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.

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 %.

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.

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 °C 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 °C are the best candidate heterogeneous acid catalysts synthesized in thus work.

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 insitu 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).