High photocatalytic activity of Fe2O3/TiO2 nanocomposites prepared by photodeposition for degradation of 2,4-dichlorophenoxyacetic acid

Two series of Fe2O3/TiO2 samples were prepared via impregnation and photodeposition methods. The effect of preparation method on the properties and performance of Fe2O3/TiO2 for photocatalytic degradation of 2,4-dichlorophenoxyacetic acid (2,4-D) under UV light irradiation was examined. The Fe2O3/TiO2 nanocomposites prepared by impregnation showed lower activity than the unmodified TiO2, mainly due to lower specific surface area caused by heat treatment. On the other hand, the Fe2O3/TiO2 nanocomposites prepared by photodeposition showed higher photocatalytic activity than the unmodified TiO2. Three times higher photocatalytic activity was obtained on the best photocatalyst, Fe2O3(0.5)/TiO2. The improved activity of TiO2 after photodeposition of Fe2O3 was contributed to the formation of a heterojunction between the Fe2O3 and TiO2 nanoparticles that improved charge transfer and suppressed electron-hole recombination. A further investigation on the role of the active species on Fe2O3/TiO2 confirmed that the crucial active species were both holes and superoxide radicals. The Fe2O3(0.5)/TiO2 sample also showed good stability and reusability, suggesting its potential for water purification applications

Supramolecular phosphorescent trinuclear copper(I) pyrazolate complexes for vapochromic chemosensors of ethanol

We highlight that by using supramolecular single crystals of phosphorescent trinuclear copper(I) pyrazolate complexes with different molecular structures (2A-E), vapochromic chemosensors were successfully designed for sensing ethanol with high sensing capability. These complexes 2A-E were synthesized from non-side chain, 3,5dimethyl, 3,5-bis(trifluoromethyl), 3,5-diphenyl and 4-(3,5-dimethoxybenzyl)-3,5-dimethyl pyrazole ligands (1A-E) in 83, 97, 99, 88 and 85% yields, respectively. All complexes showed emission bands centered at 553, 584, 570 and 616 nm upon an excitation at 280 nm for complexes 2A-C,E, respectively and 642 nm upon an excitation at 321 nm for complex 2D with lifetime in microseconds, indicating a large Stoke shift for phosphorescent compounds. These emission spectra were in good agreement with their colors from green to red upon exposure to a UV lamp with an excitation at 254 nm in dark room. Upon exposure to ethanol in 5 min, quenching, photoinduced energy transfer and shifting of emission intensities were observed for chemosensors 2A-C, 2D and 2E, respectively. Interestingly, chemosensor 2E only showed completely and autonomously recovery of its original emission intensity. Such novel finding in sensing capability might be caused by a weak intermolecular hydrogen bonding interaction of ethanol to oxygen atoms at dimethoxybenzyl side-chains of the pyrazole ring

Cobalt oxide-modified titanium dioxide nanoparticle photocatalyst for degradation of 2,4-dichlorophenoxyacetic acid

2,4-dichlorophenoxyacetic acid (2,4-D) has been recognized as a possibly carcinogenic compound to human, therefore, 2,4-D should be treated before it is discharged to the environment. Photocatalytic degradation of 2,4-D has been proposed as one of the best methods that offer environmentally safe process. In the present research, titanium dioxide (TiO2) was modified with cobalt oxide (CoO) and tested for photocatalytic degradation of 2,4-D under UV light irradiation. Different amounts of CoO (0.1, 0.5, 1 and 5 mol%) were added onto TiO2 by an impregnation method. The photocatalytic reaction was monitored and analyzed by measurement of 2,4-D absorbance using UV spectrophotometer. After 1 h photocatalytic reaction, it was confirmed that the sample with low loading of 0.1 mol% gave the highest photocatalytic activity among the bare and modified TiO2 photocatalysts. The photocatalytic activity was decreased with the increase of CoO loading, suggesting that the optimum amount of CoO was an important factor to improve the performance of TiO2. Based on fluorescence spectroscopy, such addition of CoO resulted in the reduced emission intensity, which showed the successful decrease in the electron-hole recombination

Pemaknaan Khalayak terhadap Ruang Privat pada Tayangan Suka Suka Uya

Tayangan Suka Suka Uya merupakan sebuah variety show yang ingin memberikan alternatif hiburan bagi pemirsanya dengan menghadirkan bintang tamu public figure untuk direlaksasi, menceritakan apapun tentang kehidupan pribadinya sehingga batas antara ruang privat dan ruang publik di media seolah menjadi kabur. Penelitian ini menggunakan pendekatan kualitatif dengan metode analisis resepsi Stuart Hall yang bertujuan mendeskripsikan dan menganalisis keberagaman interpretasi khalayak tentang ruang privat public figure yang dikemas dan ditampilkan dalam tayangan Suka Suka Uya serta bagaimana khalayak mendeskripsikan ruang privat di media, khususnya televisi. Hasil penelitian menunjukkan ada tiga tipe pemaknaan mengenai interpretasi khalayak terhadap ruang privat public figure yang dikemas dan ditampilkan dalam tayangan Suka Suka Uya. Dominant – hegemonic reading adalah posisi dimana khalayak menyetujui makna dominan (preferred reading) bahwa batas antara ruang privat dan publik kabur, melebur jadi satu, dan dianggap sebagai sebuah hal yang wajar bagi seorang public figure karena adanya voyeurism dan penerimaan informasi privat oleh khalayak sebagai hiburan. Negotiated reading dimana khalayak menyetujui makna dominan dari teks media dengan pertimbangan terdapat perbedaan batasan antara public figure dan orang biasa mengenai ruang privat. Khalayak menegosiasikan hal tersebut karena batasan ruang privat public figuredianggap berbeda dan lebih luas sebagai konsekuensi dari profesinya serta selera informan pada bintang tamu yang hadir. Terakhir, opositional reading adalah posisi dimana khalayak secara tegas menolak makna dominan yang ditawarkan oleh teks media karena mereka menganggap bahwa batasan ruang privat dan publik tetap ada dan masing – masing orang termasuk public figure. Ruang privat dideskripsikan sebagai aib yang tabu dibicarakan di ruang publik. Selain itu, perbedaan pemaknaan terhadap ruang privat juga muncul karena perbedaan gender informan, laki – laki dan perempuan. Informan perempuan cenderung lebih menerima terbukanya ruang privat dibandingkan informan laki – laki

Supramolecular design of benzene-1,3,5-tricarboxamide with hydrophobic alkyl side chains toward long-range liquid crystalline properties

Herein we report the first approach of benzene-1,3,5-tricarboxamides (BTAs) with long-range liquid crystalline properties by utilizing hydrophobic alkyl side chains at the amide functional group. These compounds were successfully prepared in high yields by reacting 1,3,5-benzenetricarbonyl trichloride with series of aliphatic linear alkyl amines as the side chains. By increasing the length of hydrocarbon chains at the amino, thermograms of BTAs showed the formation of mesophase rangesbetween 21.8- 196.3, 41.9 - 212.4, 57.9 - 203.7, 76.1 - 207.7 and 80.5 - 200.1 degrees for decylamine, dodecylamine, tetradecylamine, hexadecylamineand octadecylamine, respectively. Such liquid crystalline properties indicate the formation of self-assembly through supramolecular interactions with a lamellar structure. In particular, benzene tricarboxamide with short alkyl chains will reduce the Van der Waals interactions to give room temperature range of mesophase structure

Fresh Chili Agribusiness: Opportunities and Problems in Indonesia

The National Socioeconomic Survey (SUSENAS) conducted in Indonesia in September 2021 found that the average consumption of red chili per month was 0.15 kilograms (kg) per capita per month. The average consumption of fresh chili per month is 40.90 thousand tons, and the cumulative total reached 490.83 thousand tons in 2021. Uneven chili production across time and region makes prices fluctuate, which affects inflation by 0.01–0.07%. Another problem is the imbalance of supply and demand between time and region, which impacts farmers’ welfare. Setting planting time and location and improving distribution can solve these problems. The application of technology that can extend the life of fresh chilies for one month is a solution for chili distribution from farmers to areas with high demand. One-wave roasting and drying technology can extend chilies’ freshness for six months. By producing chilies that have a shelf life of more than three months, it is possible to store them in warehouses using the warehouse receipt system. The application of the warehouse receipt system to chili commodities is also an alternative to solving postharvest problems. The distribution and application of technology that can extend the life of chili can increase its economic value and make chili not a commodity that contributes to Indonesian inflation

Enhanced activity of C3N4 with addition of ZnO for photocatalytic removal of phenol under visible light

Phenol is a stable and hazardous compound that is commonly found as an industrial effluent. Phenol can be treated by photocatalysis using zinc oxide (ZnO) as a photocatalyst. Unfortunately, the use of ZnO in photocatalysis is limited due to the poor response to the visible light. On the other hand, carbon nitride (C3N4) is able to absorb visible light. In the present study, a series of ZnO-C3N4 was prepared by impregnation method. The effect of zinc to carbon mol ratio (Zn/C) on the properties and photocatalytic activity was examined. X-ray Diffraction (XRD) patterns of the samples revealed that as the Zn mol ratio increased, the intensity of diffraction peaks for ZnO also increased but the intensity for C3N4 decreased. All prepared composite materials have an extended absorption band in the visible light region due to the presence of C3N4, as supported by DR UV-Vis spectra. The prepared ZnO-C3N4composites were further investigated in the photocatalytic removal of phenol under visible light for 5 hours. All ZnO-C3N4 samples showed higher activity than the bare ZnO with Zn/C mol ratio of 1% showed the highest photocatalytic activity for removal of phenol among all the samples. The high activity observed on the ZnO-C3N4 would be due to role of ZnO tosuppress electron-hole recombination and C3N4 to extend the absorption of ZnO in the visible light region

Enhanced detection of nitrite ions over copper acetylacetonate/polymeric carbon nitride composites

Nitrogen containing compounds such as nitrite ions (NO2 -) may cause contaminations to the environment, food and drinking water, and they have a negative effect on human health. In this study, a novel fluorescence sensor was developed by modification of polymeric carbon nitride (CN) with copper(II) acetylacetonate (Cu(acac)2). The polymeric CN was prepared by using urea as a precursor via thermal polymerization technique, while the Cu(acac)2 was introduced onto the polymeric CN via an impregnation method. The formation of polymeric CN can be confirmed from the Fourier transform infrared (FTIR) and the diffuse reflectance ultraviolet visible (DR UV-Vis) spectroscopies. The polymeric CN exhibited three excitation peaks at 277, 315, and 370 nm owing to the presence of CN, CO, and CN groups, respectively, while there was only one emission peak observed at 455 nm. The emission intensity was decreased with the increase of Cu(acac)2 loading, suggesting certain interactions between the polymeric CN and the added Cu(acac)2. The performances of the polymeric CN and Cu(acac)2/CN composites as fluorescence sensors were evaluated for (NO2 -) detection with concentration range of 0.5-4 μM. It was revealed that the CN sites in the polymeric CN were the most favored quenching sites for the (NO2 -). With the addition of Cu(acac)2 (0.1 mol%), the quenching rate for CN sites was enhanced two times higher than that of the polymeric CN. This study demonstrated that the composite is a promising fluorescence sensor for the detection of (NO2 -)

Friedel–crafts acylation of anisole over heteropoly acid supported on porous montmorillonite

Porous montmorillonite (PMMT) was derived from natural montmorillonite (MMT) through functionalization using 3-aminopropyltrimethoxysilane (APTMS) and intercalation with cationic potato starch as the template. Phosphotungstic acid (HPW) supported on PMMT was synthesized by wet impregnation method. The resulting PMMT showed remarkable increase in surface area from the low value of 191 m2g−1 for parent MMT to the high value of 930 m2g−1 for PMMT. Acidity studies by pyridine adsorption followed by FTIR spectroscopy showed that both MMT and PMMT possessed strong Lewis acid sites. In contrast, the surface acidity of HPW incorporated into PMMT was shown to be significantly enhanced by forming mainly Brönsted acid sites. The catalytic activity of these materials was evaluated in the Friedel-Crafts acylation of anisole with propionic anhydride. The PMMT/30HPW catalyst which possesses the highest number of Brönsted acid sites showed excellent catalytic activity giving selectivity as high as 95% toward the main product, p-methoxypropiophenone