Sanjay Pratihar

Exploring metal detoxification and accumulation potential during vermicomposting of Tea factory coal ash: sequential extraction and fluorescence probe analysis.

Metal contamination from coal ashes (CAs) is widely recognized as a significant environmental concern. To learn more about metal detoxification and accumulation potential of earthworm species, metal-rich tea factory coal ashes (TFCA) were fed to Eisenia fetida and Lampito mauritii by employing a fluorescent tag detection method. Fascinatingly, on feeding fluorescence probed Zn and Cd along with cow dung to Eisenia fetida, the detection of the gut-proteins with a molecular mass higher than 100 kDa was a distinct evidence of metal binding. Significant increases were observed in the content of humified organic C [humic acid (HAC) and fulvic acid C (FAC)] and degree of humification during vermicomposting. Concurrently, considerably large amount of toxic metals (Cr, Cd, Pb, and Zn) was transformed from exchangeable to recalcitrant (organic matter and mineral bound) fractions. Moreover, total metal concentrations were reduced with high removal efficiency upon vermicomposting.

Oxalate capped iron nanomaterial: from methylene blue degradation to bis(indolyl)methane synthesis

An efficient, sustainable and green procedure for the synthesis of selective orthorhombic iron(oxalate) capped Fe(0) [Fe(ox)–Fe(0)] nanomaterial is developed using sodium borohydride (NaBH4) reduction of iron(II) salt in the presence of oxalic acid at room temperature in water. The reported method is a cost-effective chemical route for producing Fe(ox)–Fe(0) nanomaterial on the gram scale without high-temperature calcination. The oxidation of Fe(0) to Fe3O4 at room temperature in open air leads to Fe-oxalate capped Fe3O4 [Fe(ox)–Fe3O4] nanomaterial on the gram scale. The Fe(ox)–Fe3O4 nanomaterial is found to be useful as a magnetically recoverable catalyst for the selective synthesis of bis(indolyl)methanes from the condensation between aldehydes and indoles in water. The as-prepared Fe(ox)–Fe3O4 nanomaterials also show an excellent ability as a reusable catalyst for the degradation of methylene blue (MB) under UV irradiation and are expected to be useful in many other applications. Aqueous reaction medium, easy synthesis, effortless separation of the catalyst using an external magnet, and efficient recycling of the catalyst make the protocol economical and sustainable.

A selective ratiometric fluoride ion sensor with a (2,4-dinitrophenyl)hydrazine derivative of bis(indolyl) methane and its mode of interaction

In this report, a new easy-to-synthesize chemosensor, a (2,4-dinitrophenyl)hydrazine (DNP) derivative of 4-(di(1H-indol-3-yl)methyl)benzaldehyde (hereafter 2a), was designed, synthesized and employed as a selective optical chemosensor for fluoride through naked eye detection via patterns of color changes as well as changes in absorption signals. The binding interaction between 2a and fluoride from 1H NMR, UV-vis, and density functional studies suggests that fluoride-induced interaction followed by deprotonation to its corresponding tri-anions is responsible for the significant color and spectral changes in the absorption properties of 2a. The ratiometric responses of 2a specifically to fluoride ions allow us to detect and estimate the concentration of fluoride ions accurately up to 2 μM.

Iron oxalate capped iron–copper nanomaterial for oxidative transformation of aldehydes

An efficient, sustainable and green procedure for the synthesis of selective orthorhombic iron(oxalate) capped Fe–Cu bimetallic oxide nanomaterial [Fe(ox)Fe–CuOx] was developed using a sodium borohydride reduction of iron(II) salt in the presence of oxalic acid at room temperature followed by addition of copper sulfate in water. The reported method is a cost-effective chemical route for producing [Fe(ox)Fe–CuOx] nano material at the gram level with a surface area of 78.4 m2 g−1 and a pore volume of 0.141 cm3 g−1. The [Fe(ox)Fe–CuOx] nanomaterials were found to be useful as a recoverable catalyst for the oxidative transformation of an aldehyde to its corresponding ester and acid in presence of hydrogen peroxide.

Novel synthesis of an iron oxalate capped iron oxide nanomaterial: a unique soil conditioner and slow release eco-friendly source of iron sustenance in plants

Iron (Fe) is a vital plant-derived micronutrient in the human diet. Fe availability in soil largely depends on the pH and leaching behaviour of the soil. Although common salts (FeSO4) and chelates (EDTA) of Fe ensure high availability of the nutrient, they often interfere with P availability in the soil. Considering such disadvantages of the well-known Fe sources, we attempted to evolve efficient Fe3O4 nanomaterials that are independent of soil reaction (i.e. pH) and do not prevent P solubility in soil. The present investigation resulted in a novel, green and an easy pathway of large-scale synthesis of orthorhombic Fe–oxalate capped-Fe-oxide (Fe3O4) (OCIO) nanomaterial with a prolific agricultural applicability. This nanomaterial did not affect the growth of beneficial soil bacteria and had no phytotoxic effects on seed germination. The Fe release profile from the OCIO was uniform at different pH (4 to 9) conditions due to its exceptional H+ ion scavenging quality. Significantly higher P availability was recorded in aqueous and soil media treated with OCIO as compared to FeSO4 and Fe–EDTA. Additionally, application of OCIO@10–20 mg kg−1 considerably increased organic C, N, P, and enzyme activity in soil. Furthermore, the OCIO dramatically recovered Fe deficiency, maintained steady P availability, and stabilized pH in poorly fertile soil which promoted healthy growth and productivity of tomato.

Novel boronic acid derivatives of bis(indolyl) methane as anti-MRSA agents

Towards the search for a new generation of antibiotics to control methicillin-resistant Staphylococcus aureus (MRSA), the design and synthesis of various bis indolyl methane (BIM) derivatives based on their different electron donor and acceptor properties of the substituents have been made, in which boronic acid derivatives of BIM are found to be active against MRSA. The observed evidence with the lead compound reveals their strong anti-MRSA activity, which paves the way of design and further development of a new generation antibiotics.

Waste management in zinc promoted allylation of aldehyde

By using an efficient, sustainable and green procedure, the waste zinc material in Zn(0) promoted Grignard–Barbier type allylation of aldehydes has been successfully utilized as a reusable material for the adsorption of various dyes and also converted into the corresponding hexagonal wurtzite phase of ZnO. The need for aqueous NH4Cl was justified by experimental and theoretical evidence, which suggests that the probable coordination of H2O or NH3 to the Zn center in both the intermediate and transition states is responsible for a lower activation energy and consecutively higher yield of products in both the cases. The conversion of the corresponding Zn(0) to its hydroxide or ZnO was studied by XRD analysis, which showed the facile conversion of Zn(OH)2 to its corresponding ZnO after calcination of the sample at 300 °C. The reported method is a cost-effective chemical route for producing the ZnO nanomaterial at the gram level. The as-obtained zinc waste from allylation reaction shows an excellent ability as a reusable material for the adsorption of Congo red, methyl red and methylene blue and is expected to be useful in many other applications. The easy synthesis, effortless separation, efficient recycling and good adsorption capability of the waste zinc nanomaterial toward various dye molecules make it a competent candidate for wastewater treatment.

Synthetic Compounds for Antifungal Chemotherapy

Systemic fungal infections are major problems in phytopathology and infections caused by fungal species and to treat this various antimicrobial agents have been applied clinically, which is known as antifungal chemotherapy. Amongst various natural antifungal drugs, few are currently used in clinical practice to treat essentially systemic fungal infections because of their low spectrum of activity, toxicity and immunosuppressive nature. These limitation open up a market for new synthetic antifungal drugs or structural modifications of inactive molecules, which will provide a broad spectrum of activity with less toxicity. In this chapter, synthetic compounds for antifungal chemotherapy including various derivatives of azole, fluoropyrimidine, thiocarbamate, allyamines, morpholine, carabrol ester and carboline along with their mechanism, broad spectrum of activity, advantages and limitations have been discussed.

A theoretical study on antioxidant activity of ferulic acid and its ester derivatives

Phenolic compounds play a very crucial role as antioxidant that can prevent various diseases caused by free radicals in human body. Although, lots of natural phenolic compounds having antioxidant activity are available nowadays, the modeling of compounds with naturally available phenolics as building blocks is very important in order to get enhanced antioxidant activity. In this study, Ferulic acid (FA), one natural phenolic acid present in coffee, apples, orange, etc., is taken as building block and its ester derivatives with different alkyl groups are subjected to measure the antioxidant activity by using density functional theory (DFT). Various parameters like bond dissociation enthalpy (BDE), vertical ionization potential (IPv), reactivity descriptors, metal chelation ability, etc. are used to measure the antioxidant activity. All the parameters suggest that the ester derivatives are superior antioxidants to the parent FA. Since FA has been reported to be present as esters in many herbs and plants, hence our study provides a route to study the structure activity relationship of this class of natural phenolics with antioxidant activity.