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A complex of [Zn(pza)2(Cl)2], pza = pyrazinamide, was successfully crystallized from methanol or ethanol solvents with different morphology. The complex was synthesized using the solution method in ZnCl2: pza mol ratios of 1:2 and 1:4 in both ethanol and methanol solvents. FTIR and single crystal XRD analyses were done to confirm the complex. The complex was then used for in vitro antibacterial test against E. coli and S. aureus. Experimental data shows that the type of solvent and metal-to-ligand mol ratio yields the same compound, resulting in colorless crystals that melt at 234-236°C. Large block crystals were obtained from the methanolic solution, while a higher yield was obtained from the use of a higher mol ratio of 1:4. Infrared spectra analysis confirms the presence of characteristic carbonyl and amide groups of the pza ligand. Meanwhile, single crystal XRD screening indicates that unit cell parameters of the crystals from both solvents are identical to a known zinc(II)-pza complex. In vitro antibacterial tests against E. coli and S. aureus show that the complex had much better activity than the ZnCl2 and the free pza. In addition, the complex performs better antibacterial activity toward gram-positive S. aureus than the gram-negative E. coli. [ABSTRACT FROM AUTHOR]

Ni(II) with mixed ligand of terephthalate-pyrazine (NiTP) metal complex can form metalorganic framework (MOF) material that offer many potential applications, such as adsorbent and/or photocatalyst for dye-based wastewater treatment. Production of the NiTP by hydrothermal method in a larger scale may economically unfavorable due to it requires high temperature and long reaction time. Green synthesis of NiTP by hydrothermal method using lower temperature and shorter reaction time was investigated in this study. The synthesis was done in Ni(II):T:P mol ratio of 1:1:4 at 150 ℃ for 10 hours. The NiTP complex was characterized by infrared spectroscopy and powder-XRD. Crystallinity degree, thermal stability, band gap energy, and pore volume of the NiTP complex were compared to that of Ni(II)-terephthalate (NiT) complex, which was also made using the same condition, to study the effect of pyrazine addition on the properties of the NiTP. This study finds that the green microcrystalline NiTP complex was successfully obtained from mild reaction condition in good yield and identical to known MOF compound of [Ni(μ3-ter)(μ2-pyr)]n.(ter = terephthalate; pyr = pyrazine). Although the synthesized NiTP complex has lower crystallinity degree compared to the NiT complex, but it has better thermal stability, lower band gap energy, and bigger pore volume; therefore, it is possible to be further developed as adsorbent and/or photocatalyst for wastewater treatment. [ABSTRACT FROM AUTHOR]

Molecularly Imprinted Polymers (MIPs) have specific recognition capabilities and have been widely used for electrochemical sensors with high selectivity. In this study, an electrochemical sensor was developed for the determination of p-aminophenol (p-AP) by modifying the screen-printed carbon electrode (SPCE) with chitosan-based MIP. The MIP was made from p-AP as a template, chitosan (CH) as a base polymer, and glutaraldehyde and sodium tripolyphosphate as the crosslinkers. MIP characterization was conducted based on membrane surface morphology, FT-IR spectrum, and electrochemical properties of the modified SPCE. The results showed that the MIP was able to selectively accumulate analytes on the electrode surface, in which MIP with glutaraldehyde as a crosslinker was able to increase the signal. Under optimum conditions, the anodic peak current from the sensor increased linearly in the range of 0.5–35 µM p-AP concentration, with sensitivity of (3.6 ± 0.1) µA/µM, detection limit (S/N = 3) of (2.1 ± 0.1) µM, and quantification limit of (7.5 ± 0.1) µM. In addition, the developed sensor exhibited high selectivity with an accuracy of (94.11 ± 0.01)%. [ABSTRACT FROM AUTHOR]

Microplastics have been found in the marine environment worldwide. Due to their very small size, it could be ingested by marine organisms from small size plankton to big size fish. The aim of this study is to assess the variability of microplastics in three different organs (gills, gastrointestinal tracts, and muscles) of commercial fishes in five different fishing ports in East Java Province, Indonesia. A total of 137 fish samples from 14 species were extracted to identify the types of microplastics. The microplastics found in the fish samples were mostly dominated by fiber, fragments, and a little quantity of film. In most species, the gills accumulated more microplastics compared to the gastrointestinal tracts and muscles. Gill is the organ that is highly exposed to the environmental conditions, therefore, it is more susceptible to the microplastic contamination. The results showed that there was an inverse relationship between the size of the fish and the occurrence of microplastics (P<0.05). Small size Sardinella lemuru contained more microplastics than bigger size fish such as Katsuwonus pelamis. The variability of microplastics found in this study showed important factors such as habitat, fish size, feeding behavior, and organ function which influenced the ingestion process of microplastic. This study also revealed the presence of microplastics were not only in the gills and gastrointestinal tracts of fish, but also in its muscles. Since this study targeted commercial fishes, further research is needed to know the possible impact on human consumption of fish containing microplastics. [ABSTRACT FROM AUTHOR]

This research aims to incorporate pyrazine in the synthesis of Ni(II)-tartrate-pyrazine metal organic frameworks or Ni(II)-T-P MOF as candidate of porous material. Synthesis of the targeted MOF was conducted at room temperature in a methanolic solution by mixing Ni(II) solution, L-tartaric acid (T), and pyrazine (P) solutions sequentially in various molar ratios (Ni(II):T:P = 1:1:0; 1:0:2; 1:2:2; and 1:2:4) using two different Ni(II) salts (chloride and nitrate). Solid products were characterized by infrared spectroscopy, qualitative anion identification test, melting point test, and scanning electron microscopy. The result shows that type of nickel salt affects the precipitation of Ni(II) complex, in which pale blue solids were precipitated out only from the chloride reactions (1:0:2, 1:2:2, and 1:2:4). IR and SEM analyses from the 1:2:2 and 1:2:4 reactions show identical result as also shown by the 1:0:2 reaction, whereas qualitative anion identification test result suggests that the chloride is uncoordinated to the Ni(II). The targeted Ni(II)-T-P is unsuccessfully obtained, instead the product is proposed to be [Ni(pyrazine)x(H2O)(6-x)]Cl2. although the tartaric acid was doubled and firstly reacted with the Ni(II), the pyrazine still has higher preference to coordinate to the Ni(II) center than the tartrate ligand. [ABSTRACT FROM AUTHOR]

Pesticide is a pollution problem in agriculture. The usage of ZnCr2O4/CNS and H2O2 as additive in liquid fertilizer has potency for catalytic pesticide degradation. Colloid condition is needed for easy spraying. Rice husk and sawdust were used as carbon precursor and ZnCl2 as activator. The biomass-ZnCl2 mixtures were pyrolyzed using microwave (400-800 W, 50 min). The products were dispersed in water by blending then evaporated to obtain ZnO/CNS. The composites were reacted with KOH, CrCl3·6H2O, more ZnCl2, and little water by microwave (600 W, 5 min). The ZnCr2O4/CNS and H2O2 were used for degradation of buthylphenylmethyl carbamate (BPMC) in wet deactivated paddy soil. TOC was measured using TOC meter. The FTIR spectra of the ZnO/CNS composites indicated the completed carbonization except at 800 W without ZnCl2. The X-ray diffractograms of the composites confirmed ZnO/CNS structure. SEM images showed irregular particle shapes for using both biomass. ZnCr2O4/CNS structure was confirmed by XRD as the final product with crystallite size of 74.99 nm. The sawdust produced more stable colloids of CNS and ZnO/CNS composite than the rice husk. The pyrolysis without ZnCl2 formed more stable colloid than with ZnCl2. The ZnCr2O4/CNS from sawdust gave better dark catalytic degradation of BPMC than from rice husk, i.e., 2.5 and 1.6 times larger for 400 and 800 W pyrolysis, respectively. [ABSTRACT FROM AUTHOR]