPMP adsorption

391

could also occur on edges created by cracks in biotite basal surfaces. The adsorption of

392

DTPMP onto the biotite basal surfaces exposed abundant hydrophilic groups (-OH) of

393

DTPMP, thus favoring water spreading on the biotite surface and enhancing the

394

wettability.11 In a recent study,12 phosphate adsorption and secondary precipitation

395

induced by phosphate were reported to enhance biotite wettability, with a contact angle

396

of around 14º for a 0.1 mM phosphate sample. In our experimental systems, phosphate

397

was observed in the DTPMP systems after the high temperature and high pressure

398

reactions (Figure S7). Although phosphate could also contribute to enhancing biotite

399

wettability, we think that DTPMP adsorption was the main factor. Only a very low

400

phosphate concentration was observed in the 0.05 mM DTPMP system (about 40 µM

401

phosphate), and the contact angles for DTPMP samples (around 11º) were lower than

402

phosphate samples (around 14°). However, there is a caveat that contact angles lower

403

than 10º could not be accurately measured because the water droplet spread fully on

404

biotite basal surface and it was difficult to distinguish the droplet and analyze the angles.



405

In systems with different DTPMP concentrations, we might expect lower contact angles

406

for samples reacted with higher DTPMP concentrations, due to potentially higher

407

adsorption. Nonetheless, the limitation on contact angle measurement would make it

408

difficult to resolve the difference. However, the main thesis, that DTPMP enhanced

409

wettability, is still valid.

410

ENVIRONMENTAL IMPLICATIONS

411

In this study, we report the roles of DTPMP in brine−biotite interactions under

412

subsurface conditions, and their effects on the consequent surface morphology evolution

413

and wettability alteration. The new findings will help better predict the fate and transport

414

of scale inhibitors in subsurface environments. Furthermore, they can benefit our

415

understanding of the porosity, permeability, and wettability changes of reservoirs and

416

caprocks, affected by the application of scale inhibitors in engineered subsurface

417

operations.

418

The mechanisms by which DTPMP promotes mineral dissolution are different

419

from those of short-chain carboxylic acids and inorganic phosphate. As reported in

420

previous studies, short-chain carboxylic acids and inorganic phosphate promote mineral

421

dissolution mainly by forming surface complexation, and aqueous complexation was very

422

weak in those systems.30,48 However, DTPMP, with five phosphonate functional groups,

423

promoted biotite dissolution through both strong aqueous and surface complexation, with

424

more pronounced effects at increasing concentrations (0–1.0 mM). In addition, we also

425

observed that DTPMP altered the surface morphology of reacted biotite samples, with

426

bent cracked surface regions, which were not observed with inorganic phosphate, and

427

that the cracked layers detached from biotite surfaces into the reaction solutions. Similar 19 ACS Paragon Plus Environment

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428

to inorganic phosphate, however, DTPMP promoted significant homogeneous and

429

heterogeneous precipitation of Fe- and Al-bearing minerals. These secondary minerals

430

are unexpected scaling minerals, and are different from commonly considered scales,

431

such as CaCO3 or BaSO4. The newly formed precipitates and detached cracked surface

432

layers may clog nano- and micro- sized pores,49 reducing the permeability or porosity of

433

rocks.50 There is a need to deal with the unexpected precipitates induced by scale

434

inhibitors during subsurface operations.

435

Wettability is a key factor affecting the transport and distribution of subsurface

436

fluids. The enhanced mineral wettability by DTPMP may favor mineral’s contact with

437

water, promoting the flow of non-wetting phases, such as oil/gas and supercritical CO2.

438

The surface adsorption, secondary precipitation, and degradation of DTPMP could

439

reduce its available concentration in the aqueous solution, which may further affect its

440

scale inhibition performance when applied in subsurface environments.

441

SUPPORTING INFORMATION

442

Details on the elemental composition of biotite (S1), the high temperature and

443

high pressure experimental setup (S2), in situ pH measurments (S3), contact angle

444

measurements (S4), UV-Vis analyses (S5), SEM measurements (S6), HR-TEM

445

measurements (S7), the evolutoin of phosphate concentrations (S8), and friction mode

446

AFM image (S9) .

447

ACKNOWLEDGMENTS

448

This work was supported by the Center for Nanoscale Controls on Geologic CO2,

449

an Energy Frontier Research Center funded by the U.S. Department of Energy, Office of

450

Science, Office of Basic Energy Sciences, via Grant DE-AC02-05CH11231. We also 20 ACS Paragon Plus Environment


451

thank National Science Foundation’s CAREER Award (EAR-1057117). The authors

452

acknowledge Washington University’s Institute of Materials Science & Engineering for

453

use of HR-TEM, and the Nano Research Facility for use of SEM and ICP-OES. We also

454

thank Prof. James Ballard for carefully reviewing our manuscript.


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REFERENCES 1.

2. 3.

4. 5.

6.

7. 8. 9. 10. 11.

12.

13.

14.

15.

16.

Metz, B.; Davidson, O.; De Coninck, H.; Loos, M.; Meyer, L. IPCC special report on carbon dioxide capture and storage: Prepared by Working Group III of the Intergovernmental Panel on Climate Change; IPCC: Cambridge University Press: Cambridge, United Kingdom and New York, USA, 2005. Lake, L. W., Enhanced oil recovery. Prentice Hall: Englewood Cliffs, NJ, 1989. Dai, Z.; Middleton, R.; Viswanathan, H.; Fessenden-Rahn, J.; Bauman, J.; Pawar, R.; Lee, S.-Y.; McPherson, B., An integrated framework for optimizing CO2 sequestration and enhanced oil recovery. Environ. Sci. Technol. Lett. 2013, 1 (1), 49-54. Tomson, M.; Fu, G.; Watson, M.; Kan, A., Mechanisms of mineral scale inhibition. Soc. Petrol. Eng. J. 2002, 18 (3), 192-199. García, A. V.; Thomsen, K.; Stenby, E. H., Prediction of mineral scale formation in geothermal and oilfield operations using the Extended UNIQUAC model: part II. Carbonate-scaling minerals. Geothermics 2006, 35 (3), 239-284. Kan, A. T.; Fu, G.; Tomson, M. B.; Al-Thubaiti, M.; Xiao, A. J., Factors affecting scale inhibitor retention in carbonate-rich formation during squeeze treatment. Soc. Petrol. Eng. J. 2004, 9 (03), 280-289. Oddo, J.; Tomson, M., Why scale forms in the oil field and methods to predict it. SPE Prod. Facil. 1994, 9 (01), 47-54. Amjad, Z., Mineral scale formation and inhibition. Springer Science & Business Media: 2013. Morrow, N. R., Wettability and its effect on oil recovery. Journal of Petroleum Technology 1990, 42 (12), 1,476-1,484. Tokunaga, T. K.; Wan, J., Capillary pressure and mineral wettability influences on reservoir CO2 capacity. Rev. Mineral. Geochem. 2013, 77 (1), 481-503. Zhang, L.; Kim, Y.; Jung, H.; Wan, J.; Jun, Y.-S., Effects of Salinity-Induced Chemical Reactions on Biotite Wettability Changes under Geologic CO2 Sequestration Conditions. Environ. Sci. Technol. Lett. 2016, 3 (3), 92-97. Zhang, L.; Kim, D.; Kim, Y.; Wan, J.; Jun, Y.-S., Effects of Phosphate on Biotite Dissolution and Secondary Precipitation under Conditions Relevant to Engineered Subsurface Processes. Phys. Chem. Chem. Phys. 2017, 19, 29895-29904. Oddo, J. E.; Tomson, M. B., The solubility and stoichiometry of calciumdiethylenetriaminepenta (methylene phosphonate) at 70 in brine solutions at 4.7 and 5.0 pH. Appl. Geochem. 1990, 5 (4), 527-532. Friedfeld, S. J.; He, S.; Tomson, M. B., The temperature and ionic strength dependence of the solubility product constant of ferrous phosphonate. Langmuir 1998, 14 (13), 3698-3703. Matthus, E.; De Oude, N.; Bolte, M.; Lemaire, J., Photodegradation of ferric ethylenediaminetetra (methylenephosphonic acid)(EDTMP) in aqueous solution. Water Res. 1989, 23 (7), 845-851. Nowack, B., Environmental chemistry of phosphonates. Water Res. 2003, 37 (11), 2533-2546. 22 ACS Paragon Plus Environment


17.

18.

19.

20. 21. 22.

23. 24. 25. 26.

27. 28.

29.

30.

31.

32.

Tomson, M.; Kan, A.; Oddo, J., Acid/base and metal complex solution chemistry of the polyphosphonate DTPMP versus temperature and ionic strength. Langmuir 1994, 10 (5), 1442-1449. Yan, F.; Zhang, F.; Bhandari, N.; Wang, L.; Dai, Z.; Zhang, Z.; Liu, Y.; Ruan, G.; Kan, A.; Tomson, M., Adsorption and precipitation of scale inhibitors on shale formations. J. Pet. Sci. Eng. 2015, 136, 32-40. Ketrane, R.; Saidani, B.; Gil, O.; Leleyter, L.; Baraud, F., Efficiency of five scale inhibitors on calcium carbonate precipitation from hard water: effect of temperature and concentration. Desalination 2009, 249 (3), 1397-1404. Dyer, S.; Anderson, C.; Graham, G., Thermal stability of amine methyl phosphonate scale inhibitors. J. Pet. Sci. Eng. 2004, 43 (3), 259-270. Tollefson, J., Secrets of fracking fluids pave way for cleaner recipe. Nature 2013, 501 (7466), 146. Gill, J.; Varsanik, R., Computer modeling of the specific matching between scale inhibitors and crystal structure of scale forming minerals. J. Cryst. Growth 1986, 76 (1), 57-62. Baraka-Lokmane, S.; Sorbie, K., Effect of pH and scale inhibitor concentration on phosphonate–carbonate interaction. J. Pet. Sci. Eng. 2010, 70 (1), 10-27. Montgomery, C. T.; Smith, M. B., Hydraulic fracturing: history of an enduring technology. Journal of Petroleum Technology 2010, 62 (12), 26-40. Rahm, D., Regulating hydraulic fracturing in shale gas plays: The case of Texas. Energy Policy 2011, 39 (5), 2974-2981. Busch, A.; Alles, S.; Gensterblum, Y.; Prinz, D.; Dewhurst, D. N.; Raven, M. D.; Stanjek, H.; Krooss, B. M., Carbon dioxide storage potential of shales. Int. J. Greenhouse Gas Control 2008, 2 (3), 297-308. Blatt, H.; Tracy, R.; Owens, B., Petrology: igneous, sedimentary, and metamorphic. Macmillan: 2006. Tomson, M. B.; Kan, A. T.; Fu, G.; Shen, D.; Nasr-El-Din, H. A.; Saiari, H.; Al Thubaiti, M. M., Mechanistic Understanding of Rock/Phosphonate Interactions and Effect of Metal Ions on Inhibitor Retention. SPE J. 2008, 13 (03), 325-336. Jordan, M.; Sorbie, K.; Jiang, P.; Yuan, M.; Todd, A.; Thiery, L. The effect of clay minerals, pH, calcium and temperature on the adsorption of phosphonate scale inhibitor onto reservoir core and mineral separates; NACE International, Houston, TX (United States): 1994. Zhang, L.; Jun, Y.-S., Distinctive Reactivities at Biotite Edge and Basal Planes in the Presence of Organic Ligands: Implications for Organic-Rich Geologic CO2 Sequestration. Environ. Sci. Technol. 2015, 49 (16), 10217-10225. Jun, Y.-S.; Zhang, L.; Min, Y.; Li, Q., Nanoscale Chemical Processes Affecting Storage Capacities and Seals during Geologic CO2 Sequestration. Acc. Chem. Res. 2017, 50 (7), 1521-1529. Bradshaw, J.; Cook, P., Geological sequestration of carbon dioxide. Environ. Geosci. 2001, 8 (3), 149-151.


Page 24 of 35

Page 25 of 35


33.

34. 35. 36. 37.

38.

39.

40.

41.

42.

43. 44.

45.

46. 47.

48.

Xu, T.; Kharaka, Y. K.; Doughty, C.; Freifeld, B. M.; Daley, T. M., Reactive transport modeling to study changes in water chemistry induced by CO2 injection at the Frio-I Brine Pilot. Chem. Geol. 2010, 271 (3), 153-164. Iding, M.; Ringrose, P., Evaluating the impact of fractures on the performance of the In Salah CO2 storage site. Int. J. Greenhouse Gas Control 2010, 4 (2), 242-248. Iuliano, M.; Ciavatta, L.; De Tommaso, G., On the solubility constant of strengite. Soil Sci. Soc. Am. J. 2007, 71 (4), 1137-1140. Ferguson, J. F.; King, T., A model for aluminum phosphate precipitation. J. Water Pollut. Control Fed. 1977, 646-658. Yang, Y.; Ronzio, C.; Jun, Y.-S., The effects of initial acetate concentration on CO2–brine–anorthite interactions under geologic CO2 sequestration conditions. Energy Environ. Sci. 2011, 4 (11), 4596-4606. Biber, M. V.; dos Santos Afonso, M.; Stumm, W., The coordination chemistry of weathering: IV. Inhibition of the dissolution of oxide minerals. Geochim. Cosmochim. Acta 1994, 58 (9), 1999-2010. Bondietti, G.; Sinniger, J.; Stumm, W., The reactivity of Fe (III)(hydr) oxides: effects of ligands in inhibiting the dissolution. Colloids Surf., A. 1993, 79 (2), 157167. Wang, X.; Hu, Y.; Tang, Y.; Yang, P.; Feng, X.; Xu, W.; Zhu, M., Phosphate and phytate adsorption and precipitation on ferrihydrite surfaces. Environmental Science: Nano 2017, 4 (11), 2193-2204. Hu, Y.; Ray, J. R.; Jun, Y. S., Biotite-brine interactions under acidic hydrothermal conditions: fibrous illite, goethite, and kaolinite formation and biotite surface cracking. Environ. Sci. Technol. 2011, 45 (14), 6175-80. Garcia, D. J.; Shao, H. B.; Hu, Y. D.; Ray, J. R.; Jun, Y. S., Supercritical CO2-brine induced dissolution, swelling, and secondary mineral formation on phlogopite surfaces at 75-95 degrees C and 75 atm. Energy Environ. Sci. 2012, 5 (2), 57585767. De Yoreo, J. J.; Vekilov, P. G., Principles of crystal nucleation and growth. Rev. Mineral. Geochem. 2003, 54 (1), 57-93. Jun, Y.-S.; Lee, B.; Waychunas, G. A., In situ observations of nanoparticle early development kinetics at mineral− water interfaces. Environ. Sci. Technol. 2010, 44 (21), 8182-8189. Deluchat, V.; Bollinger, J.-C.; Serpaud, B.; Caullet, C., Divalent cations speciation with three phosphonate ligands in the pH-range of natural waters. Talanta 1997, 44 (5), 897-907. Chichagov, A. V., Information-calculating system on crystal structure data of minerals (MINCRYST). In Kristallografiya, 1990; Vol. 35, pp 610-616. Nowack, B.; Stone, A. T., Degradation of nitrilotris (methylenephosphonic acid) and related (amino) phosphonate chelating agents in the presence of manganese and molecular oxygen. Environ. Sci. Technol. 2000, 34 (22), 4759-4765. Zhang, L.; Kim, D.; Kim, Y.; Wan, J.; Jun, Y.-S., Effects of Phosphate on Biotite Dissolution and Secondary Precipitation under Conditions Relevant to Engineered Subsurface Processes. Phys. Chem. Chem. Phys. 2017. 24 ACS Paragon Plus Environment


49. 50.

Kate, J.; Gokhale, C., A simple method to estimate complete pore size distribution of rocks. Eng. Geol. 2006, 84 (1), 48-69. Jun, Y.-S.; Giammar, D. E.; Werth, C. J., Impacts of geochemical reactions on geologic carbon sequestration. Environ. Sci. Technol. 2013, 47 (1), 3-8.


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List of Figures Figure 1.

Effects of DTPMP concentrations (0, 0.05, 0.5, and 1.0 mM) on the evolution of aqueous cation concentrations of K, Si, Al, Mg, and Fe during biotite dissolution with an ionic strength of 0.5 M NaCl at 95 °C and 102 atm of CO2. Error bars are the standard deviation of triplicate experiments.

Figure 2.

(A) UV-Vis absorbance (wavelength = 260 nm) of filtered solutions and (B) analyses of P removal after reaction with different concentrations of DTPMP (0.05, 0.5, and 1.0 mM) at 95 °C and 102 atm of CO2.

Figure 3.

(A) Height mode AFM images of biotite basal surfaces after reaction in 0.5 M NaCl solution at 95 °C and 102 atm of CO2 without DTPMP (Control), with (B) 0.05, (C) 0.5, and (D) 1.0 mM DTPMP. The AFM images are 50 µm × 50 µm. The height scale is 60 nm for images A3-96 h, B3-44 h, C3-22 h, and D322 h, and is 200 nm for the other images. The color scale from dark to pink indicates height from low to high. The different height scales were used to show the results more clearly.

Figure 4.

SEM images of biotite basal surfaces after 70 h reaction with different DTPMP concentrations (0, 0.05, 0.5, 1.0 mM) at 95 °C and 102 atm of CO2. The yellow dotted circles indicate the bent cracked layers after dissolution.

Figure 5.

(A) SEM measurements of samples collected on membranes after filtering solutions reacted for 44 h at 95 °C and 102 atm of CO2 for 70 h. (B1) SEM measurements of samples collected on membranes after filtering solutions, and (B2) TEM measurements of particles from solutions collected by centrifuge, after reaction at 95 °C and 102 atm of CO2 for 70 h. (C) TEM image (left) and



electron diffraction pattern (right) of particles formed on biotite surfaces after reaction with 0.5 mM DTPMP at 95 °C and 102 atm of CO2 for 70 h. Figure 6.

Wettability, indicated by contact angle, of biotite basal surfaces after reaction with different DTPMP concentrations (0, 0.05, 0.5, 1.0 mM) over time. The error bars are standard deviations of six measurements from triplicate experiments.


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TOC Art



Figure 1


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Figure 2



Figure 3


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Figure 4



Figure 5


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Contact angle (Deg.)

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40 30

Control 0.5 mM

0.05 mM 1.0 mM

20 10 0 0

20 40 60 80 100 Reaction Time (h) Figure 6


The Effects of Phosphonate-Based Scale Inhibitor on BrineâBiotite

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