The Characterization of Indonesian's Natural Zeolite for Water Filtration System

The characterization of Indonesian's natural zeolite for water purification has been done. The objective is to obtain a general guidance for development of natural zeolite in molecular sieves, ion exchange and catalyst applications. The zeolites originated frol Lampung (ZL) was characterized by using XRD. It was found that the zeolites indicate belong to clinoptilatite and mordenite groups, respectively. The crystal system for ZL was monoclinic with end-centered lattice and space group of Cm/2 (12). The crystal system for ZB was orthorhombic with end-centered lattice and space group of CmC21 (36). The character of both zeolites were confirm by ICDD standard library. It was also found that the particle size of zeolites did not affect the XRD spectra where zeolite of 40-50 mesh was similar to that XRD spectra of zeolite of 170-200 mesh. The chemical analyses show that both zeolites contain almost similar chemical elements. The contents of Fe, Ca, and K were found higher in ZL as it is compared to ZB. Reciprocally, Na was Pb and Fe elements. These ability were improved by chemical activation of zeolites. These two elements probably were originally exist in the zeolite structure. These characterization is necessary to designing a further development of natural zeolite applications.


INTRODUCTION
Indonesia is carrying out different research work in order to improve the natural resources utilization. It was understood that the higher utilization of natural resources make higher contribution to natural development. In this work, natural zeolites which are abundance available in Indonesian wish to be developed to achieve a more added value materials such as water purification/filtration system.
In fact, the natural zeolites have been used in agriculture as soil conditioner, as component of fertilizer, animal feed as well as a neutralization agent for bad smell waste (Thamzil & Husen, 1999) (Supandi, 1999). The applications of zeolite in engineering are still very few. Some research were done to develop zeolites for its application as water filtration or as membrane system (Xiaochun, et al., 2004) (Worathanakul & Kongkachuichay, 2008) (Valentine, 2009) (Jie, et al., 2002).
According to various researches, zeolite mainly a synthetic ores may have a great potential as membrane system such as micro filtration (MF), ultra filtration (UF), ad reverse osmosis (RO) as well as a powerful catalyst, ion exchanger, and gas separation systems (Berrin, 2008) (Stankov, et al., 2003) (Drew Chemical Corporation, 1967) (Kaseno, 1999) (Hadiati, 1999) (Lanjar, 1999) (Takao,1999. In fact, however the researches for the utilization of natural zeolites are still low due to some reasons. Among of that reasons were the variety of character of natural zeolites. Two sources of natural zeolite, i.e. originated from Lampung (ZL) and originated from Bayah, Banten (ZB) are used to be characterization in the present work. The characterizations of two zeolites were carried out using x-ray diffractometer (XRD) instrument.
The objectives of this work is to obtain a JHQHUDO RULHQWDWLRQ RI ]HROLWH ¶V FU\VWDO V\stem, its properties as well as to determine a selective elements that probably affecting in the character of natural zeolite for its application as water filtration system.

Materials
Natural zeolite were supplied by PT Minamata Mineral Perdana, i.e. originated from Lampung (ZL), and by volunteer zeolite mining agency, i.e. originated from Bayah, Banten (ZB). The zeolites were treated by ball milling and sieved to obtain a homogeneous powder size of 40-200 mesh, before used. Some necessary chemicals were used as a zeolite binder or as chemical activation agent.

Instruments
Shimadzu X-Ray Diffractometer instrument type 7000 made in Japan was used to characterization of crystal system. The instrument was first calibrating using silicon standard. Perkin Elmer Atomic Absorption Spectrometer (AAS) type AAnalyst 700, made in USA was used to analyze chemical elements. Other equipments such Memmert Oven (Germany) and Vulcon Kiln type 550 (Germany) were used for drying and sintering work. Various tools, beaker glass and plastic equipments were used as necessary.

Zeolite Activation
The chemical activation of zeolite were done as follows: 50 gr of zeolites was kept in HCl 2M solution for one hour, washed and decanted by aquadest until neutral (pH=7.0). It was, they kept in NaNO 3 2M solution for 1 hour, washed and decanted adequately by aquadest until neutral, and then dried in oven at 105qC until a constant weight.

XRD Characterization
Natural zeolite powder sample was put into a sample holder appropriately, kept homogeneous surface and placed it at measurement position. The measurement was done according to computer operating system and the obtained XRD spectrum was recorded. It took about 45 minute for each sample measurement. The obtained XRD spectrum was evaluated by standard diffraction data of x-ray from ICDD (International Centre for Diffraction Data).

AAS Measurement
0.5 gr of zeolite sample was destructed by aqua regia (HCl + HNO 3 ), diluted to 100 ml by distilled water and arrange the concentration to be appropriate for AAS measurement. The measurement was done by flame detector technique and the results were computerized recorded and print-out as necessary.

Filter Preparation
The zeolite sample was poured into a glass column (dia.3cm) for 5 cm thickness for media zeolite bed. The zeolite sample may be 40-200 mesh zeolite powder or a chemical activation zeolite. The media zeolite bed ability in filtering of different solution of Pb acetate (0.2 M), FeCl 3 (0.1 M), MgSO 4 (1.0 M), and CaCl 2 (0.2 M) were observed. The filtrate was measured by AAS after a necessary dilution. The contents of Pb, Fe, Mg, and Ca either in filtrate and remain in media zeolite bed was evaluated. The filtering capability of natural zeolite that was prepared by a binder was also investigated.

RESULTS AND DISCUSSION
XRD of Lampung Zeolite (ZL) Figure 1 shows the XRD Spectrum of Lampung zeolite. As can be seen in Fig.1, there are 3 strongest peaks, followed by another 3 weaker peaks. The position of the six peaks can be summarized in Fig. 2, and it details can be seen in Table 1. In Table 1, the strongest 3 peaks were found at 2T of 27.9583q, 22.3963q, and 9.8631q where the ratio of I/I 0 were 100, 54, and 39 respectively. Another 3 peaks were found at 2T of 42.6835q, 30.0600q, and 31.9600q where the ratio of I/I 0 were 38; 27; and 21, respectively.
According to ICDD 47-1870 data library, the existence of the strongest peaks may indicate that the mineral was appropriate with potassium sodium calcium aluminum silicate hydrate of clinoptilolite-Na.
Based on Bravais classification crystal system, it was found to be a base-centered monoclinic, with a lattice of end-centered and the space group of C2/m (12).
Accordingly,there are three unequal axes, one pair not at right angle, a z b z c, D = J = 90q and E z 90q [14]. The crystal system can be illustrated as the following figure (See Fig.3).

Primitive (P)
End-centered (C)  The data indicate that the crystal structure should belong to a clinoptilolite, its density of 2.16 g/mol and a unit cell volume of 2100Å. These agreed to description that was reported by Thamzil Las (Ph.D. Thesis) [15]. The unit cell may have a dimensions of a=7.41 Å, b=17.89 Å, and c=15.85 Å. If the data are compared to that ICDD library, then it seems to be the same. In orher word, the ZL could be predicted behave a crystal structure belong clinoptilolite group. The chemical formula of clinoptilolite is assumed to be Na 6 [(AlO 2 )6 (SiO 2 ) 30 ] 24 H 2 O.
In ICDD 47-1870 data, the clinoptilolite-Na may contains of [Na,K,Ca] 5 Al 6 Si 30 O 72 .18H 2 O as can be seen in Table 2. It can be concluded therefore, that the observed zeolite (ZL) should be a clinoptilolite with a monoclinic crystal system.
Further XRD measurement of ZL with different mesh has shown the same pattern of XRD spectrum. The strongest peaks was given at 2T of 28.0520q followed by the second strongest at 2T of 22.3963q. (See Table 3) From Table 3, the peaks of XRD spectrum at 2T of 28.0520q and 22.3963q may be estimated as peaks character for natural zeolite of ZL. In fact, the XRD spectrum of ZL do not affected by the particle size, since the two XRD spectrum of ZL show the similar pattern. Fig. 4 shows the XRD spectrum of activated zeolite ZL. As can be seen in Fig. 4, there are three other strong peaks i.e. at 2T of 42.2126q, 31.4545q, and 51.4774q beside of three peaks that were assumed to be FKDUDFWHUL]DWLRQ ¶V SHDNV RI FOLQRSWLOROLWH Actually, the three other strong peaks have also available in XRD spectrum pattern of previously ZL, but in the form of weaker peaks. Perhaps a higher peak at 2T of 42.2126q as its compared to that previously ZL was caused by sodium cation that coming from activation SURFHVV ,I LW ¶V WUXH LW FDQ EH SUHGLFWHG WKDW activated ZL may containing a single cation of Na. Therefore, the activation of zeolite can be favorable for molecular siever as well as for cation exchanger.  (62), and 13.6000q (51). All the peaks may be assumed as a characteristic XRD spectrum of ZB. Detail data of XRD spectrum of ZB are presented in Table 4.

Tabel 4. The Strongest Peaks of XRD Spectrum of Bayah, Banten Zeolite (40-50 mesh)
The measurement of XRD spectrum of ZB for different particle size of 170-200 mesh results the same XRD spectrum pattern. The XRD spectrum of ZB which has particle size of 170-200 mesh shows three strongest peaks at 2T of 25.780q (100), 22.382q (78), and 9.761q (54) and these similar to that XRD spectrum of other particle size of ZB. Therefore, the particle size of zeolite may concluded do not affect the pattern of XRD spectrum. Table 5 shows ICDD data for 49-0924 If the XRD peaks of ZB is compared to that ICDD 49-0924, then it can assumed that ZB belong to be a mineral mordenite group. The crystal system should be orthorhombic, lattice of end-centered, and space group of Cmc21 (36). In this case, there are 4 possible Bravais lattice of orthorhombic crystal system i.e. simple or primitive (P), body centered (I), end centered (C), and face centered (F) as shown in Fig. 6 (Cullity, 1987). There are also exist three unequal axis at right angles, a z b z c, D = E = J = 90q. Supandi (1999) reports that crystal structure of Bayah zeolite may contains two crystal systems, there are crystal monoclinic with space group C2/m and crystal orthorhombic with space group of CmCm. Supandi conclusion based on a calculation by a refinement Rietan method. Perhaps, the conclusion was correct, because the XRD VSHFWUXP RI RXU VDPSOH =% GLGQ ¶W PHUHO\ follows the ICDD orthorhombic crystal system. Therefore, it can be assumed that our ZB sample may comprises a mixture of mineral mordenite and clinoptilolite. Table 6 show some metal oxide that containing in ZL and ZB as it was compared to others results.  Fig.6. Bravais lattice of orthorhombic.

Chemical Analysis
As can be seen in Table 6, the metal oxides that containing in ZL were almost nearly similar that containing in ZB. But it was not in case of the results that reported by others. The different may caused by the different of analysis method or different sample itself. The result of Croatian zeolite of clinoptilolite was also different (Cerjan, et al., 2004). Therefore, the different origin of zeolite may provide different characteristics and chemical containment. For the reason, the characterization of natural zeolite became very LPSRUWDQW EHIRUH LW ¶V SODQQHG WR EH XWLOL]HG IRU specific purpose. Table 7 shows the zeolite filter performance. It can be seen in Table 7, that activated ZL was found to be the best for filtering heavy metal of Pb. In this case, original solutions that contain 19.07 gr could be reduced to be 8.86 (almost 50%). On the other hand, ZL and ZB could be able to reduce only smaller i.e. it is reduces to be 15.33 and 10.33, respectively. In case of Fe, ZB shows the best as compared to that ZL and activated ZL i.e. it can reducing Fe from 0.49 gr to 0.18 gr, whereas ZL and activated ZL could reduce only 0.43 gr and 0.26 gr, respectively. All kind of zeolite (ZL, ZB, and activated ZL) was found to be worse to reduce Mg and Ca. Even more Ca became higher in case of ZL and ZB performance. The results indicate that activated zeolite became very important to design an appropriate application of natural zeolite.

CONCLUSION
Two types of natural zeolites i.e. originally from Lampung (ZL) and Bayah, Banten (ZB) have been characterized by XRD method. It may be concluded that ZL was belong to clinoptilolite mineral with monoclinic crystal structure and ZB was belong to mordenite mineral with orthorhombic crystal structure.
The ZB however may have a mixture composition of mordenite and clinoptilolite mineral. The chemical activation of natural zeolite was important to improve the performance of zeolite.
Different origin and different sample of zeolite provide different zeolite character. Therefore the caharacterization of natural zeolite became very important for further design application of zeolite. Caution : X = before filtering, Y = after filtering.