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In the present work, magnetic nickel ferrite (NiFe2O4) have been synthesised using low temperature combustion method and then modified with Cetyltrimethylammonium bromide (CTAB) to form a magnetic composite. Prepared composite (CTAB-NiFe2O4) was used as an adsorbent for removing brilliant green dye from aqueous solution. Adsorbent was investigated by using various techniques like Fourier transform infrared spectroscopy, X-ray diffraction, field emission scanning electron microscopy, energy-dispersive spectra, thermogravimetric analysis and pH of point zero charge. Different parameters such as effect of contact time, pH, adsorbent dose and initial dye concentration were studied for the adsorption of dye. The optimum values observed were 170 minutes equilibrium time at pH 6 and adsorbent dose 0.6 g. Various adsorption kinetic models such as pseudo first-order kinetic model, pseudo second-order kinetic model and Elovich model were used to determine the nature of adsorption. Pseudo second-order kinetic model fitted better with higher R2 value which indicated that the adsorption was chemical in nature. Langmuir isotherm was best fitted to experimental data for the adsorption of brilliant green dye with maximum adsorption capacity 'Qe' 250 mg/g. It revealed that the adsorption in this study takes place on homogenous surface and follows monolayer pattern. Therefore, for the removal of Brilliant green dye from wastewater using composite (CTAB-NiFe2O4) can be considered as an effective adsorbent. [ABSTRACT FROM AUTHOR]

In the present work, Zinc ferrite composites with Mango starch (MS) and carboxymethyl mango starch (CMMS) were synthesized for the removal of Ni (II) ions from aqueous solutions. Composites prepared were characterized by Fourier Transform Infrared (FTIR) Spectroscopy, X-Ray Diffraction (XRD) analysis, pH of point zero charge (pHzpc), Scanning Electron Microscopy (SEM), and BET. Batch adsorption technique was used to study effect of various parameters such as pH, adsorbent dose, contact time, concentration, and temperature for removal of Ni (II) ions from aqueous solutions. The optimum time, pH, adsorbent dose and temperature required for ZFN@ MS and ZFN@ CMMS in this study was 110 min., 7 & 8, 0.1 g and 308 K, respectively. Out of various adsorption isotherms, Freundlich isotherm model fitted best with adsorption data. Maximum adsorption capacity for removal of Ni (II) were found to be 65.3 and 208.3 mg/g, respectively by using Zinc ferrite@ MS and Zinc ferrite@ CMMS adsorbents. Lagergren Pseudo second order model best fitted with results which indicated that the process of adsorption was chemical in nature. The value of adsorption energy for ZFN@ MS was 50 kJ/mol and for ZFN@ CMMS, it was 31.62 kJ/mol. Thermodynamic study revealed that process was endothermic and non-spontaneous in nature. Regeneration studies were conducted for five cycles where Zinc ferrite@ MS showed 71% regeneration efficiency and Zinc ferrite@ CMMS showed 78% regeneration efficiency for nickel ion removal from aqueous solution. [ABSTRACT FROM AUTHOR]

Walnut shell has been used in various experimental studies for different dyes removal, but it is exciting to study the adsorption behaviour of bio‐waste (walnut shell) in combination with spinel zinc ferrite which resulted in the formation of a novel material having magnetic properties and help in easy separation after the wastewater treatment. Novel magnetic walnut shell zinc ferrite (WSZF) composite has been synthesized and used to remove Malachite Green and Methylene Blue from aqueous solution in single and binary dye systems. Different techniques have been used to characterize the composite such as Fourier Transform Infrared Spectroscopy, X‐Ray Diffraction, Field Emission Scanning Electron Microscopy, Energy Dispersive Spectroscopy, Thermogravimetric Analysis and pHzpc. Adsorption of dyes were studied to see the effect of time, pH, adsorbent dose, dye concentration and temperature. The Lagergren pseudo second order model fitted well among various kinetic models employed. Langmuir adsorption isotherm best fitted with maximum adsorption capacities of 86.20 and 169.5 mg/g in single dye and 23.92 and 18 mg/g respectively in binary dye system for Malachite Green and Methylene Blue. Process was spontaneous and ΔH° were found positive, confirmed endothermic process of adsorption. The composite's regeneration capacity was studied for five cycles and at the end of five cycle the efficiency of the material was found to be around 80 % for both single as well as binary dye systems. It is concluded that the chosen WSZF will be the optimum solution for cationic dyes removal. [ABSTRACT FROM AUTHOR]

AbstractIn waste water treatment, magnetic bio-composites are frequently investigated as an adsorbent recently due to their great capacity for adsorption and affordability. In this current work, an attempt has been made to develop spinel nickel ferrite–carboxymethyl cellulose (NiFCMC) composite and modified its surface by alginate polymer to form NiFCMC–Alg composite. Several techniques were utilized to characterize these adsorbents including Fourier transform infrared spectroscopy, x-ray diffraction, field emission scanning electron microscopy, energy-dispersive spectra, thermogravimetric analysis, vibration sample magnetometry and pH of point zero charge. These adsorbents were explored to check their potentiality to remove Ni (II) ions in aqueous medium on various parameters such as contact time, initial metal ion concentration, pH, adsorbent dose and temperature. The optimum time for establishment of equilibrium was 180 minutes at pH 8 with adsorbent dose of 0.1 g. Results of kinetic studies revealed that the best fit for the metal ion adsorption data was the Lagergren pseudo-second-order mode indicating the chemisorption nature. Likewise, the Langmuir isotherm model also showed good agreement with adsorption equilibrium data with maximum adsorption capacities 47.84 ± 2.39 and 60.24 ± 3.01 mg/g for NiFCMC and NiFCMC–Alg respectively. The calculated adsorption thermodynamic parameters confirmed the spontaneous nature of adsorption process. The regeneration efficiency of both adsorbents was studied for five cycles and showed significant results. This study has shown that NiFCMC and NiFCMC–Alg can be a good substitute for removing Ni (II) ions in aqueous medium. [ABSTRACT FROM AUTHOR]