Asian Journal of Green Chemistry
Volume:5 Issue: 3, Summer 2021

Plant phytochemicals appeared to be a promising tool to address resistance and environmental problems posed by synthetic insecticides. This study explored the larvicidal effects, and synergistic toxicity of Ficus sycomorus and Calotropis procera leaves on African malaria vector, Anopheles species sourced from agricultural fields in Kano-Nigeria. The qualitative and quantitative phytochemicals were determined using standard methods. Late third Instar larvae (L3) of Anopheles mosquitoes were subjected to bioassay at various concentrations (0.1, 0.2, 0.4, 0.6, 0.8, and 1.0 mg/mL) of ethanol extracts using the WHO standard protocol with some modifications. The synergistic potential was predicted using mathematical model. The extract of F. sycomorus revealed the highest concentration of flavonoids, alkaloids, saponins and phenols, while C. procera extract had high concentration of glycosides and tannins. However, only alkaloids concentrations (15.41 mg/mL and 7.7 mg/mL) was statistically significant between the two plants (p <0.05). The bioassays show high percentage mortalities in both plants with C. procera extract being more toxic (LC50=0.51 mg/mL; ꭓ2=0.83; 95% confidence limits, CI: 0.30-0.84; p>0.05) on Anopheles larvae than F. sycomorus extract (LC50=1.01 mg/mL; ꭓ2=0.920; 95% confidence limit, CI: 0.50-2.05; p>0.05). The binary combination (concentration LC25:LC25) of the two plants produced promising results of higher mortality than individual highest extract concentrations (LC50=0.38 mg/mL; ꭓ2=0.72; 95% confidence limits, CI: 0.23-0.61; p>0.05) due to possibly synergistic effect of the two plants (X2=13.33). The percentage mortalities in all the crude extracts tested were concentration dependent. It is evident from this study that crude extracts of F. sycomorus and C. procera have promising individual and synergistic larvicidal bioactivities and hence, can be employed in integrated approach for vectors resistance management.

A novel, practical and environmentally friendly method has been developed for bromination of toluene derivatives by using H2O2-HBr system in water as a green solvent with a mild condition. This direct and straightforward method approaches to a chemoselective and regioselective substitution. Different toluene derivatives were used in which, type of functional group has affected on chemoselectivity and the situation of them has affected on regioselectivity of the reaction. Bromination was done on aromatic rings and alkane chain by different reaction conditions.  Brominated toluene derivatives are isolated in moderate to high yields, different spectroscopic techniques were used to characterize the compounds, including GC-MS, 1H NMR, and 13C NMR.

Xanthene and their derivatives are an important class of broad-spectrum heterocyclic compounds used as fluorescent dyes to visualize biomolecules and lasers. They have been reported to be antiviral for photodynamic treatment, bactericidal activity in agriculture. In this research, a simple method for the synthesis of high-efficiency 1,8-dioxooctahydroxanthenes through the reaction from aromatic aldehyde and dimedon derivatives in the presence of nano-CeO2 catalyst in water under the reflux conditions. The results revealed that this synthetic reaction is very simple and 1,8-dioxooctahydroxanthene derivatives produced with good yields compared to other articles. The advantages of this method include catalyst recovery, high efficiency and easy operation method. As shown in Table 5, the highest efficiency (95%) in a short time (1 h) was obtained in this study, which is very important compared to other previous methods presented.

Mild steel is an affordable engineering material used for various applications, including the mild acidic environment with some precautions. The (NPK1, Urea, DAP, and NPK2), inhibition efficiency in the control of the carbon steel corrosion in solution that contains 1M HCl in the absence and presence of the potassium chromate (K₂CrO₄) as one of the oxidizing agents were assessed through the weight loss. and spectrophotometer. Results have exhibited that the formulation consisting of 100 ppm from every one of (Urea, NPK1, DAP, and NPK2) and 100 ppm K2CrO4 presents 81.08%, 92%, 90% and 97%, respectively efficiency of inhibition. Whereas 100 ppm from every one of the Urea, NPK1, DAP, and NPK2, offers 63.27%, 69.93%, 76.56% and 71.69%, respectively efficiency of inhibition and 100 ppm of K2CrO4 had given 76% efficiency of inhibition. Fe+2/Fe+3 concentration in the solution is decreased with the increase in the concentration of the inhibitor. The inhibitor’s properties of the adsorption were found to be obeying the isotherm of Langmuir adsorption.

Several corrosion inhibitors have been used in industry to eliminate the corrosive influence of harsh hydrochloric acid solutions on the mechanical behavior of copper structures. Recently, expired drug products as corrosion inhibitor have been developed to replace the organic compounds (synthesized) which are expensive and toxic molecules. In this work, the expired nontoxic Ofloxacin drug is used to study the its effectiveness as a corrosion inhibitor for copper metal in 5 M HCl solution with the aid of weight loss, potentiodynamic polarization, AC impedance spectroscopy and scanning electron microscopy (SEM) studies. The weight loss results demonstrated that, 4 mg/L of expired Ofloxacin drug was the optimum concentration for inhibition of copper corrosion in acidic system. Tafel plot results revealed the mixed corrosion inhibition property of expired Ofloxacin drug. AC impedance spectroscopy and scanning electron microscope (SEM) results well supported the weight loss and potentiodynamic polarization results.

Electricity generation has external costs that are mainly imposed on people who have no role in electricity generation. External or external costs are formed when the economic activities of one or more groups negatively affect another group or groups. For instance, construction and operation of thermal power plants emit carbon dioxide, sulfur oxides, and nitrogen, which can negatively affect buildings and human health. To determine the external costs of a unit, it is necessary to estimate the emission effects on the environment. In this study, the estimation of social costs of SO2, NOX, and CO2 emissions from fission and nuclear fusion power plants has been done for the first time by modifying the existing and related global coefficients. The scenarios used in the study include carbon trade scenarios and statistical indicators of life. First, a study was conducted on seven technologies in Iran, and then the results were compared to the entire world energy production industry. The final results show that the fusion and fission technologies performed well in a comparative cost analysis (161 and 127$/MWh, respectively). Also, cost analysis shows that the fusion power has the least health care costs (7$/MWh), which can be interpreted that fusion power is greener than the other powers, and after that comes fission with 24$/MWh.

A novel approach for utilization of seed waste is attempted in the present investigation. As the fabrication of nanomaterial using physiochemical methods have hazardous and toxic impacts on the environment, there is a vital demand for an innovative and well organized, Eco-friendly, sustainable and greener synthetic protocol for their synthesis by applying safer, renewable and inexpensive materials. This research study discuses the rapid photosensitized biosynthesis of silver nanoparticles using aqeous extract of seeds of Xanthium strumarium. The reaction was carried out in ambient sunlight. As the pathogenic organisms are getting evolved day by day due to mutation and gaining antibiotic resistance, an important industrial sector of nanoscience deals with the preparation and plays a decisive role in study of nanoparticles. Further investigation of the formation of nanoparticle was monitored periodically by UV-Vis spectroscopy. Fourier-transform infrared (FT-IR), X-ray diffraction (XRD), energy dispersive X-ray spectroscopy (EDS), selected area electron diffraction (SAED) results confirmed the crystalline nature while transmission electron microscopy (TEM) analysis revealed the shape of polydispersed nanoparticles were predominantly spherical. The antioxidant properties were tested by free radical scavenging ability on 2,2-diphenyl-2-picrylhydrazyl (DPPH) method .The antimicrobial property of the synthesized NPs tested against pathogens such as E.coli, S.typhi, Pseudomonas and S.aureus by disc diffusion method. The EDX reveals a strong signal at 3 keV. Assembling of nanoparticles and to study the effect of rate of bioreduction of Ag+ ions this conventional approach appears to be very cost effective.

In this work, a green and effective method for the synthesis of pyrazole derivatives by the reaction of a pot of various 1,3-dicarbonyl compounds with hydrazine is proposed using graphene oxide nanoparticles as the Lewis base catalyst. Advantages this methods are high yields, perform quick reactions, easy customization, and short-term reaction. The catalyst was recycled several times. The recycled catalyst was reused without any apparent performance drop in subsequent reactions. This process provided not only self-condensation but also cross-condensation by using the hydra-friendly nuclear reaction of hydrazines and high-efficiency, multisubstituted pyrazoles were formed under good and easy conditions.