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All Journal TEKNIK CHEMICA Jurnal Teknik Kimia Communications in Science and Technology Indonesian Journal of Chemical Analysis (IJCA) Jurnal Ilmu Fisika SEMAR Equilibrium Journal of Chemical Engineering
Mujtahid Kaavessina, Mujtahid
Program Studi Teknik Kimia, FT, UNS Jl. Ir. Sutami no. 36 A, Surakarta 27126 Telp/fax:0271-632112
Humanities Astronomy Chemical Engineering, Chemistry & Bioengineering Chemistry Earth & Planetary Sciences Education Energy Engineering Environmental Science Languange, Linguistic, Communication & Media Materials Science & Nanotechnology Physics Social Sciences

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Formation of fine particles using supercritical fluid (SCF) process: Short review Chafidz, Achmad; Jauhary, Thonthowy; Kaavessina, Mujtahid; Sumarno, Sumarno; Latief, Fahamsyah H.
Communications in Science and Technology Vol 3 No 2 (2018)
Publisher : Komunitas Ilmuwan dan Profesional Muslim Indonesia

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (760.44 KB) | DOI: 10.21924/cst.3.2.2018.101

Abstract

This paper will discuss about the utilization of supercritical fluid (SCF) process to produce fine particles. Supercritical fluids (SCFs) process can be considered as an emerging “clean” technology for the production of small-size or fine particles (e.g. micron-size). Microsphere is a material in micron scale which has been widely used as adsorbent, catalyst support, and drug delivery system. For advanced application, those materials are formulated in the form of porous microspheres. There are several methods that can be used using SCFs. Those method are, Rapid Expansion of Supercritical Solution (RESS), Gas Anti-Solvent/Supercritical Anti-Solvent (GAS/ SAS), Aerosol Solvent Extraction System (ASES), dan Solution Enhanced Dispersion by Supercritical Fluids (SEDS) and Particle from Gas-Saturated Solutions/Suspensions (PGSS). Considering the morphology of material which will be used to prepare microsphere, each of methods above has specific advantages and disadvantages toward the material. Based on the literatures, the ASES method is more likely to produce porous microparticles (microspheres). In the ASES method, porous microsphere formation is the result of interactions between: degrees of supersaturation, nucleation velocity and crystal growth.
Evaluation of the Chemical Structure and Thermal Properties of Polyethylene Glycol (PEG)-Doped Polylactic Acid (PLA)/Multiwalled Carbon Nanotube (MWCNT) Composites Rifa'i, Awaludin Fitroh; Kaavessina, Mujtahid; Distantina, Sperisa
Indonesian Journal of Chemical Analysis (IJCA) Vol. 7 No. 2 (2024): Indonesian Journal of Chemical Analysis
Publisher : Universitas Islam Indonesia

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.20885/ijca.vol7.iss2.art5

Abstract

This study aimed to investigate the chemical structure, thermal properties, and stability of polylactic acid (PLA) composites blended with multi-walled carbon nanotubes (MWCNTs) and polyethylene glycol (PEG). The composites were fabricated using a masterbatch blending method with two different molecular weights (Mw) of PEG. The masterbatch was initially prepared using solvent casting with chloroform as the solvent, followed by melt blending using an extruder. ATR-FTIR spectroscopy identified strong hydrogen bonds between the C=O groups of PLA and the –OH groups of PEG, as evidenced by the peak at 1748 cm¹. Differential Scanning Calorimetry (DSC) revealed that incorporating 14 wt% of PEG 10,000 into PLA/MWCNT composite significantly enhances the melting enthalpy (∆Hm) from 18.3 J/g to 24.6 J/g and the degree of crystallinity from 2% to 17.3%. The glass transition temperature (Tg) decreased with the addition of PEG, indicating increased chain mobility, while the melting temperature (Tm) remained relatively constant around 158 oC regardless of the PEG Mw. Despite the plasticizing effect of PEG, the thermal stability of the composites was maintained across different PEG Mw. Scanning Electron Microscope (SEM) images showed that MWCNTs were well dispersed within the blend, facilitated by ultrasonic stirring during preparation.
Improving Solvolysis Rate Via Under Glass-Transition Temperatures Quenching Followed by Roll Bending of Carbon Fiber Reinforced Polymer Composite Sukanto, Heru; Kusharjanta, Bambang; Kaavessina, Mujtahid
TEKNIK Vol 45, No 3 (2024): December 2024
Publisher : Diponegoro University

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.14710/teknik.v45i3.59296

Abstract

Reusing carbon fiber once it has been used as reinforcement in composite structures involves a complex recycling technique. This recycling process requires a strategy to ensure the recycled carbon fiber meets technical standards. Among various recycling processes, the solvolysis technique yields carbon fiber with high purity. However, solvolysis is also the most time-consuming method. This study proposes using quenching and roll-bending pretreatments, which increase the contact surface area between the composite and the solvent solution for expediting the solvolysis process of carbon fiber reinforced polymer (CFRP) composite. Quenching was performed by heating the composite to 75°C, 100°C, and 125°C before immersing it in water at room temperature. Roll bending was designed based on the principle of three-point bending and aimed to induce a strain in the composite that exceeds the strain of the epoxy resin. Quenching at 75°C, followed by roll bending, resulted in a 21% increase in the surface area of the composite. This increased area improved the solvolysis efficiency of CFRP composites by up to 21% after four days of immersion in a mixture of acetone and acetic acid.
Effect of Freshwater and Seawater Immersion on Mechanical Properties and Pre-Immersion Magnetic Response of Silicone Rubber–Magnetite Composite Magnets Wibowo, Wibowo; Santoso, Nehemia Herbert; Ramadhan, Brilliano Wahyu; Juwana, Wibawa Endra; Kaavessina, Mujtahid
Jurnal Ilmu Fisika Vol 18 No 1 (2026): March 2026
Publisher : Jurusan Fisika FMIPA Universitas Andalas

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.25077/jif.18.1.25-34.2026

Abstract

Magnetite (Fe₃O₄) and RTV 48 silicone rubber-based magnetic composites have potential for outdoor applications due to their flexible and tunable magnetic properties. This study investigates the effect of immersion for 14 days in fresh water and seawater on its mechanical, magnetic, and thermal properties. Specimens were made by mixing 70 wt% Fe₃O₄ powder into RTV 48 matrix, then tested for hardness using Shore A durometer, magnetic properties using Vibrating Sample Magnetometer (VSM), and thermal stability using Thermogravimetric Analysis (TGA). Results showed a decrease in surface hardness due to matrix degradation by water penetration. The magnetic properties continued to exhibit soft magnetic characteristics with low coercivity and remanence. TGA analysis revealed changes in thermal degradation patterns, signaling chemical interactions between the material and the wet environment. These findings suggest that exposure to water can affect the long-term performance of Fe₃O₄-RTV 48 composites, making moisture resistance an important aspect for their outdoor applications.
Effect of Acrylamide and Potassium Persulfate on The Characteristics of Water Hyacinth-Carrageenan Bead Gel Using Microwave Grafting Method Distantina, Sperisa; Putra, Novan Aldian Rahmadan; Naryani, Rahma Fitri; Kaavessina, Mujtahid
CHEMICA: Jurnal Teknik Kimia Vol. 10 No. 3 (2023): December 2023 [Available online since December 26, 2023]
Publisher : Universitas Ahmad Dahlan

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.26555/chemica.v10i3.27389

Abstract

The cellulose of water hyacinth (Eichhornia crassipes) was utilized as raw material in bead gel production. In this research, hydrogel was prepared by grafting of acrylamide (AA) monomers onto the water hyacinth cellulose as the backbone using the microwave to produce hydrogel. This research aimed to determine the influence of adding AA and potassium persulfate (PPS) as an initiator on characteristic of swelling capacity in water. The cellulose powder obtained from the stem of water hyacinth was immersed in NaOH solution (1.5 N) for the delignification process for 10 min. The resulted cellulose was mixed with water and varying additions of 4, 7, dan 10 g acrylamide (AA) and 0.05, 0.10, and 0.15 g PPS to undergo grafting reaction.  The obtained gel was washed and soaked in the acetone to remove the unreacted AA and PPS. The resulting precipitated solid was dried and called Water Hyacinth  Cellulose Grafted Polyacrylamide (WH cellulose-g-PAA). The mixture of carrageenan with WH cellulose-g-PAA underwent crosslinking using aqueous KCl and CaCl2 after passing through palm oil layer to form bead gel. The properties of the dried bead gel were tested for functional groups using FTIR and for swelling capacity in water. Based on the FTIR test results, it can be concluded that AA monomers were successfully grafted onto the water hyacinth cellulose backbone. The addition of AA that is too low or too high will reduce the swelling capacity, as well as PPS.
Diversifikasi Pemanfaatan Minyak Biji Nyamplung sebagai Upaya Meningkatkan Nilai Tambah Produksi di CV Plantanesia Setyawardhani, Dwi Ardiana; Rakhmawati, Rita; Kaavessina, Mujtahid; Danarto, Y. Calasanctius
SEMAR (Jurnal Ilmu Pengetahuan, Teknologi, dan Seni bagi Masyarakat) Vol 11, No 1 (2022): Mei
Publisher : LPPM UNS

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.20961/semar.v11i1.55835

Abstract

Minyak biji nyamplung telah diproduksi di industri kecil maupun menengah dengan cara pengepresan bijinya. Minyak yang belum dimurnikan dijual sebagai bahan baku kosmetik untuk produk skin care dan obat tradisional seperti minyak urut maupun obat gatal. Namun, pengetahuan bahwa minyak ini dapat diolah lebih lanjut untuk produk farmasi belum diketahui pelaku usaha. Komponen utama minyak biji nyamplung berpotensi untuk diolah menjadi bahan bakar alternatif biodiesel sedangkan komponen minornya memiliki efek antibakteri terhadap Staphylococcus aureus dan Escheria coli. Minyak nyamplung juga merupakan sumber senyawa bioaktif. Salah satu konstituen utama dari biji nyamplung, calophyllolide, memiliki aktivitas anti-inflamasi, anti-koagulan, antibakteri dan antikanker. Mengingat manfaat minyak nyamplung yang beragam, maka perlu diberikan penyuluhan pada industri penghasil minyak nyamplung untuk mengembangkan produktivitasnya melalui diversifikasi pemanfaatan minyak nyamplung. Tujuan pengabdian pada masyarakat ini adalah memberikan wawasan kemanfaatan minyak nyamplung, sehingga UMKM yang bersangkutan dapat menghasilkan produk turunan lainnya selain dijual dalam bentuk unrefined oil. Kegiatan pengabdian pada masyarakat ini dilakukan di CV. Plantanesia. Pelatihan diberikan dalam bentuk sharing pengetahuan dan perkembangan teknologi terkini mengenai pemurnian minyak biji nyamplung serta ekstraksi komponen-komponen mayor dan minor. Penyampaian materi dilakukan melalui kunjungan ke lokasi dan penyuluhan secara daring pada pelaku usaha.
Preparation and Flocculation Performance of Polyacrylamide Grafted Banana Stem Cellulose: Effect of Acrylamide and Ammonium Peroxydisulfate Distantina, Sperisa; Nainggolan, Imanuel Daniel; Fernando, Yosea Ido; Kaavessina, Mujtahid
Equilibrium Journal of Chemical Engineering Vol 9, No 2 (2025): Volume 9, No 2 December 2025
Publisher : Program studi Teknik Kimia UNS

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.20961/equilibrium.v9i2.110187

Abstract

ABSTRACT. Banana stem was identified as an attractive source of cellulose and a promising raw material for developing friendly bioflocculant hydrogels in water treatment. Polyacrylamide grafted banana stem cellulose (BS-g-PAA) was synthesized for flocculation application. The objective of this study was to investigate the effect of ammonium peroxydisulfate (APS) and acrylamide (AA) amount on the grafting efficiency and flocculation performance of obtained BS-g-PAA. In this study, 1 g banana stems flour was mixed in distilled water, followed by the addition of AA at different weight (10, 15, and 20 g) and APS at various weight (0.1, 0.15, and 0.2 g). The mixture was grafted using microwave irradiation at 540 W for 60 s per cycle, repeated for three cycles (total 180 s). The sample was then dried using an oven until constant weight and ground to obtain BS-g-PAA powder. The results of FTIR showed that the successful grafting of acrylamide onto the cellulose backbone. The grafting percentage increased with the increasing of AA amount, from 1,008% at 10 g AA to 2,098% at 20 g AA. Ammonium peroxydisulfate from 0.1 g to 0.2 g increased grafting percentage from 980% to 1,008%. BS-g-PAA hydrogel prepared by 1 g banana stem, 0.2 g APS, and 10 g AA produced the most effective turbidity reduction by reducing the turbidity value from 53.3 NTU of kaolin suspension to a final value of 15.29 NTU after 80 s flocculation test. These results demonstrated that hydrogels derived from banana stems may have promising potential as sustainable bioflocculants for wastewater treatment applications.Keywords:Banana stem, Ammonium peroxydisulfate, Acrylamide, Bioflocculant, Microwave grafting
The Prospects and Challenges of Biopolymers for Enhanced Oil Recovery (EOR) Matovanni, Maudy Pratiwi Novia; Ikhsanudin, Muhammad Nur; Arvianto, Rizky Ibnufaatih; Waluyo, Joko; Distantina, Sperisa; Kaavessina, Mujtahid; Pranolo, Sunu Herwi
Equilibrium Journal of Chemical Engineering Vol 7, No 1 (2023): Volume 7, No 1 July 2023
Publisher : Program studi Teknik Kimia UNS

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.20961/equilibrium.v7i1.73947

Abstract

Abstract. Currently, Enhanced Oil Recovery (EOR) technology is being interested in the Indonesian state as an advanced technology that can recover oil remaining in the reservoir. The discovery of new resources and EOR efforts are predicted to result in increased oil production. This paper provides a review of main types of EOR methods, which are gas injection, thermal injection, and chemical injection; mechanism of polymer flooding; and biopolymer materials for EOR, attention were given to xanthan gum, cellulose, guar gum, and lignin. Polymer flooding is a low-cost chemical injection method with a high rate of success. Polymer flooding has several advantages, including improving oil recovery by minimizing residual oil saturation, decreasing water output from oil well, and requiring less water compared with water flooding. Since the use of polymer flooding in the EOR activities, there is a lot of potential that biopolymers are materials that play a significant role in the application of EOR technology, because environmentally friendly properties and have advantages over synthetic polymers. Biopolymer can be modified to nano materials or grafted with synthetic polymer to improve its properties and stability. It have shear, salinity, and temperature resistance, long-term stability, and large availability, so it making the right choice for applications in oil recovery.Keywords:Enhanced oil recovery, EOR, biopolymer, polymer flood, modification of biopolymer
Effect of Potassium Peroxodisulphate and Microwave Power on Hydrogel Character Based on Banana Peel Waste Using Microwave Grafting Method Distantina, Sperisa; Anggreini, Ghea Safiraventa; Al Kamal, Fahrul An'nas; Kaavessina, Mujtahid; Fadilah, Fadilah
Equilibrium Journal of Chemical Engineering Vol 7, No 1 (2023): Volume 7, No 1 July 2023
Publisher : Program studi Teknik Kimia UNS

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.20961/equilibrium.v7i1.67919

Abstract

ABSTRACT. Musa paradisiaca var. raja peel waste contains cellulose which has the potential to be a raw material for synthesizing hydrogels. This research utilizes acrylamide monomer grafted onto banana peel cellulose backbone using the microwave grafting method to produce hydrogel. The banana peel waste was dried to a constant weight and then crushed into powder. Banana peel powder was through a delignification process with the addition of NaOH and bleached with NaClO to took only the cellulose of the banana peel. The mixture of banana peel cellulose-acrylamide-potassium peroxodisulfate powder through the grafting process was repeated with variations in KPS concentration and microwave power. The reaction was terminated with a hydroquinone solution, washed with acetone, and then precipitated. The precipitated solid was dried to a powder called cellulose-g-PAAM. A homogeneous solution of 2% carrageenan-cellulose-g-PAAM underwent a physical crosslinking process using KCl and CaCl2 solutions after passing through palm oil to form a bead gel. The purpose of this research was to determine the effect of potassium peroxodisulfate (KPS) initiator concentration and microwave power on the swelling capacity in water. The properties of obtained dried bead gels were characterized their functional groups using FTIR and swelling capacity test in water. From this research, it can be concluded that banana peel cellulose was successfully grafted onto acrylamide monomer as evidenced by the FTIR test results. The lower KPS concentration is the greater on the swelling capacity and the microwave power has no effect on the swelling capacity of bead gels.Keywords: Banana peel, Bead gel, Microwave, Swelling degree 
Effect of Acrylamide And Potassium Peroxodisulphate on The Quality of Bead Gel Based on Cassava Bagasse-Carrageenan Using Microwave Grafting Method Distantina, Sperisa; Hidayatun, Nurul; Nabila, Shifa Annisa; Kaavessina, Mujtahid; Fadilah, Fadilah
Equilibrium Journal of Chemical Engineering Vol 6, No 2 (2022): Volume 6, No 2 December 2022
Publisher : Program studi Teknik Kimia UNS

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.20961/equilibrium.v6i2.68130

Abstract

ABSTRACT. Hydrogels are widely used for drug delivery systems, immuno-chemotherapy applications, efficient use of water, preventing dry soil, and increasing soil infiltration. Generally, hydrogels are derived from synthetic polymers which is non-biodegradable and toxic. Cassava bagasse is an alternative cellulose to make hydrogels. The purpose of this research was to determine the effect of the amount of acrylamide and potassium peroxodisulphate (KPS) initiator on the quality of bead gel based on cassava bagasse-carrageenan. Chemical structure of the hydrogel was studied using FTIR spectroscopy. Cassava bagasse was immersed in a solution of n-hexane to separate the fat. Then, fat-free cassava bagasse was grafted with mass ratios of cassava and acrylamide 1:5, 1:10, and 1:15 in 110 mL water. The solution was added with a KPS initiator with weight variations (g) 0.04; 0.08; 0.12 then stirred 15 min. The solution was put in the microwave with 630 watts of irradiation for 450 s with the cooling cycle temperature maintained at 65-70oC. The aqueous of grafted polymer and carrageenan was injected into beaker glass that contained 1 cm of palm oil and mixture of 0.2 M CaCl2 and 0.2 M KCl in an ice bath. Results showed that the highest average swelling capacity was found in the bead gel variation 1:15 with the number of initiators 0.04 g of 1797.95% at a time of 210 minutes of immersion. From FTIR spectrum, it was found that there was a success in grafting acrylamide into bagasse’s backbone using the microwave grafting method with KPS as initiator.Keywords: Acrylamide, Bead Gel, Cassava Bagasse, Grafting Microwave, Potassium Peroxodisulphate
Co-Authors Al Kamal, Fahrul An'nas Anggreini, Ghea Safiraventa Aprian, Laura Hanifa Arvianto, Rizky Ibnufaatih Bambang Kusharjanta Banowati, Dea Espina Chafidz, Achmad Danarto, Y. Calasanctius Danarto, Yoseph Calasanctius Dwi Ardiana Setyawardhani, Dwi Ardiana Efendy, Gabrella Endang Kwartiningsih Fadilah Fadilah, Fadilah Fakhruddin, Isa Fernando, Yosea Ido Handayani, Indah Dwi Heru Sukanto Husni, N Fauziatul Ikhsanudin, Muhammad Nur Jauhary, Thonthowy Joko Waluyo Latief, Fahamsyah H. Matovanni, Maudy Pratiwi Novia Nabila, Shifa Annisa Nainggolan, Imanuel Daniel Naryani, Rahma Fitri Nurul Hidayatun Pranolo, Sunu Herwi Putra, Novan Aldian Rahmadan Ramadhan, Brilliano Wahyu Ramadhani, Aida Nur Rifa'i, Awaludin Fitroh Rita Rakhmawati, Rita Santoso, Nehemia Herbert Setyawhardani, Dwi Ardiana Siti Habibah Sperisa Distantina Sumarno . Tane, Amaldo Firjarahadi Wibawa Endra Juwana, Wibawa Endra Wibowo Wibowo