You will be shown an abstract from a materials science research paper. Your task is to extract all synthesis operations described in the abstract into a structured JSON format. Your output should be a JSON array. Each entry in the array should be a JSON object describing a single synthesis operation. This object should have the following fields:

- "trigger": A verbal predicate indicating a synthesis operation. This should be a string extracted directly from the abstract.
- "arguments": An array of arguments specifying aspects of the synthesis operation. Each entry in the array should be a length-2 array formatted as [<argument_text>, <argument_type>]. The `argument_text` should be a string extracted directly from the abstract. The `argument_type` should be one of the following types: ["Recipe_Precursor", "Atmospheric_Material", "Participant_Material", "Recipe_Target", "Solvent_Material"].

For instance, suppose an excerpt from the abstract reads:

Tetraethoxysilane (TEOS, 98%) and cetyltrimethylammonium bromide (CTAB, 98%) were purchased from Fluka. The MTTZ-siloxy derivative (triethoxysilyl-propyl-5-mercapto-1-methyl-tetrazole) was synthesized as previously described [38].

This excerpt includes two operations, which could be annotated as follows.

[{"arguments": [["Tetraethoxysilane", "Recipe_Precursor"], ["cetyltrimethylammonium bromide", "Recipe_Precursor"]], "trigger": "purchased"}, {"arguments": [["MTTZ-siloxy derivative", "Recipe_Target"]], "trigger": "synthesized"}]

In your response, please include the JSON and no other text.

Abstract:
10.1016/j.molcata.2014.11.015
Keggin type heteropoly acid, encapsulated in metal-organic framework: A heterogeneous and recyclable nanocatalyst for selective oxidation of sulfides and deep desulfurization of model fuels
For the synthesis of PMo@HKUST-1(I), PW@HKUST-1(II) and SiW@HKUST-1(III) catalysts, the mixture of BTC (0.21 g, 1 mmol) and 0.10 g of CTAB in absolute ethanol (14 mL) was prepared and then 0.06 g of PMo for (I), 0.1 g of PW for (II), 0.1 g of SiW for (III), and 1.45 g of copper(II) nitrate trihydrate (Cu(NO3)2*3H2O) were dissolved in distilled water (10 mL), Both solutions were combined and mixed under vigorous stirring for approximately 30 min and were aged without stirring for a further 2 days in the case of (I) and 4 days for (II and III) at room temperature. A green (I), blue (II) and light blue (III) precipitate were then collected, washed with distilled water three times and dried at 60 degC for 24 h. CTAB was removed by Soxhlet extraction with ethanol (laboratory use, Chem-Lab) which was performed for 24 h. The product was dried in air at 60 degC. The yields were 95%, 92.6% and 86.4% for (I), (II) and (III) respectively.
[{"arguments": [["ethanol", "Solvent_Material"], ["CTAB", "Participant_Material"], ["BTC", "Participant_Material"]], "trigger": "prepared"}, {"arguments": [["SiW", "Participant_Material"], ["PMo", "Participant_Material"], ["PW", "Participant_Material"], ["copper(II) nitrate trihydrate", "Recipe_Precursor"], ["water", "Solvent_Material"]], "trigger": "dissolved"}, {"arguments": [["solutions", "Participant_Material"]], "trigger": "combined"}, {"arguments": [["precipitate", "Participant_Material"]], "trigger": "collected"}, {"arguments": [["water", "Solvent_Material"]], "trigger": "washed"}, {"arguments": [["ethanol", "Solvent_Material"], ["CTAB", "Participant_Material"]], "trigger": "removed"}, {"arguments": [["product", "Participant_Material"], ["air", "Atmospheric_Material"]], "trigger": "dried"}, {"arguments": [["SiW@HKUST-1(III)", "Recipe_Target"], ["PMo@HKUST-1(I)", "Recipe_Target"], ["PW@HKUST-1(II)", "Recipe_Target"]], "trigger": "synthesis"}]