Valorization of castor seed shell waste as lead adsorbent by treatment with hot phosphoric acid: Optimization and evaluation of adsorption properties.

Lead is used in many industries such as refining, mining, battery manufacturing, smelting. Releases of lead from these industries is one of the major public health concerns due to widespread persistence in the environment and its resulting poisoning character. In this work, the castor seed shell (CSS) waste was exploited for preparing a beneficial bio-adsorbent for removal of Pb(II) ions from water. The raw CSS was modified with H3PO4 at different acid concentrations, impregnation ratios, activation times, and temperatures. An optimum adsorption capacity was observed for CSS modified with 2 M acid, 5 mL g-1 solid to liquid ratio, treated at 95 °C for 160 min. Exploiting acid modification, the SEM, XRD, and FTIR analyses show some alterations in functional groups and the surface morphology of the biomass. The impacts of physiochemical variables (initial lead ions concentration, pH, adsorbent dose and adsorption time) on the lead removal percentage were investigated, using response surface methodology (RSM). Maximum removal of 72.26% for raw CSS and 97.62% for modified CSS were obtained at an initial lead concentration (50 mg L-1), pH (5.7), adsorption time (123 min) and adsorbent dosage (1.1 g/100 mL). Isothermal and kinetics models were fitted to adsorption equilibrium data and kinetics data for the modified CSS and the adsorption system was evaluated thermodynamically and from the energy point of view. Isothermal scrutinization indicated the mono-layer nature of adsorption, and the kinetics experimental outcomes best fitted with the pseudo-second-order, implying that the interaction of lead ions and hot acid-treated CSS was the rate-controlling phenomenon of process. Overall, results illustrated that the hot acid-treated biomass-based adsorbent can be considered as an alternative bio-adsorbent for removing lead from water media.

A Comparative analysis of PESC and PPSC copolyesters: Insights into viscosity, thermal behavior, crystallinity, and biodegradability.

The study examined various properties of synthesized copolyesters PESC and PPSC. Inherent viscosities of the copolyesters, measured in 1,4-dioxane at 32 °C, were 0.65 dL/g for PESC and 0.73 dL/g for PPSC. Fourier-Transform Infrared Spectroscopy (FT-IR) revealed distinct absorption bands associated with ester carbonyl stretching, C-H bending vibration, C-H group symmetry stretching, and C-O stretching vibrations. 1H and 13C Nuclear magnetic Resonance (NMR) spectroscopy were used to identify specific protons and carbon groups in the polymer chain, revealing the molecular structure of the copolyesters. Differential Scanning Calorimetry (DSC) identified the glass transition, melting, and decomposition temperatures for both copolyesters, indicating variations in the crystalline nature of the copolymers. XRD Spectral studies further elaborated on the crystalline nature, indicating that PPSC is less amorphous than PESC. Biodegradation analysis showed that PESC degrades more quickly than PPSC, with degradation decreasing as the number of methylene groups increase. Scanning Electron Microscopy (SEM) images depicted the surface morphology of the copolyesters before and after degradation, revealing a more roughened surface with pits post-degradation. These findings provide comprehensive insights into the structural and degradable properties of PESC and PPSC copolyesters.

Ultrasonic assisted synthesis of RGO supported HoVO4-ZnO nanocomposites, their enhanced photocatalytic activities and Rhodamine B degradation.

The RGO-supported HoVO4-ZnO nanocomposite was synthesized using the ultra sonication process. X-ray diffraction patterns, Field emission scanning electron microscopy, high resolution transmission electron microscopy, Diffractive Reflectance spectroscopy, and photoluminescence spectroscopy were employed to examine the heterostructured photocatalyst in this research study. The photocatalytic efficiency of the RGO-supported HoVO4-ZnO nanoparticles, under UV light irradiation, in the degradation of Rhodamine-B dye was investigated. Undoped ZnO, bare HoVO4, and HoVO4 -ZnO, degraded at 55.6, 57.5, and 74.33 percent in 45 min, respectively. This new RGO coupled HoVO4-ZnO exhibits enhanced photocatalytic efficiency compared to the bare ZnO and HoVO4-ZnO nanocomposite.

Sonocatalyzed synthesis of 2-phenylvaleronitrile under controlled reaction conditions--a kinetic study.

In the current study, kinetics of synthesis of 2-phenylvaleronitrile (PVN) was successfully carried out by selective C-alkylation of benzyl cyanide (BC) with n-bromopropane (BP) using aqueous KOH and catalyzed by TBAB under ultrasonic (300W) assisted organic solvent-free conditions. Selective monoalkylation of benzyl cyanide has been achieved by controlling the reaction conditions and has been followed using gas chromatogram. The effects of various parameters such as agitation speed, catalyst concentration, KOH concentration, benzyl cyanide concentration, volume of water, ultrasonic frequency and temperature were studied systematically to understand their influence on the rate of the reaction. The experimental observations are consistent with an interfacial-type process. Further the kinetic results demonstrate clearly, that ultrasonic assisted phase-transfer catalysis significantly increased the reaction rate when compared to silent reactions.