Pemanfaatan Silika Mesopori Mcm-48-nh2 sebagai Adsorben Ion Cu2+

Ion Cu2+ merupakan unsur yang berbahaya jika terkontaminasi ke dalam lingkungan. Oleh karena itu, keberadaannya dalam lingkungan perairan harus dikurangi. Adsorpsi merupakan salah satu cara untuk mengurangi kandungan ion Cu2+ dalam larutan. Adsorpsi ion Cu2+ oleh MCM-48-NH2 dipelajari dengan variasi waktu kontak, pH, dan konsentrasi dari Cu2+. Isotermal Langmuir dan Freundlich digunakan untuk mempelajari isotermal adsorpsi Cu2+ oleh MCM-48-NH2. Hasil penelitian menunjukkan bahwa adsorpsi Cu2+ oleh MCM-48-NH2 lebih sesuai dengan isotermal adsorpsi Langmuir. Nilai kapasitas adsorpsi Cu2+ oleh MCM-48-NH2 adalah 0,52 mmol g-1.Kata Kunci : Adsorpsi, MCM-48-NH2, Cu2+, isotermal Cu2+ ion is an element harmful if contaminated into the environment. Therefore, its presence in the aquatic environment must be reduced. Adsorption is one method to reduce thecontent of Cu2+ ion in solution. Adsorption of Cu2+ ion by MCM-48-NH2 was studied with variation of contact time, pH, and concentration of Cu2+ ion. Langmuir and Freundlich models were used to study the adsorption isotherm of Cu2+ by MCM-48-NH2. The result showed that adsorption of Cu2+ by MCM-48-NH2 more suitable with Langmuir models. The adsorption capacity of Cu2+ by MCM-48-NH2 was 0.52 mmol g-1

THE POTENCY OF MESOPOROUS CARBON (CMK-1) AS ADSORBENT OF DYES

Proceeding ICCS-2007Dyes are group of substances used widely in industries. These substances can introduce problems in an aqueous environment. Adsorption is an effective method for lowering the concentration of such materials in the environment. This work deals with dye adsorption using mesoporous carbon (CMK-1) as the adsorbent. For comparison, activated carbon (Norit SX22) was also used as adsorbent. CMK-1 was synthesized using mesoporous silica (MCM-48) as a template and sucrose as a carbon source. Sulphuric acid was utilized as a catalyst in carbonization process. After carbonization, the silica wall was dissolved by sodium hydroxide solution in ethanol-water of 1:1. To synthesize MCM-48, sodium silicate was used as a silica source and a mixture of cationic surfactant (cetyltrimethylammonium bromide, CTAB) and neutral surfactant (Triton X-100) as template. Adsorbates used were reactive (reactive red-1, RR1), basic (Rhodamine B, RhB), and acid (Patent Blue V, PBV) dyes. The optimum contact time of dyes with CMK-1 was 120 min. The adsorption of the dyes in CMK-1 and activated carbon can be fitted to both the Langmuir and Freundlich models, although with the possible exception of RR1 in activated carbon, statistically better fits are obtained with the Langmuir model. The adsorption of the dyes using CMK-1 was considerable higher than that using Norit SX2. The amount of dyes adsorbed by CMK-1 was in the order of RR1 > RhB > PBV

FTIR AND NMR STUDIES OF ADSORBED TRITON X-114 IN MCM-41 MATERIALS

One source of water pollutions is caused by the high use of surface-active agents (surfactants) by industries\ud and households. As a consequence, it is required to remove such substances from the environment One of the\ud important and widely used methods for removal of substances from solution is adsorption. In this research, MCM-41\ud and its modification MCM41-TMCS were used to adsorb nonionic surfactant, Triton X-114. FTIR and NMR methods\ud were used to study the interaction between the surfactants and the adsorbents. MCM-41 was synthesized\ud hydrothermally at 100 oC and its modification was conducted by silylation of MCM-41 with trimethylchloro silane\ud (MCM41-TMCS). Both unmodified and modified MCM-41 can adsorb the surfactant. The amount adsorbed in the\ud unmodified material is higher than that in the modified one. The interaction of Triton X-114 with MCM-41 was\ud hydrogen bonding between the silanol groups in MCM-41 and hydroxyl groups of Triton X-114. For modified\ud samples, Triton X-114 interacted with alkylsilyl groups mostly through hydrophobic interaction. It is more likely that\ud the interaction was through C12, C13, C26 and C27 of Triton X-114

ADSORPTION OF WATER AND BENZENE VAPOUR IN MESOPOROUS MATERIALS

Makara Seri Sains 12(2) 2008Mesoporous materials have attracted the attention of many researchers due to the potential applications promised by the\ud materials. This article discusses adsorption of water and benzene vapour in mesoporous materials (mesoporous silica:\ud MCM-41, MCM-48 and their modification). MCM-41 and MCM-48 were synthesized hydrothermally at 100 oC using\ud cethyltrimethylammonium chloride or dodecyltrimethylammonium bromide for MCM-41 (C16) or MCM-41 (C12)\ud respectively and a mixture of cethyltrimethylammonium bromide and Triton X-100 for MCM-48 as templates. Their\ud modifications were conducted by silylation of MCM-41 (C16) and MCM-48 with trimethylchloro silane (MCM16-\ud TMCS and MCM48-TMCS) and t-butyldimethylchloro silane (MCM16-TBDMCS and MCM48-TBDMCS). Results\ud showed that MCM-41 and MCM-48 materials had hydrophobic features which were shown in the small amount of\ud water adsorption at low P/P0. The hydrophobicity of samples used in this study decrease in the sequence: MCM-41\ud (C16) > MCM-48 > MCM-41 (C12). The hydrophobicity increased when MCM-41 and MCM-48 were silylated with\ud TMCS or TBDMCS. All unsilylated MCM materials show higher affinity to benzene at low P/P0 than the silylated\ud samples. The results of water and benzene adsorption showed that silylated samples are promising candidates as\ud selective adsorbents for organic compounds

Digital subtraction radiographic analysis of the combination of bioabsorbable membrane and bovine morphogenetic protein pool in human periodontal infrabony defects

Objectives: This study assessed the bone density gain and its relationship with the periodontal clinical parameters in a case series of a regenerative therapy procedure. Material and Methods: Using a split-mouth study design, 10 pairs of infrabony defects from 15 patients were treated with a pool of bovine bone morphogenetic proteins associated with collagen membrane (test sites) or collagen membrane only (control sites). The periodontal healing was clinically and radiographically monitored for six months. Standardized presurgical and 6-month postoperative radiographs were digitized for digital subtraction analysis, which showed relative bone density gain in both groups of 0.034 ± 0.423 and 0.105 ± 0.423 in the test and control group, respectively (p>0.05). Results: As regards the area size of bone density change, the influence of the therapy was detected in 2.5 mm2 in the test group and 2 mm2 in the control group (p>0.05). Additionally, no correlation was observed between the favorable clinical results and the bone density gain measured by digital subtraction radiography (p>0.05). Conclusions: The findings of this study suggest that the clinical benefit of the regenerative therapy observed did not come with significant bone density gains. Long-term evaluation may lead to a different conclusions

Doing politics in the recent Arab uprisings: Towards a political discourse analysis of the Arab Spring slogans

The present paper aims to analyse a number of those slogans collected from the sit-in quarters in Egypt, Libya and Yemen. Using political discourse analysis, it unravels various typical discourse structures and strategies that are used in slogans in the construction of a sub-genre of political discourse in the Arab world. Drawing data from several mediums, including banners, wall graffiti, audio-visual instruments, chanting, speeches and songs, this paper tries to show the extent to which the slogans serve as a medium by which political complaints and comments are dispensed and consumed. This paper draws on a rhetorical analysis to find out their persuasive effect on shaping the Arab intellect and on the change of the political atmosphere in the region. Lastly, this paper attempts to show to what extent the slogans meet the standards of political discourse and whether they can be considered as a sub-genre of political discourse or not.IS

Amine-functionalized MCM-48 as Adsorbent of Zn2+ and Ni2+ Ions

A compound, 3-aminopropyltrimetoxy silane, has been used to modify mesoporous silica, MCM-48. The modified silica (NH2-MCM-48) was utilized to remove Zn2+ and Ni2+ ions from solutions. The mesoporous material was synthesized in the alkaline solution. Characterization of the unmodified materials was conducted by X-ray diffraction and FT-IR spectroscopy. The ions adsorbed on NH2-MCM-48 were studied at various pHs, contact times and initial ions concentrations. An Atomic Absorption Spectrophotometer (AAS) measured the ions content in the solution.. Pseudo-first-order and pseudo-second-order models performed the kinetic adsorption. The adsorption isotherm was examined by Langmuir and Freundlich isotherms. The result found that optimum contact time for the adsorption of Zn2+ ion was lower than that for Ni2+ ion. The adsorption followed the pseudo-second-order model with the adsorption rate of 4.56x10-2 g mg-1 min-1 for Zn2+ ion and 7x10-4 g mg-1 min-1 for Ni2+ ion. The optimum pH was 6 and 4 for Zn2+ and Ni2+ adsorption, respectively. The uptake of both ions from solutions by NH2-MCM-48 fixed better the Langmuir than the Freundlich model with the adsorption capacity of 0.55 and 0.43 mmol g-1, correspondingly. This research work provides valuable information on the interaction between the ions and the functional group of adsorbent