Reduction in viscosity at higher temperatures is the main limitation of utilizing cellulose ethers in high thermal reservoir conditions for petroleum industry applications. In this study, cellulose ether (hydroxyethyl methyl cellulose (HEMC)) is modified using organic carbonates, i.e., propylene carbonate (PC) and diethyl carbonate (DEC), to overcome the limitation of reduced viscosity at high temperatures. The polymer composites were characterized through various analytical techniques, including Fourier-transform infrared (FTIR), H-NMR, Xray diffraction (XRD), scanning electron microscope (SEM), thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), ζ-potential measurement, molecular weight determination, and rheology measurements. The experimental results of structural and morphological characterization confirm the modification and formation of a new organic carbonate-based cellulose ether. The thermal analysis revealed that the modified composites have greater stability, as the modified samples demonstrated higher vaporization and decomposition temperatures. ζ-potential measurement indicates higher stability of DEC-and PC-modified composites. The relative viscometry measurement revealed that the modification increased the molecular weight of PC-and DEC-containing polymers, up to 93,000 and 99,000 g/moL, respectively. Moreover, the modified composites exhibited higher levels of stability, shear strength and thermal resistance as confirmed by viscosity measurement through rheology determination. The observed increase in viscosity is likely due to the enhanced inter-and intramolecular interaction and higher molecular weight of modified composites. The organic carbonate performed as a transesterification agent that improves the overall properties of cellulose ether (HEMC) at elevated temperatures as concluded from this study. The modification approach in this study will open the doors to new applications and will be beneficial for substantial development in the petroleum industry.

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The depletion of fossil fuels calls for the development of renewable alternatives such as biodiesel and has inspired much research on catalysts for the production of biodiesel through the esterification of biomass-derived materials. Herein, a green heterogeneous catalyst for highly efficient biodiesel synthesis was fabricated from rice straw–derived cellulose, hematite, and zirconia and was shown to contain porous irregularly shaped α-Fe 2 O 3 –ZrO 2 composites (average particle size = 42.5 nm) evenly distributed on the nanocellulose surface. The optimal catalyst (nanocellulose:α-Fe 2 O 3 –ZrO 2 = 2:1, w/w) afforded biodiesel in a yield of 92.50% and with specifications close to those prescribed by international standards. This catalyst could be reused for up to five cycles without a marked activity loss, with the biodiesel yield in the fifth cycle equaling 80.0%. The developed nanocomposite holds great promise for cutting the costs of biodiesel production, as it is derived from biodegradable raw materials and is renewable, non-corrosive, easy to handle, and green. In addition, the large-scale discharge of this catalyst after use does not pose a hazard to the environment.

A novel magnetic solid base catalyst consisting of an MgFe 2 O 4 -MgO nanocomposite was successfully prepared by synthesizing magnesium ferrite (MgFe 2 O 4 ) as the catalyst support, and it was employed in an esterification reaction for the production of biodiesel. MgFe 2 O 4 was synthesized by a ball-milling mechanochemical method at various furnace temperatures (350°C, 550°C and 750°C), and the best results were obtained at 750°C. The results of TEM revealed an average size of 39 nm. A nanocomposite of MgFe 2 O 4 -MgO was successfully synthesized in this study, as confirmed by Fourier transform infrared (FTIR), X-ray diffraction (XRD), scanning electron microscopy-energy dispersive x-ray (SEM-EDX) and transmission electron microscopy (TEM) characterization. The results of the FTIR characterization revealed peaks with wavenumbers corresponding to Mg-O and Fe-O bonds in the range of 500-900 cm -1 , SEM mapping showed that MgO was distributed on the surface of the MgFe 2 O 4 catalyst support, and the MgFe 2 O 4 -MgO average size was found to be 50 nm by TEM. The influence of MgO on MgFe 2 O 4 was determined by varying the molar ratio of MgFe 2 O 4 to MgO from 1: 1, 1: 2 and 1: 3 and by studying the catalytic activity in the esterification of oleic acid to biodiesel. The best MgFe 2 O 4 -MgO nanocomposite have a molar ratio of 1: 2 and gave a percent conversion of 96.089%. Impregnating MgFe 2 O 4 with MgO increased the number of basic active sites, thereby increasing the catalytic activity. This type of nanocomposite is a promising new material for future catalysts.

ABSTRAK  Penelitian ini bertujuan untuk mengetahui kandungan fenolik total dari ekstrak etanol dan etil asetat buah mengkudu (Morinda Citrifolia, L) dan aktivitas antibakteri tehadap bakteri Escherichia coli. Ekstrak Buah mengkudu yang telah di evaporasi dilakukan analisa senyawa dengan menggunakanspektrofotometer UV untuk mengetahui kandungan total senyawa fenol. Dan ekstrak buah mengkudu di uji bioaktivitas terhadap bakteri Escherichia coli. Dari hasil penelitian didapat kadar fenol ekstrak etanol sebesar 171,91 mg/L dan pada ekstrak etil asetat 23,27 mg/L. Dan Aktivitas antibakteri ekstrak etanol buah mengkudu dan ekstrak etil asetat buah mengkudu dapat mengahambat bakteri Escherichia coli. Kata Kunci: Antibakteri, Buah mengkudu, fenolik total ABSTRACT   This research aims to determine the ability of ZnO-Zeolite to degrade Acid Orange 7. The first, synthesized zinc acetate precursors from Zn waste batteries. Next, synthesized ZnO from the precursor of zinc acetate and impregnated with zeolite to form a ZnO-Zeolite composite used the sol-gel method. Photodegradation test for Acid Orange 7 dye used a concentration of 50 ppm with variations in pH 3, 5, 7, 9 and 11. Measurement of concentration of Acid Orange 7 dye degradation results used a UV-Vis Spectrophotometer at a wavelength of 484.45 nm. The results showed that ZnO-Zeolite composites were able to degrade Acid Orange 7 dyes at pH 7 with a degradation percentage of 94.15%. Keywords: ZnO-Zeolite composite, acid orange 7, degradation