Qualitative assessment of regular and premium gasoline available in Bangladesh markets

Assessing the quality of fuel is essential to comprehend its impact on the environment and human health. In this study, the evaluation of fuel quality standards at the consumer level was conducted by analyzing the motor fuels in Khulna, Bangladesh. A total of 32 samples of petrol (regular gasoline), and octane (premium gasoline) were collected from the fuel stations in the Khulna City Corporation area and analyzed with an FTIR-Fuel Analyzer. Fuel properties, such as research octane number (RON), motor octane number (MON), ethanol content, olefins content, and oxygen content were analyzed. For petrol, the average RON, MON, olefins, and oxygen content were 95.34, 85.70, 8.23 %v/v, and 0.78 %m/m, respectively, and for octane, they were 96.96, 85.39, 1.25 %v/v, and 0.09 %m/m, respectively. Almost all of these parameters complied with both Bangladesh standard and Euro 5 fuel specifications, and those that did not comply were very close to their standard values. However, benzene concentration, which was not specified in Bangladesh Standard, was the most alarming metric for octane since none of the samples matched the Euro 5 fuel specifications of the maximum concentration of 1 %v/v benzene; on average it was 3.70 %v/v. Although petrol benzene content (average 1.50 %v/v) was not as bad as it was for octane, it was still nowhere near good enough, with only 25% of the samples within the recommended level among the studied sample. This information holds significance in establishing the fuel profile and facilitating the identification of distinct samples linked to adulteration. Therefore, the analysis of motor fuel qualities is essential for maintaining the environment, human health, and the economy of a country.

Green synthesis of zinc oxide nano particles using Allium cepa L. waste peel extracts and its antioxidant and antibacterial activities

Synthesis of nanoparticles through the green approach using plant and vegetable extracts has gained popularity since they are thought to be efficient and cost-effective materials. This study is designed to synthesize zinc oxide nanoparticles (ZnO-NPs) from onion waste peel extract (Allium cepa L.) via the green synthesis approach. The synthesized ZnO-NPs were characterized by utilizing the UV-Vis spectroscopy, Fourier transform infrared spectroscopy (FTIR), Energy Dispersive X-ray (EDX), Field Emission Scanning Electron Microscopy (FE-SEM) and X-ray Powder Diffraction (XRD)techniques. The nanoparticles formation was confirmed by the UV-Vis sharp absorption spectra at 318 and 322 nm. The synthesized ZnO-NPs size and shape was revealed by the XRD and SEM respectively. Smallest nanoparticle average crystallite size was found 57.38 nm with hexagonal shape. The bioactive functional groups that are in charge of capping and stabilizing the ZnO-NPs was assured by the FTIR data. Further, prepared ZnO-NPs were used to assess their possible antioxidant and antibacterial properties. DPPH test for free radical scavenging showed potential antioxidant properties of the synthesized ZnO-NPs. The antibacterial activity were studied against three clinical strains: P. aeruginosa, E. coli, and S. aureus with the maximum zone of inhibition 13.17 mm, 22.00 mm and 12.35 mm respectively at 100 μg/mL subsequently minimum inhibitory concentration was found 50 μg/mL for P. aeruginosa, and S. aureus whereas 100 μg/mL for E. coli. Antioxidant and antibacterial activity tests appear bio-resource based ZnO-NPs from Allium cepa L. extract have effects on free radical and growth of microorganisms.Therefore, it could be a promising candidates for agricultural and food safety applications as an effective antimicrobial agent against pathogenic microorganisms and also can address future biomedical applications after complete in vivo study.

Fabrication and performance analysis of keratin based-graphene oxide nanocomposite to remove dye from tannery wastewater

In recent years, nanomaterials and composites have become increasingly significant as adsorbents in the removal of dyes and phenolic contaminants from wastewater. This study presents the development and application of a keratin-based graphene oxide nanocomposite, distinguished by its enhanced biocompatibility, cost-effectiveness, and strong affinity for organic compounds, making it highly effective in reducing dyes within tannery effluent. The nanocomposite was prepared via solution casting method, with dispersibility, chemical bonding, and morphology analyzed by UV-Vis spectroscopy, FTIR, and SEM, respectively. Furthermore, investigations of the influence of several factors, such as contact time, pH, and adsorbent dosage on the optimization of the process were conducted. An observation indicated a reduction of approximately 98.8 % in dye content within 20 min, achieved through the use of an adsorbent dosage of 1.5 g/L, with the solution pH maintained at 5. Subsequently, adsorption kinetics and isotherm modelling were analyzed. The results revealed that the adsorption process follows the pseudo-second-order kinetics and Freundlich isotherm models. Hence, the adsorption could be explained as chemisorption with a multilayer adsorption mechanism. Notably, a substantial reduction in parameters such as Biological Oxygen Demand (BOD) and Chemical Oxygen Demand (COD) was also achieved up to 62 % and 79 %, respectively. Therefore, the developed adsorbent could be suggested as a viable candidate for eliminating dyes from the wastewater, especially from the tannery effluent.

Pore creation nanoarchitectonics from non-porous metal-organic framework to porous carbon for adsorptive elimination of sulfanilamide and chloroxylenol from aqueous solution

Three isomeric metal-organic frameworks (MOFs) such as MAF-5, - 6, and - 32 (with the same composition of [Zn(2-ethylimidazole)₂]) were carbonized and, for the first time, activated further with KOH to prepare highly porous MOF-derived carbons (MDCs). Importantly, MDC-32 derived from non-porous MAF-32 had the highest porosity among the three MDCs although it has the lowest porosity when no KOH activation was done. Adsorption of sulfanilamide and chloroxylenol from water was investigated with the MDCs. Among the MDCs, MDC-32 showed the best adsorptive performance for sulfanilamide and chloroxylenol. Moreover, MDC-32, had the highest adsorption capacity (256 mg/g) for removing sulfanilamide from water, compared with any adsorbent reported so far. Based on the observed adsorption and properties of the adsorbate and adsorbent, π-π and hydrogen bonding interactions, with a slight contribution of repulsive electrostatic interaction, could be suggested as the mechanism for the sulfanilamide adsorption over the MDC-32. Moreover, the MDC-32 could be recycled easily for up to four cycles. It could be suggested that non-porous MOFs can be a good precursor for highly porous MDCs, if activated well using KOH, for example. Finally, MAF-32-derived carbon, MDC-32, might be suggested as a plausible adsorbent to eliminate organics such as sulfanilamide from water.

Functionalized metal-organic framework-derived carbon: Effective adsorbent to eliminate methylene blue, a small cationic dye from water

Elimination of organic dyes from wastewater is very important for our safe environment and sound health. In this work, adsorptive removal of cationic dyes, especially small ones, was investigated with carbonaceous materials to develop a competitive adsorption technology. To improve the performance of metal-organic framework (MOF)-derived carbons (MDCs) in dye adsorption, an MDC, derived from a MOF (MAF-6), was oxidatively functionalized with ammonium persulfate solutions (APSs). Although the porosity of pristine MDC decreased with functionalization via oxidation, functionalized MDCs (FMDCs), especially FMDC(1.0) that was obtained via treating MDC with APS (1.0 M), showed remarkable performances in the adsorption of small cationic dyes like methylene blue (MB) and azure B. For example, FMDC(1.0) had the maximum adsorption capacity (Q_o) of 625.0 mg/g (for MB) which is larger than any reported value with carbonaceous materials. Moreover, the obtained Q_o was around 4 and 2 times that of activated carbon with Q_o of 160 mg/g and MDC with Q_o of 298 mg/g, respectively. On the contrary, oxidative treatment of MDC was negative in adsorption of an anionic dye such as methyl orange. Moreover, the functionalized MDC was not very effective in the adsorption of cationic dyes with large sizes (like brilliant green, crystal violet, Janus green B, and rhodamine B) because of the limited pore size of the studied adsorbent FMDC(1.0). The remarkable adsorption of MB over FMDC(1.0) could be explained by electrostatic and π-π interactions. Finally, the facile recyclability of the FMDC(1.0) in MB adsorption was confirmed via successive adsorptions, FT-IR, and nitrogen adsorption; therefore, FMDC(1.0) can be suggested as a potential adsorbent to remove cationic dyes, especially with small molecular sizes.