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"ABSTRAKMaterial penyerap gelombang mikro telah banyak diteliti sebelumnya, terutama mengarah ke material paduan berbahan polimer. Dalam penelitian ini polimer konduktif yang digunakan adalah polianilin (PANi) yang dipadukan dengan paduan material barium heksaferit substitusi ion Ti dan Mn dan kobalt ferit (BHFTM/CFO), dimana material tersebut mempunyai sifat magnetik, karena pada dasarnya material yang bisa digunakan sebagai penyerap gelombang mikro adalah material yang mempunyai sifat dielektrik dan magnetik. Dengan kata lain suatu material dapat dikatan penyerap gelombang mikro jika memiliki sifat permitivitas, permeabilitas, total magnetisasi, dan resistivitas yang tinggi. PANi disintesa dengan menggunakan metoda polimerisasi oksidasi, sedangkan BHFTM dan CFO disintesa menggunakan metoda pemaduan mekanik dan dilakukan sonikasi untuk memperkecil ukuran partikel. Paduan PANi/BHFTM/CFO disintesa dengan cara menambahkan material pengisi ke dalam matriks PANi dengan rasio 20:80, 50:50, dan 80:20 (% berat) kemudian dilakukan pengepresan dengan tekanan sebesar 5 ton selama 10 detik sebanyak 2 kali. Karakterisasi nanokomposit diuji dengan menggunakan spektrofotometer FTIR untuk polimer, X-ray Diffraction (XRD), Scanning Electron Microscope (SEM), Conductivity Meter (metoda four point probe), Particle Size Analyzer (PSA), Permagraph, dan Vector Network Analyzer (VNA). Dengan adanya substitusi ion pada material barium hexaferrit maka terdapat perubahan baik pada sifat magnetisasi dan penyerapan gelombang mikro. Karakterisasi XRD menunjukkan pola difraksi BHFTM tidak berbeda dengan BHF hanya terjadi pergeseran puncak. Sedangkan hasil karakterisasi SEM menunjukkan terjadi perpaduan antara BHFTM dan CFO. Hasil karakterisasi absorpsi dengan VNA menunjukkan adanya serapan pada komposit PHMM 2080 yaitu -20 dB pada frekuensi 12,8 GHz dimana komposit yang digunakan menggunkaan polianilin hasil doping (PANi-HCl) dan magnetik dalam multi kristalit partikel dengan rasio fraksi massa komponen polimer:magnetik sebesar20:80. Perubahan ukuran partikel menjadi nano kristalit partikel menghasilkan serapan sebesar -19,08 db pada frekuensi 12,75 GHz (komposit PEMN 8020 atau komposit PANi-EB:Magnetik nano partikel dengan rasio fraksi massa 80:20).

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ABSTRACTMicrowave absorber materials have been widely studied, especially leading to polymeric based composite materials. In this study, conductive polymers used are polyaniline (PANi) combined with a blend of material barium heksaferit substitution ion Ti and Mn and cobalt ferrite (BHFTM/CFO), wherein the material has magnetic properties, because basically materials that can be used as a microwave absorber if a material that has dielectric and magnetic properties. In other words the absorbent material can used absorbent if it has properties of permittivity, permeability, total magnetization and resistivity low. PANi synthesized by using the method polymerization oxidation while BHFTM and CFO were synthesized using a mechanical alloying synthesis method then sonication process for reduce particle size. PANi/BHFTM/CFO composite synthesized by adding a filler material into the matrix PANi with a ratio of 20:80,50:50, and 80:20 (% by weight) and then do the pressing with a pressure of 5 tons for 10 seconds twice. The characterization of nanocomposite tested using FTIR spectrophotometer for the polymer, X-ray Diffraction (XRD), Scanning Electron Microscope (SEM), Conductivity Meter (method four-point probe), Particle Size Analyzer (PSA), Permagraph, and Vector Network Analyzer (VNA).With the substitution of ions in the barium hexaferrite material there is a change in both the magnetization and microwave absorption properties. XRD characterization shows BHFTM diffraction pattern is not different from BHF only peak shift occurs. While the results of SEM characterization shows a combination between BHFTM and CFO. The characterization results of absorption by VNA showed absorption at 2080 PHMM composite is -20 dB at 12.8 GHz frequency where composites are used menggunkaan polyaniline doping results (PANi-HCl) and magnetic particles in a multi crystallites with the ratio of the mass fraction of the polymer components: magnetic amounted 20:80. The change crystallite size particles into nano particles produce uptake of -19.08 db at a frequency of 12.75GHz (8020 PEMN composites or composite PANi-EB:Magnetic nano-particles with mass fraction ratio of 80:20)."

"Strontium hexaferrite dengan komposisi nominal Sr0.6Fe,-<,..,jMn,TiyO, (x =0, y=; x = 0.4, y= 0.6; x = 0.5, y = 0.5; x = 0.6, y =0.4) disintesa dengan reaksi keadaan padat. Empat komponen serbnk BaCO,, SrCO,, Fe,O,, MnCO,, dan TiO, dicampur menggunakan High Energy Milling selama 10 jam dan disinterring pada 1050'C dalam tekanan atrnosfer selama 15 jam dan pendinginan eli tungku pemanas. X-ray diffraction (XRD), scanning electron microscope (SEM), energy dispersive spectroscopy (EDS), vibrating sample magnetometer (VSM) dan network analyzer digunakan untuk analisa struktur, sifat elektomagnetik dan penyerapan gelombang. Hasil memperlihatkan bahwa identifikasi fasa dengan penghalusan pola difrkasi XRD diperoleh fasa tunggal untuk substitusi Mn-Ti terhadap Sr0.6Fe,o, dengan x ~ y dan multi fasa terbentuk untnk x " y. Analsis mikrostrnktur dengan SEM menunjukkan variasi partikel adalah 2 - 5 um. Evaluasi terhadap karakteristik magnetik mengindikasikan bahwa terjadi penurunan koersifitas dengan kenaikan substitusi ion Mn2+ dan Ti4+ tetapi penurunan yang signifikan diperoleh terhadap saturasi magntetisasi pada substitusi Mn dan Ti dengan x :t: y. Penelitian saat ini menunjukkan penyerapan gelombang, reflection dan transmission dan juga reflection loss pada rentang frekuensi 7-16 GHz. Dilaporkan juga performansi penyerapan pada substitusi Mn dan Tipada strontium hexaferrite.

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Strontium hexaferrite with nominal compositions Sr0.6Fe,-{"':Y~xTiy03 (x ~ 0, y o=Q; x ~ 0.4, y ~ 0.6; x ~ 0.5, y ~ 0.5; x ~0.6, y ~ 0.4) have been synthesized by solid state reaction. The four components powder were BaCO,, S!CO,, Fe,O,, MnCO,, and Ti02 mixed with High Energy Milling for 10 hours and sintered at I 050'C in the air at atmosphere pressure for 15 hour and furnace cooling. X-ray diffraction (XRD), scanning electron microscope (SEM), energy dispersive spectroscopy (EDS), resonance vibrating sample magnetometer (R· VSM) and vector network analyzer were used to analyze its structure, electromagnetic and microwave absorption properties. The result showed that, phase identification by refinement results ofXRD pattern confirmed single phase was obtained for Mn-Ti substituted Sr0.6Fe20, with x ~ y and multiphase formed for x" y. The microstructure analyses by SEM showed that the varied particle sizes of 2 -- 5 ~-tm. Evaluation on the magnetic characteristic indicated that coercivity decreased as the number ofMn2"~" and Ti +ions increased but significant decrease in saturation magnetization obtained for Mn and Ti substitution with x ::1:- y. Present investigation demonstrates that microwave absorber. reflection and transmission as well as reflection loss in the frequency range 7-16 GHz were derived Absorption performance ofMn and Ti substituted strontium hexaferrite are also reported."

"Luka merupakan suatu kerusakan integritas kulit yang dapat terjadi ketika kulit terpapar suhu atau pH tertentu, zat kimia, ataupun gesekan. Setiap luka tentunya dapat beresiko infeksi atau peradangan apabila tidak diberi perawatan dengan baik dan benar, terlebih jika pemilihan material pembalut luka yang digunakan tidak sesuai dengan karakteristik luka. Pada penelitian ini dikembangkan material unggul berupa hidrogel nanokomposit yang diharapkan dapat diaplikasikan sebagai pembalut luka yang dapat menyeimbangkan kelembaban jaringan luka karena sifatnya yang hidrofilik dan memiliki struktur berupa jejaring tiga dimensi. Hidrogel nanokomposit disintesis dari biopolimer natrium alginat NaAlg dan polivinilalkohol PVA dengan metode pencangkokan grafting menggunakan akrilamida AAm dan N,N rsquo;-metilen-bis-akrilamida MBA sebagai agen pengikat silangnya cross-linker . Matriks jejaring dalam hidrogel nanokomposit NaAlg-PVA-g-AAm dimanfaatkan sebagai nanoreaktor untuk pembentukan nanopartikel perak AgNP menggunakan metode post-loading sehingga akan didapatkan material pembalut luka yang juga memiliki aktivitas antibakteri disamping dapat menjaga keseimbangan kelembaban luka. Karakterisasi hasil sintesis dilakukan dengan menggunakan instrumentasi FTIR, SEM, TEM, XRD dan AAS. Dilakukan variasi ukuran natrium alginat dan rasio Alg/PVA dalam proses polimerisasi dan didapatkan hasil terbaik yaitu hidrogel dengan ukuran alginat nano dan rasio Alg/PVA 3:1 kode. Hn 3 . Material hidrogel tanpa modifikasi Hn 3 memiliki kapasitas swelling maksimum sebesar 45,7260 g/g dan loading ion Ag 153,67 ppm/g. Kemudian dilakukan variasi konsentrasi prekursor AgNO3 pada material hidrogel Hn 3 dan diketahui bahwa Hn 3 dengan konsentrasi AgNO3 62,5 ppm kode. HNKn 3/62,5 memiliki hasil terbaik yang cukup untuk menghambat aktivitas antibakteri. Uji aktivitas antibakteri dilakukan secara in-vitro terhadap bakteri uji Staphylococcus aureus dan Escherichia coli. Diketahui bahwa S. aureus lebih resisten dibandingkan E. coli dengan nilai konsentrasi hambat minimum masing-masing secara berturut-turut sebesar 62,5 ppm dan 31,25 ppm. Didapatkan hasil untuk HNKn 3/62,5 yaitu kapasitas swelling maksimumnya 56,9407 g/g, loading ion Ag sebesar 54,2509 ppm/g dan kapasitas release maksimumnya sebesar 1,485 ppm/g. Studi kinetika swelling dilakukan terhadap material Hn 3 dan HNKn 3/62,5 menggunakan metode diferensial. Kinetika Hn 3 mengikuti orde pseudo dua dengan parameter laju swelling sebesar 80 menit. Sedangkan HNKn 3/62,5 mengikuti orde pseudo satu dengan parameter laju swelling 151,52 menit.

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Wounds is a skin damage that occur when the skin is exposed to temperature, pH, chemicals, or friction. Wounds can be risk of infection or inflammation if wound dressing selection that used does not match with wound characteristics. This research will developed a hydrogel nanocomposite material which is expected to be applied as a wound dressing that can balancing moisture on wound tissue because it has hydrophilic properties and three dimensional network pores. Hydrogel nanocomposite will be synthesized from sodium alginate and polyvinylalcohol with grafting method used acrylamide as a monomer and N,N rsquo methylenbisacrylamide as a crosslinker. Hydrogel matrix will be used as nanoreactor to forming silver nanoparticles AgNP rsquo s with post loaded method. So, we can get a wound dressing material with antibacterial activities beside it can balancing moisture on wound tissue. Hydrogel nanocomposite was characterized by FTIR, SEM, TEM, XRD and AAS. Sodium alginate size and Alg PVA ratio in polymerization process were variated and the best material is hydrogel with nano sodium alginate and Alg PVA 3 1 ratio Code. Hn 3 . Hydrogel without modification Hn 3 has maximum swelling capacity 45,7260 g g and Ag ion loading 153,67 ppm g. Precursors AgNO3 concentration were variated on Hn 3 and it is known that 62,5 ppm Code. HNKn 3 62,5 has a best result with maximum swelling capacity 56,9407 g g Ag ion loading 54,2509 ppm g maximum release capacity 1,485 ppm g and it has antibacterial activities. Antibacterial activities test was done to against Staphylococcus aureus and Escherichia coli with minimum inhibitory concentration is 62,5 ppm and 31,25 ppm. Swelling kinetic studies for Hn 3 and HNKn 3 62,5 was done by diferential method. Hn 3 follows pseudo second order rate law with swelling rate parameter 80 minutes. HNKn 3 62,5 follows pseudo first order rate law with swelling rate parameter 151,52 minutes."

"Nanokomposit BiFeO3/LaFeO3 dan BiFeO3/LaFeO3/Graphene dengan variasi persen berat (wt.%) graphene sebanyak 3, 5, dan 10 wt.% telah berhasil difabrikasi menggunakan metode berbantuan ultrasonik. Tidak adanya pengotor dan fasa lain pada nanokomposit ditunjukkan dari hasil karakterisasi X-ray Diffraction (XRD) dan X-ray Fluorescence (XRF). Keberadaan material graphene dan interaksinya dengan nanokomposit BiFeO3/LaFeO3 yang tidak terdeteksi oleh pengukuran XRD dan XRF dapat dilihat dengan jelas melalui pengukuran X-ray Photoelectron Spectroscopy (XPS), Thermogravimetric Analysis (TGA), dan Raman Spectroscopy. Pengukuran UV-Vis Diffuse Reflectance Spectroscopy (UV-Vis DRS) menunjukkan bahwa energi celah pita berkurang karena adanya material graphene. Kehadiran grafena sangat terlihat pengaruhnya pada hasil pengukuran isoterm adsorpsi-desorpsi N2 yang ditandai dengan peningkatan luas permukaan yang drastis dan perubahan bentuk pori-pori permukaan. Nanokomposit BiFeO3/LaFeO3/Graphene menunjukkan aktivitas fotokatalitik yang lebih unggul dibandingkan dengan BiFeO3, LaFeO3, dan BiFeO3/LaFeO3 pada paparan cahaya tampak. Uji reusability menunjukkan stabilitas nanokomposit pada penggunaan berulang sebanyak 4 kali.

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BiFeO3/LaFeO3 and BiFeO3/LaFeO3/Graphene nanocomposites with variations in weight percent (wt.%) graphene as much as 3, 5, and 10 wt.% have been successfully fabricated using ultrasonic-assisted methods. The absence of impurities and other phases in the nanocomposite was shown from the results of X-ray Diffraction (XRD) and X-ray Fluorescence (XRF) characterization. The presence of graphene material and its interactions with BiFeO3/LaFeO3 nanocomposites that were not detected by XRD and XRF measurements could be clearly seen through X-ray Photoelectron Spectroscopy (XPS), Thermogravimetric Analysis (TGA), and Raman Spectroscopy measurements. Measurement of UV-Vis Diffuse Reflectance Spectroscopy (UV-Vis DRS) showed that the band gap energy was reduced due to the presence of graphene material. The presence of graphene has a very visible effect on the measurement results of the N2 adsorption-desorption isotherm which is characterized by a drastic increase in surface area and a change in the shape of the surface pores. BiFeO3/LaFeO3/Graphene nanocomposite showed superior photocatalytic activity compared to BiFeO3, LaFeO3, and BiFeO3/LaFeO3 on exposure to visible light. The reusability test showed the stability of the nanocomposite on repeated use 4 times."

"Epoxy-organo clay nanocomposite materials are constructed from a polymer as a matrix and an organoclay as filler. Epoxy-organo clay nanocomposites have been synthesized using various curing agents. The aim of this research was to study the influence of the curing agent and the organoclay contents to the structure and mechanical properties of nanocomposites materials. Epoxy-organo clay nanocomposites were synthesized using cycloaliphatic amine as a curing agent and a montmorillonite organoclay (MMT) as filler through an in situ polymerization method. XRD and TEM technique provide more detail information to understand the structure that relates to the mechanical properties of the materials. Tensile test, compressive test and hardness test were conducted based on ASTM and JIS standards. The fracture surfaces after tensile tests were analyzed using SEM. The nanocomposite properties were compared to glass-fiber composites which were synthesized using wet-laminating method.It was found that the curing agent is influence to the nanocomposites structure which was shown by the change of d-spacing before and after the addition of the agent curing. XRD and TEM techniques showed that both intercalated and exfoliated structure have been formed. TEM image also exhibited that the number of intercalated structure was higher when the organoclay content was higher. It can be said that TEM techniques provides a better understanding of the nanocomposites structure and the number intercalated structure increase as the organoclay increases.The organoclay contain also influences to mechanical properties of nanocomposite materials. The addition of 10.5 wt.% organoclay improved the tensile modulus by 185% but and decreased tensile strength by 186% and 49%, and these values are lower of 36% and 90% compared to glass fiber composites. These decreases in the strength may be attributed to the fact that agglomerate and void was formed. From compression test, the addition of 3.1 wt.% organoclay demonstrated a 102% increase in compression strength and a 93% increase in load maximum compare to epoxy resin. But, that compression strength value lower of 11% compared to glass fiber composites. For the maximum load, the addition of 3.1 wt.% organoclay improved 246% compared to glass fiber composites. Addition of 7.3 wt.% organoclay demonstrated an increase of modulus of the epoxy resin by 93% and 2% compare to glass fiber composites. Meanwhile, the addition of 10.5% organoclay cause decreasing in yield compression up to 31%, but this higher value equal to 406% from is glass fiber composites. While that, result of hardness test do not show the make-up of value meaning in comparison with epoxy matrix."

"Pada penelitian ini, nanopartikel ZnO, NiWO4, dan ZnO/NiWO4 berhasil disintesis dengan cara metode green synthesis menggunakan ekstrak daun alpukat (Persea americana) dalam sistem satu fasa. Kandungan ekstrak air daun alpukat adalah alkaloid, saponin dan polifenol. Nanopartikel ZnO, NiWO4, dan ZnO/NiWO4 dikarakterisasi menggunakan spektrofotometer Ultraviolet-Visible Diffuse Reflectance Spectroscopy (UV-Vis DRS), X-Ray Diffraction (XRD), Fourier Transform InfraRed (FTIR), Transmission Electron Microscopy (TEM) dan Scanning Electron Microscopy Energy Disperse X-Ray (SEM-EDX). Hasil karakterisasi UV-Vis DRS, nanopartikel ZnO, NiWO4, dan ZnO/NiWO4 memiliki band gap 3,15 eV, 2,35 eV, dan 3,03 eV. Hasil uji aktivitas fotokatilitiknya menggunakan nanokomposit ZnO/NiWO4 terhadap malasit hijau dibawah iradiasi sinar tampak selama 2 jam memiliki persen degradasi tertinggi dibandingkan dengan NiWO4 dan ZnO. Persen degradasi ZnO/NiWO4, NiWO4, ZnO adalah 96,20%, 79,22%, 48,30%.

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In this research, ZnO, NiWO4, and ZnO/NiWO4 nanoparticles were successfully synthesized by means of green synthesis method using avocado (Persea americana) leaf extract in a single phase system. The secondary metabolites of avocado leaf water extract are alkaloids, saponins and polyphenols. ZnO, NiWO4, and ZnO/NiWO4 nanoparticles were characterized using a spectrophotometer Ultraviolet-Visible Diffuse Reflectance Spectroscopy (UV-Vis DRS), X-Ray Diffraction (XRD), Fourier Transform InfraRed (FTIR), Transmission Electron Microscopy (TEM) and Scanning Energy Microscopy Electron Disperse X-Ray (SEM-EDX). The results of the photocathylytic activity test using the ZnO/NiWO4 nanocomposite against malachite green under visible light irradiation for 2 hours had the highest degradation percent compared to NiWO4 and ZnO. The degradation percentages of ZnO/NiWO4, NiWO4, ZnO were 96.81%, 79.71%, 51.38%."

"Perovskit LaFeO3 menunjukan sifat konduktivitas gabungan ionik dan elektronik yang dapat diaplikasikan sebagai solid oxide fuel cell. Untuk meningkatan efisiensi katoda solid oxide fuel cell digunakan berbagai macam cara salah satunya adalah merubah ukuran grain. Ukuran grain sangat penting untuk meningkatkan efisiensi dari katoda SOFC. Salah satu cara untuk merekayasa ukuran dari grain adalah menambahkan material komposit pada basis LaFeO3. Pada penelitian ini Fe3O4 ditambahkan pada LaFeO3 merupakan senyawa untuk menghambat pertumbuhan grain dari LaFeO3. Nanokomposit LaFeO3.0,1Fe3O4 dibentuk dari LaFeO3 yang disintesis dengan metode sol-gel. LaFeO3 dicampurkan dengan Fe3O4 dan disintering pada temperatur 1300°C selama 1 jam. Setelah proses sintering nanokomposit LaFeO3.0,1Fe3O4 di annealing dengan variasi temperatur 1000°C, 1100°C, 1200°C selama 12 jam. Struktur dan morfologi sampel dipelajari menggunakan metode karakterisasi XRD and SEM. Pola dari XRD menunjukan bahwa adanya double fasa LaFeO3 dan Fe3O4. Ukuran kristalit dari sampel berada di antara rentang 30-60 nm yang dihitung dari pola XRD menggunakan Schrerrer?s formula. Sifat listrik diukur sebagai fungsi frekuensi dan temperatur menggunakan metode spektroskopi impedansi pada frekuensi (1kHz ? 1MHz) dan temperatur (RT - 373 K). Sifat listrik direpresentasikan dengan plot Nyquist, plot Bode dan konstanta dielektrik (ɛ?) sebagai fungsi frekuensi. Fenomena relaksasi dielektrik pada plot Bode Zim vs f menunjukan pergeseran puncak ke frekuensi yang lebih besar. Dari kurva log f sebagai fungsi temperatur, nilai energi aktivasi terlihat memiliki ketergantungan terhadap ukuran grain.

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Perovskite LaFeO3 show the mixed electronic and ionic conductivity has enabled their use in applications such as solid oxide fuel cell cathodes . For increasing the eficiency of SOFC used some method as change the grain size. Grain size is very important to improve the efficiency of the SOFC cathode. One way to manipulate the size of the grain is to provide a composite material based to the LaFeO3. In this research, Fe3O4 is used as the compound to inhibit grain growth of LaFeO3. LaFeO3.0,1Fe3O4 nanocompsite made of LaFeO3 synthesized by the method solgel and mixed with Fe3O4 then sintered at 1300°C for 1h. LaFeO3.0,1Fe3O4 nano-composite was annealed at temperature of 1000°C, 1100°C, 1200°C for 12 h. Structural studies was carried out using X-ray diffraction (XRD) and SEM.

XRD pattern confirmed the double phase LaFeO3 and Fe3O4. The crystallite size of the synthesized material lie in the range 30-60 nm as calculated from X-ray diffraction pattern using Schrerrer?s formula. Electrical properties evaluated as a function of frequency, temperature using an impedance spectroscopy in frequency range (1kHz - 1MHz) and temperature ( RT-373 K) . Electrical properties represented in Nyquist plot, bode plot and dielectrict constant (ɛ?) as a fuction of frequency. The phenomena can be explained on the basis of Maxwell-Wagner type of interfacial polarization and hopping mechanism. The dielectric relaxation in the bode plot Z?? vs f shown the relaxation peak shift to the higher frequency. From vs log f as a function of a temperature, the activation energy was calculated and its value depend on the grain size."

"Pada penelitian ini, telah berhasil dilakukan sintesis hidrogel nanokomposit NaAlg-PVA-g-AAm termodifikasi nanopartikel ZnO dengan pembentukan ZnO secara in situ di dalam matriks hidrogel dengan metode hidrotermal. Karakteristik hidrogel diamati dengan FTIR, SEM, TEM, EDX, XRD, AAS serta kapasitas swelling-nya. Hidrogel NaAlg-PVA-g-AAm dengan kapasitas swelling terbaik disintesis didapatkan dengan menambahkan PVA dan alginat dengan perbandingan massa sebesar 0,6:3. Hidrogel nanokomposit setelah dimodifikasi dengan ZnO memiliki kapasitas swelling yang lebih tinggi dibandingkan hidrogel yang belum dimodifikasi. Didapatkan hasil untuk hidrogel nanokomposit NaAlg-PVA-g-AAm termodifikasi nanopartikel ZnO yaitu kapasitas swelling maksimumnya 215,5278 g/g, loading ion Zn2 sebesar 285,82 ppm dan kapasitas release 3maksimumnya sebesar 0,9832 ppm. Kinetika swelling hidrogel NaAlg-PVA-g-AAm mengikuti orde pseudo-pertama dengan parameter laju swelling sebesar 350 menit. Sedangkan kinetika swelling hidrogel nanokomposit NaAlg-PVA-g-AAm termodifikasi nanopartikel ZnO mengikuti orde pseudo-kedua dengan parameter laju swelling sebesar 487,5 menit. Dari hasil uji aktivitas antibakteri yang dilakukan secara in-vitro, diketahui S.aureus lebih resisten dibandingakan P. aeruginosa dengan persen inhibisi S. aureus yang lebih besar pada konsentrasi hambat minimum yang sama yaitu 31,25 ppm.

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In this research, NaAlg PVA g AAm nanocomposite hydrogel had been successfully modified by ZnO nanoparticles in the hydrogel matrix by hydrothermal method. Characteristics of hydrogels were observed with FTIR, SEM, TEM, EDX, XRD, AAS and through their swelling capacities. The NaAlg PVA g AAm hydrogel with the best swelling capacity was synthesized by adding PVA and alginate with a mass ratio of 0.6 3. Obtained results for NaAlg PVA g AAm nanocomposite hydrogel modified ZnO nanoparticles had the maximum swelling capacity of 215.52 g g, Zn2 ion loading of 285.82 ppm and its maximum release capacity of 0.98 ppm, while the maximum swelling capacity for a NaAlg PVA g AAm nanocomposite hydrogel was 73.26 g g. Kinetics swelling of NaAlg PVA g AAm hydrogel followed the first pseudo order with a swelling rate parameter of 350 minutes, whereas kinetics swelling of NaAlg PVA g AAm nanocomposite hydrogel modified ZnO nanoparticles followed the second pseudo order with swelling rate parameter of 487.5 minutes. From in vitro antibacterial activity test, S.aureus was known to be more resistant than P. aeruginosa with a greater inhibition percentage of S. aureus at the same minimum inhibitory concentration of 31.25 ppm."

"Dalam penelitian ini, sintesis hijau nanopartikel SiO2, nanopartikel NiFe2O4, dan nanocomposites SiO2 / NiFe2O4 dalam sistem dua fase (hexane-water) berhasil dilakukan menggunakan ekstrak daun tahongai (Kleinhovia hospita L.). Alkaloid sebagai metabolit sekunder digunakan sebagai sumber basa (-OH), sedangkan saponin digunakan sebagai agen penutup. Sintesis nanopartikel SiO2 yang berhasil, nanopartikel NiFe2O4, dan nanokomposit SiO2 / NiFe2O4 dikonfirmasi melalui hasil karakterisasi. Karakterisasi XRD membuktikan bahwa nanopartikel SiO2 memiliki struktur amorf, nanopartikel NiFe2O4 memiliki struktur spinel kubik, dan nanokomposit SiO2 / NiFe2O4 memiliki nilai difraksi gabungan 2 combined yang khas. Karakterisasi TEM menunjukkan ukuran rata-rata nanokomposit SiO2 / NiFe2O4 sebesar 10 nm. Aktivitas katalitik nanokomposit SiO2 / NiFe2O4 lebih tinggi dari nanopartikel SiO2 dan nanopartikel NiFe2O4 dengan persentase reduksi masing-masing 95,68%, 29,75%, dan 79,79% selama 30 menit. Berdasarkan perhitungan kinetika reaksi reduksi 4-Nitroanilin terhadap p-phenylenediamine menunjukkan bahwa nanokomposit SiO2 / NiFe2O4 mengikuti kinetika orde satu semu.

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In this research green synthesis of SiO2 nanoparticles, NiFe2O4 nanoparticles, and SiO2 / NiFe2O4 nanocomposites in a 2 phase (hexane-water) system was successfully carried out using a tahongai (Kleinhovia hospita L.) leaf extract. The secondary metabolite compound, the alkaloid, is used as a hydrolyzing agent (base source -OH), while saponin is used as a stabilizing agent (capping agent). The success of synthesis of SiO2 nanoparticles, NiFe2O4 nanoparticles, and SiO2 / NiFe2O4 nanocomposites was confirmed through the results of characterization. XRD characterization proves that SiO2 nanoparticles have an amorphous structure, NiFe2O4 nanoparticles have a cubic spinel structure, and SiO2 / NiFe2O4 nanocomposites have a diffraction value of 2θ typical of the two combined. TEM characterization shows the average size of SiO2 / NiFe2O4 nanocomposites is 10 nm. The catalytic activity test of SiO2 nanoparticles, NiFe2O4 nanoparticles, and SiO2 / NiFe2O4 nanocomposites as reduction catalysts were carried out on 4-Nitroaniline with NaBH4 as a reducing agent. The catalytic activity of SiO2 / NiFe2O4 nanocomposite was higher than SiO2 nanoparticles and NiFe2O4 nanoparticles with reduction percentage of 95.68%, 29.75% and 79.79% for 30 minutes, respectively. Based on the kinetics calculation, the rate of reduction of 4-Nitroaniline to p-phenylendiamine was found that the SiO2 / NiFe2O4 nanocomposite followed the pseudo first order reaction kinetics."

"Pada penelitian ini nanokomposit Natrium Alginat-Bentonite-TiO2 telah berhasil disitesis. Hasil sintesis yang diperoleh dilakukan karakterisasi menggunakan FTIR, XRD, SEM, EDX dan TEM untuk mengetahui sifat dari nanokomposit yang diperoleh. Nanokomposit yang telah disintesis memiliki bandgap 3.01 eV dengan distribusi ukuran partikel TiO2 kurang dari 500 nm. Nanokomposit diaplikasikan untuk uji adsorpsi dan fotokatalisis dalam pengurangan limbah zat warna Methylene Blue MB . Persen degradasi yang didapat yaitu sebesar 95,01 dalam kondisi optimum pada pH 8, waktu adsorpsi 30 menit dan massa adsorben 30 mg. Isotherm adsorpsi dari proses yang terjadi mengikuti isotherm Langmuir dengan nilai R2 yaitu 0.971. Untuk proses fotokatalisis, telah dipelajari studi kinetika dimana reaksi yang berjalan mengikuti kinetika orde satu dengan nilai R2 yaitu 0.9420 dan konstanta lanju k sebesar 0.008.

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In this study, sodium alginate Bentonite TiO2 nanocomposite has been successfully synthesized in this study. The synthesis results obtained were characterized using FTIR, XRD, SEM, EDX and TEM to determine the properties of the acquired nanocomposites. The synthesized nanocomposite has a 3.01 ev bandgap with a particle size distribution of TiO2 less than 500 nm. Nanocomposites were applied for the adsorption and photocatalysis tests in the reduction of methylene blue MB dye waste. The percentage of degradation was 95,01 under optimum pH condition of 8, optimal adsorption time of 30 minutes, and the optimal adsorbent mass of 30 mg. The adsorption isotherm of the process that follows Langmuir isotherm with R2 value is 0.971. For the process of photocatalysis, kinetic studies have been studied in which the reaction follows the first order kinetics with the R2 value of 0.9420 and the rate constant k of 0.008."