The Effect of Surfactant on Zeolite Preparation from Iraqi Kaolin

In this study, zeolite type A was successfully prepared from kaolin; as a source for silica and alumina. The effect of a cationic surfactant (hexadecyltrimethylammonium Bromide (CTABr) was studied during the preparation of zeolite type A from kaolin clay (structurally modified). The addition ratio was (0.2, 0.4, 0.6, 0.8) CTABr. Also, CTABr was added with different amounts of (25, 75, 150 and 300) mg/l to commercial zeolite type A (surface modified). The prepared samples were characterized using FTIR, surface area and adsorption capacity. The results indicated that the adsorption capacity was decreased as the concentration of CTABr is increased. The minimum adsorption capacity was 8.4109 % gH2O / gzeolite using 300 mg/l of surfactant, while it was reached 6.907% gH2O / gzeolite by using 0.8% CTABr of kaolin within the preparation. Furthermore, the increased amounts of CTABr causes to increase the surface area of surface modified zeolite where it was increase from (19.938 to 23.8655, 24.377 and 25.2174 (m2/g achieving an increase of 22.6, 25.2 and 29.6% respectively, A large increase more than 100% in the surface area was obtained for the structurally modified samples by increasing the CTABr concentration from (13.0113 to 24.0935, 25.7594, 26.2719 and 27.12) m2/g. : ةصلاخلا عون تيلاويز ريضحت مت ةساردلا هذه يف A ةفاضإ ريثأت ةسارد مت ثيح .انيموللااو اكيليسلل ردصمك نيلوؤاكلا نم عون تيلاويز ريضحت للاخ بجوملا يحطسلا دشلا بكرم A ) بسنب نيلوؤاكلا نم رضحملا ,0.2 , 0.4 ,0.6 0.8 ( .ةفاضلإا نودب رضحملا تيلاويزلا عم هتنراقمو نيلوؤاكلا نم ةفاضإ ةسارد كلذك CTABr ةفلتخم تايمكب ) 25 , 75 No.21 Journal of Petroleum Research & Studies (JPR&S) E 72 , 150 , 300 ( عون تيلاويز ىلا رتل /غم A ،يراجتلا ةطساوب جذامنلا صيخشتو FTIR ، ةعس و ةيحطسلا ةحاسملا زازتملاا . زيكرت دايدزأب لقت زازتملاا ةعس نا ىلا جئاتنلا ريشت CTABr , زازتما ةعس لقا تناك ثيح 8.4109 % مغ /ءام مغ مادختسأب تيلاويز 300 يحطسلا دشلا بكرم نم رتل /غم , ىلا لصي امنيب 6.907% دنع تيلاويز مغ /ءام مغ مادختسأ CTABr زيكرتب 0.8 .نيلوؤاكلا نم % كلذ ىلا ةفاضأ , ةيمكب ةدايزلا نا CTABr نم لدعملا يراجتلا تيلاويزلل ةيحطسلا ةحاسملا ةدايز ىلا يدؤت ) 19.938 ا ىل 23.8655 , 24.377 و 25.2174 م ( 2 ) ةبسنب ةدايزلا تناكو مغ / 22.6 , 25.2 و 29.6 ( % ىلع .يلاوتلا نم رثكا ةدايز ىلع لوصحلا مت ثيح 100% ةدايزب نيلوؤاكلا نم ةرضحملا جذامنلل ةيحطسلا ةحاسملاب زيكرت CTABr ) نم 13.0113 ىلا 24.0935 , 25.7594 , 26.2719 و 27.12 م ( 2 / .مغ

all active sites can be easily exposed to the reactant. Furthermore, the controlling of the zeolite morphology is very important when the hydrothermal synthetic approach is utilized. [3] Zeolite type A, classified into three different kinds (3A, 4A and 5A) all of them has the same general formula but different in cation type. When 75% of sodium in zeolite is replaced by potassium it's referred to 3A, alternatively replacing of sodium by calcium referred to zeolite type 5A. [4]

Surfactant-Modified Zeolites:
Mixture of a surfactant used to prepare a mesoporous zeolite with high microporosity Therefore, the main aim of the present work was to study the effect of a cationic surfactant (hexadecyltrimethyl-ammonium Bromide (CTABr) on characterization of zeolite type A.

Experimental Work:
This study was made in two ways: first, by adding CTABr with different amounts of 25, 75,150,300 mg/l to commercial zeolite A and is designated as "surface modified commercial zeolite A". the other way, by adding CTABr during the preparation of zeolite A from kaolin clay as ratios of (0.2, 0.4, 0.6, 0.8) of the kaolin, and compared with the one prepared with no addition, and is designated as "structurally modified zeolite A".

Chemicals Components:
The chemical components used in this study were Commercial Zeolite 4A (from BAIJI

Addition of CTABr during Preparation
Step 1-The Iraqi kaolin clay was crushed by using electrical mill then grained and sieved to the grain size 150 micron.

No.21 Journal of Petroleum Research & Studies (JPR&S)
E 75 necks round bottom flask with a solid to liquid ratio (3 g: 10 ml).

3-
The mixture was agitated and heated at 100°C for 30 minutes by magnetic stirrer heater with an oil bath, condenser and thermocouple.

4-
The slurry was filtered after 30 minutes in Buckner funnel with a vacuum pump.
The clay treated was washed with deionized water and filtered many times until the filtrate was neutral.

5-
The kaolin was dried at 110°C for 7 hours, then dried kaolin was calcined at 550°C for 2 hour to convert kaolin to metakaolin.

6-
The metakaolin was treated with sodium hydroxide solutions (2N) with ratio (1 g: 5 ml), and then the mixture put in sealed vessel of polyethylene mixed by a magnetic bar for 10 minutes until the mixture became homogeneous and then the mixture was aged for 24 hours at room temperature.
7-After ageing, the reaction mixture was agitated and heated by the magnetic stirrer heater at 90 °C for 2hours.
8-When the reaction was ending, the slurry was filtered in Buchner funnel using vacuum pump and washed with deionized water then filtered several times till the pH reaches 10.5.

9-
The filter cake was dried at 100°C for 4 hours then calcined at 550°C for 4 hours. [10] In case of preparing zeolite with CTABr, the steps from (1-8) are followed and then the surfactant is added during the preparation at different ratios (0.2, 0.4, 0.6, and 0.8) as a percentages of kaolin weight.

Addition of Surfactant to Commercial Zeolite A:
1-Zeolite was mechanical ground with a mortar to a fine particle size.

Characterization
The physical and chemical properties of zeolites were characterized using X-ray powder diffraction (SHIMADZU type), Fourier Transform IR Radiation technique, surface area and pore volume (Burnauer, Emmett and Teller /BET), adsorption capacity and chemical analysis using ICP.

Results and discussion: Surface modified commercial Zeolite A:
Commercial zeolite A was used in this study, where the CTABr was added in different amounts of 25, 75,150 and 300mg/l.
The participation of CTABr on the surface of zeolite is investigated by comparing FTIR pattern of both commercial zeolite (S1) and modified zeolite samples (S6 and S10). The FTIR pattern for selected samples are shown in figures (1to 3). Also the distinguishable functional groups can be found in Table (1).The designation of samples and the results of commercial and prepared zeolite are presented in Table (2). For the parent zeolite, major peaks of Si-O-Si and Si-O-Al bending and stretching, major bands of the aluminosilicate appear in the range 500 cm -1 to1300 cm -1 .The bending vibration of water molecules HOH adsorbed on zeolite appears in (1635cm -1 ) and the stretching vibration of OH group appears in range (3610 cm -1 ) to (3387 cm -1 ) as showing in Figure (

Table (1) Active bands of Zeolite in the present work
The bands belonging to CTABr are found within the zeolite indicating that the presence of the surfactant did not alter the zeolite main structure. The vibration bands of the surfactant can be grouped into two types: those associated with methylene tails and those with alkylammonium head groups. The peak around (3015 cm -1 ) was assigned to the symmetric stretching mode of the trimethylammonium head group CH 3 -N. In the FTIR spectrum of the crystalline CTABr the most intense absorption bands at around 2915 and 2850 cm -1 arise from the CH 2 asymmetric and symmetric (CH 2 ) stretching vibration modes of methylene groups respectively, which are corresponding with the bands (2920 and 2855.73) cm -1 in the modified zeolite (S6). The bands around (2946 and 2871) cm -1 are due to the asymmetric and symmetric stretching modes of terminal CH 3 -R group respectively, which can be observed in modified zeolite as the bands (2949.71cm -1    In this study Zeolite A was successfully synthesized from kaolin clay (S10). Other samples (S6, S11, S12 and S13) were prepared by the addition of CTABr in various amounts. of typical values present in the unmodified prepared zeolite can be found in the modified zeolite and this can be found in Table (1).

The Effect of Surfactant on Adsorption Capacity:
The adsorption capacity of the samples modified by the two ways was investigated, the results can be found in Table (2). The commercial zeolite (S1) exhibited a value of 14.18 % g H2O / g zeolite for the uptake of water vapor. For the surface modified samples, it can be seen that the adsorption for water vapor is increased at low loading of 25mg/l and then decreased as the concentration of CTABr is increased, it seems that using 25mg/l had improved the adsorption capacity to 19.7084% g H2O / g zeolite as shown in figure (4), also the efficiency was calculated according to eq. below, it can be seen that the highest value of 89.5837% was obtained.

A C Efficiency
This could be explained by the decrease in particle size affecting the morphology and pore opening being more susceptible to guest molecules. But the increase of the cationic surfactant CTABr furthermore, makes the surface positively charged and causes repulsion to polar water molecules, the polar negative part of CTABr is attached to the external surface of zeolite leaving the organic positive part micelles of surfactant.
In comparison between the prepared zeolite (S10) and commercial zeolite (S1) it was found that the adsorption capacities were almost similar.In order to investigate the effect of surfactant on adsorption capacity of structurally prepared zeolite from kaolin. The results indicated that maximum adsorption capacity is obtained at concentration of (0.2 percentages of kaolin weight) from CTABr as showing in Fig. (5). The structurally modified sample got the lowest water adsorption capacity of 6.907% g H2O / g zeolite for the sample of (0.8 percentages of kaolin weight), it can be seen that the lowest value of 31.397% was obtained.

The Effect of Surfactant on Surface Area
The addition of 25 mg/l surfactant to commercial zeolite causes unpredicted change in surface area from (19.938 to 19.457m 2 /g) which could be attributed to the changes in particle size did not reach the level that can make a significant change in the surface area.

Conclusions:
Zeolite A was prepared successfully from Iraqi kaolin.
The results showed that the characteristic functional groups of the CTABr were found in the FTIR spectrum pattern of both the surface modified and the structurally modified zeolite A. This reveals the presence of the surfactant inside zeolite A.
Surface modified commercial zeolite A showed a decrease in the adsorption capacity of water vapor and the min. was 8.4109% g H2O / g zeolite while it was 6.907% g H2O / g zeolite for the structurally modified zeolite.
All samples which were treated with CTABr showed an increase in the surface area but the structurally modified samples had the higher increase than the surface modified reaching more than 100%.