Effect of Sulfation on Physicochemical Properties of ZrO₂ and TiO₂ Nanoparticles

Wijaya, Karna,Pratika, Remi Ayu,Fitri, Edhita Rahmawati,Prabani, Prisnu Fadilah,Candrasasi, Yufinta,Saputri, Wahyu Dita,Mulijani, Sri,Patah, Aep,Wibowo, Arief Cahyo Materials Research Society of Korea 2022 한국재료학회지 Vol.32 No.3

Effect of sulfation processes on the physicochemical properties of ZrO₂ and TiO₂ nanoparticles were thoroughly investigated. SO₄/ZrO₂ and SO₄/TiO₂ catalysts were synthesized to identify the acidity character of each. The wet impregnation method of ZrO₂ and TiO₂ nanoparticles was employed using H2SO₄ with various concentrations of 0.5, 0.75, and 1 M, followed by calcination at 400, 500, and 600 ℃ to obtain optimum conditions of the catalyst synthesis process. The highest total acidity was found when using 1 M SO₄/ZrO₂-500 and 1 M SO₄/TiO₂-500 catalysts, with total acidity values of 2.642 and 6.920 mmol/g, respectively. Sulfation increases titania particles via agglomeration. In contrast, sulfation did not practically change the size of zirconia particles. The sulfation process causes color of both catalyst particles to brighten due to the presence of sulfate. There was a decrease in surface area and pore volume of catalysts after sulfation; the materials' mesoporous structural properties were confirmed. The 1 M SO₄/ZrO₂ and 1 M SO₄/TiO₂ catalysts calcined at 500 ℃ are the best candidate heterogeneous acid catalysts synthesized in thus work.

Optimizations of microwave-assisted extraction and transesterification of bio-crude oil from spirulina (Arthrospira platensis)

Anggelina Purnama,Karna Wijaya,Iqmal Tahir,Eko Agus Suyono,Arief Budiman 한국화학공학회 2020 Korean Journal of Chemical Engineering Vol.37 No.3

Optimizations of microwave-assisted extraction (MAE) and transesterification of bio-crude oil from spirulina (Arthrospira platensis) were conducted. The bio-crude oil from A. platensis was initially extracted using water as a solvent, centrifugation, dissolved with n-hexane, separation, and continued to evaporation. The optimization for the extraction was conducted with varieties of biomass-to-solvent ratio, extraction temperature, extraction time, and n-hexane contact time, yielding the optimum condition with biomass/solvent 1 : 7, extraction temperature 70 oC, extraction time 15 minutes, and contact time 25 minutes (D70/15-25) 5.56%. The average yield of the bio-crude oil obtained was 4.87%, variation 0.32, standard deviation 0.57, and standard error 0.14. The optimization for transesterification was carried out with variations of bio-crude oil-to-methanol ratio, reaction temperature, and reaction time, yielding the optimum condition with bio-crude oil/methanol 1 : 6, reaction temperature 65 oC, and reaction time 50 minutes (G65/50) 98%. The average yield of the biodiesel obtained was 88%, variation 50.29, standard deviation 7.09, and standard error 2.68. The cell damage before and after extraction and also conventional heating observed using SEM showed massive damage by this method.

Microwave Radiation-Assisted Chitin Deacetylation: Optimization by Response Surface Methodology (RSM)

Iqmal Tahir,Karna Wijaya,Mudasir,Dita Krismayanti,Aldino Javier Saviola,Roswanira Abdul Wahab,Amalia Kurnia Amin,Wahyu Dita Saputri,Remi Ayu Pratika 한국재료학회 2024 한국재료학회지 Vol.34 No.2

The optimization of deacetylation process parameters for producing chitosan from isolated chitin shrimp shell waste was investigated using response surface methodology with central composite design (RSM-CCD). Three independent variables viz, NaOH concentration (X1), radiation power (X2), and reaction time (X3) were examined to determine their respective effects on the degree of deacetylation (DD). The DD of chitosan was also calculated using the baseline approach of the Fourier Transform Infrared (FTIR) spectra of the yields. RSM-CCD analysis showed that the optimal chitosan DD value of 96.45 % was obtained at an optimized condition of 63.41 % (w/v) NaOH concentration, 227.28 W radiation power, and 3.34 min deacetylation reaction. The DD was strongly controlled by NaOH concentration, irradiation power, and reaction duration. The coefficients of correlation were 0.257, 0.680, and 0.390, respectively. Because the procedure used microwave radiation absorption, radiation power had a substantial correlation of 0.600~0.800 compared to the two low variables, which were 0.200~0.400. This independently predicted robust quadratic model interaction has been validated for predicting the DD of chitin.

Component, Formulation and Regulatory of Sunscreen Materials: A Brief Review

Firi Oktavia Hariani,Mohammad Adam Jerusalem,Iqmal Tahir,Maisari Utami,오원춘,Karna Wijaya 한국재료학회 2023 한국재료학회지 Vol.33 No.3

Exposure to ultraviolet (UV) light is often associated with skin damage, sometimes very serious, and in recent times has received particular attention as a health risk. As a result, the proper use of sunscreen has long been recommended to protect against skin damage. The continued increase in the use of sunscreen may be linked to increased information about the risk of melanoma and non-melanoma skin cancer caused by prolonged exposure to ultraviolet rays. Natural and harmless materials that block and prevent UV light have emerged as essential household items in the field of skin beauty. New materials need to be considered and evaluated in relation to ultraviolet rays and their harmful effects. This study aims to explain the effect of UV exposure on human skin, the classification of sunscreens, the application of zeolite, nano clay, and LDH in sunscreen formulations, as well as the regulation of this service in various countries around the world.

Simultaneous Extraction and In-Situ Transesterification of Chlorella vulgaris Using Microwave-Assisted Method for Biodiesel Production

Adhiputra, Randy,Utami, Maisari,Suyono, Eko Agus,Budiman, Arief,Hariani, Poedji Loekitowati,Pratiwi, Ani Setyo,Wijaya, Karna Materials Research Society of Korea 2021 한국재료학회지 Vol.31 No.4

This research aims to study the simultaneous extraction and transesterification of Chlorella vulgaris (C. vulgaris) using microwave irradiation with methanol as solvent and potassium hydroxide (KOH) as catalyst. The microwave-assisted in-situ transesterification of C. vulgaris is assessed at various ratios of biomass-to-methanol, reaction times, and catalyst concentrations during the centrifugation and evaporation process. Gas chromatography-mass spectrometry (GC-MS) analysis is performed to confirm fatty acid methyl ester (FAME) composition. Biodiesel preparation is carried out by simultaneous extraction and transesterification of microalgae from C. vulgaris. The product is then characterized using Fourier transform infrared spectroscopy (FTIR) and proton nuclear magnetic resonance (¹H-NMR); microalgae are observed using scanning electron microscopy (SEM). The highest amount of FAME is obtained at a biomass-to-methanol ratio of 1:12, reaction time of 40 min, and catalyst concentration of 2 wt%. Biodiesel shows conversion to about 77.64% of methyl ester (methyl myristate, methyl palmitoleate, methyl linoleate, methyl oleate, methyl arachidonate, and methyl 5,8,11,14,17-eicosapentanoate).

Nanosulfated Silica as a Potential Heterogeneous Catalyst for the Synthesis of Nitrobenzene

Khairul Amri,Aan Sabilladin,Remi Ayu Pratika,Ari Sudarmanto,Hilda Ismail,Budhijanto,Mega Fia Lestari,오원춘,Karna Wijaya 한국재료학회 2023 한국재료학회지 Vol.33 No.7

In this study, the synthesis of nitrobenzene was carried out using sulfated silica catalyst. The study delved into H2SO4/SiO2 as a solid acid catalyst and the effect of its weight variation, as well as the use of a microwave batch reactor in the synthesis of nitrobenzene. SiO2 was prepared using the sol-gel method from TEOS precursor. The formed gel was then refluxed with methanol and calcined at a temperature of 600 °C. SiO2 with a 200-mesh size was impregnated with 98 % H2SO4 by mixing for 1 h. The resulting 33 % (w/w) H2SO4/SiO2 catalyst was separated by centrifugation, dried, and calcined at 600 °C. The catalyst was then used as a solid acid catalyst in the synthesis of nitrobenzene. The weights of catalyst used were 0.5; 1; and 1.5 grams. The synthesis of nitrobenzene was carried out with a 1:3 ratio of benzene to nitric acid in a microwave batch reactor at 60 °C for 5 h. The resulting nitrobenzene liquid was analyzed using GC-MS to determine the selectivity of the catalyst. Likewise, the use of a microwave batch reactor was found to be appropriate and successful for the synthesis of nitrobenzene. The thermal energy produced by the microwave batch reactor was efficient enough to be used for the nitration reaction. Reactivity and selectivity tests demonstrated that 1 g of H2SO4/SiO2 could generate an average benzene conversion of 40.33 %.