Ranjan Kumar Basu

Comparative study of adsorptive removal of Cr(VI) ion from aqueous solution in fixed bed column by peanut shell and almond shell using empirical models and ANN

Cr(VI) is a toxic water pollutant, which causes cancer and mutation in living organisms. Adsorption has become the most preferred method for removal of Cr(VI) due to its high efficiency and low cost. Peanut and almond shells were used as adsorbents in downflow fixed bed continuous column operation for Cr(VI) removal. The experiments were carried out to scrutinise the adsorptive capacity of the peanut shells and almond shells, as well as to find out the effect of various operating parameters such as column bed depth (5–10 cm), influent flow rate (10–22 ml min−1) and influent Cr(VI) concentration (10–20 mg L−1) on the Cr(VI) removal. The fixed bed column operation for Cr(VI) adsorption the equilibrium was illustrated by Langmuir isotherm. Different well-known mathematical models were applied to the experimental data to identify the best-fitted model to explain the bed dynamics. Prediction of the bed dynamics by Yan et al. model was found to be satisfactory. Applicability of artificial neural network (ANN) modelling is also reported. An ANN modelling of multilayer perceptron with gradient descent and Levenberg-Marquardt algorithms have also been tried to predict the percentage removal of Cr(VI). This study indicates that these adsorbents have an excellent potential and are useful for water treatment particularly small- and medium-sized industries of third world countries. Almond shell represents better adsorptive capacity as breakthrough time and exhaustion time are longer in comparison to peanut shell.

Fabrication of magnetite nanoparticle doped reduced graphene oxide grafted polyhydroxyalkanoate nanocomposites for tissue engineering application

In tissue engineering, magnetic nanoparticle based polymeric nanocomposites are attractive due to some superior properties that are demonstrated in monitoring the nature of cell proliferation, differentiation and the activation of cell construction in the tissue regeneration phase. Herein, we have developed a non-toxic, antimicrobial, biocompatible and biodegradable magnetic Fe3O4/RGO-g-PHBV composite based porous 3D scaffold. The facile and cost-effective green pathways were chosen to reduce the exfoliated graphite oxide using a new microbial strain, Lysinibacillus fusiformis at room temperature. The reduction of exfoliated graphite oxide and the fabrication of iron nanoparticle embedded Fe3O4/RGO-g-PHBV nanocomposite were confirmed by X-ray powder diffraction (XRD), X-ray Photoelectron Spectroscopy (XPS) and Fourier transform infrared spectroscopy (FTIR). The analysis of the stretching vibrations by Raman spectroscopy indicated that both the graphite oxide and reduced graphene oxide exhibit frequencies at nearly 1560 cm−1 (G-band) and 1307 cm−1 (D-band). Field Emission Scanning Electron Microscopy (FESEM) and high-resolution transmission electron microscopic studies demonstrated the exfoliated nano sheets of the graphite oxide and the uniform distribution of the deposited ferrite nanoparticles. The inclusion of magnetite nanoparticles and reduced graphene oxide in the network of the PHBV matrix revealed the improvement of the mechanical strength of the nanocomposite, in comparison to the pure PHBV copolymer. The magnetic properties measured by vibrating sample magnetometer (VSM) and magnetic imaging resonance (MRI) confirmed the super-paramagnetic behavior of the nanocomposite, evidenced by the saturation magnetization having low coercive field and dark contrast images in the presence of applied magnetic fields. The confocal and scanning electron microscopy analyses demonstrated the excellent fibroblast cell infiltration, adhesion and proliferation into the micro-porous 3D scaffold, indicating the biocompatibility of the Fe3O4/RGO-g-PHBV nanocomposite based supporting biomaterials.

Characterization and evaluation of curcumin loaded guar gum/polyhydroxyalkanoates blend films for wound healing applications

The present paper explores the ‘in situ’ fabrication of guar gum/polyhydroxyalkanoates-curcumin blend (GPCC) films in view of their increasing applications as wound dressings and antibacterial materials. Curcumin is incorporated to assess its bactericidal activity and to enhance the production and accumulation of the extracellular matrix in the healing process. In order to characterize the nature of the polymer network in the blend, FTIR/ATR spectra analysis and TGA are performed. The results reveal that the rigidity of the guar gum/PHBV blend improves with the increase of PHBV content due to the formation of non-covalent interactions, especially H-bonds, between these molecules. Electron microscopy analyses reveal the homogenecity of the blends and surface roughness of the blended films, favoring cell attachment and cell proliferation compared with the film without curcumin. The anti-microbial study demonstrate that the bactericidal activity is more effective against Gram-positive strains than Gram-negative strains. Results of the in vivo wound healing study in an animal model demonstrates that the developed curcumin loaded guar gum/PHBV blend film shows markedly enhanced wound healing compared to the control one.

Removal of Cr(VI) from Its Aqueous Solution Using Green Adsorbent Pistachio Shell: a Fixed Bed Column Study and GA-ANN Modeling

Long-term exposure of Cr(VI) causes severe health effects to the living beings. A continuous fixed bed experimental study is carried out by using pistachio shell as green and eco-friendly adsorbent for Cr(VI) adsorption. Effects of several operating parameters on Cr(VI) removal were investigated using the breakthrough curves (CtC0

Absorption of sulfur dioxide in citric acid-sodium citrate buffer solutions

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Absorption of sulfur dioxide in aqueous dispersions of dimethyl aniline

versus time) and determination of saturation time (CtC0≤1).

Cu(II) removal using green adsorbents: kinetic modeling and plant scale-up design

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