Jerapan C-4-fenasiloksifenilkaliks[4]resorsinarena terhadap Pb(II), Cd(II) dan Cr(III)) UNDRI RASTUTI, DWI SISWANTA, WISNU PAMBUDI, BETA ACHROMI NUROHMAH, BOHARI M. YAMIN & JUMINA* ABSTRACT C-4-phenacyloxy phenyl calix[4]resorcinarene (CPPCR) was synthesized by acidic condensation of 4-hydroxybenzaldehyde and resorcinol. The adsorption of CPPCR for Pb(II), Cd(II) and Cr(III) has been studied by measuring the metal concentration in aqueous solution using Atomic Absorption Spectrophotometry (AAS). The effects of solution pH, contact time and initial concentration of metal ions on the adsorption capacity of CPPCR were investigated. The adsorption kinetic of all the ions obeyed the Ho and McKay pseudo 2 nd order rate law and the adsorption isotherm profile matched very well with Langmuir model. The separation factor (R L) of CPPCR for Pb(II), Cd(II) and Cr(III) were 0.190, 0.017, and 0.065, respectively, indicating the formation of monolayer behaviour. The Gibb free energy (ΔG) of the adsorption for all the metal ions have negative values indicating the adsorption process of Pb(II), Cd(II) and Cr(III) by CPPCR are spontaneous.

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Karet jenis poliisoprena, styrene butadiene rubber dan polybutadiene rubber dapat menghasilkan produk karet dengan karakteristik mekanik yang baik dan berbiaya rendah. Akan tetapi, jenis karet tersebut tidak memiliki ketahanan terhadap minyak yang baik. Penggunaan filler dapat memperbaiki kelemahan ini dengan memberikan interaksi antara filler dan karet sehingga memperbaiki struktur jejaring karetnya. Penelitian ini dilakukan untuk mempelajari pengaruh penggunaan as-given geothermal silica (AGS) dan silika komersial dalam jumlah tertentu sebagai filler terhadap nilai swelling dan crosslink density kompon karet. Vulkanisat karet disiapkan menggunakan alat two roll mill dan press molding. Sampel diuji swelling menggunakan dua jenis pelarut pada suhu yang berbeda, yaitu n-Pentana pada suhu kamar dan oli pada suhu 100oC. Nilai crosslink density didekati dengan tiga metode yaitu perhitungan modulus, pendekatan sarkawi dan persamaan flory-rehner. Hasil penelitian menunjukan jika vulkanisat karet yang diperkuat dengan AGS memiliki nilai crosslink density yang lebih tinggi dibandingkan chemisil. Sampel komposit memiliki ketahanan yang baik pada pelarut n-Pentana pada suhu kamar. Akan tetapi, kedua vulkanisat menunjukan nilai swelling yang tinggi saat berkontak dengan oil pada suhu 100oC.

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Soursop leaf tea is a health drink that contains steroid compounds, terpenoids, flavonoids, kumari, tannins, and alkaloids. The flavonoids and tannins in soursop leaves act as antioxidants. Since it has an unpleasant aroma, cinnamon is added to add scent and flavor. This study aimed to determine the effect of cinnamon powder on the soursop leaf tea's antioxidant activity. This study employed the completely randomized design method (CRD) with two factors: the soursop leaves and cinnamon powder concentrations. This study consisted of four treatments, namely SP0 (100% soursop leaves), SP1 (90% soursop leaves and 10% cinnamon powder), SP2 (80% soursop leaves and 20% cinnamon powder), and SP3 (70% soursop leaves and 30% cinnamon powder) within three repetitions. The proximate test was focused on antioxidant activity analyzed by ANOVA at α = 5%. The organoleptic test covered the color, taste, aroma, and other overall preferences by qualitative descriptive tests. The results showed that the highest antioxidant (29.19%) could be found in the SP3 sample (70% soursop leaves and 30% cinnamon powder), while the preferred organoleptic test was the SP2 sample.