Synthesis, characterization, and performance evaluation of hybrid waste sludge biochar for cod and color removal from agro-industrial effluent

Agro-waste management processes are evolving through the development of novel experimental approaches to understand the mechanisms in reducing their pollution levels efficiently and economically from industrial effluents. Agro-industrial effluent (AIE) from biorefineries that contain high concentrations of COD and color are discharged into the ecosystem. Thus, the AIE from these biorefineries requires treatment prior to discharge. Therefore, the effectiveness of a continuous flow bioreactor system (CFBS) in the treatment of AIE using hybrid waste sludge biochar (HWSB) was investigated. The use of a bioreactor with hydraulic retention time (HRT) of 1–3 days and AIE concentrations of 10–50% was used in experiments based on a statistical design. AIE concentration and HRT were optimized using response surface methodology (RSM) as the process variables. The performance of CFBS was analyzed in terms of COD and color removal. Findings indicated 76.52% and 66.97% reduction in COD and color, respectively. During biokinetic studies, the modified Stover models were found to be perfectly suited for the observed measurements with R2 values 0.9741 attained for COD. Maximum contaminants elimination was attained at 30% AIE and 2-day HRT. Thus, this study proves that the HWSB made from biomass waste can potentially help preserve nonrenewable resources and promote zero-waste attainment and principles of circular economy

Nickel vanadate nitrogen-doped carbon nanocomposites for high-performance supercapacitor electrode

A nickel-vanadium-based bimetallic precursor was produced using the polymerization process by urea-formaldehyde copolymers. The precursor was then calcined at 800 °C in an argon ambiance to form a Ni3V2O8-NC magnetic nanocomposite. Powerful techniques were used to study the physical characteristics and chemical composition of the fabricated Ni3V2O8-NC electrode. PXRD, Raman, and FTIR analyses proved that the crystal structure of Ni3V2O8-NC included N-doped graphitic carbon. FESEM and TEM analyses imaging showed the distribution of the Ni3V2O8 nanoparticles on the layered graphitic carbon structure. TEM images showed the prepared sample has a particle size of around 10–15 nm with an enhanced active site area of 146 m2/g, as demonstrated by BET analysis. Ni3V2O8-NC nanocomposite exhibits magnetic behaviors and a magnetization saturation value of 35.99 emu/g. The electrochemical (EC) studies of the synthesized Ni3V2O8-NC electrode proceeded in an EC workstation of three-electrode. In a 5 M potassium hydroxide as an electrolyte, the cyclic voltmeter exhibited an enhanced capacitance (CS) of 915 F/g at 50 mV/s. Galvanic charge-discharge (GCD) study also exhibited a superior capacitive improvement of 1045 F/g at a current density (It) of 10 A/g. Moreover, the fabricated Ni3V2O8-NC nanocomposite displays a good power density (Pt) of 356.67 W/kg, improved ion accessibility, and substantial charge storage. At the high energy density (Et) of 67.34 W h/kg, the obtained Pt was 285.17 W/kg. The enhanced GCD rate, cycle stability, and Et of the Ni3V2O8-NC magnetic nanocomposite nominate the sample as an excellent supercapacitor electrode. This study paves the way for developing effective, efficient, affordable, and ecologically friendly electrode materials

Synthesis, structure elucidation, Hirshfeld surface analysis, energy frameworks and DFT studies of novel ethyl 2-(5-methyl-2-oxopyridin-N-yl)acetate (OPA)

The compound ethyl 2-(5-methyl-2-oxopyridin-N-yl)acetate (OPA) has been synthesized and characterized by H-1, C-13 NMR and mass spectra. The molecular structure was confirmed by single crystal X-ray diffraction studies. The compound crystallizes in triclinic crystal system with asymmetric unit Z = 2. The structure exhibits C-H center dot center dot center dot O type of intermolecular interaction. The compound is stabilized by C-H center dot center dot center dot pi and pi - pi interaction. The intermolecular interactions present in the molecule are validated by Hirshfeld surface analysis and the percentage contribution from individual atoms are calculated by 2D fingerprint plots. The interaction energies are visualized through energy frameworks which show dispersion energy is predominant. The Density Functional Theory (DFT) calculations were done in gaseous, aqueous, and solvent (acetone) phase. The energy gap between the molecular orbitals HOMO and LUMO in different phases is 4.573, 4.677, 4.673 eV respectively. The charge distribution in the molecule is visualized using molecular electrostatic potential map. The noncovalent interactions present in the molecule are revealed by reduced density gradient analysis. (C) 2022 Elsevier B.V. All rights reserved