I
Molybdenum
-99(
99Mo) Adsorption Profile of
^ Zirconia-Based Materials For
99Mo/
99mTc Generator
^ Application
4 5 6 7
4 9 10
II 12
13 A R T I C L E I N F O A B S T R A C T
14 ________________________________________ ___________________________________________________________________________________________
Technetium-99m (99mTc) plays a major role in diagnostic nuclear medicine and has not yet been replaced with any other radionuclides. It is available through the 99Mo/99mTc generator. The use of low specific activity of 99Mo for 99Mo/99mTc generator application requires high adsorptive capacity sorbents. This study focused on the determination of 99Mo adsorption capacity of some zirconia materials, namely monoclinic nanozirconia, orthorhombic nanozirconia, sulfated zirconia, and phoshated zirconia. These materials were synthesized by using the sol-gel method and characterized using FT-IR spectroscopy, X-ray diffraction (XRD), and Scanning Electron Microscope/Energy Dispersive X-Ray Spectroscopy (SEM- EDS). The determination of 99Mo adsorption capacity of these materials was carried out by soaking the materials in a Na299MoO4
solution of pH 3 and 7, at temperatures ranging from room temperature to 90°C, for 1 and 3 hours. The results indicated that monoclinic nanozirconia has 99Mo adsorption capacity of 76.9 mg Mo/g, whereas orthorhombic nanozirconia, sulfated zirconia, and phosphated zirconia have
99Mo adsorption capacity of 150.1 mg Mo/g, 15.58 mg Mo/g, 12.74 mg Mo/g, respectively. It appears that orthorhombic nanozirconia has the highest 99Mo adsorption capacity among the synthesized materials and can be applied as a candidate material for the 99Mo/99mTc generator.
© 2010 Atom Indonesia. All rights reserved
15 INT
RODUCTION1
16
16 Technetium-99m (99mTc) plays a major role in
17 diagnostic nuclear medicine, for approximately 8019 85% of all nuclear medicine procedure, and has not
20 yet been replaced with any other radionuclides [1]
21 [2] [3]. The 99mTc-99m which has a half-life ( (tJ/2) of = 6 h, energy of ;140 keV), the daughter
22 radionuclide of mMolybdenum-99 (99Mo) through
23 beta (P"). Tc-decay, is the most widely used radioisotope
24 for diagnostic radiopharmaceuticals in nuclear
25 medicine [4]. The 99mTc-based radiopharmaceuticals are
26 primarily used primarily in the study of some organs system.
27 These radiopharmaceuticals are 99mTc- sestamibi, 99mTc-tetrofosmin and, 99mTc-
1
Corresponding author.
E-mail address:
28 teboroxime are used to diagnosis of heart.
99mTc- pertechnetate
29 pentetate is used to measure the glomerular filtration
30 rate in the kidney. For liver diagnostic is used
31 99mTc-lidofenin. For skeletal imaging are used
32 99mTc-medronate, 99mTc-xydronate, etc. 99mTc-
33 propyleneamineoxime is used as a cerebral
34 perfusion agent in the brain [5][6].
AIJ use only:
Received date Revised date Accepted date Keywords:
Low specific activity Zirconia
Adsorption capacity
99Mo/99mTc generator
Atom Indonesia
38 The 99mTc-99m is usually available through
99Mo/99mTc
39 g Generators and . oOver 95% of its precursor, the 99Mo, required for 99mTc 37generators is produced by the fission reaction of uranium-
40 235 (235U) targets in nuclear research reactors [7][8]. Mo-99 which
41 This fission reaction resulted from this fission reaction has in athe very high specific
40activity of 99Mo (>104 Ci/g Mo). 99 Mo/The
99mTc
41 generators based on the high specific activity of
42 99Mo commonly use alumina as an adsorbent for
43 its generator column.
44 The 99Mo/99mTc generators, which are currently
45 commercially available, sareuch as from POLATOM,
46 ANSTO, and Ultra-Technekow V4 (produced by
47 Curium). Their supplies some time are Recently, an unstable due to the limited supply of 99Mo which is caused by restriction of the use of high enricheda
48 global issue due to uranium restriction and reactor
49 aging problems [9] [10]. Therefore, an alternative
50 technology in production of Mo-99 as well as of 99Mo/99mTc generator preparation ihas s
51 necessary to be developed to overcomeface theseat problems.
52 L The low specific activity of 99Mo (<10 Ci/g of
53 molybdenum) could be produced by neutron
54 activation of natural or enriched 98Mo in a nuclear
55 research reactor, by gamma irradiation of
100Mo in
56 accelerator facility, as well as by charged- particle
57 activation of 100Mo in cyclotron facility
58 [11][12][13][14]. The achievable low specific
Atom Indonesia
59activity of 99Mo is less favorable for the above- mentioned procedurethat way, however, but the
60absolute amounts can be amply sufficient for local
61needs [10]. For 99Mo/99mTc generator application, a
62low specific activity of 99Mo could not be adsorbed
63to the alumina adsorbent (due to the limited
64adsorption capacity of alumina to molybdenum). , This
99 Mo but
65it has to be adsorbed to high capacity adsorbents.
66N Recently, nanomaterial-based adsorbents seem to
67have a promising prospect as high capacity
67adsorbents due to their physical properties. It is reported that nanomaterial The
68small particle size of nanomaterial adsorbents can
69increase its surface energy and adsorption capacity
70to metal ions [15].
71Some nanomaterial adsorbents have been
72developed for 99Mo/99mTc generator application,
73namely polymer embedded nanocrystalline titania,
74tetragonal nanocrystalline zirconia, and
75nanocrystalline alumina [15][16][17].
76This study focused on the determination of
7799Mo adsorption capacity of some zirconia materials, namely monoclinic nanozirconia, orthorhombic
78nanozirconia, sulfated zirconia, and phosphated
79zirconia,
80which have been synthesized in previous work [18].,
81namely monoclinic nanozirconia, orthorhombic
82nanozirconia, sulfated zirconia, and phosphated
83zirconia.
84The introduction of anionic groups (e.g.
85sulfate, phosphate) at the surface of metal oxides
86markedly enhances its acidic properties [19]. Thus,
87it is expected to improve Mo adsorption capacity of
88zirconia materials.
89Sulfates zirconia was used as a catalyst for
90organic transformations due to its strong acidic
91properties, especially for developing
92environmentally friendly processes in alkane
93isomerization at mild temperature [20] as well as for
94hydrocarbon isomerization, alkylation, and
95esterification [21].
94 95
96EXPERIMENTAL METHOD
97
97Reagents used including ZrOCl2-8H2O, isopropyl
98alcohol, ammonia 32%, and pH-indicator strips pH
99 0-14 Universal indicator, sulfuric acid, phosphoric
100 acid was purchased from Merck, while water and
101 demineralized water were purchased from a local
102 company, IPHA, Bandung, Indonesia.
Molybdenum
114 In order tTo produce 99Mo via 98Mo(n,y) reaction, 4
115 grams of natural Molybdenum trioxide (MoO3) was 116irradiated in the GA. Siwabessy Multi Purpose nuclear Rreactor,
117
BATAN, Serpong, Indonesia. The irradiation was118
carried out at reactor power of 15 MW, the cross-119
section of 0.13 barn, neutron flux of 1.3 x 1014 120n/cm2.s, for 5 (4 instead???) days. After irradiation process, the121 MoO3 target was dissolved using 4 M sodium
122 hydroxide solution. This process resulted in a
99Mo
123 solution with a specific activity of 0.3 - 0.5 Ci/g Mo.
124 All work was carried out in a hot cell facility.
Solution of The
125 99Mo with pH solution of pH 3 and 7, were prepared by
126 Addition ofing 6 M HCl to the bulk of the 99Mo solution.
127 The radioactivity of the 99Mo solution was then measured
128 by using a dose calibrator (Atom Lab 100 Plus).
129
129 Synthesis of monoclinic nanozirconia and 130 orthorhombic nanozirconia
131 Monoclinic nanozirconia and orthorhombic
132 nanozirconia were synthesized based on the method
133 described in our previous works [18].
135
134 Synthesis of Sulfated zirconia
135 Zirconium solution was prepared by
136 dissolving ZrOCl2-8H2O in 80% isopropyl alcohol.
137 Ammonium solution (20%)Then, 20%
ammonium solution in isopropyl alcohol
138 was then added to the zirconium solution. The mixture
139 was strongly stirred without heat until the white gel
140 was formed. The mixture keeps stirred for 14 hours.
141 The filtrate was separated, then the gel then washed with
142 80% of 2-propanol solution until freed of Cl- ion.
Sulfuric acid solution Then
(0.5 M, 40 mL) of 0.5 M sulfuric acid solution was then added to
143 the gel. The mixture was refluxed at 95°C for 12 hours at
144 95°C. The gel was transferred into the evaporating
145 dish and then heated at 110°C to drdrynessy the precipitate.
146 . The precipitate was calcined at 600°C for 2 hours.
147 The white solid formed was sieved in the size of 50151 100 mesh.
152
152 Synthesis of Phosphated zirconia
153 The phosphatedphosphated-form of zirconia was synthesized by
154 using a similar manner procedure to that of sulfated- zirconia, wherebut
168
103 trioxide was purchased from Sigma-Aldrich. All
104 reagents used were analytical grade.
105 The equipment used was beaker glass, hot
106 plate stirrer, evaporating dish, thermometer, furnace
107 (Raypa®). Characterization was carried out by
108 Alpha FT-IR Spectrometer (Bruker), which spectra
109 were recorded in the range of 450-4,000 cm-1, and
110 Miniflex 600 X-Ray Diffraction.
112
113 Preparation of Na299MoO4 solution
Time treatment (hours) 1 Roo m temp eratu re 3 Roo m temp
eratu re 1 90°C 3 90°C 192
193
192 RESULTS AND DISCUSSION
195
193 Monoclinic nanozirconia and orthorhombic
169 Determination of 99Mo absorption capacity
170 Determination of 99Mo absorption capacity
171 of synthesized zirconia materials was performed
172 using Na299 MoO4 solution pH 3 and 7 of the Na299MoO4 solution. A total
173 of 100 mg of zirconia, each loadedinserted into 4 tubes
174 containing 0.001 M HNO3 solution and left for 1 h
175 at temperature room. The Filtrate was removed by
176 decantation. Aliquot (1 mL) of the 99Mo solution (pH 3 or 7)
177was added to the zirconia material. Table 1 show the conditions of tThe zirconia 178 materials which were was immersed in Na299 MoO4 solution.the certain conditions i79sho\\n in Table 1. In this work, the as-synthesizd-e 223
isozirconia-basecd material products were denoted as
181 monoclinic nanozirconia (MZ-y), orthorhombic
182 nanozirconia (OZ-y), sulfated zirconia (SZ-y), and
183 phosphated zirconia (PZ-y), where y means time
184 treatment (meaning???). The filtrate was separated, then the
185 precipitate was then washed with 500 L of water.
The
186 filtrate and the washed water were collected and then their 99 Mo
187 radioactivitiesy of 99Mo was measured by using Dose
188 Calibrator.
189
189 Table 1. The condition of the zirconia-based material adsorption 190 in 99Mo Na299 MoO4solution
Temperature Tube
224 225226
194 nanozirconia
195 The synthesis and characterization of monoclinic
196 nanozirconia and orthorhombic nanozirconia had been were
197 discussed in our previous
reportwork [18].
201
198 Sulfated zirconia
199 The physical appearance of synthesized
sulfated zirconia was shown in
200 FigFigureure 1.
The sulfated
zirconia prior to calcination is
201 a light yellow solid (Figure. 1.a) and turns white a. After calcination., the color
202 turns white.
207 208 209
209 The FTIR spectra of sulfated zirconia arewere
210 shown in
FigFigureure 2.
FigFigureure 2a shows the FT-IR
211 spectra of sulfated zirconia prior to calcination. The
212 absorption peaks at 3283 and 1635 cm-1 are
213 attributed to stretching and bending vibration of OH
214 groups of the
water. These
absorption peaks are
215 disappeared after calcination of 600°C
(FigFigureure 2b).
217The absorption peaks at 450-600 cm-1 show the
218presence of a Zr-
O-Zr group
(FigFigureures 2a and 2b).
219 The absorption peak at 900-1200 cm-1 is attributed
220 to the S = O and S- O groups, which is typical for
221 bidentate sulfate
groups with
inorganic chelates
222 [22].
Wavenumber (cm') (a)
229
229 The SEM image of the synthesized sulfated
230 zirconia shows that the particles have a sphere-like
231 shape, (see ( FigFigure 3). The composition of elements in the
232 surface of
synthesized
sulfated zirconia and its
233 energy is shown in Table 2. Based on the SEM-
234 EDX
measurements (FigFigure. 4), the presence of S
235 element indicates that sulfated zirconia has been
236 formed.
238 227
227 (b)
FigFigureure 2. The FTIR spectra of sulfated zirconia: (a) prior to calcination (b) after calcination
242
243 244
245 246
243 The XRD analysis of the synthesized
244 sulfated zirconia is shown in
FigFigureure 5.
The crystal
245 peaks at 20 = 30.1;
34.9; 50.1; and 59.7° are the
246
246 characteristic peaks
for sulfated zirconia with
247 tetragonal crystal [22] [23].
252 253
248 FigFigureure 5. The XRD pattern of the synthesized sulfated zirconia 255
249 Phosphated zirconia
240 Figure 3. The SEM images of synthesized sulfated zirconia:
Figure 4. EDS spectra of the synthesized sulfated zirconia
Table 2. The composition of elements in the surface of the synthesized sulfated zirconia ________________________________________
Energy (keV) % Mass 271
Carbon (C) 0.277 24.79 272
Oxygen (O) 0.525 29.10 273
Sulfur (S) 2.307 2.46
Chlorine (Cl) 2.621 0.43
Zirconium (Zr) 2.042 38.41
Molybdenum (Mo) 2.293 4.80
276
250 The FTIR spectra of synthesized phosphated
251 zirconia are shown in FigFigureure 6.
FigFigureure 6a shows the
252 FTIR spectra of synthesized phosphated zirconia
253 prior to calcination.
The absorption peaks at 3139
254 and 1616 cm-1 are attributed to stretching and
255 bending vibration of OH groups of the water. These
256 absorption peaks are disappeared after calcination of
257 600°C (FigFigureure
6b). The
absorption peaks at 900265 1200 cm-1 show the presence of P-Zr- O groups
266 (FigFigureures 6a and 6b). The absorption peak at 495 cm-
267 1 (FigFigureure 6a) is attributed to the Zr-O group which
268 shifts to the wave number of 545 cm-1 after
269 calcination
(FigFigureure 6b) [19].
270
274
274 (b)
FigFigureure 6. The FTIR spectra of phosphated zirconia: (a) before calcination (b) after calcination
277 The SEM image of the synthesized
278 phosphated
zirconia shows that the material has a
279 sphere-like shape (FigFigure. 7). The composition of
280 elements in the
surface of
synthesized phosphated
281 zirconia and its energy isare shown in Table 3. Based
282 on the SEM-EDX measurements (FigFigure. 8), the
283 presence of P element indicates that phosphated
284 zirconia has been formed.
285
286
287 290
291
291 The XRD analysis of the synthesized
292 phosphated
zirconia compared to the database in
293 Match software.
Based on this comparison, it was found that, the synthesized
294 phosphated
zirconia wasthere is a 100% similarity with the
295 Zr2P2O7 compound.
The comparison of X-ray
296 diffraction patterns
between the
synthesized
297 phosphated
zirconia with the Zr2P2O7 compound is
298 shown in FigFigureure 9. It can be seenBased on the
FigFigureure 9 that, there are
299 peaks at 20 = 18.63; 21.55;
24,12; 26,47;
30.66; 30036.12;
37.78; 39,39;
43.92; 45,32;
48.08; 49,41;
301 54,49; 58,11;
63,84; 67.13 and 68.22°. These peaks
302 are characteristic for the phosphated zirconia with
303 orthorhombic crystals.
Figure 7. The high-magnification of SEM image of the synthesized phosphated zirconia
£ -
— CKa 1: CuLI Cul
3 £ 3 3
1 - L
900 600 300-
28 8 0,00 1,00 2.00 3.00 4.00 5.00 6.00 7.00 8.00 9.00 101.00
289 keV
Figure 8. EDS spectra of the synthesized phosphated zirconia
Table 3. The composition of elements in the surface of the synthesized phosphated zirconia_____________________________________
Element Energy (keV) % Mass
Carbon (C) 0.277 28.41
Oxygen (O) 0.525 34.72
Phosphor (P) 2.013 20.33
Copper (Cu) 8.040 1.51
Zirconium (Zr) 2.042 15.03
308 The 99Mo adsorption capacities of the synthesized
309materials
310 The 99Mo
adsorption capacity of monoclinic
311 nanozirconia, orthorhombic nanozirconia, sulfated
312 zirconia, and phosphated
zirconia, are shown in
313 FigFigureure 10.
The monoclinic nanozirconia has itsthe
314 highest 99Mo adsorption capacity of 76.9 mg Mo/g,
315 which was obtained under adsorption condition in
316 the 99Mo solution of pH 3, at the temperature of
31790°C andfor 3- hours adsorption time. Whereas the orthorhombic
318 nanozirconia has itsthe highest 99Mo adsorption
319 capacity of 150.14 mg Mo/g which was obtained
320 under adsorption conditions in the
99Mo solution of
321 pH 3, at the temperature of
90°C and for 1
hour1 hour
adsorption time.
322 The sulfated zirconia has itsthe highest 99Mo
323 adsorption capacity of 15.58 mg Mo/g which was
324 obtained under adsorption
condition in the
99Mo
327 solution of pH 7, at the temperature of 90°C andfor 3
326hours adsorption time. In term of measuring
adsorption capacity of sulfated zirconia towardsIn the 99Mo solution of pH 3 at room
328 temperature, it was found that the filtrate of sulfated zirconia becaomes
329 turbid during submersion,
nevertheless, the solid
330 and filtrate could still be separated by decantation.
331 For sulfated zirconia suspended iIn the 99Mo solution of pH 3 at the temperature of
304
306 FigFiguure 9. The XRD pattern of the synthesized phosphated
307 zirconia
332 90°C, it was found that the sulfated zirconia was suspended in the
333 99Mo solution. The solid and the filtrate (sulfated zirconia) could not be
334 s Separated from
99 Mo solution.
Therefore, both the activity of the solid
335 and filtrate could not be measured, so that the
336 absorption capacity of the sulfated zirconia at this
337 temperature could not be determined.
338 In the 99Mo solution of pH 3, the largest
339 99Mo absorption capacity of the phosphated
zirconia 339(12.74 mg Mo/g) was obtained under adsorption
340 conditions at room temperature for 3 hours. In the
341 99Mo solution of pH 7, the largest
99Mo absorption
342 capacity of the phosphated
zirconia (4.56 mg Mo/g)
343 was obtained under adsorption
conditions at a
344 temperature of 90°
C for 3 hours.
345 In this study, it was found that it seemeds that the introduction
346 of sulfate and phosphate groups onto the surface of
347 zirconia material, did not improve the adsorption
348 capacity of molybdenum compared to
349 monoclinic/orthorh ombic zirconia.
The sulfated and phosphated-
materials
350 tend to be unstable (forms turbidity) in the
351 molybdenum solution.
352
353 The improved synthesis of
354 sulfated and phosphated
zirconia, or the introduction
355 of the other anionic groups, need tomay be carried out in order to
356 enhance the Mo adsorption
capacities.
357 Z The zirconium based-materials namely polymeric Zirconium
Compound (PZC), which have 99 Mo
358 adsorption capacity of ~250 mg Mo/g PZC, have been
359 been applied as adsorbent of low specific activity
99 Mo for 99Mo/99mTc generator, namely PZC
360 (polymeric Zirconium
Compound) has
99Mo
361 adsorption capacity of ~250 mg Mo/g PZC [24]., and
362 the Another Zirconium Based Material ZBM ( ZBMZirconium Based Material) has 99Mo
363 adsorption capacity of 177-193 mg Mo/g ZBM
364 [13][25]. These materials have been developed by
365 Center for
Radioisotope and Radiopharmaceutic al
366 Technology,
BATAN in
collaboration with Japan
367 Atomic Energy Agency (JAEA), Kaken, Co. Japan, 369 compounds which have 99Mo adsorption capacity of
368 and Chiyoda Technol. Corp. Japan [24] [26]. 370 150.1 mg Mo/g, it is expected to be an alternative
369 Another zirconia material namely t-ZrO2
has been 371 material as an adsorbent for the
99Mo/99 mTc
370 reported
has 368Mo/g
[15],
373374
374
CONCLUSION
376
375 In the present study, the synthesized
376 monoclinic nanozirconia has been found to have
99Mo adsorption 379capacity of 76.9 mg Mo/g, whereas orthorhombic
380 nanozirconia, sulfated zirconia, and phosphated
381 zirconia have 99Mo adsorption capacity of 150.1 mg
382 Mo/g, 15.58 mg Mo/g, 12.74 mg Mo/g,
383 respectively. It appears that orthorhombic
384 nanozirconia has the highest 99Mo adsorption
385 capacity among the synthesized materials.
386 Therefore, the orthorhombic nanozirconia is
387 expected to be applied as an alternative candidate
388 material for the 99Mo/99mTc generator.
389
389 ACKNOWLEDGMENT
391
390 This work is supported by the Indonesian
391 government funding through the National Nuclear
392 Energy Agency, BATAN, as well as the
393 International Atomic Energy Agency (IAEA)
394 Coordinated Research Project F22068 (IAEA
395 Research Contract No. 21033). The author would
396 like to thank E. Sarmini, Herlina, and Sriyono for
397 technical assistances.
400 401
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Proceeding of National Conference on Basic
