Effectiveness of a biogenic composite derived from cattle horn core/iron nanoparticles via wet chemical impregnation for cadmium (II) removal in aqueous solution.

The objective of the current study was focused on the potential adsorption capability of a biogenic hydroxyapatite/iron nanoparticles-based composite tailored for the elimination of toxic pollutant, Cd(II) ions. Morphological along with physicochemical properties of composites were analyzed by different techniques including Scanning electron microscopy (SEM), Energy-dispersive X-ray spectroscopy (EDAX), X-ray diffraction (XRD), and Fourier Transform Infrared Spectroscopy (FTIR). It has been noticed an increase in cell parameters of prepared composites with an increase in the amount of nanoparticles. The best adsorbent was found to be the one with a 5% amount of nanoparticles (P400Fe(5%)). The kinetics studies have shown that the pseudo-first-order-models were in good agreement for the removal of Cd(II) ions onto P400Fe(5%) at any concentration, suggesting a physisorption mechanism. Besides, isotherms analysis has consistently revealed Freundlich as the model better explained the isotherm data, with a maximum removal capacity of 392.3 mg g-1, higher compared to many adsorbents. Thermodynamically, the removal adsorption process of Cd(II) ions onto the composite favorable, exothermic, and spontaneous. The regeneration study has been also investigated with reusability used until four cycles. The overall results pointed out the suitability and efficiency of the prepared biogenic composite for the elimination of metal pollutants in wastewater.

Effective removal of malachite green dye from aqueous solution in hybrid system utilizing agricultural waste as particle electrodes.

A comparison study of an electrolytic, adsorption, and a novel hybrid method towards the removal of malachite green (MGD) dye from the aquatic environment utilizing agricultural biomass, Eucalyptus globulus seeds was examined. The synthesized material has been characterized by thermogravimetric analysis, SEM, FTIR, and XRD. The acid-modified biosorbent developed a microporous structure suggesting a suitable removal process of MDG. The hybrid method was carried in an indigenously designed three-phase three-dimensional electrolytic reactor with varying applied voltage (6, 9, and 12 V) with biosorbent serving as particle electrode. The hybrid method gave the highest removal rate at a voltage of 12 V, compared to other methods. Moreover, the dye removal capacity increased with increased voltage, and contact time was optimized at 15 min. The adsorption isotherm was well fitted with Freundlich isotherm and kinetic data represented pseudo-second-order. Intra particle diffusion studies suggested no interference with gradual adsorption from macropores to micropores. The removal efficiency of particles electrodes for 6, 9, and 12 V were 95, 97, and 99.8%, respectively. The higher removal of MDG towards the hybrid system may be assigned to the synergistic effect of electrolytic and adsorption systems. Regeneration studies indicated that the biosorbent can be reused up to ten times without appreciable loss of efficiency.

Investigation of magnetic silica nanocomposite immobilized Pseudomonas fluorescens as a biosorbent for the effective sequestration of Rhodamine B from aqueous systems.

In the current research work, a novel eco-friendly Fe3O4@SiO2 nanocomposite immobilized with Pseudomonas fluorescens biomass in calcium alginate beads (MSAB) was used as biosorbent for the elimination of hazardous Rhodamine B dye from aqueous system. The FTIR, XRD and SEM results showed that the MSAB possessed excellent surface properties for the effective sequestration of Rhodamine B. The batch adsorption results concluded that the adsorption of Rhodamine B using MSAB is highly influenced by the parameters such as pH, adsorbent dosage, initial dye concentration and contact time. The equilibrium and kinetics data get best fitted in the Freundlich isotherm and Pseudo first order kinetics for the studied adsorption system. The Langmuir monolayer adsorption capacity was found to be 229.6 mg/g. The thermodynamic studies showed that the adsorption was spontaneous, feasible and exothermic in nature. The adsorption mechanisms are understood using the Intraparticle diffusion and Boyd model. Thus, this Magnetic silica alginate beads (MSAB) containing dead biomass of Pseudomonas fluorescens is considered to be an ideal biosorbent which can be used as an effective tool in treating the industrial dye wastewater treatment.